CTAN sync 201910140300

24 files changed, 17871 insertions, 17845 deletions

diff --git a/systems/doc/luatex/luatex-backend.tex b/systems/doc/luatex/luatex-backend.tex
index 21cdd728c1..e99a95ed26 100644
--- a/systems/doc/luatex/luatex-backend.tex
+++ b/systems/doc/luatex/luatex-backend.tex
@@ -1,1084 +1,1084 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-backend

-

-\startchapter[reference=backend,title={The backend libraries}]

-

-\startsection[title={The \type {pdf} library}][library=pdf]

-

-\topicindex{backend}

-\topicindex{\PDF}

-

-This library contains variables and functions that are related to the \PDF\

-backend. You can find more details about the expected values to setters in \in

-{section} [backendprimitives].

-

-\startsubsection[title={\type {mapfile}, \type {mapline}}]

-

-\topicindex{map files}

-\topicindex{files+map}

-

-\startfunctioncall

-pdf.mapfile(<string> map file)

-pdf.mapline(<string> map line)

-\stopfunctioncall

-

-These two functions can be used to replace primitives \orm {pdfmapfile} and

-\orm {pdfmapline} inherited from \PDFTEX. They expect a string as only

-parameter and have no return value. The first character in a map line can be

-\type {-}, \type {+} or \type {=} which means as much as remove, add or replace

-this line. They are not state setters but act immediately.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][catalog|info|names|trailer]}}]

-

-\topicindex{\PDF+trailer}

-\topicindex{\PDF+catalog}

-\topicindex{\PDF+info}

-

-\libindex{setcatalog} \libindex{getcatalog}

-\libindex{setinfo}    \libindex{getinfo}

-\libindex{setnames}   \libindex{getnames}

-\libindex{settrailer} \libindex{gettrailer}

-

-These functions complement the corresponding \PDF\ backend token lists dealing

-with metadata. The value types are strings and they are written to the \PDF\

-file directly after the token registers set at the \TEX\ end are written.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][pageattributes|pageresources|pagesattributes]}}]

-

-\libindex{setpageattributes}  \libindex{getpageattributes}

-\libindex{setpageresources}   \libindex{getpageresources}

-\libindex{setpagesattributes} \libindex{getpagesattributes}

-

-\topicindex{\PDF+page attributes}

-\topicindex{\PDF+page resources}

-

-These functions complement the corresponding \PDF\ backend token lists dealing

-with page resources. The variables have no interaction with the corresponding \PDF\

-backend token register. They are written to the \PDF\ file directly after the

-token registers set at the \TEX\ end are written.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][xformattributes|xformresources]}}]

-

-\libindex{setxformattributes} \libindex{getxformattributes}

-\libindex{setxformresources}  \libindex{getxformresources}

-

-\topicindex{\PDF+xform attributes}

-\topicindex{\PDF+xform resources}

-

-These functions complement the corresponding \PDF\ backend token lists dealing

-with reuseable boxes and images. The variables have no interaction with the

-corresponding \PDF\ backend token register. They are written to the \PDF\

-file directly after the token registers set at the \TEX\ end are written.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][major|minor]version}}]

-

-\topicindex{\PDF+version}

-

-\libindex{getmajorversion} \libindex{setmajorversion}

-\libindex{getminorversion} \libindex{setminorversion}

-

-You can set both the major and minor version of the output. The major version is

-normally~1 but when set to~2 some data will not be written to the file in order

-to comply with the standard. What minor version you set depends on what \PDF\

-features you use. This is out of control of \LUATEX.

-

-\stopsubsection

-

-\startsubsection[title={\type {getcreationdate}}]

-

-\topicindex{\PDF+date}

-

-\libindex{getcreationdate}

-

-This function returns a string with the date in the format that ends up in the

-\PDF\ file, in this case it's: {\tttf \cldcontext{pdf.getcreationdate()}}.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]inclusionerrorlevel} and \type {[set|get]ignoreunknownimages}}]

-

-\topicindex{\PDF+options}

-

-\libindex{getinclusionerrorlevel} \libindex{setinclusionerrorlevel}

-\libindex{getignoreunknownimages} \libindex{setignoreunknownimages}

-

-These variable control how error in included image are treated. They are modeled

-after the \PDFTEX\ equivalents.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]suppressoptionalinfo}, \type {[set|get]trailerid}

-and \type {[set|get]omitcidset}}]

-

-\topicindex{\PDF+options}

-\topicindex{\PDF+trailer}

-

-\libindex{getsuppressoptionalinfo} \libindex{setsuppressoptionalinfo}

-\libindex{gettrailerid}            \libindex{settrailerid}

-\libindex{getomitcidset}           \libindex{setomitcidset}

-\libindex{getomitcharset}          \libindex{setomitcharset}

-

-The optional info bitset (a number) determines what kind of info gets flushed.

-By default we flush all. See \in {section} [sec:pdfextensions] for more details.

-

-You can set your own trailer id. This has to be string containing valid \PDF\

-array content with checksums.

-

-The cidset and charset flags (numbers) disables inclusion of a so called \type

-{CIDSet} and \type {CharSet} entries, which can be handy when aiming at some of

-the many \PDF\ substandards.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][obj|]compresslevel} and \type {[set|get]recompress}}]

-

-\topicindex{\PDF+compression}

-

-\libindex{getcompresslevel}    \libindex{setcompresslevel}

-\libindex{getobjcompresslevel} \libindex{setobjcompresslevel}

-\libindex{getrecompress}       \libindex{setrecompress}

-

-These functions set the level stream compression. When object compression is

-enabled multiple objects will be packed in a compressed stream which saves space.

-The minimum values are~0, the maxima are~9.

-

-When recompression is to~1 compressed objects will be decompressed and when

-compresslevel is larger than zero they will then be recompressed. This is mostly

-a debugging feature and should not be relied upon.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]gentounicode}}]

-

-\topicindex{\PDF+unicode}

-

-\libindex{getgentounicode} \libindex{setgentounicode}

-

-This flag enables tounicode generation (like in \PDFTEX). Normally the values are

-provided by the font loader.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]decimaldigits}}]

-

-\topicindex{\PDF+precision}

-

-\libindex{getdecimaldigits} \libindex{setdecimaldigits}

-

-These two functions set the accuracy of floats written to the \PDF file. You can

-set any value but the backend will not go below~3 and above~6.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]pkresolution}}]

-

-\topicindex{\PDF+resolution}

-

-\libindex{getpkresolution} \libindex{setpkresolution}

-

-These setter takes two arguments: the resolution and an optional zero or one that

-indicates if this is a fixed one. The getter returns these two values.

-

-\stopsubsection

-

-\startsubsection[title={\type {getlast[obj|link|annot]} and \type {getretval}}]

-

-\topicindex{\PDF+objects}

-\topicindex{\PDF+annotations}

-

-\libindex{getlastobj}   \libindex{setlastobj}

-\libindex{getlastlink}  \libindex{setlastlink}

-\libindex{getlastannot} \libindex{setlastannot}

-\libindex{getretval}

-

-These status variables are similar to the ones traditionally used in the backend

-interface at the \TEX\ end.

-

-\stopsubsection

-

-\startsubsection[title={\type {getmaxobjnum} and \type {getobjtype}, \type {getfontname},

-\type {getfontobjnum}, \type {getfontsize}, \type {getxformname}}]

-

-\libindex{getmaxobjnum}

-\libindex{getobjtype}

-\libindex{getfontname}

-\libindex{getfontobjnum}

-\libindex{getfontsize}

-\libindex{getxformname}

-

-These introspective helpers are mostly used when you construct \PDF\ objects

-yourself and need for instance information about a (to be) embedded font.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]origin}}]

-

-\topicindex{\PDF+positioning}

-

-\libindex{setorigin} \libindex{getorigin}

-

-This one is used to set the horizonal and|/|or vertical offset, a traditional

-backend property.

-

-\starttyping

-pdf.setorigin() -- sets both to 0pt

-pdf.setorigin(tex.sp("1in")) -- sets both to 1in

-pdf.setorigin(tex.sp("1in"),tex.sp("1in"))

-\stoptyping

-

-The counterpart of this function returns two values.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get]imageresolution}}]

-

-\topicindex{\PDF+resolution}

-

-\libindex{setimageresolution} \libindex{getimageresolution}

-

-These two functions relate to the imageresolution that is used when the image

-itself doesn't provide a non|-|zero x or y resolution.

-

-\stopsubsection

-

-\startsubsection[title={\type {[set|get][link|dest|thread|xform]margin}}]

-

-\topicindex{\PDF+margins}

-

-\libindex{getlinkmargin}   \libindex{setlinkmargin}

-\libindex{getdestmargin}   \libindex{setdestmargin}

-\libindex{getthreadmargin} \libindex{setthreadmargin}

-\libindex{getxformmargin}  \libindex{setxformmargin}

-\libindex{getmarginmargin} \libindex{setmarginmargin}

-

-These functions can be used to set and retrieve the margins that are added to the

-natural bounding boxes of the respective objects.

-

-\stopsubsection

-

-\startsubsection[title={\type {get[pos|hpos|vpos]}}]

-

-\topicindex{\PDF+positions}

-

-\libindex{getpos}

-\libindex{gethpos}

-\libindex{getvpos}

-

-These functions get current location on the output page, measured from its lower

-left corner. The values return scaled points as units.

-

-\starttyping

-local h, v = pdf.getpos()

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {[has|get]matrix}}]

-

-\topicindex{\PDF+matrix}

-

-\libindex{getmatrix} \libindex{hasmatrix}

-

-The current matrix transformation is available via the \type {getmatrix} command,

-which returns 6 values: \type {sx}, \type {rx}, \type {ry}, \type {sy}, \type

-{tx}, and \type {ty}. The \type {hasmatrix} function returns \type {true} when a

-matrix is applied.

-

-\starttyping

-if pdf.hasmatrix() then

-    local sx, rx, ry, sy, tx, ty = pdf.getmatrix()

-    -- do something useful or not

-end

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {print}}]

-

-\topicindex{\PDF+print to}

-

-\libindex{print}

-

-You can print a string to the \PDF\ document from within a \lpr {latelua} call.

-This function is not to be used inside \prm {directlua} unless you know {\it

-exactly} what you are doing.

-

-\startfunctioncall

-pdf.print(<string> s)

-pdf.print(<string> type, <string> s)

-\stopfunctioncall

-

-The optional parameter can be used to mimic the behavior of \PDF\ literals: the

-\type {type} is \type {direct} or \type {page}.

-

-\stopsubsection

-

-\startsubsection[title={\type {immediateobj}}]

-

-\topicindex{\PDF+objects}

-

-\libindex{immediateobj}

-

-This function creates a \PDF\ object and immediately writes it to the \PDF\ file.

-It is modelled after \PDFTEX's \prm {immediate} \orm {pdfobj} primitives. All

-function variants return the object number of the newly generated object.

-

-\startfunctioncall

-<number> n =

-    pdf.immediateobj(<string> objtext)

-<number> n =

-    pdf.immediateobj("file", <string> filename)

-<number> n =

-    pdf.immediateobj("stream", <string> streamtext, <string> attrtext)

-<number> n =

-    pdf.immediateobj("streamfile", <string> filename, <string> attrtext)

-\stopfunctioncall

-

-The first version puts the \type {objtext} raw into an object. Only the object

-wrapper is automatically generated, but any internal structure (like \type {<<

->>} dictionary markers) needs to be provided by the user. The second version with

-keyword \type {file} as first argument puts the contents of the file with name

-\type {filename} raw into the object. The third version with keyword \type

-{stream} creates a stream object and puts the \type {streamtext} raw into the

-stream. The stream length is automatically calculated. The optional \type

-{attrtext} goes into the dictionary of that object. The fourth version with

-keyword \type {streamfile} does the same as the third one, it just reads the

-stream data raw from a file.

-

-An optional first argument can be given to make the function use a previously

-reserved \PDF\ object.

-

-\startfunctioncall

-<number> n =

-    pdf.immediateobj(<integer> n, <string> objtext)

-<number> n =

-    pdf.immediateobj(<integer> n, "file", <string> filename)

-<number> n =

-    pdf.immediateobj(<integer> n, "stream", <string> streamtext, <string> attrtext)

-<number> n =

-    pdf.immediateobj(<integer> n, "streamfile", <string> filename, <string> attrtext)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type{obj}}]

-

-\topicindex{\PDF+objects}

-

-\libindex{obj}

-

-This function creates a \PDF\ object, which is written to the \PDF\ file only

-when referenced, e.g., by \type {refobj()}.

-

-All function variants return the object number of the newly generated object, and

-there are two separate calling modes. The first mode is modelled after \PDFTEX's

-\orm {pdfobj} primitive.

-

-\startfunctioncall

-<number> n =

-    pdf.obj(<string> objtext)

-<number> n =

-    pdf.obj("file", <string> filename)

-<number> n =

-    pdf.obj("stream", <string> streamtext, <string> attrtext)

-<number> n =

-    pdf.obj("streamfile", <string> filename, <string> attrtext)

-\stopfunctioncall

-

-An optional first argument can be given to make the function use a previously

-reserved \PDF\ object.

-

-\startfunctioncall

-<number> n =

-    pdf.obj(<integer> n, <string> objtext)

-<number> n =

-    pdf.obj(<integer> n, "file", <string> filename)

-<number> n =

-    pdf.obj(<integer> n, "stream", <string> streamtext, <string> attrtext)

-<number> n =

-    pdf.obj(<integer> n, "streamfile", <string> filename, <string> attrtext)

-\stopfunctioncall

-

-The second mode accepts a single argument table with key--value pairs.

-

-\startfunctioncall

-<number> n = pdf.obj {

-    type           = <string>,

-    immediate      = <boolean>,

-    objnum         = <number>,

-    attr           = <string>,

-    compresslevel  = <number>,

-    objcompression = <boolean>,

-    file           = <string>,

-    string         = <string>,

-    nolength       = <boolean>,

-}

-\stopfunctioncall

-

-The \type {type} field can have the values \type {raw} and \type {stream}, this

-field is required, the others are optional (within constraints). When \type

-{nolength} is set, there will be no \type {/Length} entry added to the

-dictionary.

-

-Note: this mode makes \type{obj} look more flexible than it actually is: the

-constraints from the separate parameter version still apply, so for example you

-can't have both \type {string} and \type {file} at the same time.

-

-\stopsubsection

-

-\startsubsection[title={\type {refobj}}]

-

-\topicindex{\PDF+objects}

-

-\libindex{refobj}

-

-This function, the \LUA\ version of the \orm {pdfrefobj} primitive, references an

-object by its object number, so that the object will be written to the \PDF\ file.

-

-\startfunctioncall

-pdf.refobj(<integer> n)

-\stopfunctioncall

-

-This function works in both the \prm {directlua} and \lpr {latelua} environment.

-Inside \prm {directlua} a new whatsit node \quote {pdf_refobj} is created, which

-will be marked for flushing during page output and the object is then written

-directly after the page, when also the resources objects are written to the \PDF\

-file. Inside \lpr {latelua} the object will be marked for flushing.

-

-This function has no return values.

-

-\stopsubsection

-

-\startsubsection[title={\type {reserveobj}}]

-

-\topicindex{\PDF+objects}

-

-\libindex{reserveobj}

-

-This function creates an empty \PDF\ object and returns its number.

-

-\startfunctioncall

-<number> n = pdf.reserveobj()

-<number> n = pdf.reserveobj("annot")

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {getpageref}}]

-

-\topicindex{\PDF+pages}

-

-\libindex{getpageref}

-

-The object number of a page can be fetched with this function. This can be a

-forward reference so when you ask for a future page, you do get a number back.

-

-\startfunctioncall

-<number> n = pdf.getpageref(123)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {registerannot}}]

-

-\topicindex{\PDF+annotations}

-

-\libindex{registerannot}

-

-This function adds an object number to the \type {/Annots} array for the current

-page without doing anything else. This function can only be used from within

-\lpr {latelua}.

-

-\startfunctioncall

-pdf.registerannot (<number> objnum)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {newcolorstack}}]

-

-\topicindex{\PDF+color stack}

-

-\libindex{newcolorstack}

-

-This function allocates a new color stack and returns it's id. The arguments

-are the same as for the similar backend extension primitive.

-

-\startfunctioncall

-pdf.newcolorstack("0 g","page",true) -- page|direct|origin

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {setfontattributes}}]

-

-\topicindex{\PDF+fonts}

-

-\libindex{setfontattributes}

-

-This function will force some additional code into the font resource. It can for

-instance be used to add a custom \type {ToUnicode} vector to a bitmap file.

-

-\startfunctioncall

-pdf.setfontattributes(<number> font id, <string> pdf code)

-\stopfunctioncall

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={The \type {pdfe} library}][library=pdfe]

-

-\startsubsection[title={Introduction}]

-

-\topicindex{\PDF+objects}

-

-\topicindex{\PDF+analyze}

-\topicindex{\PDF+\type{pdfe}}

-

-The \type {pdfe} library replaces the \type {epdf} library and provides an

-interface to \PDF\ files. It uses the same code as is used for \PDF\ image

-inclusion. The \type {pplib} library by Paweł Jackowski replaces the \type

-{poppler} (derived from \type {xpdf}) library.

-

-A \PDF\ file is basically a tree of objects and one descends into the tree via

-dictionaries (key/value) and arrays (index/value). There are a few topmost

-dictionaries that start at root that are accessed more directly.

-

-Although everything in \PDF\ is basically an object we only wrap a few in so

-called userdata \LUA\ objects.

-

-\starttabulate

-\BC \PDF          \BC \LUA \NC \NR

-\NC null          \NC nil \NC \NR

-\NC boolean       \NC boolean \NC \NR

-\NC integer       \NC integer \NC \NR

-\NC float         \NC number \NC \NR

-\NC name          \NC string \NC \NR

-\NC string        \NC string \NC \NR

-\NC array         \NC array userdatum \NC \NR

-\NC dictionary    \NC dictionary userdatum \NC \NR

-\NC stream        \NC stream userdatum (with related dictionary) \NC \NR

-\NC reference     \NC reference userdatum \NC \NR

-\stoptabulate

-

-The regular getters return these \LUA\ data types but one can also get more

-detailed information.

-

-\stopsubsection

-

-\startsubsection[title={\type {open}, \type {new}, \type {getstatus}, \type {close}, \type {unencrypt}}]

-

-\libindex {open}

-\libindex {new}

-\libindex {new}

-\libindex {getstatus}

-\libindex {close}

-\libindex {unencrypt}

-

-A document is loaded from a file or string

-

-\starttyping

-<pdfe document> = pdfe.open(filename)

-<pdfe document> = pdfe.new(somestring,somelength)

-\stoptyping

-

-Such a document is closed with:

-

-\starttyping

-pdfe.close(<pdfe document>)

-\stoptyping

-

-You can check if a document opened well by:

-

-\starttyping

-pdfe.getstatus(<pdfe document>)

-\stoptyping

-

-The returned codes are:

-

-\starttabulate[|c|l|]

-\DB value       \BC explanation \NC \NR

-\TB

-\NC \type {-2}  \NC the document failed to open \NC \NR

-\NC \type {-1}  \NC the document is (still) protected \NC \NR

-\NC \type {0}   \NC the document is not encrypted \NC \NR

-\NC \type {2}   \NC the document has been unencrypted \NC \NR

-\LL

-\stoptabulate

-

-An encrypted document can be unencrypted by the next command where instead of

-either password you can give \type {nil}:

-

-\starttyping

-pdfe.unencrypt(<pdfe document>,userpassword,ownerpassword)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {getsize}, \type {getversion}, \type {getnofobjects}, \type {getnofpages}}]

-

-\libindex {getsize}

-\libindex {getversion}

-\libindex {getnofobjects}

-\libindex {getnofpages}

-

-A successfully opened document can provide some information:

-

-\starttyping

-bytes = getsize(<pdfe document>)

-major, minor = getversion(<pdfe document>)

-n = getnofobjects(<pdfe document>)

-n = getnofpages(<pdfe document>)

-bytes, waste = getnofpages(<pdfe document>)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {get[catalog|trailer|info]}}]

-

-\libindex {getcatalog}

-\libindex {gettrailer}

-\libindex {getinfo}

-

-For accessing the document structure you start with the so called catalog, a

-dictionary:

-

-\starttyping

-<pdfe dictionary> = pdfe.getcatalog(<pdfe document>)

-\stoptyping

-

-The other two root dictionaries are accessed with:

-

-\starttyping

-<pdfe dictionary> = pdfe.gettrailer(<pdfe document>)

-<pdfe dictionary> = pdfe.getinfo(<pdfe document>)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {getpage}, \type {getbox}}]

-

-\libindex {getpage}

-\libindex {getbox}

-

-A specific page can conveniently be reached with the next command, which

-returns a dictionary. The first argument is to be a page dictionary.

-

-\starttyping

-<pdfe dictionary> = pdfe.getpage(<pdfe dictionary>,pagenumber)

-\stoptyping

-

-Another convenience command gives you the (bounding) box of a (normally page)

-which can be inheritted from the document itself. An example of a valid box name

-is \type {MediaBox}.

-

-\starttyping

-pages = pdfe.getbox(<pdfe document>,boxname)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {get[string|integer|number|boolean|name]}}]

-

-\libindex {getstring}

-\libindex {getinteger}

-\libindex {getnumber}

-\libindex {getboolean}

-\libindex {getname}

-

-Common values in dictionaries and arrays are strings, integers, floats, booleans

-and names (which are also strings) and these are also normal \LUA\ objects:

-

-\starttyping

-s = getstring (<pdfe array|dictionary>,index|key)

-i = getinteger(<pdfe array|dictionary>,index|key)

-n = getnumber (<pdfe array|dictionary>,index|key)

-b = getboolean(<pdfe array|dictionary>,index|key)

-n = getname   (<pdfe array|dictionary>,index|key)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {get[from][dictionary|array|stream]}}]

-

-\libindex {getdictionary} \libindex {getfromdictionary}

-\libindex {getarray}      \libindex {getfromarray}

-\libindex {getstream}     \libindex {getfromstream}

-

-Normally you will use an index in an array and key in a dictionary but dictionaries

-also accept an index. The size of an array or dictionary is available with the

-usual \type {#} operator.

-

-\starttyping

-<pdfe dictionary>   = getdictionary(<pdfe array|dictionary>,index|key)

-<pdfe array>        = getarray     (<pdfe array|dictionary>,index|key)

-<pdfe stream>,

-<pdfe dictionary>   = getstream    (<pdfe array|dictionary>,index|key)

-\stoptyping

-

-These commands return dictionaries, arrays and streams, which are dictionaries

-with a blob of data attached.

-

-Before we come to an alternative access mode, we mention that the objects provide

-access in a different way too, for instance this is valid:

-

-\starttyping

-print(pdfe.open("foo.pdf").Catalog.Type)

-\stoptyping

-

-At the topmost level there are \type {Catalog}, \type {Info}, \type {Trailer}

-and \type {Pages}, so this is also okay:

-

-\starttyping

-print(pdfe.open("foo.pdf").Pages[1])

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {[open|close|readfrom][whole|]stream}}]

-

-\libindex {openstream}

-\libindex {closestream}

-\libindex {readfromstream}

-\libindex {readfromwholestream}

-

-Streams are sort of special. When your index or key hits a stream you get back a

-stream object and dictionary object. The dictionary you can access in the usual

-way and for the stream there are the following methods:

-

-\starttyping

-okay   = openstream(<pdfe stream>,[decode])

-         closestream(<pdfe stream>)

-str, n = readfromstream(<pdfe stream>)

-str, n = readwholestream(<pdfe stream>,[decode])

-\stoptyping

-

-You either read in chunks, or you ask for the whole. When reading in chunks, you

-need to open and close the stream yourself. The \type {n} value indicates the

-length read. The \type {decode} parameter controls if the stream data gets

-uncompressed.

-

-As with dictionaries, you can access fields in a stream dictionary in the usual

-\LUA\ way too. You get the content when you \quote {call} the stream. You can

-pass a boolean that indicates if the stream has to be decompressed.

-

-% pdfe.objectcodes      = objectcodes

-% pdfe.stringcodes      = stringcodes

-% pdfe.encryptioncodes  = encryptioncodes

-

-\stopsubsection

-

-\startsubsection[title={\type {getfrom[dictionary|array]}}]

-

-\libindex {getfromdictionary}

-\libindex {getfromarray}

-

-In addition to the interface described before, there is also a bit lower level

-interface available.

-

-\starttyping

-key, type, value, detail = getfromdictionary(<pdfe dictionary>,index)

-type, value, detail = getfromarray(<pdfe array>,index)

-\stoptyping

-

-\starttabulate[|c|l|l|l|]

-\DB type       \BC meaning    \BC value            \BC detail \NC \NR

-\NC \type {0}  \NC none       \NC nil              \NC \NC \NR

-\NC \type {1}  \NC null       \NC nil              \NC \NC \NR

-\NC \type {2}  \NC boolean    \NC boolean          \NC \NC \NR

-\NC \type {3}  \NC boolean    \NC integer          \NC \NC \NR

-\NC \type {4}  \NC number     \NC float            \NC \NC \NR

-\NC \type {5}  \NC name       \NC string           \NC \NC \NR

-\NC \type {6}  \NC string     \NC string           \NC hex \NC \NR

-\NC \type {7}  \NC array      \NC arrayobject      \NC size \NC \NR

-\NC \type {8}  \NC dictionary \NC dictionaryobject \NC size \NC \NR

-\NC \type {9}  \NC stream     \NC streamobject     \NC dictionary size \NC \NR

-\NC \type {10} \NC reference  \NC integer          \NC \NC \NR

-\LL

-\stoptabulate

-

-A \type {hex} string is (in the \PDF\ file) surrounded by \type {<>} while plain

-strings are bounded by \type {<>}.

-

-\stopsubsection

-

-\startsubsection[title={\type {[dictionary|array]totable}}]

-

-\libindex {dictionarytotable}

-\libindex {arraytotable}

-

-All entries in a dictionary or table can be fetched with the following commands

-where the return values are a hashed or indexed table.

-

-\starttyping

-hash = dictionarytotable(<pdfe dictionary>)

-list = arraytotable(<pdfe array>)

-\stoptyping

-

-You can get a list of pages with:

-

-\starttyping

-{ { <pdfe dictionary>, size, objnum }, ... } = pagestotable(<pdfe document>)

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\type {getfromreference}}]

-

-\libindex {getfromreference}

-

-Because you can have unresolved references, a reference object can be resolved

-with:

-

-\starttyping

-<pdfe dictionary|array|stream> = getfromreference(<pdfe reference>)

-\stoptyping

-

-So, you get back a new \type {pdfe} userdata object that you can query.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Memory streams}][library=pdfe]

-

-\topicindex{\PDF+memory streams}

-

-\libindex {new}

-

-The \type {pdfe.new} that takes three arguments:

-

-\starttabulate

-\DB value           \BC explanation      \NC \NR

-\TB

-\NC \type {stream}  \NC this is a (in low level \LUA\ speak) light userdata

-                        object, i.e.\ a pointer to a sequence of bytes \NC \NR

-\NC \type {length}  \NC this is the length of the stream in bytes (the stream can

-                        have embedded zeros) \NC \NR

-\NC \type {name}    \NC optional, this is a unique identifier that is used for

-                        hashing the stream, so that multiple doesn't use more

-                        memory \NC \NR

-\LL

-\stoptabulate

-

-The third argument is optional. When it is not given the function will return an

-\type {pdfe} document object as with a regular file, otherwise it will return a

-filename that can be used elsewhere (e.g.\ in the image library) to reference the

-stream as pseudo file.

-

-Instead of a light userdata stream (which is actually fragile but handy when you

-come from a library) you can also pass a \LUA\ string, in which case the given

-length is (at most) the string length.

-

-The function returns an \type {pdfe} object and a string. The string can be used in

-the \type {img} library instead of a filename. You need to prevent garbage

-collection of the object when you use it as image (for instance by storing it

-somewhere).

-

-Both the memory stream and it's use in the image library is experimental and can

-change. In case you wonder where this can be used: when you use the swiglib

-library for \type {graphicmagick}, it can return such a userdata object. This

-permits conversion in memory and passing the result directly to the backend. This

-might save some runtime in one|-|pass workflows. This feature is currently not

-meant for production and we might come up with a better implementation.

-

-\stopsection

-

-\startsection[title={The \type {pdfscanner} library}][library=pdfscanner]

-

-\topicindex{\PDF+scanner}

-

-\libindex {scan}

-

-The \type {pdfscanner} library allows interpretation of \PDF\ content streams and

-\type {/ToUnicode} (cmap) streams. You can get those streams from the \type

-{pdfe} library, as explained in an earlier section. There is only a single

-top|-|level function in this library:

-

-\startfunctioncall

-pdfscanner.scan (<pdfe stream>, <table> operatortable, <table> info)

-pdfscanner.scan (<pdfe array>, <table> operatortable, <table> info)

-pdfscanner.scan (<string>, <table> operatortable, <table> info)

-\stopfunctioncall

-

-The first argument should be a \LUA\ string or a stream or array onject coming

-from the \type {pdfe} library. The second argument, \type {operatortable}, should

-be a \LUA\ table where the keys are \PDF\ operator name strings and the values

-are \LUA\ functions (defined by you) that are used to process those operators.

-The functions are called whenever the scanner finds one of these \PDF\ operators

-in the content stream(s). The functions are called with two arguments: the \type

-{scanner} object itself, and the \type {info} table that was passed are the third

-argument to \type {pdfscanner.scan}.

-

-Internally, \type {pdfscanner.scan} loops over the \PDF\ operators in the

-stream(s), collecting operands on an internal stack until it finds a \PDF\

-operator. If that \PDF\ operator's name exists in \type {operatortable}, then the

-associated function is executed. After the function has run (or when there is no

-function to execute) the internal operand stack is cleared in preparation for the

-next operator, and processing continues.

-

-The \type {scanner} argument to the processing functions is needed because it

-offers various methods to get the actual operands from the internal operand

-stack.

-

-A simple example of processing a \PDF's document stream could look like this:

-

-\starttyping

-local operatortable = { }

-

-operatortable.Do = function(scanner,info)

-    local resources = info.resources

-    if resources then

-        local val     = scanner:pop()

-        local name    = val[2]

-        local xobject = resources.XObject

-        print(info.space .. "Uses XObject " .. name)

-        local resources = xobject.Resources

-        if resources then

-            local newinfo =  {

-                space     = info.space .. "  ",

-                resources = resources,

-            }

-            pdfscanner.scan(entry, operatortable, newinfo)

-        end

-    end

-end

-

-local function Analyze(filename)

-    local doc = pdfe.open(filename)

-    if doc then

-        local pages = doc.Pages

-        for i=1,#pages do

-            local page = pages[i]

-            local info = {

-              space     = "  " ,

-              resources = page.Resources,

-            }

-            print("Page " .. i)

-         -- pdfscanner.scan(page.Contents,operatortable,info)

-            pdfscanner.scan(page.Contents(),operatortable,info)

-        end

-    end

-end

-

-Analyze("foo.pdf")

-\stoptyping

-

-This example iterates over all the actual content in the \PDF, and prints out the

-found \type {XObject} names. While the code demonstrates quite some of the \type

-{pdfe} functions, let's focus on the type \type {pdfscanner} specific code

-instead.

-

-From the bottom up, the following line runs the scanner with the \PDF\ page's

-top|-|level content given in the first argument.

-

-The third argument, \type {info}, contains two entries: \type {space} is used to

-indent the printed output, and \type {resources} is needed so that embedded \type

-{XForms} can find their own content.

-

-The second argument, \type {operatortable} defines a processing function for a

-single \PDF\ operator, \type {Do}.

-

-The function \type {Do} prints the name of the current \type {XObject}, and then

-starts a new scanner for that object's content stream, under the condition that

-the \type {XObject} is in fact a \type {/Form}. That nested scanner is called

-with new \type {info} argument with an updated \type {space} value so that the

-indentation of the output nicely nests, and with a new \type {resources} field

-to help the next iteration down to properly process any other, embedded \type

-{XObject}s.

-

-Of course, this is not a very useful example in practice, but for the purpose of

-demonstrating \type {pdfscanner}, it is just long enough. It makes use of only

-one \type {scanner} method: \type {scanner:pop()}. That function pops the top

-operand of the internal stack, and returns a \LUA\ table where the object at index

-one is a string representing the type of the operand, and object two is its

-value.

-

-The list of possible operand types and associated \LUA\ value types is:

-

-\starttabulate[|l|l|]

-\DB types           \BC type      \NC \NR

-\TB

-\NC \type{integer}  \NC <number>  \NC \NR

-\NC \type{real}     \NC <number>  \NC \NR

-\NC \type{boolean}  \NC <boolean> \NC \NR

-\NC \type{name}     \NC <string>  \NC \NR

-\NC \type{operator} \NC <string>  \NC \NR

-\NC \type{string}   \NC <string>  \NC \NR

-\NC \type{array}    \NC <table>   \NC \NR

-\NC \type{dict}     \NC <table>   \NC \NR

-\LL

-\stoptabulate

-

-In case of \type {integer} or \type {real}, the value is always a \LUA\ (floating

-point) number. In case of \type {name}, the leading slash is always stripped.

-

-In case of \type {string}, please bear in mind that \PDF\ actually supports

-different types of strings (with different encodings) in different parts of the

-\PDF\ document, so you may need to reencode some of the results; \type {pdfscanner}

-always outputs the byte stream without reencoding anything. \type {pdfscanner}

-does not differentiate between literal strings and hexadecimal strings (the

-hexadecimal values are decoded), and it treats the stream data for inline images

-as a string that is the single operand for \type {EI}.

-

-In case of \type {array}, the table content is a list of \type {pop} return

-values and in case of \type {dict}, the table keys are \PDF\ name strings and the

-values are \type {pop} return values.

-

-\libindex{pop}

-\libindex{popnumber}

-\libindex{popname}

-\libindex{popstring}

-\libindex{poparray}

-\libindex{popdictionary}

-\libindex{popboolean}

-\libindex{done}

-

-There are a few more methods defined that you can ask \type {scanner}:

-

-\starttabulate[|l|p|]

-\DB method               \BC explanation \NC \NR

-\TB

-\NC \type{pop}           \NC see above \NC \NR

-\NC \type{popnumber}     \NC return only the value of a \type {real} or \type {integer} \NC \NR

-\NC \type{popname}       \NC return only the value of a \type {name} \NC \NR

-\NC \type{popstring}     \NC return only the value of a \type {string} \NC \NR

-\NC \type{poparray}      \NC return only the value of a \type {array} \NC \NR

-\NC \type{popdictionary} \NC return only the value of a \type {dict} \NC \NR

-\NC \type{popboolean}    \NC return only the value of a \type {boolean} \NC \NR

-\NC \type{done}          \NC abort further processing of this \type {scan()} call \NC \NR

-\LL

-\stoptabulate

-

-The \type {pop*} are convenience functions, and come in handy when you know the

-type of the operands beforehand (which you usually do, in \PDF). For example, the

-\type {Do} function could have used \type {local name = scanner:popname()}

-instead, because the single operand to the \type {Do} operator is always a \PDF\

-name object.

-

-The \type {done} function allows you to abort processing of a stream once you

-have learned everything you want to learn. This comes in handy while parsing

-\type {/ToUnicode}, because there usually is trailing garbage that you are not

-interested in. Without \type {done}, processing only ends at the end of the

-stream, possibly wasting \CPU\ cycles.

-

-{\em We keep the older names \type {popNumber}, \type {popName}, \type

-{popString}, \type {popArray}, \type {popDict} and \type {popBool} around.}

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-backend
+
+\startchapter[reference=backend,title={The backend libraries}]
+
+\startsection[title={The \type {pdf} library}][library=pdf]
+
+\topicindex{backend}
+\topicindex{\PDF}
+
+This library contains variables and functions that are related to the \PDF\
+backend. You can find more details about the expected values to setters in \in
+{section} [backendprimitives].
+
+\startsubsection[title={\type {mapfile}, \type {mapline}}]
+
+\topicindex{map files}
+\topicindex{files+map}
+
+\startfunctioncall
+pdf.mapfile(<string> map file)
+pdf.mapline(<string> map line)
+\stopfunctioncall
+
+These two functions can be used to replace primitives \orm {pdfmapfile} and
+\orm {pdfmapline} inherited from \PDFTEX. They expect a string as only
+parameter and have no return value. The first character in a map line can be
+\type {-}, \type {+} or \type {=} which means as much as remove, add or replace
+this line. They are not state setters but act immediately.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][catalog|info|names|trailer]}}]
+
+\topicindex{\PDF+trailer}
+\topicindex{\PDF+catalog}
+\topicindex{\PDF+info}
+
+\libindex{setcatalog} \libindex{getcatalog}
+\libindex{setinfo}    \libindex{getinfo}
+\libindex{setnames}   \libindex{getnames}
+\libindex{settrailer} \libindex{gettrailer}
+
+These functions complement the corresponding \PDF\ backend token lists dealing
+with metadata. The value types are strings and they are written to the \PDF\
+file directly after the token registers set at the \TEX\ end are written.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][pageattributes|pageresources|pagesattributes]}}]
+
+\libindex{setpageattributes}  \libindex{getpageattributes}
+\libindex{setpageresources}   \libindex{getpageresources}
+\libindex{setpagesattributes} \libindex{getpagesattributes}
+
+\topicindex{\PDF+page attributes}
+\topicindex{\PDF+page resources}
+
+These functions complement the corresponding \PDF\ backend token lists dealing
+with page resources. The variables have no interaction with the corresponding \PDF\
+backend token register. They are written to the \PDF\ file directly after the
+token registers set at the \TEX\ end are written.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][xformattributes|xformresources]}}]
+
+\libindex{setxformattributes} \libindex{getxformattributes}
+\libindex{setxformresources}  \libindex{getxformresources}
+
+\topicindex{\PDF+xform attributes}
+\topicindex{\PDF+xform resources}
+
+These functions complement the corresponding \PDF\ backend token lists dealing
+with reuseable boxes and images. The variables have no interaction with the
+corresponding \PDF\ backend token register. They are written to the \PDF\
+file directly after the token registers set at the \TEX\ end are written.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][major|minor]version}}]
+
+\topicindex{\PDF+version}
+
+\libindex{getmajorversion} \libindex{setmajorversion}
+\libindex{getminorversion} \libindex{setminorversion}
+
+You can set both the major and minor version of the output. The major version is
+normally~1 but when set to~2 some data will not be written to the file in order
+to comply with the standard. What minor version you set depends on what \PDF\
+features you use. This is out of control of \LUATEX.
+
+\stopsubsection
+
+\startsubsection[title={\type {getcreationdate}}]
+
+\topicindex{\PDF+date}
+
+\libindex{getcreationdate}
+
+This function returns a string with the date in the format that ends up in the
+\PDF\ file, in this case it's: {\tttf \cldcontext{pdf.getcreationdate()}}.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]inclusionerrorlevel} and \type {[set|get]ignoreunknownimages}}]
+
+\topicindex{\PDF+options}
+
+\libindex{getinclusionerrorlevel} \libindex{setinclusionerrorlevel}
+\libindex{getignoreunknownimages} \libindex{setignoreunknownimages}
+
+These variable control how error in included image are treated. They are modeled
+after the \PDFTEX\ equivalents.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]suppressoptionalinfo}, \type {[set|get]trailerid}
+and \type {[set|get]omitcidset}}]
+
+\topicindex{\PDF+options}
+\topicindex{\PDF+trailer}
+
+\libindex{getsuppressoptionalinfo} \libindex{setsuppressoptionalinfo}
+\libindex{gettrailerid}            \libindex{settrailerid}
+\libindex{getomitcidset}           \libindex{setomitcidset}
+\libindex{getomitcharset}          \libindex{setomitcharset}
+
+The optional info bitset (a number) determines what kind of info gets flushed.
+By default we flush all. See \in {section} [sec:pdfextensions] for more details.
+
+You can set your own trailer id. This has to be string containing valid \PDF\
+array content with checksums.
+
+The cidset and charset flags (numbers) disables inclusion of a so called \type
+{CIDSet} and \type {CharSet} entries, which can be handy when aiming at some of
+the many \PDF\ substandards.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][obj|]compresslevel} and \type {[set|get]recompress}}]
+
+\topicindex{\PDF+compression}
+
+\libindex{getcompresslevel}    \libindex{setcompresslevel}
+\libindex{getobjcompresslevel} \libindex{setobjcompresslevel}
+\libindex{getrecompress}       \libindex{setrecompress}
+
+These functions set the level stream compression. When object compression is
+enabled multiple objects will be packed in a compressed stream which saves space.
+The minimum values are~0, the maxima are~9.
+
+When recompression is to~1 compressed objects will be decompressed and when
+compresslevel is larger than zero they will then be recompressed. This is mostly
+a debugging feature and should not be relied upon.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]gentounicode}}]
+
+\topicindex{\PDF+unicode}
+
+\libindex{getgentounicode} \libindex{setgentounicode}
+
+This flag enables tounicode generation (like in \PDFTEX). Normally the values are
+provided by the font loader.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]decimaldigits}}]
+
+\topicindex{\PDF+precision}
+
+\libindex{getdecimaldigits} \libindex{setdecimaldigits}
+
+These two functions set the accuracy of floats written to the \PDF file. You can
+set any value but the backend will not go below~3 and above~6.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]pkresolution}}]
+
+\topicindex{\PDF+resolution}
+
+\libindex{getpkresolution} \libindex{setpkresolution}
+
+These setter takes two arguments: the resolution and an optional zero or one that
+indicates if this is a fixed one. The getter returns these two values.
+
+\stopsubsection
+
+\startsubsection[title={\type {getlast[obj|link|annot]} and \type {getretval}}]
+
+\topicindex{\PDF+objects}
+\topicindex{\PDF+annotations}
+
+\libindex{getlastobj}   \libindex{setlastobj}
+\libindex{getlastlink}  \libindex{setlastlink}
+\libindex{getlastannot} \libindex{setlastannot}
+\libindex{getretval}
+
+These status variables are similar to the ones traditionally used in the backend
+interface at the \TEX\ end.
+
+\stopsubsection
+
+\startsubsection[title={\type {getmaxobjnum} and \type {getobjtype}, \type {getfontname},
+\type {getfontobjnum}, \type {getfontsize}, \type {getxformname}}]
+
+\libindex{getmaxobjnum}
+\libindex{getobjtype}
+\libindex{getfontname}
+\libindex{getfontobjnum}
+\libindex{getfontsize}
+\libindex{getxformname}
+
+These introspective helpers are mostly used when you construct \PDF\ objects
+yourself and need for instance information about a (to be) embedded font.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]origin}}]
+
+\topicindex{\PDF+positioning}
+
+\libindex{setorigin} \libindex{getorigin}
+
+This one is used to set the horizonal and|/|or vertical offset, a traditional
+backend property.
+
+\starttyping
+pdf.setorigin() -- sets both to 0pt
+pdf.setorigin(tex.sp("1in")) -- sets both to 1in
+pdf.setorigin(tex.sp("1in"),tex.sp("1in"))
+\stoptyping
+
+The counterpart of this function returns two values.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get]imageresolution}}]
+
+\topicindex{\PDF+resolution}
+
+\libindex{setimageresolution} \libindex{getimageresolution}
+
+These two functions relate to the imageresolution that is used when the image
+itself doesn't provide a non|-|zero x or y resolution.
+
+\stopsubsection
+
+\startsubsection[title={\type {[set|get][link|dest|thread|xform]margin}}]
+
+\topicindex{\PDF+margins}
+
+\libindex{getlinkmargin}   \libindex{setlinkmargin}
+\libindex{getdestmargin}   \libindex{setdestmargin}
+\libindex{getthreadmargin} \libindex{setthreadmargin}
+\libindex{getxformmargin}  \libindex{setxformmargin}
+\libindex{getmarginmargin} \libindex{setmarginmargin}
+
+These functions can be used to set and retrieve the margins that are added to the
+natural bounding boxes of the respective objects.
+
+\stopsubsection
+
+\startsubsection[title={\type {get[pos|hpos|vpos]}}]
+
+\topicindex{\PDF+positions}
+
+\libindex{getpos}
+\libindex{gethpos}
+\libindex{getvpos}
+
+These functions get current location on the output page, measured from its lower
+left corner. The values return scaled points as units.
+
+\starttyping
+local h, v = pdf.getpos()
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {[has|get]matrix}}]
+
+\topicindex{\PDF+matrix}
+
+\libindex{getmatrix} \libindex{hasmatrix}
+
+The current matrix transformation is available via the \type {getmatrix} command,
+which returns 6 values: \type {sx}, \type {rx}, \type {ry}, \type {sy}, \type
+{tx}, and \type {ty}. The \type {hasmatrix} function returns \type {true} when a
+matrix is applied.
+
+\starttyping
+if pdf.hasmatrix() then
+    local sx, rx, ry, sy, tx, ty = pdf.getmatrix()
+    -- do something useful or not
+end
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {print}}]
+
+\topicindex{\PDF+print to}
+
+\libindex{print}
+
+You can print a string to the \PDF\ document from within a \lpr {latelua} call.
+This function is not to be used inside \prm {directlua} unless you know {\it
+exactly} what you are doing.
+
+\startfunctioncall
+pdf.print(<string> s)
+pdf.print(<string> type, <string> s)
+\stopfunctioncall
+
+The optional parameter can be used to mimic the behavior of \PDF\ literals: the
+\type {type} is \type {direct} or \type {page}.
+
+\stopsubsection
+
+\startsubsection[title={\type {immediateobj}}]
+
+\topicindex{\PDF+objects}
+
+\libindex{immediateobj}
+
+This function creates a \PDF\ object and immediately writes it to the \PDF\ file.
+It is modelled after \PDFTEX's \prm {immediate} \orm {pdfobj} primitives. All
+function variants return the object number of the newly generated object.
+
+\startfunctioncall
+<number> n =
+    pdf.immediateobj(<string> objtext)
+<number> n =
+    pdf.immediateobj("file", <string> filename)
+<number> n =
+    pdf.immediateobj("stream", <string> streamtext, <string> attrtext)
+<number> n =
+    pdf.immediateobj("streamfile", <string> filename, <string> attrtext)
+\stopfunctioncall
+
+The first version puts the \type {objtext} raw into an object. Only the object
+wrapper is automatically generated, but any internal structure (like \type {<<
+>>} dictionary markers) needs to be provided by the user. The second version with
+keyword \type {file} as first argument puts the contents of the file with name
+\type {filename} raw into the object. The third version with keyword \type
+{stream} creates a stream object and puts the \type {streamtext} raw into the
+stream. The stream length is automatically calculated. The optional \type
+{attrtext} goes into the dictionary of that object. The fourth version with
+keyword \type {streamfile} does the same as the third one, it just reads the
+stream data raw from a file.
+
+An optional first argument can be given to make the function use a previously
+reserved \PDF\ object.
+
+\startfunctioncall
+<number> n =
+    pdf.immediateobj(<integer> n, <string> objtext)
+<number> n =
+    pdf.immediateobj(<integer> n, "file", <string> filename)
+<number> n =
+    pdf.immediateobj(<integer> n, "stream", <string> streamtext, <string> attrtext)
+<number> n =
+    pdf.immediateobj(<integer> n, "streamfile", <string> filename, <string> attrtext)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type{obj}}]
+
+\topicindex{\PDF+objects}
+
+\libindex{obj}
+
+This function creates a \PDF\ object, which is written to the \PDF\ file only
+when referenced, e.g., by \type {refobj()}.
+
+All function variants return the object number of the newly generated object, and
+there are two separate calling modes. The first mode is modelled after \PDFTEX's
+\orm {pdfobj} primitive.
+
+\startfunctioncall
+<number> n =
+    pdf.obj(<string> objtext)
+<number> n =
+    pdf.obj("file", <string> filename)
+<number> n =
+    pdf.obj("stream", <string> streamtext, <string> attrtext)
+<number> n =
+    pdf.obj("streamfile", <string> filename, <string> attrtext)
+\stopfunctioncall
+
+An optional first argument can be given to make the function use a previously
+reserved \PDF\ object.
+
+\startfunctioncall
+<number> n =
+    pdf.obj(<integer> n, <string> objtext)
+<number> n =
+    pdf.obj(<integer> n, "file", <string> filename)
+<number> n =
+    pdf.obj(<integer> n, "stream", <string> streamtext, <string> attrtext)
+<number> n =
+    pdf.obj(<integer> n, "streamfile", <string> filename, <string> attrtext)
+\stopfunctioncall
+
+The second mode accepts a single argument table with key--value pairs.
+
+\startfunctioncall
+<number> n = pdf.obj {
+    type           = <string>,
+    immediate      = <boolean>,
+    objnum         = <number>,
+    attr           = <string>,
+    compresslevel  = <number>,
+    objcompression = <boolean>,
+    file           = <string>,
+    string         = <string>,
+    nolength       = <boolean>,
+}
+\stopfunctioncall
+
+The \type {type} field can have the values \type {raw} and \type {stream}, this
+field is required, the others are optional (within constraints). When \type
+{nolength} is set, there will be no \type {/Length} entry added to the
+dictionary.
+
+Note: this mode makes \type{obj} look more flexible than it actually is: the
+constraints from the separate parameter version still apply, so for example you
+can't have both \type {string} and \type {file} at the same time.
+
+\stopsubsection
+
+\startsubsection[title={\type {refobj}}]
+
+\topicindex{\PDF+objects}
+
+\libindex{refobj}
+
+This function, the \LUA\ version of the \orm {pdfrefobj} primitive, references an
+object by its object number, so that the object will be written to the \PDF\ file.
+
+\startfunctioncall
+pdf.refobj(<integer> n)
+\stopfunctioncall
+
+This function works in both the \prm {directlua} and \lpr {latelua} environment.
+Inside \prm {directlua} a new whatsit node \quote {pdf_refobj} is created, which
+will be marked for flushing during page output and the object is then written
+directly after the page, when also the resources objects are written to the \PDF\
+file. Inside \lpr {latelua} the object will be marked for flushing.
+
+This function has no return values.
+
+\stopsubsection
+
+\startsubsection[title={\type {reserveobj}}]
+
+\topicindex{\PDF+objects}
+
+\libindex{reserveobj}
+
+This function creates an empty \PDF\ object and returns its number.
+
+\startfunctioncall
+<number> n = pdf.reserveobj()
+<number> n = pdf.reserveobj("annot")
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {getpageref}}]
+
+\topicindex{\PDF+pages}
+
+\libindex{getpageref}
+
+The object number of a page can be fetched with this function. This can be a
+forward reference so when you ask for a future page, you do get a number back.
+
+\startfunctioncall
+<number> n = pdf.getpageref(123)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {registerannot}}]
+
+\topicindex{\PDF+annotations}
+
+\libindex{registerannot}
+
+This function adds an object number to the \type {/Annots} array for the current
+page without doing anything else. This function can only be used from within
+\lpr {latelua}.
+
+\startfunctioncall
+pdf.registerannot (<number> objnum)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {newcolorstack}}]
+
+\topicindex{\PDF+color stack}
+
+\libindex{newcolorstack}
+
+This function allocates a new color stack and returns it's id. The arguments
+are the same as for the similar backend extension primitive.
+
+\startfunctioncall
+pdf.newcolorstack("0 g","page",true) -- page|direct|origin
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {setfontattributes}}]
+
+\topicindex{\PDF+fonts}
+
+\libindex{setfontattributes}
+
+This function will force some additional code into the font resource. It can for
+instance be used to add a custom \type {ToUnicode} vector to a bitmap file.
+
+\startfunctioncall
+pdf.setfontattributes(<number> font id, <string> pdf code)
+\stopfunctioncall
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={The \type {pdfe} library}][library=pdfe]
+
+\startsubsection[title={Introduction}]
+
+\topicindex{\PDF+objects}
+
+\topicindex{\PDF+analyze}
+\topicindex{\PDF+\type{pdfe}}
+
+The \type {pdfe} library replaces the \type {epdf} library and provides an
+interface to \PDF\ files. It uses the same code as is used for \PDF\ image
+inclusion. The \type {pplib} library by Paweł Jackowski replaces the \type
+{poppler} (derived from \type {xpdf}) library.
+
+A \PDF\ file is basically a tree of objects and one descends into the tree via
+dictionaries (key/value) and arrays (index/value). There are a few topmost
+dictionaries that start at root that are accessed more directly.
+
+Although everything in \PDF\ is basically an object we only wrap a few in so
+called userdata \LUA\ objects.
+
+\starttabulate
+\BC \PDF          \BC \LUA \NC \NR
+\NC null          \NC nil \NC \NR
+\NC boolean       \NC boolean \NC \NR
+\NC integer       \NC integer \NC \NR
+\NC float         \NC number \NC \NR
+\NC name          \NC string \NC \NR
+\NC string        \NC string \NC \NR
+\NC array         \NC array userdatum \NC \NR
+\NC dictionary    \NC dictionary userdatum \NC \NR
+\NC stream        \NC stream userdatum (with related dictionary) \NC \NR
+\NC reference     \NC reference userdatum \NC \NR
+\stoptabulate
+
+The regular getters return these \LUA\ data types but one can also get more
+detailed information.
+
+\stopsubsection
+
+\startsubsection[title={\type {open}, \type {new}, \type {getstatus}, \type {close}, \type {unencrypt}}]
+
+\libindex {open}
+\libindex {new}
+\libindex {new}
+\libindex {getstatus}
+\libindex {close}
+\libindex {unencrypt}
+
+A document is loaded from a file or string
+
+\starttyping
+<pdfe document> = pdfe.open(filename)
+<pdfe document> = pdfe.new(somestring,somelength)
+\stoptyping
+
+Such a document is closed with:
+
+\starttyping
+pdfe.close(<pdfe document>)
+\stoptyping
+
+You can check if a document opened well by:
+
+\starttyping
+pdfe.getstatus(<pdfe document>)
+\stoptyping
+
+The returned codes are:
+
+\starttabulate[|c|l|]
+\DB value       \BC explanation \NC \NR
+\TB
+\NC \type {-2}  \NC the document failed to open \NC \NR
+\NC \type {-1}  \NC the document is (still) protected \NC \NR
+\NC \type {0}   \NC the document is not encrypted \NC \NR
+\NC \type {2}   \NC the document has been unencrypted \NC \NR
+\LL
+\stoptabulate
+
+An encrypted document can be unencrypted by the next command where instead of
+either password you can give \type {nil}:
+
+\starttyping
+pdfe.unencrypt(<pdfe document>,userpassword,ownerpassword)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {getsize}, \type {getversion}, \type {getnofobjects}, \type {getnofpages}}]
+
+\libindex {getsize}
+\libindex {getversion}
+\libindex {getnofobjects}
+\libindex {getnofpages}
+
+A successfully opened document can provide some information:
+
+\starttyping
+bytes = getsize(<pdfe document>)
+major, minor = getversion(<pdfe document>)
+n = getnofobjects(<pdfe document>)
+n = getnofpages(<pdfe document>)
+bytes, waste = getnofpages(<pdfe document>)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {get[catalog|trailer|info]}}]
+
+\libindex {getcatalog}
+\libindex {gettrailer}
+\libindex {getinfo}
+
+For accessing the document structure you start with the so called catalog, a
+dictionary:
+
+\starttyping
+<pdfe dictionary> = pdfe.getcatalog(<pdfe document>)
+\stoptyping
+
+The other two root dictionaries are accessed with:
+
+\starttyping
+<pdfe dictionary> = pdfe.gettrailer(<pdfe document>)
+<pdfe dictionary> = pdfe.getinfo(<pdfe document>)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {getpage}, \type {getbox}}]
+
+\libindex {getpage}
+\libindex {getbox}
+
+A specific page can conveniently be reached with the next command, which
+returns a dictionary. The first argument is to be a page dictionary.
+
+\starttyping
+<pdfe dictionary> = pdfe.getpage(<pdfe dictionary>,pagenumber)
+\stoptyping
+
+Another convenience command gives you the (bounding) box of a (normally page)
+which can be inheritted from the document itself. An example of a valid box name
+is \type {MediaBox}.
+
+\starttyping
+pages = pdfe.getbox(<pdfe document>,boxname)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {get[string|integer|number|boolean|name]}}]
+
+\libindex {getstring}
+\libindex {getinteger}
+\libindex {getnumber}
+\libindex {getboolean}
+\libindex {getname}
+
+Common values in dictionaries and arrays are strings, integers, floats, booleans
+and names (which are also strings) and these are also normal \LUA\ objects:
+
+\starttyping
+s = getstring (<pdfe array|dictionary>,index|key)
+i = getinteger(<pdfe array|dictionary>,index|key)
+n = getnumber (<pdfe array|dictionary>,index|key)
+b = getboolean(<pdfe array|dictionary>,index|key)
+n = getname   (<pdfe array|dictionary>,index|key)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {get[from][dictionary|array|stream]}}]
+
+\libindex {getdictionary} \libindex {getfromdictionary}
+\libindex {getarray}      \libindex {getfromarray}
+\libindex {getstream}     \libindex {getfromstream}
+
+Normally you will use an index in an array and key in a dictionary but dictionaries
+also accept an index. The size of an array or dictionary is available with the
+usual \type {#} operator.
+
+\starttyping
+<pdfe dictionary>   = getdictionary(<pdfe array|dictionary>,index|key)
+<pdfe array>        = getarray     (<pdfe array|dictionary>,index|key)
+<pdfe stream>,
+<pdfe dictionary>   = getstream    (<pdfe array|dictionary>,index|key)
+\stoptyping
+
+These commands return dictionaries, arrays and streams, which are dictionaries
+with a blob of data attached.
+
+Before we come to an alternative access mode, we mention that the objects provide
+access in a different way too, for instance this is valid:
+
+\starttyping
+print(pdfe.open("foo.pdf").Catalog.Type)
+\stoptyping
+
+At the topmost level there are \type {Catalog}, \type {Info}, \type {Trailer}
+and \type {Pages}, so this is also okay:
+
+\starttyping
+print(pdfe.open("foo.pdf").Pages[1])
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {[open|close|readfrom][whole|]stream}}]
+
+\libindex {openstream}
+\libindex {closestream}
+\libindex {readfromstream}
+\libindex {readfromwholestream}
+
+Streams are sort of special. When your index or key hits a stream you get back a
+stream object and dictionary object. The dictionary you can access in the usual
+way and for the stream there are the following methods:
+
+\starttyping
+okay   = openstream(<pdfe stream>,[decode])
+         closestream(<pdfe stream>)
+str, n = readfromstream(<pdfe stream>)
+str, n = readwholestream(<pdfe stream>,[decode])
+\stoptyping
+
+You either read in chunks, or you ask for the whole. When reading in chunks, you
+need to open and close the stream yourself. The \type {n} value indicates the
+length read. The \type {decode} parameter controls if the stream data gets
+uncompressed.
+
+As with dictionaries, you can access fields in a stream dictionary in the usual
+\LUA\ way too. You get the content when you \quote {call} the stream. You can
+pass a boolean that indicates if the stream has to be decompressed.
+
+% pdfe.objectcodes      = objectcodes
+% pdfe.stringcodes      = stringcodes
+% pdfe.encryptioncodes  = encryptioncodes
+
+\stopsubsection
+
+\startsubsection[title={\type {getfrom[dictionary|array]}}]
+
+\libindex {getfromdictionary}
+\libindex {getfromarray}
+
+In addition to the interface described before, there is also a bit lower level
+interface available.
+
+\starttyping
+key, type, value, detail = getfromdictionary(<pdfe dictionary>,index)
+type, value, detail = getfromarray(<pdfe array>,index)
+\stoptyping
+
+\starttabulate[|c|l|l|l|]
+\DB type       \BC meaning    \BC value            \BC detail \NC \NR
+\NC \type {0}  \NC none       \NC nil              \NC \NC \NR
+\NC \type {1}  \NC null       \NC nil              \NC \NC \NR
+\NC \type {2}  \NC boolean    \NC boolean          \NC \NC \NR
+\NC \type {3}  \NC boolean    \NC integer          \NC \NC \NR
+\NC \type {4}  \NC number     \NC float            \NC \NC \NR
+\NC \type {5}  \NC name       \NC string           \NC \NC \NR
+\NC \type {6}  \NC string     \NC string           \NC hex \NC \NR
+\NC \type {7}  \NC array      \NC arrayobject      \NC size \NC \NR
+\NC \type {8}  \NC dictionary \NC dictionaryobject \NC size \NC \NR
+\NC \type {9}  \NC stream     \NC streamobject     \NC dictionary size \NC \NR
+\NC \type {10} \NC reference  \NC integer          \NC \NC \NR
+\LL
+\stoptabulate
+
+A \type {hex} string is (in the \PDF\ file) surrounded by \type {<>} while plain
+strings are bounded by \type {<>}.
+
+\stopsubsection
+
+\startsubsection[title={\type {[dictionary|array]totable}}]
+
+\libindex {dictionarytotable}
+\libindex {arraytotable}
+
+All entries in a dictionary or table can be fetched with the following commands
+where the return values are a hashed or indexed table.
+
+\starttyping
+hash = dictionarytotable(<pdfe dictionary>)
+list = arraytotable(<pdfe array>)
+\stoptyping
+
+You can get a list of pages with:
+
+\starttyping
+{ { <pdfe dictionary>, size, objnum }, ... } = pagestotable(<pdfe document>)
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\type {getfromreference}}]
+
+\libindex {getfromreference}
+
+Because you can have unresolved references, a reference object can be resolved
+with:
+
+\starttyping
+<pdfe dictionary|array|stream> = getfromreference(<pdfe reference>)
+\stoptyping
+
+So, you get back a new \type {pdfe} userdata object that you can query.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Memory streams}][library=pdfe]
+
+\topicindex{\PDF+memory streams}
+
+\libindex {new}
+
+The \type {pdfe.new} that takes three arguments:
+
+\starttabulate
+\DB value           \BC explanation      \NC \NR
+\TB
+\NC \type {stream}  \NC this is a (in low level \LUA\ speak) light userdata
+                        object, i.e.\ a pointer to a sequence of bytes \NC \NR
+\NC \type {length}  \NC this is the length of the stream in bytes (the stream can
+                        have embedded zeros) \NC \NR
+\NC \type {name}    \NC optional, this is a unique identifier that is used for
+                        hashing the stream, so that multiple doesn't use more
+                        memory \NC \NR
+\LL
+\stoptabulate
+
+The third argument is optional. When it is not given the function will return an
+\type {pdfe} document object as with a regular file, otherwise it will return a
+filename that can be used elsewhere (e.g.\ in the image library) to reference the
+stream as pseudo file.
+
+Instead of a light userdata stream (which is actually fragile but handy when you
+come from a library) you can also pass a \LUA\ string, in which case the given
+length is (at most) the string length.
+
+The function returns an \type {pdfe} object and a string. The string can be used in
+the \type {img} library instead of a filename. You need to prevent garbage
+collection of the object when you use it as image (for instance by storing it
+somewhere).
+
+Both the memory stream and it's use in the image library is experimental and can
+change. In case you wonder where this can be used: when you use the swiglib
+library for \type {graphicmagick}, it can return such a userdata object. This
+permits conversion in memory and passing the result directly to the backend. This
+might save some runtime in one|-|pass workflows. This feature is currently not
+meant for production and we might come up with a better implementation.
+
+\stopsection
+
+\startsection[title={The \type {pdfscanner} library}][library=pdfscanner]
+
+\topicindex{\PDF+scanner}
+
+\libindex {scan}
+
+The \type {pdfscanner} library allows interpretation of \PDF\ content streams and
+\type {/ToUnicode} (cmap) streams. You can get those streams from the \type
+{pdfe} library, as explained in an earlier section. There is only a single
+top|-|level function in this library:
+
+\startfunctioncall
+pdfscanner.scan (<pdfe stream>, <table> operatortable, <table> info)
+pdfscanner.scan (<pdfe array>, <table> operatortable, <table> info)
+pdfscanner.scan (<string>, <table> operatortable, <table> info)
+\stopfunctioncall
+
+The first argument should be a \LUA\ string or a stream or array onject coming
+from the \type {pdfe} library. The second argument, \type {operatortable}, should
+be a \LUA\ table where the keys are \PDF\ operator name strings and the values
+are \LUA\ functions (defined by you) that are used to process those operators.
+The functions are called whenever the scanner finds one of these \PDF\ operators
+in the content stream(s). The functions are called with two arguments: the \type
+{scanner} object itself, and the \type {info} table that was passed are the third
+argument to \type {pdfscanner.scan}.
+
+Internally, \type {pdfscanner.scan} loops over the \PDF\ operators in the
+stream(s), collecting operands on an internal stack until it finds a \PDF\
+operator. If that \PDF\ operator's name exists in \type {operatortable}, then the
+associated function is executed. After the function has run (or when there is no
+function to execute) the internal operand stack is cleared in preparation for the
+next operator, and processing continues.
+
+The \type {scanner} argument to the processing functions is needed because it
+offers various methods to get the actual operands from the internal operand
+stack.
+
+A simple example of processing a \PDF's document stream could look like this:
+
+\starttyping
+local operatortable = { }
+
+operatortable.Do = function(scanner,info)
+    local resources = info.resources
+    if resources then
+        local val     = scanner:pop()
+        local name    = val[2]
+        local xobject = resources.XObject
+        print(info.space .. "Uses XObject " .. name)
+        local resources = xobject.Resources
+        if resources then
+            local newinfo =  {
+                space     = info.space .. "  ",
+                resources = resources,
+            }
+            pdfscanner.scan(entry, operatortable, newinfo)
+        end
+    end
+end
+
+local function Analyze(filename)
+    local doc = pdfe.open(filename)
+    if doc then
+        local pages = doc.Pages
+        for i=1,#pages do
+            local page = pages[i]
+            local info = {
+              space     = "  " ,
+              resources = page.Resources,
+            }
+            print("Page " .. i)
+         -- pdfscanner.scan(page.Contents,operatortable,info)
+            pdfscanner.scan(page.Contents(),operatortable,info)
+        end
+    end
+end
+
+Analyze("foo.pdf")
+\stoptyping
+
+This example iterates over all the actual content in the \PDF, and prints out the
+found \type {XObject} names. While the code demonstrates quite some of the \type
+{pdfe} functions, let's focus on the type \type {pdfscanner} specific code
+instead.
+
+From the bottom up, the following line runs the scanner with the \PDF\ page's
+top|-|level content given in the first argument.
+
+The third argument, \type {info}, contains two entries: \type {space} is used to
+indent the printed output, and \type {resources} is needed so that embedded \type
+{XForms} can find their own content.
+
+The second argument, \type {operatortable} defines a processing function for a
+single \PDF\ operator, \type {Do}.
+
+The function \type {Do} prints the name of the current \type {XObject}, and then
+starts a new scanner for that object's content stream, under the condition that
+the \type {XObject} is in fact a \type {/Form}. That nested scanner is called
+with new \type {info} argument with an updated \type {space} value so that the
+indentation of the output nicely nests, and with a new \type {resources} field
+to help the next iteration down to properly process any other, embedded \type
+{XObject}s.
+
+Of course, this is not a very useful example in practice, but for the purpose of
+demonstrating \type {pdfscanner}, it is just long enough. It makes use of only
+one \type {scanner} method: \type {scanner:pop()}. That function pops the top
+operand of the internal stack, and returns a \LUA\ table where the object at index
+one is a string representing the type of the operand, and object two is its
+value.
+
+The list of possible operand types and associated \LUA\ value types is:
+
+\starttabulate[|l|l|]
+\DB types           \BC type      \NC \NR
+\TB
+\NC \type{integer}  \NC <number>  \NC \NR
+\NC \type{real}     \NC <number>  \NC \NR
+\NC \type{boolean}  \NC <boolean> \NC \NR
+\NC \type{name}     \NC <string>  \NC \NR
+\NC \type{operator} \NC <string>  \NC \NR
+\NC \type{string}   \NC <string>  \NC \NR
+\NC \type{array}    \NC <table>   \NC \NR
+\NC \type{dict}     \NC <table>   \NC \NR
+\LL
+\stoptabulate
+
+In case of \type {integer} or \type {real}, the value is always a \LUA\ (floating
+point) number. In case of \type {name}, the leading slash is always stripped.
+
+In case of \type {string}, please bear in mind that \PDF\ actually supports
+different types of strings (with different encodings) in different parts of the
+\PDF\ document, so you may need to reencode some of the results; \type {pdfscanner}
+always outputs the byte stream without reencoding anything. \type {pdfscanner}
+does not differentiate between literal strings and hexadecimal strings (the
+hexadecimal values are decoded), and it treats the stream data for inline images
+as a string that is the single operand for \type {EI}.
+
+In case of \type {array}, the table content is a list of \type {pop} return
+values and in case of \type {dict}, the table keys are \PDF\ name strings and the
+values are \type {pop} return values.
+
+\libindex{pop}
+\libindex{popnumber}
+\libindex{popname}
+\libindex{popstring}
+\libindex{poparray}
+\libindex{popdictionary}
+\libindex{popboolean}
+\libindex{done}
+
+There are a few more methods defined that you can ask \type {scanner}:
+
+\starttabulate[|l|p|]
+\DB method               \BC explanation \NC \NR
+\TB
+\NC \type{pop}           \NC see above \NC \NR
+\NC \type{popnumber}     \NC return only the value of a \type {real} or \type {integer} \NC \NR
+\NC \type{popname}       \NC return only the value of a \type {name} \NC \NR
+\NC \type{popstring}     \NC return only the value of a \type {string} \NC \NR
+\NC \type{poparray}      \NC return only the value of a \type {array} \NC \NR
+\NC \type{popdictionary} \NC return only the value of a \type {dict} \NC \NR
+\NC \type{popboolean}    \NC return only the value of a \type {boolean} \NC \NR
+\NC \type{done}          \NC abort further processing of this \type {scan()} call \NC \NR
+\LL
+\stoptabulate
+
+The \type {pop*} are convenience functions, and come in handy when you know the
+type of the operands beforehand (which you usually do, in \PDF). For example, the
+\type {Do} function could have used \type {local name = scanner:popname()}
+instead, because the single operand to the \type {Do} operator is always a \PDF\
+name object.
+
+The \type {done} function allows you to abort processing of a stream once you
+have learned everything you want to learn. This comes in handy while parsing
+\type {/ToUnicode}, because there usually is trailing garbage that you are not
+interested in. Without \type {done}, processing only ends at the end of the
+stream, possibly wasting \CPU\ cycles.
+
+{\em We keep the older names \type {popNumber}, \type {popName}, \type
+{popString}, \type {popArray}, \type {popDict} and \type {popBool} around.}
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-callbacks.tex b/systems/doc/luatex/luatex-callbacks.tex
index b2b706ea91..9be3e36354 100644
--- a/systems/doc/luatex/luatex-callbacks.tex
+++ b/systems/doc/luatex/luatex-callbacks.tex
@@ -1,1149 +1,1165 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-callbacks

-

-\startchapter[reference=callbacks,title={\LUA\ callbacks}]

-

-\startsection[title={Registering callbacks}][library=callback]

-

-\topicindex{callbacks}

-

-\libindex{register}

-\libindex{list}

-\libindex{find}

-

-This library has functions that register, find and list callbacks. Callbacks are

-\LUA\ functions that are called in well defined places. There are two kind of

-callbacks: those that mix with existing functionality, and those that (when

-enabled) replace functionality. In mosty cases the second category is expected to

-behave similar to the built in functionality because in a next step specific

-data is expected. For instance, you can replace the hyphenation routine. The

-function gets a list that can be hyphenated (or not). The final list should be

-valid and is (normally) used for constructing a paragraph. Another function can

-replace the ligature builder and|/|or kerner. Doing something else is possible

-but in the end might not give the user the expected outcome.

-

-The first thing you need to do is registering a callback:

-

-\startfunctioncall

-id, error =

-    callback.register(<string> callback_name, <function> func)

-id, error =

-    callback.register(<string> callback_name, nil)

-id, error =

-    callback.register(<string> callback_name, false)

-\stopfunctioncall

-

-Here the \syntax {callback_name} is a predefined callback name, see below. The

-function returns the internal \type {id} of the callback or \type {nil}, if the

-callback could not be registered. In the latter case, \type {error} contains an

-error message, otherwise it is \type {nil}.

-

-\LUATEX\ internalizes the callback function in such a way that it does not matter

-if you redefine a function accidentally.

-

-Callback assignments are always global. You can use the special value \type {nil}

-instead of a function for clearing the callback.

-

-For some minor speed gain, you can assign the boolean \type {false} to the

-non|-|file related callbacks, doing so will prevent \LUATEX\ from executing

-whatever it would execute by default (when no callback function is registered at

-all). Be warned: this may cause all sorts of grief unless you know \notabene

-{exactly} what you are doing!

-

-\startfunctioncall

-<table> info =

-    callback.list()

-\stopfunctioncall

-

-The keys in the table are the known callback names, the value is a boolean where

-\type {true} means that the callback is currently set (active).

-

-\startfunctioncall

-<function> f = callback.find(callback_name)

-\stopfunctioncall

-

-If the callback is not set, \type {find} returns \type {nil}.

-

-\stopsection

-

-\startsection[title={File discovery callbacks}][library=callback]

-

-The behaviour documented in this subsection is considered stable in the sense that

-there will not be backward|-|incompatible changes any more.

-

-\subsection{\cbk {find_read_file} and \cbk {find_write_file}}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<number> id_number, <string> asked_name)

-\stopfunctioncall

-

-Arguments:

-

-\startitemize

-

-\sym{id_number}

-

-This number is zero for the log or \prm {input} files. For \TEX's \prm {read}

-or \prm {write} the number is incremented by one, so \type {\read0} becomes~1.

-

-\sym{asked_name}

-

-This is the user|-|supplied filename, as found by \prm {input}, \prm {openin}

-or \prm {openout}.

-

-\stopitemize

-

-Return value:

-

-\startitemize

-

-\sym{actual_name}

-

-This is the filename used. For the very first file that is read in by \TEX, you

-have to make sure you return an \type {actual_name} that has an extension and

-that is suitable for use as \type {jobname}. If you don't, you will have to

-manually fix the name of the log file and output file after \LUATEX\ is finished,

-and an eventual format filename will become mangled. That is because these file

-names depend on the jobname.

-

-You have to return \type {nil} if the file cannot be found.

-

-\stopitemize

-

-\subsection{\cbk {find_font_file}}

-

-\topicindex{callbacks+font files}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<string> asked_name)

-\stopfunctioncall

-

-The \type {asked_name} is an \OTF\ or \TFM\ font metrics file.

-

-Return \type {nil} if the file cannot be found.

-

-\subsection{\cbk {find_output_file}}

-

-\topicindex{callbacks+output file}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<string> asked_name)

-\stopfunctioncall

-

-The \type {asked_name} is the \PDF\ or \DVI\ file for writing.

-

-\subsection{\cbk {find_format_file}}

-

-\topicindex{callbacks+format file}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<string> asked_name)

-\stopfunctioncall

-

-The \type {asked_name} is a format file for reading (the format file for writing

-is always opened in the current directory).

-

-\subsection{\cbk {find_vf_file}}

-

-\topicindex{callbacks+font files}

-

-Like \cbk {find_font_file}, but for virtual fonts. This applies to both \ALEPH's

-\OVF\ files and traditional Knuthian \VF\ files.

-

-\subsection{\cbk {find_map_file}}

-

-\topicindex{callbacks+font files}

-

-Like \cbk {find_font_file}, but for map files.

-

-\subsection{\cbk {find_enc_file}}

-

-\topicindex{callbacks+font files}

-

-Like \cbk {find_font_file}, but for enc files.

-

-\subsection{\cbk {find_pk_file}}

-

-\topicindex{callbacks+font files}

-

-Like \cbk {find_font_file}, but for pk bitmap files. This callback takes two

-arguments: \type {name} and \type {dpi}. In your callback you can decide to

-look for:

-

-\starttyping

-<base res>dpi/<fontname>.<actual res>pk

-\stoptyping

-

-but other strategies are possible. It is up to you to find a \quote {reasonable}

-bitmap file to go with that specification.

-

-\subsection{\cbk {find_data_file}}

-

-\topicindex{callbacks+data files}

-

-Like \cbk {find_font_file}, but for embedded files (\type {\pdfobj file '...'}).

-

-\subsection{\cbk {find_opentype_file}}

-

-\topicindex{callbacks+font files}

-

-Like \cbk {find_font_file}, but for \OPENTYPE\ font files.

-

-\subsection{\cbk {find_truetype_file} and \cbk {find_type1_file}}

-

-\topicindex{callbacks+font files}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<string> asked_name)

-\stopfunctioncall

-

-The \type {asked_name} is a font file. This callback is called while \LUATEX\ is

-building its internal list of needed font files, so the actual timing may

-surprise you. Your return value is later fed back into the matching \type

-{read_file} callback.

-

-Strangely enough, \cbk {find_type1_file} is also used for \OPENTYPE\ (\OTF)

-fonts.

-

-\subsection{\cbk {find_image_file}}

-

-\topicindex{callbacks+image files}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<string> actual_name =

-    function (<string> asked_name)

-\stopfunctioncall

-

-The \type {asked_name} is an image file. Your return value is used to open a file

-from the hard disk, so make sure you return something that is considered the name

-of a valid file by your operating system.

-

-\subsection[iocallback]{File reading callbacks}

-

-The behavior documented in this subsection is considered stable in the sense that

-there will not be backward-incompatible changes any more.

-

-\subsection{\cbk {open_read_file}}

-

-\topicindex{callbacks+opening files}

-

-Your callback function should have the following conventions:

-

-\startfunctioncall

-<table> env =

-    function (<string> file_name)

-\stopfunctioncall

-

-Argument:

-

-\startitemize

-

-\sym{file_name}

-

-The filename returned by a previous \cbk {find_read_file} or the return value of

-\type {kpse.find_file()} if there was no such callback defined.

-

-\stopitemize

-

-Return value:

-

-\startitemize

-

-\sym{env}

-

-This is a table containing at least one required and one optional callback

-function for this file. The required field is \type {reader} and the associated

-function will be called once for each new line to be read, the optional one is

-\type {close} that will be called once when \LUATEX\ is done with the file.

-

-\LUATEX\ never looks at the rest of the table, so you can use it to store your

-private per|-|file data. Both the callback functions will receive the table as

-their only argument.

-

-\stopitemize

-

-\subsubsection{\type {reader}}

-

-\topicindex{callbacks+reader}

-

-\LUATEX\ will run this function whenever it needs a new input line from the file.

-

-\startfunctioncall

-function(<table> env)

-    return <string> line

-end

-\stopfunctioncall

-

-Your function should return either a string or \type {nil}. The value \type {nil}

-signals that the end of file has occurred, and will make \TEX\ call the optional

-\type {close} function next.

-

-\subsubsection{\type {close}}

-

-\topicindex{callbacks+closing files}

-

-\LUATEX\ will run this optional function when it decides to close the file.

-

-\startfunctioncall

-function(<table> env)

-end

-\stopfunctioncall

-

-Your function should not return any value.

-

-\subsection{General file readers}

-

-\topicindex{callbacks+readers}

-

-There is a set of callbacks for the loading of binary data files. These all use

-the same interface:

-

-\startfunctioncall

-function(<string> name)

-    return <boolean> success, <string> data, <number> data_size

-end

-\stopfunctioncall

-

-The \type {name} will normally be a full path name as it is returned by either

-one of the file discovery callbacks or the internal version of \type

-{kpse.find_file()}.

-

-\startitemize

-

-\sym{success}

-

-Return \type {false} when a fatal error occurred (e.g.\ when the file cannot be

-found, after all).

-

-\sym{data}

-

-The bytes comprising the file.

-

-\sym{data_size}

-

-The length of the \type {data}, in bytes.

-

-\stopitemize

-

-Return an empty string and zero if the file was found but there was a

-reading problem.

-

-The list of functions is:

-

-\starttabulate[|l|p|]

-\DB function  \BC usage \NC \NR

-\TB

-\NC \type{read_font_file}     \NC ofm or tfm files \NC \NR

-\NC \type{read_vf_file}       \NC virtual fonts \NC \NR

-\NC \type{read_map_file}      \NC map files \NC \NR

-\NC \type{read_enc_file}      \NC encoding files \NC \NR

-\NC \type{read_pk_file}       \NC pk bitmap files \NC \NR

-\NC \type{read_data_file}     \NC embedded files (as is possible with \PDF\ objects) \NC \NR

-\NC \type{read_truetype_file} \NC \TRUETYPE\ font files \NC \NR

-\NC \type{read_type1_file}    \NC \TYPEONE\ font files \NC \NR

-\NC \type{read_opentype_file} \NC \OPENTYPE\ font files \NC \NR

-\LL

-\stoptabulate

-

-\stopsection

-

-\startsection[title={Data processing callbacks}][library=callback]

-

-\subsection{\cbk {process_input_buffer}}

-

-\topicindex{callbacks+input buffer}

-

-This callback allows you to change the contents of the line input buffer just

-before \LUATEX\ actually starts looking at it.

-

-\startfunctioncall

-function(<string> buffer)

-    return <string> adjusted_buffer

-end

-\stopfunctioncall

-

-If you return \type {nil}, \LUATEX\ will pretend like your callback never

-happened. You can gain a small amount of processing time from that. This callback

-does not replace any internal code.

-

-\subsection{\cbk {process_output_buffer}}

-

-\topicindex{callbacks+output buffer}

-

-This callback allows you to change the contents of the line output buffer just

-before \LUATEX\ actually starts writing it to a file as the result of a \prm

-{write} command. It is only called for output to an actual file (that is,

-excluding the log, the terminal, and so called \prm {write} 18 calls).

-

-\startfunctioncall

-function(<string> buffer)

-    return <string> adjusted_buffer

-end

-\stopfunctioncall

-

-If you return \type {nil}, \LUATEX\ will pretend like your callback never

-happened. You can gain a small amount of processing time from that. This callback

-does not replace any internal code.

-

-\subsection{\cbk {process_jobname}}

-

-\topicindex{callbacks+jobname}

-

-This callback allows you to change the jobname given by \prm {jobname} in \TEX\

-and \type {tex.jobname} in Lua. It does not affect the internal job name or the

-name of the output or log files.

-

-\startfunctioncall

-function(<string> jobname)

-    return <string> adjusted_jobname

-end

-\stopfunctioncall

-

-The only argument is the actual job name; you should not use \type {tex.jobname}

-inside this function or infinite recursion may occur. If you return \type {nil},

-\LUATEX\ will pretend your callback never happened. This callback does not

-replace any internal code.

-

-\stopsection

-

-\startsection[title={Node list processing callbacks}][library=callback]

-

-The description of nodes and node lists is in~\in{chapter}[nodes].

-

-\subsection{\cbk {contribute_filter}}

-

-\topicindex{callbacks+contributions}

-

-This callback is called when \LUATEX\ adds contents to list:

-

-\startfunctioncall

-function(<string> extrainfo)

-end

-\stopfunctioncall

-

-The string reports the group code. From this you can deduce from

-what list you can give a treat.

-

-\starttabulate[|l|p|]

-\DB value             \BC explanation                                  \NC \NR

-\TB

-\NC \type{pre_box}    \NC interline material is being added            \NC \NR

-\NC \type{pre_adjust} \NC \prm {vadjust} material is being added       \NC \NR

-\NC \type{box}        \NC a typeset box is being added (always called) \NC \NR

-\NC \type{adjust}     \NC \prm {vadjust} material is being added       \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\cbk {buildpage_filter}}

-

-\topicindex{callbacks+building pages}

-

-This callback is called whenever \LUATEX\ is ready to move stuff to the main

-vertical list. You can use this callback to do specialized manipulation of the

-page building stage like imposition or column balancing.

-

-\startfunctioncall

-function(<string> extrainfo)

-end

-\stopfunctioncall

-

-The string \type {extrainfo} gives some additional information about what \TEX's

-state is with respect to the \quote {current page}. The possible values for the

-\cbk {buildpage_filter} callback are:

-

-\starttabulate[|l|p|]

-\DB value                  \BC explanation                             \NC \NR

-\TB

-\NC \type{alignment}       \NC a (partial) alignment is being added    \NC \NR

-\NC \type{after_output}    \NC an output routine has just finished     \NC \NR

-\NC \type{new_graf}        \NC the beginning of a new paragraph        \NC \NR

-\NC \type{vmode_par}       \NC \prm {par} was found in vertical mode   \NC \NR

-\NC \type{hmode_par}       \NC \prm {par} was found in horizontal mode \NC \NR

-\NC \type{insert}          \NC an insert is added                      \NC \NR

-\NC \type{penalty}         \NC a penalty (in vertical mode)            \NC \NR

-\NC \type{before_display}  \NC immediately before a display starts     \NC \NR

-\NC \type{after_display}   \NC a display is finished                   \NC \NR

-\NC \type{end}             \NC \LUATEX\ is terminating (it's all over) \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\cbk {build_page_insert}}

-

-\topicindex{callbacks+inserts}

-

-This callback is called when the pagebuilder adds an insert. There is not much

-control over this mechanism but this callback permits some last minute

-manipulations of the spacing before an insert, something that might be handy when

-for instance multiple inserts (types) are appended in a row.

-

-\startfunctioncall

-function(<number> n, <number> i)

-    return <number> register

-end

-\stopfunctioncall

-

-with

-

-\starttabulate[|l|p|]

-\DB value    \BC explanation             \NC \NR

-\TB

-\NC \type{n} \NC the insert class        \NC \NR

-\NC \type{i} \NC the order of the insert \NC \NR

-\LL

-\stoptabulate

-

-The return value is a number indicating the skip register to use for the

-prepended spacing. This permits for instance a different top space (when \type

-{i} equals one) and intermediate space (when \type {i} is larger than one). Of

-course you can mess with the insert box but you need to make sure that \LUATEX\

-is happy afterwards.

-

-\subsection{\cbk {pre_linebreak_filter}}

-

-\topicindex{callbacks+linebreaks}

-

-This callback is called just before \LUATEX\ starts converting a list of nodes

-into a stack of \prm {hbox}es, after the addition of \prm {parfillskip}.

-

-\startfunctioncall

-function(<node> head, <string> groupcode)

-    return true | false | <node> newhead

-end

-\stopfunctioncall

-

-The string called \type {groupcode} identifies the nodelist's context within

-\TEX's processing. The range of possibilities is given in the table below, but

-not all of those can actually appear in \cbk {pre_linebreak_filter}, some are

-for the \cbk {hpack_filter} and \cbk {vpack_filter} callbacks that will be

-explained in the next two paragraphs.

-

-\starttabulate[|l|p|]

-\DB value                \BC explanation                                 \NC \NR

-\TB

-\NC \type{<empty>}       \NC main vertical list                          \NC \NR

-\NC \type{hbox}          \NC \prm {hbox} in horizontal mode              \NC \NR

-\NC \type{adjusted_hbox} \NC \prm {hbox} in vertical mode                \NC \NR

-\NC \type{vbox}          \NC \prm {vbox}                                 \NC \NR

-\NC \type{vtop}          \NC \prm {vtop}                                 \NC \NR

-\NC \type{align}         \NC \prm {halign} or \prm {valign}              \NC \NR

-\NC \type{disc}          \NC discretionaries                             \NC \NR

-\NC \type{insert}        \NC packaging an insert                         \NC \NR

-\NC \type{vcenter}       \NC \prm {vcenter}                              \NC \NR

-\NC \type{local_box}     \NC \lpr {localleftbox} or \lpr {localrightbox} \NC \NR

-\NC \type{split_off}     \NC top of a \prm {vsplit}                      \NC \NR

-\NC \type{split_keep}    \NC remainder of a \prm {vsplit}                \NC \NR

-\NC \type{align_set}     \NC alignment cell                              \NC \NR

-\NC \type{fin_row}       \NC alignment row                               \NC \NR

-\LL

-\stoptabulate

-

-As for all the callbacks that deal with nodes, the return value can be one of

-three things:

-

-\startitemize

-\startitem

-    boolean \type {true} signals successful processing

-\stopitem

-\startitem

-    \type {<node>} signals that the \quote {head} node should be replaced by the

-    returned node

-\stopitem

-\startitem

-    boolean \type {false} signals that the \quote {head} node list should be

-    ignored and flushed from memory

-\stopitem

-\stopitemize

-

-This callback does not replace any internal code.

-

-\subsection{\cbk {linebreak_filter}}

-

-\topicindex{callbacks+linebreaks}

-

-This callback replaces \LUATEX's line breaking algorithm.

-

-\startfunctioncall

-function(<node> head, <boolean> is_display)

-    return <node> newhead

-end

-\stopfunctioncall

-

-The returned node is the head of the list that will be added to the main vertical

-list, the boolean argument is true if this paragraph is interrupted by a

-following math display.

-

-If you return something that is not a \type {<node>}, \LUATEX\ will apply the

-internal linebreak algorithm on the list that starts at \type {<head>}.

-Otherwise, the \type {<node>} you return is supposed to be the head of a list of

-nodes that are all allowed in vertical mode, and at least one of those has to

-represent a hbox. Failure to do so will result in a fatal error.

-

-Setting this callback to \type {false} is possible, but dangerous, because it is

-possible you will end up in an unfixable \quote {deadcycles loop}.

-

-\subsection{\type {append_to_vlist_filter}}

-

-\topicindex{callbacks+contributions}

-

-This callback is called whenever \LUATEX\ adds a box to a vertical list:

-

-\startfunctioncall

-function(<node> box, <string> locationcode, <number prevdepth>,

-    <boolean> mirrored)

-    return list, prevdepth

-end

-\stopfunctioncall

-

-It is ok to return nothing in which case you also need to flush the box or deal

-with it yourself. The prevdepth is also optional. Locations are \type {box},

-\type {alignment}, \type {equation}, \type {equation_number} and \type

-{post_linebreak}.

-

-\subsection{\cbk {post_linebreak_filter}}

-

-\topicindex{callbacks+linebreaks}

-

-This callback is called just after \LUATEX\ has converted a list of nodes into a

-stack of \prm {hbox}es.

-

-\startfunctioncall

-function(<node> head, <string> groupcode)

-    return true | false | <node> newhead

-end

-\stopfunctioncall

-

-This callback does not replace any internal code.

-

-\subsection{\cbk {hpack_filter}}

-

-\topicindex{callbacks+packing}

-

-This callback is called when \TEX\ is ready to start boxing some horizontal mode

-material. Math items and line boxes are ignored at the moment.

-

-\startfunctioncall

-function(<node> head, <string> groupcode, <number> size,

-         <string> packtype [, <string> direction] [, <node> attributelist])

-    return true | false | <node> newhead

-end

-\stopfunctioncall

-

-The \type {packtype} is either \type {additional} or \type {exactly}. If \type

-{additional}, then the \type {size} is a \type {\hbox spread ...} argument. If

-\type {exactly}, then the \type {size} is a \type {\hbox to ...}. In both cases,

-the number is in scaled points.

-

-The \type {direction} is either one of the three-letter direction specifier

-strings, or \type {nil}.

-

-This callback does not replace any internal code.

-

-\subsection{\cbk {vpack_filter}}

-

-\topicindex{callbacks+packing}

-

-This callback is called when \TEX\ is ready to start boxing some vertical mode

-material. Math displays are ignored at the moment.

-

-This function is very similar to the \cbk {hpack_filter}. Besides the fact

-that it is called at different moments, there is an extra variable that matches

-\TEX's \prm {maxdepth} setting.

-

-\startfunctioncall

-function(<node> head, <string> groupcode, <number> size, <string> packtype,

-        <number> maxdepth [, <string> direction] [, <node> attributelist]))

-    return true | false | <node> newhead

-end

-\stopfunctioncall

-

-This callback does not replace any internal code.

-

-\subsection{\type {hpack_quality}}

-

-\topicindex{callbacks+packing}

-

-This callback can be used to intercept the overfull messages that can result from

-packing a horizontal list (as happens in the par builder). The function takes a

-few arguments:

-

-\startfunctioncall

-function(<string> incident, <number> detail, <node> head, <number> first,

-         <number> last)

-    return <node> whatever

-end

-\stopfunctioncall

-

-The incident is one of \type {overfull}, \type {underfull}, \type {loose} or

-\type {tight}. The detail is either the amount of overflow in case of \type

-{overfull}, or the badness otherwise. The head is the list that is constructed

-(when protrusion or expansion is enabled, this is an intermediate list).

-Optionally you can return a node, for instance an overfull rule indicator. That

-node will be appended to the list (just like \TEX's own rule would).

-

-\subsection{\type {vpack_quality}}

-

-\topicindex{callbacks+packing}

-

-This callback can be used to intercept the overfull messages that can result from

-packing a vertical list (as happens in the page builder). The function takes a

-few arguments:

-

-\startfunctioncall

-function(<string> incident, <number> detail, <node> head, <number> first,

-         <number> last)

-end

-\stopfunctioncall

-

-The incident is one of \type {overfull}, \type {underfull}, \type {loose} or

-\type {tight}. The detail is either the amount of overflow in case of \type

-{overfull}, or the badness otherwise. The head is the list that is constructed.

-

-\subsection{\cbk {process_rule}}

-

-\topicindex{callbacks+rules}

-

-This is an experimental callback. It can be used with rules of subtype~4

-(user). The callback gets three arguments: the node, the width and the

-height. The callback can use \type {pdf.print} to write code to the \PDF\

-file but beware of not messing up the final result. No checking is done.

-

-\subsection{\type {pre_output_filter}}

-

-\topicindex{callbacks+output}

-

-This callback is called when \TEX\ is ready to start boxing the box 255 for \prm

-{output}.

-

-\startfunctioncall

-function(<node> head, <string> groupcode, <number> size, <string> packtype,

-        <number> maxdepth [, <string> direction])

-    return true | false | <node> newhead

-end

-\stopfunctioncall

-

-This callback does not replace any internal code.

-

-\subsection{\cbk {hyphenate}}

-

-\topicindex{callbacks+hyphenation}

-

-\startfunctioncall

-function(<node> head, <node> tail)

-end

-\stopfunctioncall

-

-No return values. This callback has to insert discretionary nodes in the node

-list it receives.

-

-Setting this callback to \type {false} will prevent the internal discretionary

-insertion pass.

-

-\subsection{\cbk {ligaturing}}

-

-\topicindex{callbacks+ligature building}

-

-\startfunctioncall

-function(<node> head, <node> tail)

-end

-\stopfunctioncall

-

-No return values. This callback has to apply ligaturing to the node list it

-receives.

-

-You don't have to worry about return values because the \type {head} node that is

-passed on to the callback is guaranteed not to be a glyph_node (if need be, a

-temporary node will be prepended), and therefore it cannot be affected by the

-mutations that take place. After the callback, the internal value of the \quote

-{tail of the list} will be recalculated.

-

-The \type {next} of \type {head} is guaranteed to be non-nil.

-

-The \type {next} of \type {tail} is guaranteed to be nil, and therefore the

-second callback argument can often be ignored. It is provided for orthogonality,

-and because it can sometimes be handy when special processing has to take place.

-

-Setting this callback to \type {false} will prevent the internal ligature

-creation pass.

-

-You must not ruin the node list. For instance, the head normally is a local par node,

-and the tail a glue. Messing too much can push \LUATEX\ into panic mode.

-

-\subsection{\cbk {kerning}}

-

-\topicindex{callbacks+kerning}

-

-\startfunctioncall

-function(<node> head, <node> tail)

-end

-\stopfunctioncall

-

-No return values. This callback has to apply kerning between the nodes in the

-node list it receives. See \cbk {ligaturing} for calling conventions.

-

-Setting this callback to \type {false} will prevent the internal kern insertion

-pass.

-

-You must not ruin the node list. For instance, the head normally is a local par node,

-and the tail a glue. Messing too much can push \LUATEX\ into panic mode.

-

-\subsection{\type {insert_local_par}}

-

-Each paragraph starts with a local par node that keeps track of for instance

-the direction. You can hook a callback into the creator:

-

-\startfunctioncall

-function(<node> local_par, <string> location)

-end

-\stopfunctioncall

-

-There is no return value and you should make sure that the node stays valid

-as otherwise \TEX\ can get confused.

-

-\subsection{\cbk {mlist_to_hlist}}

-

-\topicindex{callbacks+math}

-

-This callback replaces \LUATEX's math list to node list conversion algorithm.

-

-\startfunctioncall

-function(<node> head, <string> display_type, <boolean> need_penalties)

-    return <node> newhead

-end

-\stopfunctioncall

-

-The returned node is the head of the list that will be added to the vertical or

-horizontal list, the string argument is either \quote {text} or \quote {display}

-depending on the current math mode, the boolean argument is \type {true} if

-penalties have to be inserted in this list, \type {false} otherwise.

-

-Setting this callback to \type {false} is bad, it will almost certainly result in

-an endless loop.

-

-\stopsection

-

-\startsection[title={Information reporting callbacks}][library=callback]

-

-\subsection{\cbk {pre_dump}}

-

-\topicindex{callbacks+dump}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This function is called just before dumping to a format file starts. It does not

-replace any code and there are neither arguments nor return values.

-

-\subsection{\cbk {start_run}}

-

-\topicindex{callbacks+job run}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback replaces the code that prints \LUATEX's banner. Note that for

-successful use, this callback has to be set in the \LUA\ initialization script,

-otherwise it will be seen only after the run has already started.

-

-\subsection{\cbk {stop_run}}

-

-\topicindex{callbacks+job run}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback replaces the code that prints \LUATEX's statistics and \quote

-{output written to} messages. The engine can still do housekeeping and therefore

-you should not rely on this hook for postprocessing the \PDF\ or log file.

-

-\subsection{\cbk {start_page_number}}

-

-\topicindex{callbacks+pages}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-Replaces the code that prints the \type {[} and the page number at the begin of

-\prm {shipout}. This callback will also override the printing of box information

-that normally takes place when \prm {tracingoutput} is positive.

-

-\subsection{\cbk {stop_page_number}}

-

-\topicindex{callbacks+pages}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-Replaces the code that prints the \type {]} at the end of \prm {shipout}.

-

-\subsection{\cbk {show_error_hook}}

-

-\topicindex{callbacks+errors}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback is run from inside the \TEX\ error function, and the idea is to

-allow you to do some extra reporting on top of what \TEX\ already does (none of

-the normal actions are removed). You may find some of the values in the \type

-{status} table useful. This callback does not replace any internal code.

-

-\subsection{\cbk {show_error_message}}

-

-\topicindex{callbacks+errors}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback replaces the code that prints the error message. The usual

-interaction after the message is not affected.

-

-\subsection{\cbk {show_lua_error_hook}}

-

-\topicindex{callbacks+errors}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback replaces the code that prints the extra \LUA\ error message.

-

-\subsection{\cbk {start_file}}

-

-\topicindex{callbacks+files}

-

-\startfunctioncall

-function(category,filename)

-end

-\stopfunctioncall

-

-This callback replaces the code that prints \LUATEX's when a file is opened like

-\type {(filename} for regular files. The category is a number:

-

-\starttabulate[|c|l|]

-\DB value  \BC meaning \NC \NR

-\TB

-\NC 1 \NC a normal data file, like a \TEX\ source \NC \NR

-\NC 2 \NC a font map coupling font names to resources \NC \NR

-\NC 3 \NC an image file (\type {png}, \type {pdf}, etc) \NC \NR

-\NC 4 \NC an embedded font subset \NC \NR

-\NC 5 \NC a fully embedded font \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\cbk {stop_file}}

-

-\topicindex{callbacks+files}

-

-\startfunctioncall

-function(category)

-end

-\stopfunctioncall

-

-This callback replaces the code that prints \LUATEX's when a file is closed like

-the \type {)} for regular files.

-

-\subsection{\cbk {call_edit}}

-

-\topicindex{callbacks+editing}

-

-\startfunctioncall

-function(filename,linenumber)

-end

-\stopfunctioncall

-

-This callback replaces the call to an external editor when \quote{E} is pressed

-in reply to an error message. Processing will end immediately after the callback

-returns control to the main program.

-

-\subsection{\cbk {finish_synctex}}

-

-\topicindex{callbacks+synctex}

-

-This callback can be used to wrap up alternative synctex methods. It kicks in

-after the normal synctex finalizer (that happens to remove the synctex files

-after a run when native synctex is not enabled).

-

-\subsection{\cbk {wrapup_run}}

-

-\topicindex{callbacks+wrapping up}

-

-This callback is called after the \PDF\ and log files are closed. Use it at your own

-risk.

-

-\stopsection

-

-\startsection[title={\PDF\ related callbacks}][library=callback]

-

-\subsection{\cbk {finish_pdffile}}

-

-\topicindex{callbacks+\PDF\ file}

-

-\startfunctioncall

-function()

-end

-\stopfunctioncall

-

-This callback is called when all document pages are already written to the \PDF\

-file and \LUATEX\ is about to finalize the output document structure. Its

-intended use is final update of \PDF\ dictionaries such as \type {/Catalog} or

-\type {/Info}. The callback does not replace any code. There are neither

-arguments nor return values.

-

-\subsection{\cbk {finish_pdfpage}}

-

-\topicindex{callbacks+\PDF\ file}

-

-\startfunctioncall

-function(shippingout)

-end

-\stopfunctioncall

-

-This callback is called after the \PDF\ page stream has been assembled and before

-the page object gets finalized.

-

-\subsection{\cbk {page_objnum_provider}}

-

-\topicindex{callbacks+\PDF\ file}

-

-This is one that experts can use to juggle the page tree, a data structure

-that determines the order in a \PDF\ file:

-

-\startfunctioncall

-function(objnum)

-  return objnum

-end

-\stopfunctioncall

-

-We can for instance swap the first and last page:

-

-\starttyping

-local n = 0

-callback.register("page_objnum_provider",function(objnum)

-    n = n + 1

-    if n == 1 then

-        return pdf.getpageref(tex.count[0])

-    elseif n == tex.count[0] then

-        return pdf.getpageref(1)

-    else

-        return objnum

-    end

-end)

-\stoptyping

-

-When you mess things up \unknown\ don't complain.

-

-\subsection{\cbk {process_pdf_image_content}}

-

-\topicindex{callbacks+image content}

-

-When a page from a \PDF\ file is embedded its page stream as well as related

-objects are copied to the target file. However, it can be that the page stream

-has operators that assume additional resources, for instance marked text. You can

-decide to filter that for which \LUATEX\ provides a callback. Here is a simple

-demonstration of use:

-

-\starttyping

-pdf.setrecompress(1)

-

-callback.register("process_pdf_image_content",function(s)

-    print(s)

-    return s

-end)

-\stoptyping

-

-You need to explicitly enable recompression because otherwise the content stream

-gets just passed on in its original compressed form.

-

-\stopsection

-

-\startsection[title={Font-related callbacks}][library=callback]

-

-\subsection{\cbk {define_font}}

-

-\topicindex{callbacks+fonts}

-

-\startfunctioncall

-function(<string> name, <number> size, <number> id)

-    return <table> font | <number> id

-end

-\stopfunctioncall

-

-The string \type {name} is the filename part of the font specification, as given

-by the user.

-

-The number \type {size} is a bit special:

-

-\startitemize[packed]

-\startitem

-    If it is positive, it specifies an \quote{at size} in scaled points.

-\stopitem

-\startitem

-    If it is negative, its absolute value represents a \quote {scaled} setting

-    relative to the designsize of the font.

-\stopitem

-\stopitemize

-

-The \type {id} is the internal number assigned to the font.

-

-The internal structure of the \type {font} table that is to be returned is

-explained in \in {chapter} [fonts]. That table is saved internally, so you can

-put extra fields in the table for your later \LUA\ code to use. In alternative,

-\type {retval} can be a previously defined fontid. This is useful if a previous

-definition can be reused instead of creating a whole new font structure.

-

-Setting this callback to \type {false} is pointless as it will prevent font

-loading completely but will nevertheless generate errors.

-

-\subsection{\cbk {glyph_not_found}}

-

-\topicindex{callbacks+fonts}

-

-This callback kicks in when the backend cannot insert a glyph. When no callback

-is defined a message is written to the log.

-

-\startfunctioncall

-function(<number> id, <number> char)

-    -- do something with font id and char code

-end

-\stopfunctioncall

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-callbacks
+
+\startchapter[reference=callbacks,title={\LUA\ callbacks}]
+
+\startsection[title={Registering callbacks}][library=callback]
+
+\topicindex{callbacks}
+
+\libindex{register}
+\libindex{list}
+\libindex{find}
+
+This library has functions that register, find and list callbacks. Callbacks are
+\LUA\ functions that are called in well defined places. There are two kind of
+callbacks: those that mix with existing functionality, and those that (when
+enabled) replace functionality. In mosty cases the second category is expected to
+behave similar to the built in functionality because in a next step specific
+data is expected. For instance, you can replace the hyphenation routine. The
+function gets a list that can be hyphenated (or not). The final list should be
+valid and is (normally) used for constructing a paragraph. Another function can
+replace the ligature builder and|/|or kerner. Doing something else is possible
+but in the end might not give the user the expected outcome.
+
+The first thing you need to do is registering a callback:
+
+\startfunctioncall
+id, error =
+    callback.register(<string> callback_name, <function> func)
+id, error =
+    callback.register(<string> callback_name, nil)
+id, error =
+    callback.register(<string> callback_name, false)
+\stopfunctioncall
+
+Here the \syntax {callback_name} is a predefined callback name, see below. The
+function returns the internal \type {id} of the callback or \type {nil}, if the
+callback could not be registered. In the latter case, \type {error} contains an
+error message, otherwise it is \type {nil}.
+
+\LUATEX\ internalizes the callback function in such a way that it does not matter
+if you redefine a function accidentally.
+
+Callback assignments are always global. You can use the special value \type {nil}
+instead of a function for clearing the callback.
+
+For some minor speed gain, you can assign the boolean \type {false} to the
+non|-|file related callbacks, doing so will prevent \LUATEX\ from executing
+whatever it would execute by default (when no callback function is registered at
+all). Be warned: this may cause all sorts of grief unless you know \notabene
+{exactly} what you are doing!
+
+\startfunctioncall
+<table> info =
+    callback.list()
+\stopfunctioncall
+
+The keys in the table are the known callback names, the value is a boolean where
+\type {true} means that the callback is currently set (active).
+
+\startfunctioncall
+<function> f = callback.find(callback_name)
+\stopfunctioncall
+
+If the callback is not set, \type {find} returns \type {nil}.
+
+\stopsection
+
+\startsection[title={File discovery callbacks}][library=callback]
+
+The behaviour documented in this subsection is considered stable in the sense that
+there will not be backward|-|incompatible changes any more.
+
+\subsection{\cbk {find_read_file} and \cbk {find_write_file}}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<number> id_number, <string> asked_name)
+\stopfunctioncall
+
+Arguments:
+
+\startitemize
+
+\sym{id_number}
+
+This number is zero for the log or \prm {input} files. For \TEX's \prm {read}
+or \prm {write} the number is incremented by one, so \type {\read0} becomes~1.
+
+\sym{asked_name}
+
+This is the user|-|supplied filename, as found by \prm {input}, \prm {openin}
+or \prm {openout}.
+
+\stopitemize
+
+Return value:
+
+\startitemize
+
+\sym{actual_name}
+
+This is the filename used. For the very first file that is read in by \TEX, you
+have to make sure you return an \type {actual_name} that has an extension and
+that is suitable for use as \type {jobname}. If you don't, you will have to
+manually fix the name of the log file and output file after \LUATEX\ is finished,
+and an eventual format filename will become mangled. That is because these file
+names depend on the jobname.
+
+You have to return \type {nil} if the file cannot be found.
+
+\stopitemize
+
+\subsection{\cbk {find_font_file}}
+
+\topicindex{callbacks+font files}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<string> asked_name)
+\stopfunctioncall
+
+The \type {asked_name} is an \OTF\ or \TFM\ font metrics file.
+
+Return \type {nil} if the file cannot be found.
+
+\subsection{\cbk {find_output_file}}
+
+\topicindex{callbacks+output file}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<string> asked_name)
+\stopfunctioncall
+
+The \type {asked_name} is the \PDF\ or \DVI\ file for writing.
+
+\subsection{\cbk {find_format_file}}
+
+\topicindex{callbacks+format file}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<string> asked_name)
+\stopfunctioncall
+
+The \type {asked_name} is a format file for reading (the format file for writing
+is always opened in the current directory).
+
+\subsection{\cbk {find_vf_file}}
+
+\topicindex{callbacks+font files}
+
+Like \cbk {find_font_file}, but for virtual fonts. This applies to both \ALEPH's
+\OVF\ files and traditional Knuthian \VF\ files.
+
+\subsection{\cbk {find_map_file}}
+
+\topicindex{callbacks+font files}
+
+Like \cbk {find_font_file}, but for map files.
+
+\subsection{\cbk {find_enc_file}}
+
+\topicindex{callbacks+font files}
+
+Like \cbk {find_font_file}, but for enc files.
+
+\subsection{\cbk {find_pk_file}}
+
+\topicindex{callbacks+font files}
+
+Like \cbk {find_font_file}, but for pk bitmap files. This callback takes two
+arguments: \type {name} and \type {dpi}. In your callback you can decide to
+look for:
+
+\starttyping
+<base res>dpi/<fontname>.<actual res>pk
+\stoptyping
+
+but other strategies are possible. It is up to you to find a \quote {reasonable}
+bitmap file to go with that specification.
+
+\subsection{\cbk {find_data_file}}
+
+\topicindex{callbacks+data files}
+
+Like \cbk {find_font_file}, but for embedded files (\type {\pdfobj file '...'}).
+
+\subsection{\cbk {find_opentype_file}}
+
+\topicindex{callbacks+font files}
+
+Like \cbk {find_font_file}, but for \OPENTYPE\ font files.
+
+\subsection{\cbk {find_truetype_file} and \cbk {find_type1_file}}
+
+\topicindex{callbacks+font files}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<string> asked_name)
+\stopfunctioncall
+
+The \type {asked_name} is a font file. This callback is called while \LUATEX\ is
+building its internal list of needed font files, so the actual timing may
+surprise you. Your return value is later fed back into the matching \type
+{read_file} callback.
+
+Strangely enough, \cbk {find_type1_file} is also used for \OPENTYPE\ (\OTF)
+fonts.
+
+\subsection{\cbk {find_image_file}}
+
+\topicindex{callbacks+image files}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<string> actual_name =
+    function (<string> asked_name)
+\stopfunctioncall
+
+The \type {asked_name} is an image file. Your return value is used to open a file
+from the hard disk, so make sure you return something that is considered the name
+of a valid file by your operating system.
+
+\stopsection
+
+\startsection[iocallback][title={File reading callbacks}]
+
+The behavior documented in this subsection is considered stable in the sense that
+there will not be backward-incompatible changes any more.
+
+\subsection{\cbk {open_read_file}}
+
+\topicindex{callbacks+opening files}
+
+Your callback function should have the following conventions:
+
+\startfunctioncall
+<table> env =
+    function (<string> file_name)
+\stopfunctioncall
+
+Argument:
+
+\startitemize
+
+\sym{file_name}
+
+The filename returned by a previous \cbk {find_read_file} or the return value of
+\type {kpse.find_file()} if there was no such callback defined.
+
+\stopitemize
+
+Return value:
+
+\startitemize
+
+\sym{env}
+
+This is a table containing at least one required and one optional callback
+function for this file. The required field is \type {reader} and the associated
+function will be called once for each new line to be read, the optional one is
+\type {close} that will be called once when \LUATEX\ is done with the file.
+
+\LUATEX\ never looks at the rest of the table, so you can use it to store your
+private per|-|file data. Both the callback functions will receive the table as
+their only argument.
+
+\stopitemize
+
+\subsubsection{\type {reader}}
+
+\topicindex{callbacks+reader}
+
+\LUATEX\ will run this function whenever it needs a new input line from the file.
+
+\startfunctioncall
+function(<table> env)
+    return <string> line
+end
+\stopfunctioncall
+
+Your function should return either a string or \type {nil}. The value \type {nil}
+signals that the end of file has occurred, and will make \TEX\ call the optional
+\type {close} function next.
+
+\subsubsection{\type {close}}
+
+\topicindex{callbacks+closing files}
+
+\LUATEX\ will run this optional function when it decides to close the file.
+
+\startfunctioncall
+function(<table> env)
+end
+\stopfunctioncall
+
+Your function should not return any value.
+
+\subsection{General file readers}
+
+\topicindex{callbacks+readers}
+
+There is a set of callbacks for the loading of binary data files. These all use
+the same interface:
+
+\startfunctioncall
+function(<string> name)
+    return <boolean> success, <string> data, <number> data_size
+end
+\stopfunctioncall
+
+The \type {name} will normally be a full path name as it is returned by either
+one of the file discovery callbacks or the internal version of \type
+{kpse.find_file()}.
+
+\startitemize
+
+\sym{success}
+
+Return \type {false} when a fatal error occurred (e.g.\ when the file cannot be
+found, after all).
+
+\sym{data}
+
+The bytes comprising the file.
+
+\sym{data_size}
+
+The length of the \type {data}, in bytes.
+
+\stopitemize
+
+Return an empty string and zero if the file was found but there was a
+reading problem.
+
+The list of functions is:
+
+\starttabulate[|l|p|]
+\DB function  \BC usage \NC \NR
+\TB
+\NC \type{read_font_file}     \NC ofm or tfm files \NC \NR
+\NC \type{read_vf_file}       \NC virtual fonts \NC \NR
+\NC \type{read_map_file}      \NC map files \NC \NR
+\NC \type{read_enc_file}      \NC encoding files \NC \NR
+\NC \type{read_pk_file}       \NC pk bitmap files \NC \NR
+\NC \type{read_data_file}     \NC embedded files (as is possible with \PDF\ objects) \NC \NR
+\NC \type{read_truetype_file} \NC \TRUETYPE\ font files \NC \NR
+\NC \type{read_type1_file}    \NC \TYPEONE\ font files \NC \NR
+\NC \type{read_opentype_file} \NC \OPENTYPE\ font files \NC \NR
+\LL
+\stoptabulate
+
+\stopsection
+
+\startsection[title={Data processing callbacks}][library=callback]
+
+\subsection{\cbk {process_input_buffer}}
+
+\topicindex{callbacks+input buffer}
+
+This callback allows you to change the contents of the line input buffer just
+before \LUATEX\ actually starts looking at it.
+
+\startfunctioncall
+function(<string> buffer)
+    return <string> adjusted_buffer
+end
+\stopfunctioncall
+
+If you return \type {nil}, \LUATEX\ will pretend like your callback never
+happened. You can gain a small amount of processing time from that. This callback
+does not replace any internal code.
+
+\subsection{\cbk {process_output_buffer}}
+
+\topicindex{callbacks+output buffer}
+
+This callback allows you to change the contents of the line output buffer just
+before \LUATEX\ actually starts writing it to a file as the result of a \prm
+{write} command. It is only called for output to an actual file (that is,
+excluding the log, the terminal, and so called \prm {write} 18 calls).
+
+\startfunctioncall
+function(<string> buffer)
+    return <string> adjusted_buffer
+end
+\stopfunctioncall
+
+If you return \type {nil}, \LUATEX\ will pretend like your callback never
+happened. You can gain a small amount of processing time from that. This callback
+does not replace any internal code.
+
+\subsection{\cbk {process_jobname}}
+
+\topicindex{callbacks+jobname}
+
+This callback allows you to change the jobname given by \prm {jobname} in \TEX\
+and \type {tex.jobname} in Lua. It does not affect the internal job name or the
+name of the output or log files.
+
+\startfunctioncall
+function(<string> jobname)
+    return <string> adjusted_jobname
+end
+\stopfunctioncall
+
+The only argument is the actual job name; you should not use \type {tex.jobname}
+inside this function or infinite recursion may occur. If you return \type {nil},
+\LUATEX\ will pretend your callback never happened. This callback does not
+replace any internal code.
+
+\stopsection
+
+\startsection[title={Node list processing callbacks}][library=callback]
+
+The description of nodes and node lists is in~\in{chapter}[nodes].
+
+\subsection{\cbk {contribute_filter}}
+
+\topicindex{callbacks+contributions}
+
+This callback is called when \LUATEX\ adds contents to list:
+
+\startfunctioncall
+function(<string> extrainfo)
+end
+\stopfunctioncall
+
+The string reports the group code. From this you can deduce from
+what list you can give a treat.
+
+\starttabulate[|l|p|]
+\DB value             \BC explanation                                  \NC \NR
+\TB
+\NC \type{pre_box}    \NC interline material is being added            \NC \NR
+\NC \type{pre_adjust} \NC \prm {vadjust} material is being added       \NC \NR
+\NC \type{box}        \NC a typeset box is being added (always called) \NC \NR
+\NC \type{adjust}     \NC \prm {vadjust} material is being added       \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\cbk {buildpage_filter}}
+
+\topicindex{callbacks+building pages}
+
+This callback is called whenever \LUATEX\ is ready to move stuff to the main
+vertical list. You can use this callback to do specialized manipulation of the
+page building stage like imposition or column balancing.
+
+\startfunctioncall
+function(<string> extrainfo)
+end
+\stopfunctioncall
+
+The string \type {extrainfo} gives some additional information about what \TEX's
+state is with respect to the \quote {current page}. The possible values for the
+\cbk {buildpage_filter} callback are:
+
+\starttabulate[|l|p|]
+\DB value                  \BC explanation                             \NC \NR
+\TB
+\NC \type{alignment}       \NC a (partial) alignment is being added    \NC \NR
+\NC \type{after_output}    \NC an output routine has just finished     \NC \NR
+\NC \type{new_graf}        \NC the beginning of a new paragraph        \NC \NR
+\NC \type{vmode_par}       \NC \prm {par} was found in vertical mode   \NC \NR
+\NC \type{hmode_par}       \NC \prm {par} was found in horizontal mode \NC \NR
+\NC \type{insert}          \NC an insert is added                      \NC \NR
+\NC \type{penalty}         \NC a penalty (in vertical mode)            \NC \NR
+\NC \type{before_display}  \NC immediately before a display starts     \NC \NR
+\NC \type{after_display}   \NC a display is finished                   \NC \NR
+\NC \type{end}             \NC \LUATEX\ is terminating (it's all over) \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\cbk {build_page_insert}}
+
+\topicindex{callbacks+inserts}
+
+This callback is called when the pagebuilder adds an insert. There is not much
+control over this mechanism but this callback permits some last minute
+manipulations of the spacing before an insert, something that might be handy when
+for instance multiple inserts (types) are appended in a row.
+
+\startfunctioncall
+function(<number> n, <number> i)
+    return <number> register
+end
+\stopfunctioncall
+
+with
+
+\starttabulate[|l|p|]
+\DB value    \BC explanation             \NC \NR
+\TB
+\NC \type{n} \NC the insert class        \NC \NR
+\NC \type{i} \NC the order of the insert \NC \NR
+\LL
+\stoptabulate
+
+The return value is a number indicating the skip register to use for the
+prepended spacing. This permits for instance a different top space (when \type
+{i} equals one) and intermediate space (when \type {i} is larger than one). Of
+course you can mess with the insert box but you need to make sure that \LUATEX\
+is happy afterwards.
+
+\subsection{\cbk {pre_linebreak_filter}}
+
+\topicindex{callbacks+linebreaks}
+
+This callback is called just before \LUATEX\ starts converting a list of nodes
+into a stack of \prm {hbox}es, after the addition of \prm {parfillskip}.
+
+\startfunctioncall
+function(<node> head, <string> groupcode)
+    return true | false | <node> newhead
+end
+\stopfunctioncall
+
+The string called \type {groupcode} identifies the nodelist's context within
+\TEX's processing. The range of possibilities is given in the table below, but
+not all of those can actually appear in \cbk {pre_linebreak_filter}, some are
+for the \cbk {hpack_filter} and \cbk {vpack_filter} callbacks that will be
+explained in the next two paragraphs.
+
+\starttabulate[|l|p|]
+\DB value                \BC explanation                                 \NC \NR
+\TB
+\NC \type{<empty>}       \NC main vertical list                          \NC \NR
+\NC \type{hbox}          \NC \prm {hbox} in horizontal mode              \NC \NR
+\NC \type{adjusted_hbox} \NC \prm {hbox} in vertical mode                \NC \NR
+\NC \type{vbox}          \NC \prm {vbox}                                 \NC \NR
+\NC \type{vtop}          \NC \prm {vtop}                                 \NC \NR
+\NC \type{align}         \NC \prm {halign} or \prm {valign}              \NC \NR
+\NC \type{disc}          \NC discretionaries                             \NC \NR
+\NC \type{insert}        \NC packaging an insert                         \NC \NR
+\NC \type{vcenter}       \NC \prm {vcenter}                              \NC \NR
+\NC \type{local_box}     \NC \lpr {localleftbox} or \lpr {localrightbox} \NC \NR
+\NC \type{split_off}     \NC top of a \prm {vsplit}                      \NC \NR
+\NC \type{split_keep}    \NC remainder of a \prm {vsplit}                \NC \NR
+\NC \type{align_set}     \NC alignment cell                              \NC \NR
+\NC \type{fin_row}       \NC alignment row                               \NC \NR
+\LL
+\stoptabulate
+
+As for all the callbacks that deal with nodes, the return value can be one of
+three things:
+
+\startitemize
+\startitem
+    boolean \type {true} signals successful processing
+\stopitem
+\startitem
+    \type {<node>} signals that the \quote {head} node should be replaced by the
+    returned node
+\stopitem
+\startitem
+    boolean \type {false} signals that the \quote {head} node list should be
+    ignored and flushed from memory
+\stopitem
+\stopitemize
+
+This callback does not replace any internal code.
+
+\subsection{\cbk {linebreak_filter}}
+
+\topicindex{callbacks+linebreaks}
+
+This callback replaces \LUATEX's line breaking algorithm.
+
+\startfunctioncall
+function(<node> head, <boolean> is_display)
+    return <node> newhead
+end
+\stopfunctioncall
+
+The returned node is the head of the list that will be added to the main vertical
+list, the boolean argument is true if this paragraph is interrupted by a
+following math display.
+
+If you return something that is not a \type {<node>}, \LUATEX\ will apply the
+internal linebreak algorithm on the list that starts at \type {<head>}.
+Otherwise, the \type {<node>} you return is supposed to be the head of a list of
+nodes that are all allowed in vertical mode, and at least one of those has to
+represent a hbox. Failure to do so will result in a fatal error.
+
+Setting this callback to \type {false} is possible, but dangerous, because it is
+possible you will end up in an unfixable \quote {deadcycles loop}.
+
+\subsection{\type {append_to_vlist_filter}}
+
+\topicindex{callbacks+contributions}
+
+This callback is called whenever \LUATEX\ adds a box to a vertical list:
+
+\startfunctioncall
+function(<node> box, <string> locationcode, <number prevdepth>,
+    <boolean> mirrored)
+    return list, prevdepth
+end
+\stopfunctioncall
+
+It is ok to return nothing in which case you also need to flush the box or deal
+with it yourself. The prevdepth is also optional. Locations are \type {box},
+\type {alignment}, \type {equation}, \type {equation_number} and \type
+{post_linebreak}.
+
+\subsection{\cbk {post_linebreak_filter}}
+
+\topicindex{callbacks+linebreaks}
+
+This callback is called just after \LUATEX\ has converted a list of nodes into a
+stack of \prm {hbox}es.
+
+\startfunctioncall
+function(<node> head, <string> groupcode)
+    return true | false | <node> newhead
+end
+\stopfunctioncall
+
+This callback does not replace any internal code.
+
+\subsection{\cbk {hpack_filter}}
+
+\topicindex{callbacks+packing}
+
+This callback is called when \TEX\ is ready to start boxing some horizontal mode
+material. Math items and line boxes are ignored at the moment.
+
+\startfunctioncall
+function(<node> head, <string> groupcode, <number> size,
+         <string> packtype [, <string> direction] [, <node> attributelist])
+    return true | false | <node> newhead
+end
+\stopfunctioncall
+
+The \type {packtype} is either \type {additional} or \type {exactly}. If \type
+{additional}, then the \type {size} is a \type {\hbox spread ...} argument. If
+\type {exactly}, then the \type {size} is a \type {\hbox to ...}. In both cases,
+the number is in scaled points.
+
+The \type {direction} is either one of the three-letter direction specifier
+strings, or \type {nil}.
+
+This callback does not replace any internal code.
+
+\subsection{\cbk {vpack_filter}}
+
+\topicindex{callbacks+packing}
+
+This callback is called when \TEX\ is ready to start boxing some vertical mode
+material. Math displays are ignored at the moment.
+
+This function is very similar to the \cbk {hpack_filter}. Besides the fact
+that it is called at different moments, there is an extra variable that matches
+\TEX's \prm {maxdepth} setting.
+
+\startfunctioncall
+function(<node> head, <string> groupcode, <number> size, <string> packtype,
+        <number> maxdepth [, <string> direction] [, <node> attributelist]))
+    return true | false | <node> newhead
+end
+\stopfunctioncall
+
+This callback does not replace any internal code.
+
+\subsection{\type {hpack_quality}}
+
+\topicindex{callbacks+packing}
+
+This callback can be used to intercept the overfull messages that can result from
+packing a horizontal list (as happens in the par builder). The function takes a
+few arguments:
+
+\startfunctioncall
+function(<string> incident, <number> detail, <node> head, <number> first,
+         <number> last)
+    return <node> whatever
+end
+\stopfunctioncall
+
+The incident is one of \type {overfull}, \type {underfull}, \type {loose} or
+\type {tight}. The detail is either the amount of overflow in case of \type
+{overfull}, or the badness otherwise. The head is the list that is constructed
+(when protrusion or expansion is enabled, this is an intermediate list).
+Optionally you can return a node, for instance an overfull rule indicator. That
+node will be appended to the list (just like \TEX's own rule would).
+
+\subsection{\type {vpack_quality}}
+
+\topicindex{callbacks+packing}
+
+This callback can be used to intercept the overfull messages that can result from
+packing a vertical list (as happens in the page builder). The function takes a
+few arguments:
+
+\startfunctioncall
+function(<string> incident, <number> detail, <node> head, <number> first,
+         <number> last)
+end
+\stopfunctioncall
+
+The incident is one of \type {overfull}, \type {underfull}, \type {loose} or
+\type {tight}. The detail is either the amount of overflow in case of \type
+{overfull}, or the badness otherwise. The head is the list that is constructed.
+
+\subsection{\cbk {process_rule}}
+
+\topicindex{callbacks+rules}
+
+This is an experimental callback. It can be used with rules of subtype~4
+(user). The callback gets three arguments: the node, the width and the
+height. The callback can use \type {pdf.print} to write code to the \PDF\
+file but beware of not messing up the final result. No checking is done.
+
+\subsection{\type {pre_output_filter}}
+
+\topicindex{callbacks+output}
+
+This callback is called when \TEX\ is ready to start boxing the box 255 for \prm
+{output}.
+
+\startfunctioncall
+function(<node> head, <string> groupcode, <number> size, <string> packtype,
+        <number> maxdepth [, <string> direction])
+    return true | false | <node> newhead
+end
+\stopfunctioncall
+
+This callback does not replace any internal code.
+
+\subsection{\cbk {hyphenate}}
+
+\topicindex{callbacks+hyphenation}
+
+\startfunctioncall
+function(<node> head, <node> tail)
+end
+\stopfunctioncall
+
+No return values. This callback has to insert discretionary nodes in the node
+list it receives.
+
+Setting this callback to \type {false} will prevent the internal discretionary
+insertion pass.
+
+\subsection{\cbk {ligaturing}}
+
+\topicindex{callbacks+ligature building}
+
+\startfunctioncall
+function(<node> head, <node> tail)
+end
+\stopfunctioncall
+
+No return values. This callback has to apply ligaturing to the node list it
+receives.
+
+You don't have to worry about return values because the \type {head} node that is
+passed on to the callback is guaranteed not to be a glyph_node (if need be, a
+temporary node will be prepended), and therefore it cannot be affected by the
+mutations that take place. After the callback, the internal value of the \quote
+{tail of the list} will be recalculated.
+
+The \type {next} of \type {head} is guaranteed to be non-nil.
+
+The \type {next} of \type {tail} is guaranteed to be nil, and therefore the
+second callback argument can often be ignored. It is provided for orthogonality,
+and because it can sometimes be handy when special processing has to take place.
+
+Setting this callback to \type {false} will prevent the internal ligature
+creation pass.
+
+You must not ruin the node list. For instance, the head normally is a local par node,
+and the tail a glue. Messing too much can push \LUATEX\ into panic mode.
+
+\subsection{\cbk {kerning}}
+
+\topicindex{callbacks+kerning}
+
+\startfunctioncall
+function(<node> head, <node> tail)
+end
+\stopfunctioncall
+
+No return values. This callback has to apply kerning between the nodes in the
+node list it receives. See \cbk {ligaturing} for calling conventions.
+
+Setting this callback to \type {false} will prevent the internal kern insertion
+pass.
+
+You must not ruin the node list. For instance, the head normally is a local par node,
+and the tail a glue. Messing too much can push \LUATEX\ into panic mode.
+
+\subsection{\type {insert_local_par}}
+
+Each paragraph starts with a local par node that keeps track of for instance
+the direction. You can hook a callback into the creator:
+
+\startfunctioncall
+function(<node> local_par, <string> location)
+end
+\stopfunctioncall
+
+There is no return value and you should make sure that the node stays valid
+as otherwise \TEX\ can get confused.
+
+\subsection{\cbk {mlist_to_hlist}}
+
+\topicindex{callbacks+math}
+
+This callback replaces \LUATEX's math list to node list conversion algorithm.
+
+\startfunctioncall
+function(<node> head, <string> display_type, <boolean> need_penalties)
+    return <node> newhead
+end
+\stopfunctioncall
+
+The returned node is the head of the list that will be added to the vertical or
+horizontal list, the string argument is either \quote {text} or \quote {display}
+depending on the current math mode, the boolean argument is \type {true} if
+penalties have to be inserted in this list, \type {false} otherwise.
+
+Setting this callback to \type {false} is bad, it will almost certainly result in
+an endless loop.
+
+\stopsection
+
+\startsection[title={Information reporting callbacks}][library=callback]
+
+\subsection{\cbk {pre_dump}}
+
+\topicindex{callbacks+dump}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This function is called just before dumping to a format file starts. It does not
+replace any code and there are neither arguments nor return values.
+
+\subsection{\cbk {start_run}}
+
+\topicindex{callbacks+job run}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback replaces the code that prints \LUATEX's banner. Note that for
+successful use, this callback has to be set in the \LUA\ initialization script,
+otherwise it will be seen only after the run has already started.
+
+\subsection{\cbk {stop_run}}
+
+\topicindex{callbacks+job run}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback replaces the code that prints \LUATEX's statistics and \quote
+{output written to} messages. The engine can still do housekeeping and therefore
+you should not rely on this hook for postprocessing the \PDF\ or log file.
+
+\subsection{\cbk {start_page_number}}
+
+\topicindex{callbacks+pages}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+Replaces the code that prints the \type {[} and the page number at the begin of
+\prm {shipout}. This callback will also override the printing of box information
+that normally takes place when \prm {tracingoutput} is positive.
+
+\subsection{\cbk {stop_page_number}}
+
+\topicindex{callbacks+pages}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+Replaces the code that prints the \type {]} at the end of \prm {shipout}.
+
+\subsection{\cbk {show_error_hook}}
+
+\topicindex{callbacks+errors}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback is run from inside the \TEX\ error function, and the idea is to
+allow you to do some extra reporting on top of what \TEX\ already does (none of
+the normal actions are removed). You may find some of the values in the \type
+{status} table useful. This callback does not replace any internal code.
+
+\subsection{\cbk {show_error_message}}
+
+\topicindex{callbacks+errors}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback replaces the code that prints the error message. The usual
+interaction after the message is not affected.
+
+\subsection{\cbk {show_lua_error_hook}}
+
+\topicindex{callbacks+errors}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback replaces the code that prints the extra \LUA\ error message.
+
+\subsection{\cbk {start_file}}
+
+\topicindex{callbacks+files}
+
+\startfunctioncall
+function(category,filename)
+end
+\stopfunctioncall
+
+This callback replaces the code that prints \LUATEX's when a file is opened like
+\type {(filename} for regular files. The category is a number:
+
+\starttabulate[|c|l|]
+\DB value  \BC meaning \NC \NR
+\TB
+\NC 1 \NC a normal data file, like a \TEX\ source \NC \NR
+\NC 2 \NC a font map coupling font names to resources \NC \NR
+\NC 3 \NC an image file (\type {png}, \type {pdf}, etc) \NC \NR
+\NC 4 \NC an embedded font subset \NC \NR
+\NC 5 \NC a fully embedded font \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\cbk {stop_file}}
+
+\topicindex{callbacks+files}
+
+\startfunctioncall
+function(category)
+end
+\stopfunctioncall
+
+This callback replaces the code that prints \LUATEX's when a file is closed like
+the \type {)} for regular files.
+
+\subsection{\cbk {call_edit}}
+
+\topicindex{callbacks+editing}
+
+\startfunctioncall
+function(filename,linenumber)
+end
+\stopfunctioncall
+
+This callback replaces the call to an external editor when \quote{E} is pressed
+in reply to an error message. Processing will end immediately after the callback
+returns control to the main program.
+
+\subsection{\cbk {finish_synctex}}
+
+\topicindex{callbacks+synctex}
+
+This callback can be used to wrap up alternative synctex methods. It kicks in
+after the normal synctex finalizer (that happens to remove the synctex files
+after a run when native synctex is not enabled).
+
+\subsection{\cbk {wrapup_run}}
+
+\topicindex{callbacks+wrapping up}
+
+This callback is called after the \PDF\ and log files are closed. Use it at your own
+risk.
+
+\stopsection
+
+\startsection[title={\PDF\ related callbacks}][library=callback]
+
+\subsection{\cbk {finish_pdffile}}
+
+\topicindex{callbacks+\PDF\ file}
+
+\startfunctioncall
+function()
+end
+\stopfunctioncall
+
+This callback is called when all document pages are already written to the \PDF\
+file and \LUATEX\ is about to finalize the output document structure. Its
+intended use is final update of \PDF\ dictionaries such as \type {/Catalog} or
+\type {/Info}. The callback does not replace any code. There are neither
+arguments nor return values.
+
+\subsection{\cbk {finish_pdfpage}}
+
+\topicindex{callbacks+\PDF\ file}
+
+\startfunctioncall
+function(shippingout)
+end
+\stopfunctioncall
+
+This callback is called after the \PDF\ page stream has been assembled and before
+the page object gets finalized.
+
+\subsection{\cbk {page_objnum_provider}}
+
+\topicindex{callbacks+\PDF\ file}
+
+This is one that experts can use to juggle the page tree, a data structure
+that determines the order in a \PDF\ file:
+
+\startfunctioncall
+function(objnum)
+  return objnum
+end
+\stopfunctioncall
+
+We can for instance swap the first and last page:
+
+\starttyping
+local n = 0
+callback.register("page_objnum_provider",function(objnum)
+    n = n + 1
+    if n == 1 then
+        return pdf.getpageref(tex.count[0])
+    elseif n == tex.count[0] then
+        return pdf.getpageref(1)
+    else
+        return objnum
+    end
+end)
+\stoptyping
+
+When you mess things up \unknown\ don't complain.
+
+\subsection{\cbk {process_pdf_image_content}}
+
+\topicindex{callbacks+image content}
+
+When a page from a \PDF\ file is embedded its page stream as well as related
+objects are copied to the target file. However, it can be that the page stream
+has operators that assume additional resources, for instance marked text. You can
+decide to filter that for which \LUATEX\ provides a callback. Here is a simple
+demonstration of use:
+
+\starttyping
+pdf.setrecompress(1)
+
+callback.register("process_pdf_image_content",function(s)
+    print(s)
+    return s
+end)
+\stoptyping
+
+You need to explicitly enable recompression because otherwise the content stream
+gets just passed on in its original compressed form.
+
+\stopsection
+
+\startsection[title={Font-related callbacks}][library=callback]
+
+\subsection{\cbk {define_font}}
+
+\topicindex{callbacks+fonts}
+
+\startfunctioncall
+function(<string> name, <number> size, <number> id)
+    return <table> font | <number> id
+end
+\stopfunctioncall
+
+The string \type {name} is the filename part of the font specification, as given
+by the user.
+
+The number \type {size} is a bit special:
+
+\startitemize[packed]
+\startitem
+    If it is positive, it specifies an \quote{at size} in scaled points.
+\stopitem
+\startitem
+    If it is negative, its absolute value represents a \quote {scaled} setting
+    relative to the designsize of the font.
+\stopitem
+\stopitemize
+
+The \type {id} is the internal number assigned to the font.
+
+The internal structure of the \type {font} table that is to be returned is
+explained in \in {chapter} [fonts]. That table is saved internally, so you can
+put extra fields in the table for your later \LUA\ code to use. In alternative,
+\type {retval} can be a previously defined fontid. This is useful if a previous
+definition can be reused instead of creating a whole new font structure.
+
+Setting this callback to \type {false} is pointless as it will prevent font
+loading completely but will nevertheless generate errors.
+
+\subsection{\cbk {glyph_not_found} and \cbk {glyph_info}}
+
+\topicindex{callbacks+fonts}
+
+The \type {glyph_not_found} callback, when set, kicks in when the backend cannot
+insert a glyph. When no callback is defined a message is written to the log.
+
+\startfunctioncall
+function(<number> id, <number> char)
+    -- do something with font id and char code
+end
+\stopfunctioncall
+
+The \type {glyph_info} callback can be set to report a useful representation of a
+glyph.
+
+\startfunctioncall
+function(<node> g)
+    -- return a string or nil
+end
+\stopfunctioncall
+
+When \type {nil} is returned the character code is printed, otherwise the
+returned string is used. By default the \UTF\ representation is shown which is
+not always that useful, especially when there is no real representation. Keep in
+mind that setting this callback can change the log in an incompatible way.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-contents.tex b/systems/doc/luatex/luatex-contents.tex
index 815ca4bbe7..2582a81c72 100644
--- a/systems/doc/luatex/luatex-contents.tex
+++ b/systems/doc/luatex/luatex-contents.tex
@@ -1,19 +1,19 @@
-\environment luatex-style

-

-\startcomponent luatex-contents

-

-\starttitle[title=Contents]

-

-\start

-

-    \definecolor[maincolor][black]

-

-    \placelist

-      [chapter,section,subsection]

-      [criterium=text]

-

-\stop

-

-\stoptitle

-

-\stopcomponent

+\environment luatex-style
+
+\startcomponent luatex-contents
+
+\starttitle[title=Contents]
+
+\start
+
+    \definecolor[maincolor][black]
+
+    \placelist
+      [chapter,section,subsection]
+      [criterium=text]
+
+\stop
+
+\stoptitle
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-enhancements.tex b/systems/doc/luatex/luatex-enhancements.tex
index d6651507a2..b81e1dbdae 100644
--- a/systems/doc/luatex/luatex-enhancements.tex
+++ b/systems/doc/luatex/luatex-enhancements.tex
@@ -1,1371 +1,1371 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-enhancements

-

-\startchapter[reference=enhancements,title={Basic \TEX\ enhancements}]

-

-\startsection[title={Introduction}]

-

-\startsubsection[title={Primitive behaviour}]

-

-From day one, \LUATEX\ has offered extra features compared to the superset of

-\PDFTEX, which includes \ETEX, and \ALEPH. This has not been limited to the

-possibility to execute \LUA\ code via \prm {directlua}, but \LUATEX\ also adds

-functionality via new \TEX|-|side primitives or extensions to existing ones.

-

-When \LUATEX\ starts up in \quote {iniluatex} mode (\type {luatex -ini}), it

-defines only the primitive commands known by \TEX82 and the one extra command

-\prm {directlua}. As is fitting, a \LUA\ function has to be called to add the

-extra primitives to the user environment. The simplest method to get access to

-all of the new primitive commands is by adding this line to the format generation

-file:

-

-\starttyping

-\directlua { tex.enableprimitives('',tex.extraprimitives()) }

-\stoptyping

-

-But be aware that the curly braces may not have the proper \prm {catcode}

-assigned to them at this early time (giving a \quote {Missing number} error), so

-it may be needed to put these assignments before the above line:

-

-\starttyping

-\catcode `\{=1

-\catcode `\}=2

-\stoptyping

-

-More fine|-|grained primitives control is possible and you can look up the

-details in \in {section} [luaprimitives]. For simplicity's sake, this manual

-assumes that you have executed the \prm {directlua} command as given above.

-

-The startup behaviour documented above is considered stable in the sense that

-there will not be backward|-|incompatible changes any more. We have promoted some

-rather generic \PDFTEX\ primitives to core \LUATEX\ ones, and the few that we

-inherited from \ALEPH\ (\OMEGA) are also promoted. Effectively this means that we

-now only have the \type {tex}, \type {etex} and \type {luatex} sets left.

-

-In \in {Chapter} [modifications] we discuss several primitives that are derived

-from \PDFTEX\ and \ALEPH\ (\OMEGA). Here we stick to real new ones. In the

-chapters on fonts and math we discuss a few more new ones.

-

-\stopsubsection

-

-\startsubsection[title={Version information}]

-

-\startsubsubsection[title={\lpr {luatexbanner}, \lpr {luatexversion} and \lpr {luatexrevision}}]

-

-\topicindex{version}

-\topicindex{banner}

-

-There are three new primitives to test the version of \LUATEX:

-

-\unexpanded\def\VersionHack#1% otherwise different luatex and luajittex runs

-  {\ctxlua{%

-     local banner = "\luatexbanner"

-     local banner = string.match(banner,"(.+)\letterpercent(") or banner

-     context(string.gsub(banner ,"jit",""))%

-  }}

-

-\starttabulate[|l|l|pl|]

-\DB primitive             \BC value

-                          \BC explanation \NC \NR

-\TB

-\NC \lpr {luatexbanner}   \NC \VersionHack{\luatexbanner}

-                          \NC the banner reported on the command line \NC \NR

-\NC \lpr {luatexversion}  \NC \the\luatexversion

-                          \NC a combination of major and minor number \NC \NR

-\NC \lpr {luatexrevision} \NC \luatexrevision

-                          \NC the revision number, the current value is \NC \NR

-\LL

-\stoptabulate

-

-The official \LUATEX\ version is defined as follows:

-

-\startitemize

-\startitem

-    The major version is the integer result of \lpr {luatexversion} divided by

-    100. The primitive is an \quote {internal variable}, so you may need to prefix

-    its use with \prm {the} depending on the context.

-\stopitem

-\startitem

-    The minor version is the two|-|digit result of \lpr {luatexversion} modulo 100.

-\stopitem

-\startitem

-    The revision is reported by \lpr {luatexrevision}. This primitive expands to

-    a positive integer.

-\stopitem

-\startitem

-    The full version number consists of the major version, minor version and

-    revision, separated by dots.

-\stopitem

-\stopitemize

-

-\stopsubsubsection

-

-\startsubsubsection[title={\lpr {formatname}}]

-

-\topicindex{format}

-

-The \lpr {formatname} syntax is identical to \prm {jobname}. In \INITEX, the

-expansion is empty. Otherwise, the expansion is the value that \prm {jobname} had

-during the \INITEX\ run that dumped the currently loaded format. You can use this

-token list to provide your own version info.

-

-\stopsubsubsection

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={\UNICODE\ text support}]

-

-\startsubsection[title={Extended ranges}]

-

-\topicindex{\UNICODE}

-

-Text input and output is now considered to be \UNICODE\ text, so input characters

-can use the full range of \UNICODE\ ($2^{20}+2^{16}-1 = \hbox{0x10FFFF}$). Later

-chapters will talk of characters and glyphs. Although these are not

-interchangeable, they are closely related. During typesetting, a character is

-always converted to a suitable graphic representation of that character in a

-specific font. However, while processing a list of to|-|be|-|typeset nodes, its

-contents may still be seen as a character. Inside \LUATEX\ there is no clear

-separation between the two concepts. Because the subtype of a glyph node can be

-changed in \LUA\ it is up to the user. Subtypes larger than 255 indicate that

-font processing has happened.

-

-A few primitives are affected by this, all in a similar fashion: each of them has

-to accommodate for a larger range of acceptable numbers. For instance, \prm

-{char} now accepts values between~0 and $1{,}114{,}111$. This should not be a

-problem for well|-|behaved input files, but it could create incompatibilities for

-input that would have generated an error when processed by older \TEX|-|based

-engines. The affected commands with an altered initial (left of the equal sign)

-or secondary (right of the equal sign) value are: \prm {char}, \prm {lccode},

-\prm {uccode}, \lpr {hjcode}, \prm {catcode}, \prm {sfcode}, \lpr {efcode}, \lpr

-{lpcode}, \lpr {rpcode}, \prm {chardef}.

-

-As far as the core engine is concerned, all input and output to text files is

-\UTF-8 encoded. Input files can be pre|-|processed using the \type {reader}

-callback. This will be explained in \in {section} [iocallback]. Normalization of

-the \UNICODE\ input is on purpose not built|-|in and can be handled by a macro

-package during callback processing. We have made some practical choices and the

-user has to live with those.

-

-Output in byte|-|sized chunks can be achieved by using characters just outside of

-the valid \UNICODE\ range, starting at the value $1{,}114{,}112$ (0x110000). When

-the time comes to print a character $c>=1{,}114{,}112$, \LUATEX\ will actually

-print the single byte corresponding to $c$ minus 1{,}114{,}112.

-

-Output to the terminal uses \type {^^} notation for the lower control range

-($c<32$), with the exception of \type {^^I}, \type {^^J} and \type {^^M}. These

-are considered \quote {safe} and therefore printed as|-|is. You can disable

-escaping with \type {texio.setescape(false)} in which case you get the normal

-characters on the console.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {Uchar}}]

-

-\topicindex{\UNICODE}

-

-The expandable command \lpr {Uchar} reads a number between~0 and $1{,}114{,}111$

-and expands to the associated \UNICODE\ character.

-

-\stopsubsection

-

-\startsubsection[title={Extended tables}]

-

-All traditional \TEX\ and \ETEX\ registers can be 16-bit numbers. The affected

-commands are:

-

-\startfourcolumns

-\startlines

-\prm {count}

-\prm {dimen}

-\prm {skip}

-\prm {muskip}

-\prm {marks}

-\prm {toks}

-\prm {countdef}

-\prm {dimendef}

-\prm {skipdef}

-\prm {muskipdef}

-\prm {toksdef}

-\prm {insert}

-\prm {box}

-\prm {unhbox}

-\prm {unvbox}

-\prm {copy}

-\prm {unhcopy}

-\prm {unvcopy}

-\prm {wd}

-\prm {ht}

-\prm {dp}

-\prm {setbox}

-\prm {vsplit}

-\stoplines

-\stopfourcolumns

-

-Because font memory management has been rewritten, character properties in fonts

-are no longer shared among font instances that originate from the same metric

-file. Of course we share fonts in the backend when possible so that the resulting

-\PDF\ file is as efficient as possible, but for instance also expansion and

-protrusion no longer use copies as in \PDFTEX.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Attributes}]

-

-\startsubsection[title={Nodes}]

-

-\topicindex {nodes}

-

-When \TEX\ reads input it will interpret the stream according to the properties

-of the characters. Some signal a macro name and trigger expansion, others open

-and close groups, trigger math mode, etc. What's left over becomes the typeset

-text. Internally we get linked list of nodes. Characters become \nod {glyph}

-nodes that have for instance a \type {font} and \type {char} property and \typ

-{\kern 10pt} becomes a \nod {kern} node with a \type {width} property. Spaces are

-alien to \TEX\ as they are turned into \nod {glue} nodes. So, a simple paragraph

-is mostly a mix of sequences of \nod {glyph} nodes (words) and \nod {glue} nodes

-(spaces).

-

-The sequences of characters at some point are extended with \nod {disc} nodes

-that relate to hyphenation. After that font logic can be applied and we get a

-list where some characters can be replaced, for instance multiple characters can

-become one ligature, and font kerns can be injected. This is driven by the

-font properties.

-

-Boxes (like \prm {hbox} and \prm {vbox}) become \nod {hlist} or \nod {vlist}

-nodes with \type {width}, \type {height}, \type {depth} and \type {shift}

-properties and a pointer \type {list} to its actual content. Boxes can be

-constructed explicitly or can be the result of subprocesses. For instance, when

-lines are broken into paragraphs, the lines are a linked list of \nod {hlist}

-nodes.

-

-So, to summarize: all that you enter as content eventually becomes a node, often

-as part of a (nested) list structure. They have a relative small memory footprint

-and carry only the minimal amount of information needed. In traditional \TEX\ a

-character node only held the font and slot number, in \LUATEX\ we also store some

-language related information, the expansion factor, etc. Now that we have access

-to these nodes from \LUA\ it makes sense to be able to carry more information

-with an node and this is where attributes kick in.

-

-\stopsubsection

-

-\startsubsection[title={Attribute registers}]

-

-\topicindex {attributes}

-

-Attributes are a completely new concept in \LUATEX. Syntactically, they behave a

-lot like counters: attributes obey \TEX's nesting stack and can be used after

-\prm {the} etc.\ just like the normal \prm {count} registers.

-

-\startsyntax

-\attribute <16-bit number> <optional equals> <32-bit number>!crlf

-\attributedef <csname> <optional equals> <16-bit number>

-\stopsyntax

-

-Conceptually, an attribute is either \quote {set} or \quote {unset}. Unset

-attributes have a special negative value to indicate that they are unset, that

-value is the lowest legal value: \type {-"7FFFFFFF} in hexadecimal, a.k.a.

-$-2147483647$ in decimal. It follows that the value \type {-"7FFFFFFF} cannot be

-used as a legal attribute value, but you {\it can\/} assign \type {-"7FFFFFFF} to

-\quote {unset} an attribute. All attributes start out in this \quote {unset}

-state in \INITEX.

-

-Attributes can be used as extra counter values, but their usefulness comes mostly

-from the fact that the numbers and values of all \quote {set} attributes are

-attached to all nodes created in their scope. These can then be queried from any

-\LUA\ code that deals with node processing. Further information about how to use

-attributes for node list processing from \LUA\ is given in~\in {chapter}[nodes].

-

-Attributes are stored in a sorted (sparse) linked list that are shared when

-possible. This permits efficient testing and updating. You can define many

-thousands of attributes but normally such a large number makes no sense and is

-also not that efficient because each node carries a (possibly shared) link to a

-list of currently set attributes. But they are a convenient extension and one of

-the first extensions we implemented in \LUATEX.

-

-\stopsubsection

-

-\startsubsection[title={Box attributes}]

-

-\topicindex {attributes}

-\topicindex {boxes}

-

-Nodes typically receive the list of attributes that is in effect when they are

-created. This moment can be quite asynchronous. For example: in paragraph

-building, the individual line boxes are created after the \prm {par} command has

-been processed, so they will receive the list of attributes that is in effect

-then, not the attributes that were in effect in, say, the first or third line of

-the paragraph.

-

-Similar situations happen in \LUATEX\ regularly. A few of the more obvious

-problematic cases are dealt with: the attributes for nodes that are created

-during hyphenation, kerning and ligaturing borrow their attributes from their

-surrounding glyphs, and it is possible to influence box attributes directly.

-

-When you assemble a box in a register, the attributes of the nodes contained in

-the box are unchanged when such a box is placed, unboxed, or copied. In this

-respect attributes act the same as characters that have been converted to

-references to glyphs in fonts. For instance, when you use attributes to implement

-color support, each node carries information about its eventual color. In that

-case, unless you implement mechanisms that deal with it, applying a color to

-already boxed material will have no effect. Keep in mind that this

-incompatibility is mostly due to the fact that separate specials and literals are

-a more unnatural approach to colors than attributes.

-

-It is possible to fine-tune the list of attributes that are applied to a \type

-{hbox}, \type {vbox} or \type {vtop} by the use of the keyword \type {attr}. The

-\type {attr} keyword(s) should come before a \type {to} or \type {spread}, if

-that is also specified. An example is:

-

-\startbuffer[tex]

-\attribute997=123

-\attribute998=456

-\setbox0=\hbox {Hello}

-\setbox2=\hbox attr 999 = 789 attr 998 = -"7FFFFFFF{Hello}

-\stopbuffer

-

-\startbuffer[lua]

-  for b=0,2,2 do

-    for a=997, 999 do

-      tex.sprint("box ", b, " : attr ",a," : ",tostring(tex.box[b]     [a]))

-      tex.sprint("\\quad\\quad")

-      tex.sprint("list ",b, " : attr ",a," : ",tostring(tex.box[b].list[a]))

-      tex.sprint("\\par")

-    end

-  end

-\stopbuffer

-

-\typebuffer[tex]

-

-Box 0 now has attributes 997 and 998 set while box 2 has attributes 997 and 999

-set while the nodes inside that box will all have attributes 997 and 998 set.

-Assigning the maximum negative value causes an attribute to be ignored.

-

-To give you an idea of what this means at the \LUA\ end, take the following

-code:

-

-\typebuffer[lua]

-

-Later we will see that you can access properties of a node. The boxes here are so

-called \nod {hlist} nodes that have a field \type {list} that points to the

-content. Because the attributes are a list themselves you can access them by

-indexing the node (here we do that with \type {[a]}. Running this snippet gives:

-

-\start

-    \getbuffer[tex]

-    \startpacked \tt

-        \ctxluabuffer[lua]

-    \stoppacked

-\stop

-

-Because some values are not set we need to apply the \type {tostring} function

-here so that we get the word \type {nil}.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={\LUA\ related primitives}]

-

-\startsubsection[title={\prm {directlua}}]

-

-In order to merge \LUA\ code with \TEX\ input, a few new primitives are needed.

-The primitive \prm {directlua} is used to execute \LUA\ code immediately. The

-syntax is

-

-\startsyntax

-\directlua <general text>!crlf

-\directlua <16-bit number> <general text>

-\stopsyntax

-

-The \syntax {<general text>} is expanded fully, and then fed into the \LUA\

-interpreter. After reading and expansion has been applied to the \syntax

-{<general text>}, the resulting token list is converted to a string as if it was

-displayed using \type {\the\toks}. On the \LUA\ side, each \prm {directlua} block

-is treated as a separate chunk. In such a chunk you can use the \type {local}

-directive to keep your variables from interfering with those used by the macro

-package.

-

-The conversion to and from a token list means that you normally can not use \LUA\

-line comments (starting with \type {--}) within the argument. As there typically

-will be only one \quote {line} the first line comment will run on until the end

-of the input. You will either need to use \TEX|-|style line comments (starting

-with \%), or change the \TEX\ category codes locally. Another possibility is to

-say:

-

-\starttyping

-\begingroup

-\endlinechar=10

-\directlua ...

-\endgroup

-\stoptyping

-

-Then \LUA\ line comments can be used, since \TEX\ does not replace line endings

-with spaces. Of course such an approach depends on the macro package that you

-use.

-

-The \syntax {<16-bit number>} designates a name of a \LUA\ chunk and is

-taken from the \type {lua.name} array (see the documentation of the \type {lua}

-table further in this manual). When a chunk name starts with a \type {@} it will

-be displayed as a file name. This is a side effect of the way \LUA\ implements

-error handling.

-

-The \prm {directlua} command is expandable. Since it passes \LUA\ code to the

-\LUA\ interpreter its expansion from the \TEX\ viewpoint is usually empty.

-However, there are some \LUA\ functions that produce material to be read by \TEX,

-the so called print functions. The most simple use of these is \type

-{tex.print(<string> s)}. The characters of the string \type {s} will be placed on

-the \TEX\ input buffer, that is, \quote {before \TEX's eyes} to be read by \TEX\

-immediately. For example:

-

-\startbuffer

-\count10=20

-a\directlua{tex.print(tex.count[10]+5)}b

-\stopbuffer

-

-\typebuffer

-

-expands to

-

-\getbuffer

-

-Here is another example:

-

-\startbuffer

-$\pi = \directlua{tex.print(math.pi)}$

-\stopbuffer

-

-\typebuffer

-

-will result in

-

-\getbuffer

-

-Note that the expansion of \prm {directlua} is a sequence of characters, not of

-tokens, contrary to all \TEX\ commands. So formally speaking its expansion is

-null, but it places material on a pseudo-file to be immediately read by \TEX, as

-\ETEX's \prm {scantokens}. For a description of print functions look at \in

-{section} [sec:luaprint].

-

-Because the \syntax {<general text>} is a chunk, the normal \LUA\ error handling

-is triggered if there is a problem in the included code. The \LUA\ error messages

-should be clear enough, but the contextual information is still pretty bad.

-Often, you will only see the line number of the right brace at the end of the

-code.

-

-While on the subject of errors: some of the things you can do inside \LUA\ code

-can break up \LUATEX\ pretty bad. If you are not careful while working with the

-node list interface, you may even end up with assertion errors from within the

-\TEX\ portion of the executable.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {latelua} and \lpr {lateluafunction}}]

-

-Contrary to \prm {directlua}, \lpr {latelua} stores \LUA\ code in a whatsit

-that will be processed at the time of shipping out. Its intended use is a cross

-between \PDF\ literals (often available as \orm {pdfliteral}) and the

-traditional \TEX\ extension \prm {write}. Within the \LUA\ code you can print

-\PDF\ statements directly to the \PDF\ file via \type {pdf.print}, or you can

-write to other output streams via \type {texio.write} or simply using \LUA\ \IO\

-routines.

-

-\startsyntax

-\latelua <general text>!crlf

-\latelua <16-bit number> <general text>

-\stopsyntax

-

-Expansion of macros in the final \type {<general text>} is delayed until just

-before the whatsit is executed (like in \prm {write}). With regard to \PDF\

-output stream \lpr {latelua} behaves as \PDF\ page literals. The \syntax

-{name <general text>} and \syntax {<16-bit number>} behave in the same way as

-they do for \prm {directlua}.

-

-The \lpr {lateluafunction} primitive takes a number and is similar to \lpr

-{luafunction} but gets delated to shipout time. It's just there for completeness.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {luaescapestring}}]

-

-\topicindex {escaping}

-

-This primitive converts a \TEX\ token sequence so that it can be safely used as

-the contents of a \LUA\ string: embedded backslashes, double and single quotes,

-and newlines and carriage returns are escaped. This is done by prepending an

-extra token consisting of a backslash with category code~12, and for the line

-endings, converting them to \type {n} and \type {r} respectively. The token

-sequence is fully expanded.

-

-\startsyntax

-\luaescapestring <general text>

-\stopsyntax

-

-Most often, this command is not actually the best way to deal with the

-differences between \TEX\ and \LUA. In very short bits of \LUA\ code it is often

-not needed, and for longer stretches of \LUA\ code it is easier to keep the code

-in a separate file and load it using \LUA's \type {dofile}:

-

-\starttyping

-\directlua { dofile('mysetups.lua') }

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\lpr {luafunction}, \lpr {luafunctioncall} and \lpr {luadef}}]

-

-The \prm {directlua} commands involves tokenization of its argument (after

-picking up an optional name or number specification). The tokenlist is then

-converted into a string and given to \LUA\ to turn into a function that is

-called. The overhead is rather small but when you have millions of calls it can

-have some impact. For this reason there is a variant call available: \lpr

-{luafunction}. This command is used as follows:

-

-\starttyping

-\directlua {

-    local t = lua.get_functions_table()

-    t[1] = function() tex.print("!") end

-    t[2] = function() tex.print("?") end

-}

-

-\luafunction1

-\luafunction2

-\stoptyping

-

-Of course the functions can also be defined in a separate file. There is no limit

-on the number of functions apart from normal \LUA\ limitations. Of course there

-is the limitation of no arguments but that would involve parsing and thereby give

-no gain. The function, when called in fact gets one argument, being the index, so

-in the following example the number \type {8} gets typeset.

-

-\starttyping

-\directlua {

-    local t = lua.get_functions_table()

-    t[8] = function(slot) tex.print(slot) end

-}

-\stoptyping

-

-The \lpr {luafunctioncall} primitive does the same but is unexpandable, for

-instance in an \prm {edef}. In addition \LUATEX\ provides a definer:

-

-\starttyping

-                 \luadef\MyFunctionA 1

-          \global\luadef\MyFunctionB 2

-\protected\global\luadef\MyFunctionC 3

-\stoptyping

-

-You should really use these commands with care. Some references get stored in

-tokens and assume that the function is available when that token expands. On the

-other hand, as we have tested this functionality in relative complex situations

-normal usage should not give problems.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {luabytecode} and \lpr {luabytecodecall}}]

-

-Analogue to the function callers discussed in the previous section we have byte

-code callers. Again the call variant is unexpandable.

-

-\starttyping

-\directlua {

-    lua.bytecode[9998] = function(s)

-        tex.sprint(s*token.scan_int())

-    end

-    lua.bytecode[5555] = function(s)

-        tex.sprint(s*token.scan_dimen())

-    end

-}

-\stoptyping

-

-This works with:

-

-\starttyping

-\luabytecode    9998 5  \luabytecode    5555 5sp

-\luabytecodecall9998 5  \luabytecodecall5555 5sp

-\stoptyping

-

-The variable \type {s} in the code is the number of the byte code register that

-can be used for diagnostic purposes. The advantage of bytecode registers over

-function calls is that they are stored in the format (but without upvalues).

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Catcode tables}]

-

-\startsubsection[title={Catcodes}]

-

-\topicindex {catcodes}

-

-Catcode tables are a new feature that allows you to switch to a predefined

-catcode regime in a single statement. You can have a practically unlimited number

-of different tables. This subsystem is backward compatible: if you never use the

-following commands, your document will not notice any difference in behaviour

-compared to traditional \TEX. The contents of each catcode table is independent

-from any other catcode table, and its contents is stored and retrieved from the

-format file.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {catcodetable}}]

-

-\startsyntax

-\catcodetable <15-bit number>

-\stopsyntax

-

-The primitive \lpr {catcodetable} switches to a different catcode table. Such a

-table has to be previously created using one of the two primitives below, or it

-has to be zero. Table zero is initialized by \INITEX.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {initcatcodetable}}]

-

-\startsyntax

-\initcatcodetable <15-bit number>

-\stopsyntax

-

-The primitive \lpr {initcatcodetable} creates a new table with catcodes

-identical to those defined by \INITEX. The new catcode table is allocated

-globally: it will not go away after the current group has ended. If the supplied

-number is identical to the currently active table, an error is raised. The

-initial values are:

-

-\starttabulate[|c|c|l|l|]

-\DB catcode \BC character               \BC equivalent \BC category          \NC \NR

-\TB

-\NC  0 \NC \tttf \letterbackslash       \NC         \NC \type {escape}       \NC \NR

-\NC  5 \NC \tttf \letterhat\letterhat M \NC return  \NC \type {car_ret}      \NC \NR

-\NC  9 \NC \tttf \letterhat\letterhat @ \NC null    \NC \type {ignore}       \NC \NR

-\NC 10 \NC \tttf <space>                \NC space   \NC \type {spacer}       \NC \NR

-\NC 11 \NC {\tttf a} \endash\ {\tttf z} \NC         \NC \type {letter}       \NC \NR

-\NC 11 \NC {\tttf A} \endash\ {\tttf Z} \NC         \NC \type {letter}       \NC \NR

-\NC 12 \NC everything else              \NC         \NC \type {other}        \NC \NR

-\NC 14 \NC \tttf \letterpercent         \NC         \NC \type {comment}      \NC \NR

-\NC 15 \NC \tttf \letterhat\letterhat ? \NC delete  \NC \type {invalid_char} \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\lpr {savecatcodetable}}]

-

-\startsyntax

-\savecatcodetable <15-bit number>

-\stopsyntax

-

-\lpr {savecatcodetable} copies the current set of catcodes to a new table with

-the requested number. The definitions in this new table are all treated as if

-they were made in the outermost level.

-

-The new table is allocated globally: it will not go away after the current group

-has ended. If the supplied number is the currently active table, an error is

-raised.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Suppressing errors}]

-

-\startsubsection[title={\lpr {suppressfontnotfounderror}}]

-

-\topicindex {errors}

-

-If this integer parameter is non|-|zero, then \LUATEX\ will not complain about

-font metrics that are not found. Instead it will silently skip the font

-assignment, making the requested csname for the font \prm {ifx} equal to \prm

-{nullfont}, so that it can be tested against that without bothering the user.

-

-\startsyntax

-\suppressfontnotfounderror = 1

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\lpr {suppresslongerror}}]

-

-\topicindex {errors}

-

-If this integer parameter is non|-|zero, then \LUATEX\ will not complain about

-\prm {par} commands encountered in contexts where that is normally prohibited

-(most prominently in the arguments of macros not defined as \prm {long}).

-

-\startsyntax

-\suppresslongerror = 1

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\lpr {suppressifcsnameerror}}]

-

-\topicindex {errors}

-

-If this integer parameter is non|-|zero, then \LUATEX\ will not complain about

-non-expandable commands appearing in the middle of a \prm {ifcsname} expansion.

-Instead, it will keep getting expanded tokens from the input until it encounters

-an \prm {endcsname} command. If the input expansion is unbalanced with respect

-to \prm {csname} \ldots \prm {endcsname} pairs, the \LUATEX\ process may hang

-indefinitely.

-

-\startsyntax

-\suppressifcsnameerror = 1

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\lpr {suppressoutererror}}]

-

-\topicindex {errors}

-

-If this new integer parameter is non|-|zero, then \LUATEX\ will not complain

-about \prm {outer} commands encountered in contexts where that is normally

-prohibited.

-

-\startsyntax

-\suppressoutererror = 1

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\lpr {suppressmathparerror}}]

-

-\topicindex {errors}

-\topicindex {math}

-

-The following setting will permit \prm {par} tokens in a math formula:

-

-\startsyntax

-\suppressmathparerror = 1

-\stopsyntax

-

-So, the next code is valid then:

-

-\starttyping

-$ x + 1 =

-

-a $

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={\lpr {suppressprimitiveerror}}]

-

-\topicindex {errors}

-\topicindex {primitives}

-

-When set to a non|-|zero value the following command will not issue an error:

-

-\startsyntax

-\suppressprimitiveerror = 1

-

-\primitive\notaprimitive

-\stopsyntax

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Fonts}]

-

-\startsubsection[title={Font syntax}]

-

-\topicindex {fonts}

-

-\LUATEX\ will accept a braced argument as a font name:

-

-\starttyping

-\font\myfont = {cmr10}

-\stoptyping

-

-This allows for embedded spaces, without the need for double quotes. Macro

-expansion takes place inside the argument.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {fontid} and \lpr {setfontid}}]

-

-\startsyntax

-\fontid\font

-\stopsyntax

-

-This primitive expands into a number. It is not a register so there is no need to

-prefix with \prm {number} (and using \prm {the} gives an error). The currently

-used font id is \fontid\font. Here are some more:

-

-\starttabulate[|l|c|c|]

-\DB style \BC command \BC font id \NC \NR

-\TB

-\NC normal      \NC \type {\tf} \NC \bf \fontid\font \NC \NR

-\NC bold        \NC \type {\bf} \NC \bf \fontid\font \NC \NR

-\NC italic      \NC \type {\it} \NC \it \fontid\font \NC \NR

-\NC bold italic \NC \type {\bi} \NC \bi \fontid\font \NC \NR

-\LL

-\stoptabulate

-

-These numbers depend on the macro package used because each one has its own way

-of dealing with fonts. They can also differ per run, as they can depend on the

-order of loading fonts. For instance, when in \CONTEXT\ virtual math \UNICODE\

-fonts are used, we can easily get over a hundred ids in use. Not all ids have to

-be bound to a real font, after all it's just a number.

-

-The primitive \lpr {setfontid} can be used to enable a font with the given id,

-which of course needs to be a valid one.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {noligs} and \lpr {nokerns}}]

-

-\topicindex {ligatures+suppress}

-\topicindex {kerns+suppress}

-

-These primitives prohibit ligature and kerning insertion at the time when the

-initial node list is built by \LUATEX's main control loop. You can enable these

-primitives when you want to do node list processing of \quote {characters}, where

-\TEX's normal processing would get in the way.

-

-\startsyntax

-\noligs <integer>!crlf

-\nokerns <integer>

-\stopsyntax

-

-These primitives can also be implemented by overloading the ligature building and

-kerning functions, i.e.\ by assigning dummy functions to their associated

-callbacks. Keep in mind that when you define a font (using \LUA) you can also

-omit the kern and ligature tables, which has the same effect as the above.

-

-\stopsubsection

-

-\startsubsection[title={\type{\nospaces}}]

-

-\topicindex {spaces+suppress}

-

-This new primitive can be used to overrule the usual \prm {spaceskip} related

-heuristics when a space character is seen in a text flow. The value~\type{1}

-triggers no injection while \type{2} results in injection of a zero skip. In \in

-{figure} [fig:nospaces] we see the results for four characters separated by a

-space.

-

-\startplacefigure[reference=fig:nospaces,title={The \lpr {nospaces} options.}]

-\startcombination[3*2]

-    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 10mm}}

-    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 10mm}}

-    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 10mm}}

-    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 1mm}}

-    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 1mm}}

-    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 1mm}}

-\stopcombination

-\stopplacefigure

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Tokens, commands and strings}]

-

-\startsubsection[title={\lpr {scantextokens}}]

-

-\topicindex {tokens+scanning}

-

-The syntax of \lpr {scantextokens} is identical to \prm {scantokens}. This

-primitive is a slightly adapted version of \ETEX's \prm {scantokens}. The

-differences are:

-

-\startitemize

-\startitem

-    The last (and usually only) line does not have a \prm {endlinechar}

-    appended.

-\stopitem

-\startitem

-    \lpr {scantextokens} never raises an EOF error, and it does not execute

-    \prm {everyeof} tokens.

-\stopitem

-\startitem

-    There are no \quote {\unknown\ while end of file \unknown} error tests

-    executed. This allows the expansion to end on a different grouping level or

-    while a conditional is still incomplete.

-\stopitem

-\stopitemize

-

-\stopsubsection

-

-\startsubsection[title={\lpr {toksapp}, \lpr {tokspre}, \lpr {etoksapp}, \lpr {etokspre},

-\lpr {gtoksapp}, \lpr {gtokspre}, \lpr {xtoksapp},  \lpr {xtokspre}}]

-

-Instead of:

-

-\starttyping

-\toks0\expandafter{\the\toks0 foo}

-\stoptyping

-

-you can use:

-

-\starttyping

-\etoksapp0{foo}

-\stoptyping

-

-The \type {pre} variants prepend instead of append, and the \type {e} variants

-expand the passed general text. The \type {g} and \type {x} variants are global.

-

-\stopsubsection

-

-\startsubsection[title={\prm {csstring}, \lpr {begincsname} and \lpr {lastnamedcs}}]

-

-These are somewhat special. The \prm {csstring} primitive is like

-\prm {string} but it omits the leading escape character. This can be

-somewhat more efficient than stripping it afterwards.

-

-The \lpr {begincsname} primitive is like \prm {csname} but doesn't create

-a relaxed equivalent when there is no such name. It is equivalent to

-

-\starttyping

-\ifcsname foo\endcsname

-  \csname foo\endcsname

-\fi

-\stoptyping

-

-The advantage is that it saves a lookup (don't expect much speedup) but more

-important is that it avoids using the \prm {if} test. The \lpr {lastnamedcs}

-is one that should be used with care. The above example could be written as:

-

-\starttyping

-\ifcsname foo\endcsname

-  \lastnamedcs

-\fi

-\stoptyping

-

-This is slightly more efficient than constructing the string twice (deep down in

-\LUATEX\ this also involves some \UTF8 juggling), but probably more relevant is

-that it saves a few tokens and can make code a bit more readable.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {clearmarks}}]

-

-\topicindex {marks}

-

-This primitive complements the \ETEX\ mark primitives and clears a mark class

-completely, resetting all three connected mark texts to empty. It is an

-immediate command.

-

-\startsyntax

-\clearmarks <16-bit number>

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\lpr {alignmark} and \lpr {aligntab}}]

-

-The primitive \lpr {alignmark} duplicates the functionality of \type {#} inside

-alignment preambles, while \lpr {aligntab} duplicates the functionality of \type

-{&}.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {letcharcode}}]

-

-This primitive can be used to assign a meaning to an active character, as in:

-

-\starttyping

-\def\foo{bar} \letcharcode123=\foo

-\stoptyping

-

-This can be a bit nicer than using the uppercase tricks (using the property of

-\prm {uppercase} that it treats active characters special).

-

-\stopsubsection

-

-\startsubsection[title={\lpr {glet}}]

-

-This primitive is similar to:

-

-\starttyping

-\protected\def\glet{\global\let}

-\stoptyping

-

-but faster (only measurable with millions of calls) and probably more convenient

-(after all we also have \type {\gdef}).

-

-\stopsubsection

-

-\startsubsection[title={\lpr {expanded}, \lpr {immediateassignment} and \lpr {immediateassigned}}]

-

-\topicindex {expansion}

-

-The \lpr {expanded} primitive takes a token list and expands it content which can

-come in handy: it avoids a tricky mix of \prm {expandafter} and \prm {noexpand}.

-You can compare it with what happens inside the body of an \prm {edef}. But this

-kind of expansion it still doesn't expand some primitive operations.

-

-\startbuffer

-\newcount\NumberOfCalls

-

-\def\TestMe{\advance\NumberOfCalls1 }

-

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-

-\meaning\Tested

-\stopbuffer

-

-\typebuffer

-

-The result is a macro that has the not expanded code in its body:

-

-\getbuffer

-

-Instead we can define \tex {TestMe} in a way that expands the assignment

-immediately. You need of course to be aware of preventing look ahead interference

-by using a space or \tex {relax} (often an expression works better as it doesn't

-leave an \tex {relax}).

-

-\startbuffer

-\def\TestMe{\immediateassignment\advance\NumberOfCalls1 }

-

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-\edef\Tested{\TestMe foo:\the\NumberOfCalls}

-

-\meaning\Tested

-\stopbuffer

-

-\typebuffer

-

-This time the counter gets updates and we don't see interference in the

-resulting \tex {Tested} macro:

-

-\getbuffer

-

-Here is a somewhat silly example of expanded comparison:

-

-\startbuffer

-\def\expandeddoifelse#1#2#3#4%

-  {\immediateassignment\edef\tempa{#1}%

-   \immediateassignment\edef\tempb{#2}%

-   \ifx\tempa\tempb

-     \immediateassignment\def\next{#3}%

-   \else

-     \immediateassignment\def\next{#4}%

-   \fi

-   \next}

-

-\edef\Tested

-  {(\expandeddoifelse{abc}{def}{yes}{nop}/%

-    \expandeddoifelse{abc}{abc}{yes}{nop})}

-

-\meaning\Tested

-\stopbuffer

-

-\typebuffer

-

-It gives:

-

-\getbuffer

-

-A variant is:

-

-\starttyping

-\def\expandeddoifelse#1#2#3#4%

-  {\immediateassigned{

-     \edef\tempa{#1}%

-     \edef\tempb{#2}%

-   }%

-   \ifx\tempa\tempb

-     \immediateassignment\def\next{#3}%

-   \else

-     \immediateassignment\def\next{#4}%

-   \fi

-   \next}

-\stoptyping

-

-The possible error messages are the same as using assignments in preambles of

-alignments and after the \prm {accent} command. The supported assignments are the

-so called prefixed commands (except box assignments).

-

-\stopsubsection

-

-\startsubsection[title={\lpr {ifcondition}}]

-

-\topicindex {conditions}

-

-This is a somewhat special one. When you write macros conditions need to be

-properly balanced in order to let \TEX's fast branch skipping work well. This new

-primitive is basically a no||op flagged as a condition so that the scanner can

-recognize it as an if|-|test. However, when a real test takes place the work is

-done by what follows, in the next example \tex {something}.

-

-\starttyping

-\unexpanded\def\something#1#2%

-  {\edef\tempa{#1}%

-   \edef\tempb{#2}

-   \ifx\tempa\tempb}

-

-\ifcondition\something{a}{b}%

-    \ifcondition\something{a}{a}%

-        true 1

-    \else

-        false 1

-    \fi

-\else

-    \ifcondition\something{a}{a}%

-        true 2

-    \else

-        false 2

-    \fi

-\fi

-\stoptyping

-

-If you are familiar with \METAPOST, this is a bit like \type {vardef} where the macro

-has a return value. Here the return value is a test.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Boxes, rules and leaders}]

-

-\startsubsection[title={\lpr {outputbox}}]

-

-\topicindex {output}

-

-This integer parameter allows you to alter the number of the box that will be

-used to store the page sent to the output routine. Its default value is 255, and

-the acceptable range is from 0 to 65535.

-

-\startsyntax

-\outputbox = 12345

-\stopsyntax

-

-\stopsubsection

-

-\startsubsection[title={\prm {vpack}, \prm {hpack} and \prm {tpack}}]

-

-These three primitives are like \prm {vbox}, \prm {hbox} and \prm {vtop}

-but don't apply the related callbacks.

-

-\stopsubsection

-

-\startsubsection[title={\prm {vsplit}}]

-

-\topicindex {splitting}

-

-The \prm {vsplit} primitive has to be followed by a specification of the required

-height. As alternative for the \type {to} keyword you can use \type {upto} to get

-a split of the given size but result has the natural dimensions then.

-

-\stopsubsection

-

-\startsubsection[title={Images and reused box objects},reference=sec:imagedandforms]

-

-These two concepts are now core concepts and no longer whatsits. They are in fact

-now implemented as rules with special properties. Normal rules have subtype~0,

-saved boxes have subtype~1 and images have subtype~2. This has the positive side

-effect that whenever we need to take content with dimensions into account, when

-we look at rule nodes, we automatically also deal with these two types.

-

-The syntax of the \type {\save...resource} is the same as in \PDFTEX\ but you

-should consider them to be backend specific. This means that a macro package

-should treat them as such and check for the current output mode if applicable.

-

-\starttabulate[|l|p|]

-\DB command \BC explanation \NC \NR

-\TB

-\NC \lpr {saveboxresource}             \NC save the box as an object to be included later \NC \NR

-\NC \lpr {saveimageresource}           \NC save the image as an object to be included later \NC \NR

-\NC \lpr {useboxresource}              \NC include the saved box object here (by index) \NC \NR

-\NC \lpr {useimageresource}            \NC include the saved image object here (by index) \NC \NR

-\NC \lpr {lastsavedboxresourceindex}   \NC the index of the last saved box object \NC \NR

-\NC \lpr {lastsavedimageresourceindex} \NC the index of the last saved image object \NC \NR

-\NC \lpr {lastsavedimageresourcepages} \NC the number of pages in the last saved image object \NC \NR

-\LL

-\stoptabulate

-

-\LUATEX\ accepts optional dimension parameters for \type {\use...resource} in the

-same format as for rules. With images, these dimensions are then used instead of

-the ones given to \lpr {useimageresource} but the original dimensions are not

-overwritten, so that a \lpr {useimageresource} without dimensions still

-provides the image with dimensions defined by \lpr {saveimageresource}. These

-optional parameters are not implemented for \lpr {saveboxresource}.

-

-\starttyping

-\useimageresource width 20mm height 10mm depth 5mm \lastsavedimageresourceindex

-\useboxresource   width 20mm height 10mm depth 5mm \lastsavedboxresourceindex

-\stoptyping

-

-The box resources are of course implemented in the backend and therefore we do

-support the \type {attr} and \type {resources} keys that accept a token list. New

-is the \type {type} key. When set to non|-|zero the \type {/Type} entry is

-omitted. A value of 1 or 3 still writes a \type {/BBox}, while 2 or 3 will write

-a \type {/Matrix}.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {nohrule} and \lpr {novrule}}]

-

-\topicindex {rules}

-

-Because introducing a new keyword can cause incompatibilities, two new primitives

-were introduced: \lpr {nohrule} and \lpr {novrule}. These can be used to

-reserve space. This is often more efficient than creating an empty box with fake

-dimensions.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {gleaders}}]

-

-\topicindex {leaders}

-

-This type of leaders is anchored to the origin of the box to be shipped out. So

-they are like normal \prm {leaders} in that they align nicely, except that the

-alignment is based on the {\it largest\/} enclosing box instead of the {\it

-smallest\/}. The \type {g} stresses this global nature.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Languages}]

-

-\startsubsection[title={\lpr {hyphenationmin}}]

-

-\topicindex {languages}

-\topicindex {hyphenation}

-

-This primitive can be used to set the minimal word length, so setting it to a value

-of~$5$ means that only words of 6 characters and more will be hyphenated, of course

-within the constraints of the \prm {lefthyphenmin} and \prm {righthyphenmin}

-values (as stored in the glyph node). This primitive accepts a number and stores

-the value with the language.

-

-\stopsubsection

-

-\startsubsection[title={\prm {boundary}, \prm {noboundary}, \prm {protrusionboundary} and \prm {wordboundary}}]

-

-The \prm {noboundary} command is used to inject a whatsit node but now injects a normal

-node with type \nod {boundary} and subtype~0. In addition you can say:

-

-\starttyping

-x\boundary 123\relax y

-\stoptyping

-

-This has the same effect but the subtype is now~1 and the value~123 is stored.

-The traditional ligature builder still sees this as a cancel boundary directive

-but at the \LUA\ end you can implement different behaviour. The added benefit of

-passing this value is a side effect of the generalization. The subtypes~2 and~3

-are used to control protrusion and word boundaries in hyphenation and have

-related primitives.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Control and debugging}]

-

-\startsubsection[title={Tracing}]

-

-\topicindex {tracing}

-

-If \prm {tracingonline} is larger than~2, the node list display will also print

-the node number of the nodes.

-

-\stopsubsection

-

-\startsubsection[title={\lpr {outputmode}}]

-

-\topicindex {output}

-\topicindex {backend}

-

-The \lpr {outputmode} variable tells \LUATEX\ what it has to produce:

-

-\starttabulate[|l|l|]

-\DB value \BC output \NC \NR

-\TB

-\NC \type {0} \NC \DVI\ code \NC \NR

-\NC \type {1} \NC \PDF\ code \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\lpr {draftmode}}]

-

-The value of the \lpr {draftmode} counter signals the backend if it should output

-less. The \PDF\ backend accepts a value of~1, while the \DVI\ backend ignores the

-value. This is no critical feature so we can remove it in future versions when it

-can make the backend cleaner.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Files}]

-

-\startsubsection[title={File syntax}]

-

-\topicindex {files+names}

-

-\LUATEX\ will accept a braced argument as a file name:

-

-\starttyping

-\input {plain}

-\openin 0 {plain}

-\stoptyping

-

-This allows for embedded spaces, without the need for double quotes. Macro

-expansion takes place inside the argument.

-

-The \lpr {tracingfonts} primitive that has been inherited from \PDFTEX\ has

-been adapted to support variants in reporting the font. The reason for this

-extension is that a csname not always makes sense. The zero case is the default.

-

-\starttabulate[|l|l|]

-\DB value \BC reported \NC \NR

-\TB

-\NC \type{0} \NC \type{\foo xyz} \NC \NR

-\NC \type{1} \NC \type{\foo (bar)} \NC \NR

-\NC \type{2} \NC \type{<bar> xyz} \NC \NR

-\NC \type{3} \NC \type{<bar @ ..pt> xyz} \NC \NR

-\NC \type{4} \NC \type{<id>} \NC \NR

-\NC \type{5} \NC \type{<id: bar>} \NC \NR

-\NC \type{6} \NC \type{<id: bar @ ..pt> xyz} \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={Writing to file}]

-

-\topicindex {files+writing}

-

-You can now open upto 127 files with \prm {openout}. When no file is open

-writes will go to the console and log. As a consequence a system command is

-no longer possible but one can use \type {os.execute} to do the same.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={Math}]

-

-\topicindex {math}

-

-We will cover math extensions in its own chapter because not only the font

-subsystem and spacing model have been enhanced (thereby introducing many new

-primitives) but also because some more control has been added to existing

-functionality. Much of this relates to the different approaches of traditional

-\TEX\ fonts and \OPENTYPE\ math.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-enhancements
+
+\startchapter[reference=enhancements,title={Basic \TEX\ enhancements}]
+
+\startsection[title={Introduction}]
+
+\startsubsection[title={Primitive behaviour}]
+
+From day one, \LUATEX\ has offered extra features compared to the superset of
+\PDFTEX, which includes \ETEX, and \ALEPH. This has not been limited to the
+possibility to execute \LUA\ code via \prm {directlua}, but \LUATEX\ also adds
+functionality via new \TEX|-|side primitives or extensions to existing ones.
+
+When \LUATEX\ starts up in \quote {iniluatex} mode (\type {luatex -ini}), it
+defines only the primitive commands known by \TEX82 and the one extra command
+\prm {directlua}. As is fitting, a \LUA\ function has to be called to add the
+extra primitives to the user environment. The simplest method to get access to
+all of the new primitive commands is by adding this line to the format generation
+file:
+
+\starttyping
+\directlua { tex.enableprimitives('',tex.extraprimitives()) }
+\stoptyping
+
+But be aware that the curly braces may not have the proper \prm {catcode}
+assigned to them at this early time (giving a \quote {Missing number} error), so
+it may be needed to put these assignments before the above line:
+
+\starttyping
+\catcode `\{=1
+\catcode `\}=2
+\stoptyping
+
+More fine|-|grained primitives control is possible and you can look up the
+details in \in {section} [luaprimitives]. For simplicity's sake, this manual
+assumes that you have executed the \prm {directlua} command as given above.
+
+The startup behaviour documented above is considered stable in the sense that
+there will not be backward|-|incompatible changes any more. We have promoted some
+rather generic \PDFTEX\ primitives to core \LUATEX\ ones, and the few that we
+inherited from \ALEPH\ (\OMEGA) are also promoted. Effectively this means that we
+now only have the \type {tex}, \type {etex} and \type {luatex} sets left.
+
+In \in {Chapter} [modifications] we discuss several primitives that are derived
+from \PDFTEX\ and \ALEPH\ (\OMEGA). Here we stick to real new ones. In the
+chapters on fonts and math we discuss a few more new ones.
+
+\stopsubsection
+
+\startsubsection[title={Version information}]
+
+\startsubsubsection[title={\lpr {luatexbanner}, \lpr {luatexversion} and \lpr {luatexrevision}}]
+
+\topicindex{version}
+\topicindex{banner}
+
+There are three new primitives to test the version of \LUATEX:
+
+\unexpanded\def\VersionHack#1% otherwise different luatex and luajittex runs
+  {\ctxlua{%
+     local banner = "\luatexbanner"
+     local banner = string.match(banner,"(.+)\letterpercent(") or banner
+     context(string.gsub(banner ,"jit",""))%
+  }}
+
+\starttabulate[|l|l|pl|]
+\DB primitive             \BC value
+                          \BC explanation \NC \NR
+\TB
+\NC \lpr {luatexbanner}   \NC \VersionHack{\luatexbanner}
+                          \NC the banner reported on the command line \NC \NR
+\NC \lpr {luatexversion}  \NC \the\luatexversion
+                          \NC a combination of major and minor number \NC \NR
+\NC \lpr {luatexrevision} \NC \luatexrevision
+                          \NC the revision number, the current value is \NC \NR
+\LL
+\stoptabulate
+
+The official \LUATEX\ version is defined as follows:
+
+\startitemize
+\startitem
+    The major version is the integer result of \lpr {luatexversion} divided by
+    100. The primitive is an \quote {internal variable}, so you may need to prefix
+    its use with \prm {the} depending on the context.
+\stopitem
+\startitem
+    The minor version is the two|-|digit result of \lpr {luatexversion} modulo 100.
+\stopitem
+\startitem
+    The revision is reported by \lpr {luatexrevision}. This primitive expands to
+    a positive integer.
+\stopitem
+\startitem
+    The full version number consists of the major version, minor version and
+    revision, separated by dots.
+\stopitem
+\stopitemize
+
+\stopsubsubsection
+
+\startsubsubsection[title={\lpr {formatname}}]
+
+\topicindex{format}
+
+The \lpr {formatname} syntax is identical to \prm {jobname}. In \INITEX, the
+expansion is empty. Otherwise, the expansion is the value that \prm {jobname} had
+during the \INITEX\ run that dumped the currently loaded format. You can use this
+token list to provide your own version info.
+
+\stopsubsubsection
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={\UNICODE\ text support}]
+
+\startsubsection[title={Extended ranges}]
+
+\topicindex{\UNICODE}
+
+Text input and output is now considered to be \UNICODE\ text, so input characters
+can use the full range of \UNICODE\ ($2^{20}+2^{16}-1 = \hbox{0x10FFFF}$). Later
+chapters will talk of characters and glyphs. Although these are not
+interchangeable, they are closely related. During typesetting, a character is
+always converted to a suitable graphic representation of that character in a
+specific font. However, while processing a list of to|-|be|-|typeset nodes, its
+contents may still be seen as a character. Inside \LUATEX\ there is no clear
+separation between the two concepts. Because the subtype of a glyph node can be
+changed in \LUA\ it is up to the user. Subtypes larger than 255 indicate that
+font processing has happened.
+
+A few primitives are affected by this, all in a similar fashion: each of them has
+to accommodate for a larger range of acceptable numbers. For instance, \prm
+{char} now accepts values between~0 and $1{,}114{,}111$. This should not be a
+problem for well|-|behaved input files, but it could create incompatibilities for
+input that would have generated an error when processed by older \TEX|-|based
+engines. The affected commands with an altered initial (left of the equal sign)
+or secondary (right of the equal sign) value are: \prm {char}, \prm {lccode},
+\prm {uccode}, \lpr {hjcode}, \prm {catcode}, \prm {sfcode}, \lpr {efcode}, \lpr
+{lpcode}, \lpr {rpcode}, \prm {chardef}.
+
+As far as the core engine is concerned, all input and output to text files is
+\UTF-8 encoded. Input files can be pre|-|processed using the \type {reader}
+callback. This will be explained in \in {section} [iocallback]. Normalization of
+the \UNICODE\ input is on purpose not built|-|in and can be handled by a macro
+package during callback processing. We have made some practical choices and the
+user has to live with those.
+
+Output in byte|-|sized chunks can be achieved by using characters just outside of
+the valid \UNICODE\ range, starting at the value $1{,}114{,}112$ (0x110000). When
+the time comes to print a character $c>=1{,}114{,}112$, \LUATEX\ will actually
+print the single byte corresponding to $c$ minus 1{,}114{,}112.
+
+Output to the terminal uses \type {^^} notation for the lower control range
+($c<32$), with the exception of \type {^^I}, \type {^^J} and \type {^^M}. These
+are considered \quote {safe} and therefore printed as|-|is. You can disable
+escaping with \type {texio.setescape(false)} in which case you get the normal
+characters on the console.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {Uchar}}]
+
+\topicindex{\UNICODE}
+
+The expandable command \lpr {Uchar} reads a number between~0 and $1{,}114{,}111$
+and expands to the associated \UNICODE\ character.
+
+\stopsubsection
+
+\startsubsection[title={Extended tables}]
+
+All traditional \TEX\ and \ETEX\ registers can be 16-bit numbers. The affected
+commands are:
+
+\startfourcolumns
+\startlines
+\prm {count}
+\prm {dimen}
+\prm {skip}
+\prm {muskip}
+\prm {marks}
+\prm {toks}
+\prm {countdef}
+\prm {dimendef}
+\prm {skipdef}
+\prm {muskipdef}
+\prm {toksdef}
+\prm {insert}
+\prm {box}
+\prm {unhbox}
+\prm {unvbox}
+\prm {copy}
+\prm {unhcopy}
+\prm {unvcopy}
+\prm {wd}
+\prm {ht}
+\prm {dp}
+\prm {setbox}
+\prm {vsplit}
+\stoplines
+\stopfourcolumns
+
+Because font memory management has been rewritten, character properties in fonts
+are no longer shared among font instances that originate from the same metric
+file. Of course we share fonts in the backend when possible so that the resulting
+\PDF\ file is as efficient as possible, but for instance also expansion and
+protrusion no longer use copies as in \PDFTEX.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Attributes}]
+
+\startsubsection[title={Nodes}]
+
+\topicindex {nodes}
+
+When \TEX\ reads input it will interpret the stream according to the properties
+of the characters. Some signal a macro name and trigger expansion, others open
+and close groups, trigger math mode, etc. What's left over becomes the typeset
+text. Internally we get linked list of nodes. Characters become \nod {glyph}
+nodes that have for instance a \type {font} and \type {char} property and \typ
+{\kern 10pt} becomes a \nod {kern} node with a \type {width} property. Spaces are
+alien to \TEX\ as they are turned into \nod {glue} nodes. So, a simple paragraph
+is mostly a mix of sequences of \nod {glyph} nodes (words) and \nod {glue} nodes
+(spaces).
+
+The sequences of characters at some point are extended with \nod {disc} nodes
+that relate to hyphenation. After that font logic can be applied and we get a
+list where some characters can be replaced, for instance multiple characters can
+become one ligature, and font kerns can be injected. This is driven by the
+font properties.
+
+Boxes (like \prm {hbox} and \prm {vbox}) become \nod {hlist} or \nod {vlist}
+nodes with \type {width}, \type {height}, \type {depth} and \type {shift}
+properties and a pointer \type {list} to its actual content. Boxes can be
+constructed explicitly or can be the result of subprocesses. For instance, when
+lines are broken into paragraphs, the lines are a linked list of \nod {hlist}
+nodes.
+
+So, to summarize: all that you enter as content eventually becomes a node, often
+as part of a (nested) list structure. They have a relative small memory footprint
+and carry only the minimal amount of information needed. In traditional \TEX\ a
+character node only held the font and slot number, in \LUATEX\ we also store some
+language related information, the expansion factor, etc. Now that we have access
+to these nodes from \LUA\ it makes sense to be able to carry more information
+with an node and this is where attributes kick in.
+
+\stopsubsection
+
+\startsubsection[title={Attribute registers}]
+
+\topicindex {attributes}
+
+Attributes are a completely new concept in \LUATEX. Syntactically, they behave a
+lot like counters: attributes obey \TEX's nesting stack and can be used after
+\prm {the} etc.\ just like the normal \prm {count} registers.
+
+\startsyntax
+\attribute <16-bit number> <optional equals> <32-bit number>!crlf
+\attributedef <csname> <optional equals> <16-bit number>
+\stopsyntax
+
+Conceptually, an attribute is either \quote {set} or \quote {unset}. Unset
+attributes have a special negative value to indicate that they are unset, that
+value is the lowest legal value: \type {-"7FFFFFFF} in hexadecimal, a.k.a.
+$-2147483647$ in decimal. It follows that the value \type {-"7FFFFFFF} cannot be
+used as a legal attribute value, but you {\it can\/} assign \type {-"7FFFFFFF} to
+\quote {unset} an attribute. All attributes start out in this \quote {unset}
+state in \INITEX.
+
+Attributes can be used as extra counter values, but their usefulness comes mostly
+from the fact that the numbers and values of all \quote {set} attributes are
+attached to all nodes created in their scope. These can then be queried from any
+\LUA\ code that deals with node processing. Further information about how to use
+attributes for node list processing from \LUA\ is given in~\in {chapter}[nodes].
+
+Attributes are stored in a sorted (sparse) linked list that are shared when
+possible. This permits efficient testing and updating. You can define many
+thousands of attributes but normally such a large number makes no sense and is
+also not that efficient because each node carries a (possibly shared) link to a
+list of currently set attributes. But they are a convenient extension and one of
+the first extensions we implemented in \LUATEX.
+
+\stopsubsection
+
+\startsubsection[title={Box attributes}]
+
+\topicindex {attributes}
+\topicindex {boxes}
+
+Nodes typically receive the list of attributes that is in effect when they are
+created. This moment can be quite asynchronous. For example: in paragraph
+building, the individual line boxes are created after the \prm {par} command has
+been processed, so they will receive the list of attributes that is in effect
+then, not the attributes that were in effect in, say, the first or third line of
+the paragraph.
+
+Similar situations happen in \LUATEX\ regularly. A few of the more obvious
+problematic cases are dealt with: the attributes for nodes that are created
+during hyphenation, kerning and ligaturing borrow their attributes from their
+surrounding glyphs, and it is possible to influence box attributes directly.
+
+When you assemble a box in a register, the attributes of the nodes contained in
+the box are unchanged when such a box is placed, unboxed, or copied. In this
+respect attributes act the same as characters that have been converted to
+references to glyphs in fonts. For instance, when you use attributes to implement
+color support, each node carries information about its eventual color. In that
+case, unless you implement mechanisms that deal with it, applying a color to
+already boxed material will have no effect. Keep in mind that this
+incompatibility is mostly due to the fact that separate specials and literals are
+a more unnatural approach to colors than attributes.
+
+It is possible to fine-tune the list of attributes that are applied to a \type
+{hbox}, \type {vbox} or \type {vtop} by the use of the keyword \type {attr}. The
+\type {attr} keyword(s) should come before a \type {to} or \type {spread}, if
+that is also specified. An example is:
+
+\startbuffer[tex]
+\attribute997=123
+\attribute998=456
+\setbox0=\hbox {Hello}
+\setbox2=\hbox attr 999 = 789 attr 998 = -"7FFFFFFF{Hello}
+\stopbuffer
+
+\startbuffer[lua]
+  for b=0,2,2 do
+    for a=997, 999 do
+      tex.sprint("box ", b, " : attr ",a," : ",tostring(tex.box[b]     [a]))
+      tex.sprint("\\quad\\quad")
+      tex.sprint("list ",b, " : attr ",a," : ",tostring(tex.box[b].list[a]))
+      tex.sprint("\\par")
+    end
+  end
+\stopbuffer
+
+\typebuffer[tex]
+
+Box 0 now has attributes 997 and 998 set while box 2 has attributes 997 and 999
+set while the nodes inside that box will all have attributes 997 and 998 set.
+Assigning the maximum negative value causes an attribute to be ignored.
+
+To give you an idea of what this means at the \LUA\ end, take the following
+code:
+
+\typebuffer[lua]
+
+Later we will see that you can access properties of a node. The boxes here are so
+called \nod {hlist} nodes that have a field \type {list} that points to the
+content. Because the attributes are a list themselves you can access them by
+indexing the node (here we do that with \type {[a]}. Running this snippet gives:
+
+\start
+    \getbuffer[tex]
+    \startpacked \tt
+        \ctxluabuffer[lua]
+    \stoppacked
+\stop
+
+Because some values are not set we need to apply the \type {tostring} function
+here so that we get the word \type {nil}.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={\LUA\ related primitives}]
+
+\startsubsection[title={\prm {directlua}}]
+
+In order to merge \LUA\ code with \TEX\ input, a few new primitives are needed.
+The primitive \prm {directlua} is used to execute \LUA\ code immediately. The
+syntax is
+
+\startsyntax
+\directlua <general text>!crlf
+\directlua <16-bit number> <general text>
+\stopsyntax
+
+The \syntax {<general text>} is expanded fully, and then fed into the \LUA\
+interpreter. After reading and expansion has been applied to the \syntax
+{<general text>}, the resulting token list is converted to a string as if it was
+displayed using \type {\the\toks}. On the \LUA\ side, each \prm {directlua} block
+is treated as a separate chunk. In such a chunk you can use the \type {local}
+directive to keep your variables from interfering with those used by the macro
+package.
+
+The conversion to and from a token list means that you normally can not use \LUA\
+line comments (starting with \type {--}) within the argument. As there typically
+will be only one \quote {line} the first line comment will run on until the end
+of the input. You will either need to use \TEX|-|style line comments (starting
+with \%), or change the \TEX\ category codes locally. Another possibility is to
+say:
+
+\starttyping
+\begingroup
+\endlinechar=10
+\directlua ...
+\endgroup
+\stoptyping
+
+Then \LUA\ line comments can be used, since \TEX\ does not replace line endings
+with spaces. Of course such an approach depends on the macro package that you
+use.
+
+The \syntax {<16-bit number>} designates a name of a \LUA\ chunk and is
+taken from the \type {lua.name} array (see the documentation of the \type {lua}
+table further in this manual). When a chunk name starts with a \type {@} it will
+be displayed as a file name. This is a side effect of the way \LUA\ implements
+error handling.
+
+The \prm {directlua} command is expandable. Since it passes \LUA\ code to the
+\LUA\ interpreter its expansion from the \TEX\ viewpoint is usually empty.
+However, there are some \LUA\ functions that produce material to be read by \TEX,
+the so called print functions. The most simple use of these is \type
+{tex.print(<string> s)}. The characters of the string \type {s} will be placed on
+the \TEX\ input buffer, that is, \quote {before \TEX's eyes} to be read by \TEX\
+immediately. For example:
+
+\startbuffer
+\count10=20
+a\directlua{tex.print(tex.count[10]+5)}b
+\stopbuffer
+
+\typebuffer
+
+expands to
+
+\getbuffer
+
+Here is another example:
+
+\startbuffer
+$\pi = \directlua{tex.print(math.pi)}$
+\stopbuffer
+
+\typebuffer
+
+will result in
+
+\getbuffer
+
+Note that the expansion of \prm {directlua} is a sequence of characters, not of
+tokens, contrary to all \TEX\ commands. So formally speaking its expansion is
+null, but it places material on a pseudo-file to be immediately read by \TEX, as
+\ETEX's \prm {scantokens}. For a description of print functions look at \in
+{section} [sec:luaprint].
+
+Because the \syntax {<general text>} is a chunk, the normal \LUA\ error handling
+is triggered if there is a problem in the included code. The \LUA\ error messages
+should be clear enough, but the contextual information is still pretty bad.
+Often, you will only see the line number of the right brace at the end of the
+code.
+
+While on the subject of errors: some of the things you can do inside \LUA\ code
+can break up \LUATEX\ pretty bad. If you are not careful while working with the
+node list interface, you may even end up with assertion errors from within the
+\TEX\ portion of the executable.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {latelua} and \lpr {lateluafunction}}]
+
+Contrary to \prm {directlua}, \lpr {latelua} stores \LUA\ code in a whatsit
+that will be processed at the time of shipping out. Its intended use is a cross
+between \PDF\ literals (often available as \orm {pdfliteral}) and the
+traditional \TEX\ extension \prm {write}. Within the \LUA\ code you can print
+\PDF\ statements directly to the \PDF\ file via \type {pdf.print}, or you can
+write to other output streams via \type {texio.write} or simply using \LUA\ \IO\
+routines.
+
+\startsyntax
+\latelua <general text>!crlf
+\latelua <16-bit number> <general text>
+\stopsyntax
+
+Expansion of macros in the final \type {<general text>} is delayed until just
+before the whatsit is executed (like in \prm {write}). With regard to \PDF\
+output stream \lpr {latelua} behaves as \PDF\ page literals. The \syntax
+{name <general text>} and \syntax {<16-bit number>} behave in the same way as
+they do for \prm {directlua}.
+
+The \lpr {lateluafunction} primitive takes a number and is similar to \lpr
+{luafunction} but gets delated to shipout time. It's just there for completeness.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {luaescapestring}}]
+
+\topicindex {escaping}
+
+This primitive converts a \TEX\ token sequence so that it can be safely used as
+the contents of a \LUA\ string: embedded backslashes, double and single quotes,
+and newlines and carriage returns are escaped. This is done by prepending an
+extra token consisting of a backslash with category code~12, and for the line
+endings, converting them to \type {n} and \type {r} respectively. The token
+sequence is fully expanded.
+
+\startsyntax
+\luaescapestring <general text>
+\stopsyntax
+
+Most often, this command is not actually the best way to deal with the
+differences between \TEX\ and \LUA. In very short bits of \LUA\ code it is often
+not needed, and for longer stretches of \LUA\ code it is easier to keep the code
+in a separate file and load it using \LUA's \type {dofile}:
+
+\starttyping
+\directlua { dofile('mysetups.lua') }
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\lpr {luafunction}, \lpr {luafunctioncall} and \lpr {luadef}}]
+
+The \prm {directlua} commands involves tokenization of its argument (after
+picking up an optional name or number specification). The tokenlist is then
+converted into a string and given to \LUA\ to turn into a function that is
+called. The overhead is rather small but when you have millions of calls it can
+have some impact. For this reason there is a variant call available: \lpr
+{luafunction}. This command is used as follows:
+
+\starttyping
+\directlua {
+    local t = lua.get_functions_table()
+    t[1] = function() tex.print("!") end
+    t[2] = function() tex.print("?") end
+}
+
+\luafunction1
+\luafunction2
+\stoptyping
+
+Of course the functions can also be defined in a separate file. There is no limit
+on the number of functions apart from normal \LUA\ limitations. Of course there
+is the limitation of no arguments but that would involve parsing and thereby give
+no gain. The function, when called in fact gets one argument, being the index, so
+in the following example the number \type {8} gets typeset.
+
+\starttyping
+\directlua {
+    local t = lua.get_functions_table()
+    t[8] = function(slot) tex.print(slot) end
+}
+\stoptyping
+
+The \lpr {luafunctioncall} primitive does the same but is unexpandable, for
+instance in an \prm {edef}. In addition \LUATEX\ provides a definer:
+
+\starttyping
+                 \luadef\MyFunctionA 1
+          \global\luadef\MyFunctionB 2
+\protected\global\luadef\MyFunctionC 3
+\stoptyping
+
+You should really use these commands with care. Some references get stored in
+tokens and assume that the function is available when that token expands. On the
+other hand, as we have tested this functionality in relative complex situations
+normal usage should not give problems.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {luabytecode} and \lpr {luabytecodecall}}]
+
+Analogue to the function callers discussed in the previous section we have byte
+code callers. Again the call variant is unexpandable.
+
+\starttyping
+\directlua {
+    lua.bytecode[9998] = function(s)
+        tex.sprint(s*token.scan_int())
+    end
+    lua.bytecode[5555] = function(s)
+        tex.sprint(s*token.scan_dimen())
+    end
+}
+\stoptyping
+
+This works with:
+
+\starttyping
+\luabytecode    9998 5  \luabytecode    5555 5sp
+\luabytecodecall9998 5  \luabytecodecall5555 5sp
+\stoptyping
+
+The variable \type {s} in the code is the number of the byte code register that
+can be used for diagnostic purposes. The advantage of bytecode registers over
+function calls is that they are stored in the format (but without upvalues).
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Catcode tables}]
+
+\startsubsection[title={Catcodes}]
+
+\topicindex {catcodes}
+
+Catcode tables are a new feature that allows you to switch to a predefined
+catcode regime in a single statement. You can have a practically unlimited number
+of different tables. This subsystem is backward compatible: if you never use the
+following commands, your document will not notice any difference in behaviour
+compared to traditional \TEX. The contents of each catcode table is independent
+from any other catcode table, and its contents is stored and retrieved from the
+format file.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {catcodetable}}]
+
+\startsyntax
+\catcodetable <15-bit number>
+\stopsyntax
+
+The primitive \lpr {catcodetable} switches to a different catcode table. Such a
+table has to be previously created using one of the two primitives below, or it
+has to be zero. Table zero is initialized by \INITEX.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {initcatcodetable}}]
+
+\startsyntax
+\initcatcodetable <15-bit number>
+\stopsyntax
+
+The primitive \lpr {initcatcodetable} creates a new table with catcodes
+identical to those defined by \INITEX. The new catcode table is allocated
+globally: it will not go away after the current group has ended. If the supplied
+number is identical to the currently active table, an error is raised. The
+initial values are:
+
+\starttabulate[|c|c|l|l|]
+\DB catcode \BC character               \BC equivalent \BC category          \NC \NR
+\TB
+\NC  0 \NC \tttf \letterbackslash       \NC         \NC \type {escape}       \NC \NR
+\NC  5 \NC \tttf \letterhat\letterhat M \NC return  \NC \type {car_ret}      \NC \NR
+\NC  9 \NC \tttf \letterhat\letterhat @ \NC null    \NC \type {ignore}       \NC \NR
+\NC 10 \NC \tttf <space>                \NC space   \NC \type {spacer}       \NC \NR
+\NC 11 \NC {\tttf a} \endash\ {\tttf z} \NC         \NC \type {letter}       \NC \NR
+\NC 11 \NC {\tttf A} \endash\ {\tttf Z} \NC         \NC \type {letter}       \NC \NR
+\NC 12 \NC everything else              \NC         \NC \type {other}        \NC \NR
+\NC 14 \NC \tttf \letterpercent         \NC         \NC \type {comment}      \NC \NR
+\NC 15 \NC \tttf \letterhat\letterhat ? \NC delete  \NC \type {invalid_char} \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\lpr {savecatcodetable}}]
+
+\startsyntax
+\savecatcodetable <15-bit number>
+\stopsyntax
+
+\lpr {savecatcodetable} copies the current set of catcodes to a new table with
+the requested number. The definitions in this new table are all treated as if
+they were made in the outermost level.
+
+The new table is allocated globally: it will not go away after the current group
+has ended. If the supplied number is the currently active table, an error is
+raised.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Suppressing errors}]
+
+\startsubsection[title={\lpr {suppressfontnotfounderror}}]
+
+\topicindex {errors}
+
+If this integer parameter is non|-|zero, then \LUATEX\ will not complain about
+font metrics that are not found. Instead it will silently skip the font
+assignment, making the requested csname for the font \prm {ifx} equal to \prm
+{nullfont}, so that it can be tested against that without bothering the user.
+
+\startsyntax
+\suppressfontnotfounderror = 1
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\lpr {suppresslongerror}}]
+
+\topicindex {errors}
+
+If this integer parameter is non|-|zero, then \LUATEX\ will not complain about
+\prm {par} commands encountered in contexts where that is normally prohibited
+(most prominently in the arguments of macros not defined as \prm {long}).
+
+\startsyntax
+\suppresslongerror = 1
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\lpr {suppressifcsnameerror}}]
+
+\topicindex {errors}
+
+If this integer parameter is non|-|zero, then \LUATEX\ will not complain about
+non-expandable commands appearing in the middle of a \prm {ifcsname} expansion.
+Instead, it will keep getting expanded tokens from the input until it encounters
+an \prm {endcsname} command. If the input expansion is unbalanced with respect
+to \prm {csname} \ldots \prm {endcsname} pairs, the \LUATEX\ process may hang
+indefinitely.
+
+\startsyntax
+\suppressifcsnameerror = 1
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\lpr {suppressoutererror}}]
+
+\topicindex {errors}
+
+If this new integer parameter is non|-|zero, then \LUATEX\ will not complain
+about \prm {outer} commands encountered in contexts where that is normally
+prohibited.
+
+\startsyntax
+\suppressoutererror = 1
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\lpr {suppressmathparerror}}]
+
+\topicindex {errors}
+\topicindex {math}
+
+The following setting will permit \prm {par} tokens in a math formula:
+
+\startsyntax
+\suppressmathparerror = 1
+\stopsyntax
+
+So, the next code is valid then:
+
+\starttyping
+$ x + 1 =
+
+a $
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={\lpr {suppressprimitiveerror}}]
+
+\topicindex {errors}
+\topicindex {primitives}
+
+When set to a non|-|zero value the following command will not issue an error:
+
+\startsyntax
+\suppressprimitiveerror = 1
+
+\primitive\notaprimitive
+\stopsyntax
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Fonts}]
+
+\startsubsection[title={Font syntax}]
+
+\topicindex {fonts}
+
+\LUATEX\ will accept a braced argument as a font name:
+
+\starttyping
+\font\myfont = {cmr10}
+\stoptyping
+
+This allows for embedded spaces, without the need for double quotes. Macro
+expansion takes place inside the argument.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {fontid} and \lpr {setfontid}}]
+
+\startsyntax
+\fontid\font
+\stopsyntax
+
+This primitive expands into a number. It is not a register so there is no need to
+prefix with \prm {number} (and using \prm {the} gives an error). The currently
+used font id is \fontid\font. Here are some more:
+
+\starttabulate[|l|c|c|]
+\DB style \BC command \BC font id \NC \NR
+\TB
+\NC normal      \NC \type {\tf} \NC \bf \fontid\font \NC \NR
+\NC bold        \NC \type {\bf} \NC \bf \fontid\font \NC \NR
+\NC italic      \NC \type {\it} \NC \it \fontid\font \NC \NR
+\NC bold italic \NC \type {\bi} \NC \bi \fontid\font \NC \NR
+\LL
+\stoptabulate
+
+These numbers depend on the macro package used because each one has its own way
+of dealing with fonts. They can also differ per run, as they can depend on the
+order of loading fonts. For instance, when in \CONTEXT\ virtual math \UNICODE\
+fonts are used, we can easily get over a hundred ids in use. Not all ids have to
+be bound to a real font, after all it's just a number.
+
+The primitive \lpr {setfontid} can be used to enable a font with the given id,
+which of course needs to be a valid one.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {noligs} and \lpr {nokerns}}]
+
+\topicindex {ligatures+suppress}
+\topicindex {kerns+suppress}
+
+These primitives prohibit ligature and kerning insertion at the time when the
+initial node list is built by \LUATEX's main control loop. You can enable these
+primitives when you want to do node list processing of \quote {characters}, where
+\TEX's normal processing would get in the way.
+
+\startsyntax
+\noligs <integer>!crlf
+\nokerns <integer>
+\stopsyntax
+
+These primitives can also be implemented by overloading the ligature building and
+kerning functions, i.e.\ by assigning dummy functions to their associated
+callbacks. Keep in mind that when you define a font (using \LUA) you can also
+omit the kern and ligature tables, which has the same effect as the above.
+
+\stopsubsection
+
+\startsubsection[title={\type{\nospaces}}]
+
+\topicindex {spaces+suppress}
+
+This new primitive can be used to overrule the usual \prm {spaceskip} related
+heuristics when a space character is seen in a text flow. The value~\type{1}
+triggers no injection while \type{2} results in injection of a zero skip. In \in
+{figure} [fig:nospaces] we see the results for four characters separated by a
+space.
+
+\startplacefigure[reference=fig:nospaces,title={The \lpr {nospaces} options.}]
+\startcombination[3*2]
+    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 10mm}}
+    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 10mm}}
+    {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 10mm}}
+    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 1mm}}
+    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 1mm}}
+    {\ruledhbox to 5cm{\vtop{\hsize  1mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 1mm}}
+\stopcombination
+\stopplacefigure
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Tokens, commands and strings}]
+
+\startsubsection[title={\lpr {scantextokens}}]
+
+\topicindex {tokens+scanning}
+
+The syntax of \lpr {scantextokens} is identical to \prm {scantokens}. This
+primitive is a slightly adapted version of \ETEX's \prm {scantokens}. The
+differences are:
+
+\startitemize
+\startitem
+    The last (and usually only) line does not have a \prm {endlinechar}
+    appended.
+\stopitem
+\startitem
+    \lpr {scantextokens} never raises an EOF error, and it does not execute
+    \prm {everyeof} tokens.
+\stopitem
+\startitem
+    There are no \quote {\unknown\ while end of file \unknown} error tests
+    executed. This allows the expansion to end on a different grouping level or
+    while a conditional is still incomplete.
+\stopitem
+\stopitemize
+
+\stopsubsection
+
+\startsubsection[title={\lpr {toksapp}, \lpr {tokspre}, \lpr {etoksapp}, \lpr {etokspre},
+\lpr {gtoksapp}, \lpr {gtokspre}, \lpr {xtoksapp},  \lpr {xtokspre}}]
+
+Instead of:
+
+\starttyping
+\toks0\expandafter{\the\toks0 foo}
+\stoptyping
+
+you can use:
+
+\starttyping
+\etoksapp0{foo}
+\stoptyping
+
+The \type {pre} variants prepend instead of append, and the \type {e} variants
+expand the passed general text. The \type {g} and \type {x} variants are global.
+
+\stopsubsection
+
+\startsubsection[title={\prm {csstring}, \lpr {begincsname} and \lpr {lastnamedcs}}]
+
+These are somewhat special. The \prm {csstring} primitive is like
+\prm {string} but it omits the leading escape character. This can be
+somewhat more efficient than stripping it afterwards.
+
+The \lpr {begincsname} primitive is like \prm {csname} but doesn't create
+a relaxed equivalent when there is no such name. It is equivalent to
+
+\starttyping
+\ifcsname foo\endcsname
+  \csname foo\endcsname
+\fi
+\stoptyping
+
+The advantage is that it saves a lookup (don't expect much speedup) but more
+important is that it avoids using the \prm {if} test. The \lpr {lastnamedcs}
+is one that should be used with care. The above example could be written as:
+
+\starttyping
+\ifcsname foo\endcsname
+  \lastnamedcs
+\fi
+\stoptyping
+
+This is slightly more efficient than constructing the string twice (deep down in
+\LUATEX\ this also involves some \UTF8 juggling), but probably more relevant is
+that it saves a few tokens and can make code a bit more readable.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {clearmarks}}]
+
+\topicindex {marks}
+
+This primitive complements the \ETEX\ mark primitives and clears a mark class
+completely, resetting all three connected mark texts to empty. It is an
+immediate command.
+
+\startsyntax
+\clearmarks <16-bit number>
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\lpr {alignmark} and \lpr {aligntab}}]
+
+The primitive \lpr {alignmark} duplicates the functionality of \type {#} inside
+alignment preambles, while \lpr {aligntab} duplicates the functionality of \type
+{&}.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {letcharcode}}]
+
+This primitive can be used to assign a meaning to an active character, as in:
+
+\starttyping
+\def\foo{bar} \letcharcode123=\foo
+\stoptyping
+
+This can be a bit nicer than using the uppercase tricks (using the property of
+\prm {uppercase} that it treats active characters special).
+
+\stopsubsection
+
+\startsubsection[title={\lpr {glet}}]
+
+This primitive is similar to:
+
+\starttyping
+\protected\def\glet{\global\let}
+\stoptyping
+
+but faster (only measurable with millions of calls) and probably more convenient
+(after all we also have \type {\gdef}).
+
+\stopsubsection
+
+\startsubsection[title={\lpr {expanded}, \lpr {immediateassignment} and \lpr {immediateassigned}}]
+
+\topicindex {expansion}
+
+The \lpr {expanded} primitive takes a token list and expands it content which can
+come in handy: it avoids a tricky mix of \prm {expandafter} and \prm {noexpand}.
+You can compare it with what happens inside the body of an \prm {edef}. But this
+kind of expansion it still doesn't expand some primitive operations.
+
+\startbuffer
+\newcount\NumberOfCalls
+
+\def\TestMe{\advance\NumberOfCalls1 }
+
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+
+\meaning\Tested
+\stopbuffer
+
+\typebuffer
+
+The result is a macro that has the not expanded code in its body:
+
+\getbuffer
+
+Instead we can define \tex {TestMe} in a way that expands the assignment
+immediately. You need of course to be aware of preventing look ahead interference
+by using a space or \tex {relax} (often an expression works better as it doesn't
+leave an \tex {relax}).
+
+\startbuffer
+\def\TestMe{\immediateassignment\advance\NumberOfCalls1 }
+
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+\edef\Tested{\TestMe foo:\the\NumberOfCalls}
+
+\meaning\Tested
+\stopbuffer
+
+\typebuffer
+
+This time the counter gets updates and we don't see interference in the
+resulting \tex {Tested} macro:
+
+\getbuffer
+
+Here is a somewhat silly example of expanded comparison:
+
+\startbuffer
+\def\expandeddoifelse#1#2#3#4%
+  {\immediateassignment\edef\tempa{#1}%
+   \immediateassignment\edef\tempb{#2}%
+   \ifx\tempa\tempb
+     \immediateassignment\def\next{#3}%
+   \else
+     \immediateassignment\def\next{#4}%
+   \fi
+   \next}
+
+\edef\Tested
+  {(\expandeddoifelse{abc}{def}{yes}{nop}/%
+    \expandeddoifelse{abc}{abc}{yes}{nop})}
+
+\meaning\Tested
+\stopbuffer
+
+\typebuffer
+
+It gives:
+
+\getbuffer
+
+A variant is:
+
+\starttyping
+\def\expandeddoifelse#1#2#3#4%
+  {\immediateassigned{
+     \edef\tempa{#1}%
+     \edef\tempb{#2}%
+   }%
+   \ifx\tempa\tempb
+     \immediateassignment\def\next{#3}%
+   \else
+     \immediateassignment\def\next{#4}%
+   \fi
+   \next}
+\stoptyping
+
+The possible error messages are the same as using assignments in preambles of
+alignments and after the \prm {accent} command. The supported assignments are the
+so called prefixed commands (except box assignments).
+
+\stopsubsection
+
+\startsubsection[title={\lpr {ifcondition}}]
+
+\topicindex {conditions}
+
+This is a somewhat special one. When you write macros conditions need to be
+properly balanced in order to let \TEX's fast branch skipping work well. This new
+primitive is basically a no||op flagged as a condition so that the scanner can
+recognize it as an if|-|test. However, when a real test takes place the work is
+done by what follows, in the next example \tex {something}.
+
+\starttyping
+\unexpanded\def\something#1#2%
+  {\edef\tempa{#1}%
+   \edef\tempb{#2}
+   \ifx\tempa\tempb}
+
+\ifcondition\something{a}{b}%
+    \ifcondition\something{a}{a}%
+        true 1
+    \else
+        false 1
+    \fi
+\else
+    \ifcondition\something{a}{a}%
+        true 2
+    \else
+        false 2
+    \fi
+\fi
+\stoptyping
+
+If you are familiar with \METAPOST, this is a bit like \type {vardef} where the macro
+has a return value. Here the return value is a test.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Boxes, rules and leaders}]
+
+\startsubsection[title={\lpr {outputbox}}]
+
+\topicindex {output}
+
+This integer parameter allows you to alter the number of the box that will be
+used to store the page sent to the output routine. Its default value is 255, and
+the acceptable range is from 0 to 65535.
+
+\startsyntax
+\outputbox = 12345
+\stopsyntax
+
+\stopsubsection
+
+\startsubsection[title={\prm {vpack}, \prm {hpack} and \prm {tpack}}]
+
+These three primitives are like \prm {vbox}, \prm {hbox} and \prm {vtop}
+but don't apply the related callbacks.
+
+\stopsubsection
+
+\startsubsection[title={\prm {vsplit}}]
+
+\topicindex {splitting}
+
+The \prm {vsplit} primitive has to be followed by a specification of the required
+height. As alternative for the \type {to} keyword you can use \type {upto} to get
+a split of the given size but result has the natural dimensions then.
+
+\stopsubsection
+
+\startsubsection[title={Images and reused box objects},reference=sec:imagedandforms]
+
+These two concepts are now core concepts and no longer whatsits. They are in fact
+now implemented as rules with special properties. Normal rules have subtype~0,
+saved boxes have subtype~1 and images have subtype~2. This has the positive side
+effect that whenever we need to take content with dimensions into account, when
+we look at rule nodes, we automatically also deal with these two types.
+
+The syntax of the \type {\save...resource} is the same as in \PDFTEX\ but you
+should consider them to be backend specific. This means that a macro package
+should treat them as such and check for the current output mode if applicable.
+
+\starttabulate[|l|p|]
+\DB command \BC explanation \NC \NR
+\TB
+\NC \lpr {saveboxresource}             \NC save the box as an object to be included later \NC \NR
+\NC \lpr {saveimageresource}           \NC save the image as an object to be included later \NC \NR
+\NC \lpr {useboxresource}              \NC include the saved box object here (by index) \NC \NR
+\NC \lpr {useimageresource}            \NC include the saved image object here (by index) \NC \NR
+\NC \lpr {lastsavedboxresourceindex}   \NC the index of the last saved box object \NC \NR
+\NC \lpr {lastsavedimageresourceindex} \NC the index of the last saved image object \NC \NR
+\NC \lpr {lastsavedimageresourcepages} \NC the number of pages in the last saved image object \NC \NR
+\LL
+\stoptabulate
+
+\LUATEX\ accepts optional dimension parameters for \type {\use...resource} in the
+same format as for rules. With images, these dimensions are then used instead of
+the ones given to \lpr {useimageresource} but the original dimensions are not
+overwritten, so that a \lpr {useimageresource} without dimensions still
+provides the image with dimensions defined by \lpr {saveimageresource}. These
+optional parameters are not implemented for \lpr {saveboxresource}.
+
+\starttyping
+\useimageresource width 20mm height 10mm depth 5mm \lastsavedimageresourceindex
+\useboxresource   width 20mm height 10mm depth 5mm \lastsavedboxresourceindex
+\stoptyping
+
+The box resources are of course implemented in the backend and therefore we do
+support the \type {attr} and \type {resources} keys that accept a token list. New
+is the \type {type} key. When set to non|-|zero the \type {/Type} entry is
+omitted. A value of 1 or 3 still writes a \type {/BBox}, while 2 or 3 will write
+a \type {/Matrix}.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {nohrule} and \lpr {novrule}}]
+
+\topicindex {rules}
+
+Because introducing a new keyword can cause incompatibilities, two new primitives
+were introduced: \lpr {nohrule} and \lpr {novrule}. These can be used to
+reserve space. This is often more efficient than creating an empty box with fake
+dimensions.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {gleaders}}]
+
+\topicindex {leaders}
+
+This type of leaders is anchored to the origin of the box to be shipped out. So
+they are like normal \prm {leaders} in that they align nicely, except that the
+alignment is based on the {\it largest\/} enclosing box instead of the {\it
+smallest\/}. The \type {g} stresses this global nature.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Languages}]
+
+\startsubsection[title={\lpr {hyphenationmin}}]
+
+\topicindex {languages}
+\topicindex {hyphenation}
+
+This primitive can be used to set the minimal word length, so setting it to a value
+of~$5$ means that only words of 6 characters and more will be hyphenated, of course
+within the constraints of the \prm {lefthyphenmin} and \prm {righthyphenmin}
+values (as stored in the glyph node). This primitive accepts a number and stores
+the value with the language.
+
+\stopsubsection
+
+\startsubsection[title={\prm {boundary}, \prm {noboundary}, \prm {protrusionboundary} and \prm {wordboundary}}]
+
+The \prm {noboundary} command is used to inject a whatsit node but now injects a normal
+node with type \nod {boundary} and subtype~0. In addition you can say:
+
+\starttyping
+x\boundary 123\relax y
+\stoptyping
+
+This has the same effect but the subtype is now~1 and the value~123 is stored.
+The traditional ligature builder still sees this as a cancel boundary directive
+but at the \LUA\ end you can implement different behaviour. The added benefit of
+passing this value is a side effect of the generalization. The subtypes~2 and~3
+are used to control protrusion and word boundaries in hyphenation and have
+related primitives.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Control and debugging}]
+
+\startsubsection[title={Tracing}]
+
+\topicindex {tracing}
+
+If \prm {tracingonline} is larger than~2, the node list display will also print
+the node number of the nodes.
+
+\stopsubsection
+
+\startsubsection[title={\lpr {outputmode}}]
+
+\topicindex {output}
+\topicindex {backend}
+
+The \lpr {outputmode} variable tells \LUATEX\ what it has to produce:
+
+\starttabulate[|l|l|]
+\DB value \BC output \NC \NR
+\TB
+\NC \type {0} \NC \DVI\ code \NC \NR
+\NC \type {1} \NC \PDF\ code \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\lpr {draftmode}}]
+
+The value of the \lpr {draftmode} counter signals the backend if it should output
+less. The \PDF\ backend accepts a value of~1, while the \DVI\ backend ignores the
+value. This is no critical feature so we can remove it in future versions when it
+can make the backend cleaner.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Files}]
+
+\startsubsection[title={File syntax}]
+
+\topicindex {files+names}
+
+\LUATEX\ will accept a braced argument as a file name:
+
+\starttyping
+\input {plain}
+\openin 0 {plain}
+\stoptyping
+
+This allows for embedded spaces, without the need for double quotes. Macro
+expansion takes place inside the argument.
+
+The \lpr {tracingfonts} primitive that has been inherited from \PDFTEX\ has
+been adapted to support variants in reporting the font. The reason for this
+extension is that a csname not always makes sense. The zero case is the default.
+
+\starttabulate[|l|l|]
+\DB value \BC reported \NC \NR
+\TB
+\NC \type{0} \NC \type{\foo xyz} \NC \NR
+\NC \type{1} \NC \type{\foo (bar)} \NC \NR
+\NC \type{2} \NC \type{<bar> xyz} \NC \NR
+\NC \type{3} \NC \type{<bar @ ..pt> xyz} \NC \NR
+\NC \type{4} \NC \type{<id>} \NC \NR
+\NC \type{5} \NC \type{<id: bar>} \NC \NR
+\NC \type{6} \NC \type{<id: bar @ ..pt> xyz} \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={Writing to file}]
+
+\topicindex {files+writing}
+
+You can now open upto 127 files with \prm {openout}. When no file is open
+writes will go to the console and log. As a consequence a system command is
+no longer possible but one can use \type {os.execute} to do the same.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={Math}]
+
+\topicindex {math}
+
+We will cover math extensions in its own chapter because not only the font
+subsystem and spacing model have been enhanced (thereby introducing many new
+primitives) but also because some more control has been added to existing
+functionality. Much of this relates to the different approaches of traditional
+\TEX\ fonts and \OPENTYPE\ math.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-export-titlepage.tex b/systems/doc/luatex/luatex-export-titlepage.tex
index db841a7851..4417b52310 100644
--- a/systems/doc/luatex/luatex-export-titlepage.tex
+++ b/systems/doc/luatex/luatex-export-titlepage.tex
@@ -1,31 +1,31 @@
-\environment luatex-style

-

-\startcomponent luatex-export-titlepage

-

-\setupexport

-  [cssfile=extra-styles.css]

-

-\settaggedmetadata

-  [    title={LuaTeX Reference Manual},

-   copyright={LuaTeX Development Team},

-     version={\documentvariable{version}},

-      status={\documentvariable{status}},

-    snapshot={\documentvariable{snapshot}},

-        date={\rawdate[weekday,day,month,year]},

-         url={www.luatex.org}]

-

-\setupbackgrounds

-  [leftpage]

-  [setups=pagenumber:left]

-

-\setupbackgrounds

-  [rightpage]

-  [setups=pagenumber:right]

-

-\startpreamble

-    This document is derived from the original manual. When examples are given,

-    they assume processing by \LUATEX\ and therefore will not show up as

-    intended. The \PDF\ version is the real reference.

-\stoppreamble

-

-\stopcomponent

+\environment luatex-style
+
+\startcomponent luatex-export-titlepage
+
+\setupexport
+  [cssfile=extra-styles.css]
+
+\settaggedmetadata
+  [    title={LuaTeX Reference Manual},
+   copyright={LuaTeX Development Team},
+     version={\documentvariable{version}},
+      status={\documentvariable{status}},
+    snapshot={\documentvariable{snapshot}},
+        date={\rawdate[weekday,day,month,year]},
+         url={www.luatex.org}]
+
+\setupbackgrounds
+  [leftpage]
+  [setups=pagenumber:left]
+
+\setupbackgrounds
+  [rightpage]
+  [setups=pagenumber:right]
+
+\startpreamble
+    This document is derived from the original manual. When examples are given,
+    they assume processing by \LUATEX\ and therefore will not show up as
+    intended. The \PDF\ version is the real reference.
+\stoppreamble
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-firstpage.tex b/systems/doc/luatex/luatex-firstpage.tex
index e64cc61528..772fbb3fe2 100644
--- a/systems/doc/luatex/luatex-firstpage.tex
+++ b/systems/doc/luatex/luatex-firstpage.tex
@@ -1,32 +1,32 @@
-\startcomponent luatex-firstpage

-

-\startstandardmakeup

-

-    \start

-        \raggedleft

-        \definedfont[Bold*default at 48pt]

-        \setupinterlinespace

-        \blue \documentvariable{manual} \endgraf Reference \endgraf Manual \endgraf

-    \stop

-

-    \vfill

-

-    \definedfont[Bold*default at 12pt]

-

-    \starttabulate[|l|l|]

-        \NC copyright \EQ Lua\TeX\ development team \NC \NR

-        \NC more info \EQ www.luatex.org \NC \NR

-        \NC version   \EQ \currentdate \doifsomething{\documentvariable{snapshot}}{(snapshot \documentvariable{snapshot})} \NC \NR

-    \stoptabulate

-

-\stopstandardmakeup

-

-\setupbackgrounds

-  [leftpage]

-  [setups=pagenumber:left]

-

-\setupbackgrounds

-  [rightpage]

-  [setups=pagenumber:right]

-

-\stopcomponent

+\startcomponent luatex-firstpage
+
+\startstandardmakeup
+
+    \start
+        \raggedleft
+        \definedfont[Bold*default at 48pt]
+        \setupinterlinespace
+        \blue \documentvariable{manual} \endgraf Reference \endgraf Manual \endgraf
+    \stop
+
+    \vfill
+
+    \definedfont[Bold*default at 12pt]
+
+    \starttabulate[|l|l|]
+        \NC copyright \EQ Lua\TeX\ development team \NC \NR
+        \NC more info \EQ www.luatex.org \NC \NR
+        \NC version   \EQ \currentdate \doifsomething{\documentvariable{snapshot}}{(snapshot \documentvariable{snapshot})} \NC \NR
+    \stoptabulate
+
+\stopstandardmakeup
+
+\setupbackgrounds
+  [leftpage]
+  [setups=pagenumber:left]
+
+\setupbackgrounds
+  [rightpage]
+  [setups=pagenumber:right]
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-fontloader.tex b/systems/doc/luatex/luatex-fontloader.tex
index e99ea1d2ff..0a830ed003 100644
--- a/systems/doc/luatex/luatex-fontloader.tex
+++ b/systems/doc/luatex/luatex-fontloader.tex
@@ -1,1164 +1,1164 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-fontloader

-

-\startchapter[reference=fontloader,title={The fontloader}]

-

-\topicindex {fonts+loading}

-

-The fontloader library is sort of independent of the rest in the sense that it

-can load font into a \LUA\ table that then can be converted into a table suitable

-for \TEX. The library is an adapted subset of \FONTFORGE\ and as such gives a

-similar view on a font (which has advantages when you want to debug). We will not

-discuss \OPENTYPE\ in detail here as the \MICROSOFT\ website offers enough

-information about it. The tables returned by the loader are not that far from the

-standard. We have no plans to extend the loader (it may even become an external

-module at some time).

-

-\startsection[title={Getting quick information on a font}][library=fontloader]

-

-\topicindex {fonts+information}

-

-\libindex{info}

-

-When you want to locate font by name you need some basic information that is

-hidden in the font files. For that reason we provide an efficient helper that

-gets the basic information without loading all of the font. Normally this helper

-is used to create a font (name) database.

-

-\startfunctioncall

-<table> info =

-    fontloader.info(<string> filename)

-\stopfunctioncall

-

-This function returns either \type {nil}, or a \type {table}, or an array of

-small tables (in the case of a \TRUETYPE\ collection). The returned table(s) will

-contain some fairly interesting information items from the font(s) defined by the

-file:

-

-\starttabulate[|l|l|p|]

-\DB key                 \BC type     \BC explanation \NC \NR

-\TB

-\NC \type{fontname}     \NC string   \NC the \POSTSCRIPT\ name of the font\NC \NR

-\NC \type{fullname}     \NC string   \NC the formal name of the font\NC \NR

-\NC \type{familyname}   \NC string   \NC the family name this font belongs to\NC \NR

-\NC \type{weight}       \NC string   \NC a string indicating the color value of the font\NC \NR

-\NC \type{version}      \NC string   \NC the internal font version\NC \NR

-\NC \type{italicangle}  \NC float    \NC the slant angle\NC \NR

-\NC \type{units_per_em} \NC number   \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR

-\NC \type{pfminfo}      \NC table    \NC (see \in{section}[fontloaderpfminfotable])\NC \NR

-\LL

-\stoptabulate

-

-Getting information through this function is (sometimes much) more efficient than

-loading the font properly, and is therefore handy when you want to create a

-dictionary of available fonts based on a directory contents.

-

-\stopsection

-

-\startsection[title={Loading an \OPENTYPE\ or \TRUETYPE\ file}][library=fontloader]

-

-\topicindex {\OPENTYPE}

-\topicindex {\TRUETYPE}

-

-\libindex{open}

-\libindex{close}

-\libindex{to_table}

-

-If you want to use an \OPENTYPE\ font, you have to get the metric information

-from somewhere. Using the \type {fontloader} library, the simplest way to get

-that information is thus:

-

-\starttyping

-function load_font (filename)

-  local metrics = nil

-  local font = fontloader.open(filename)

-  if font then

-     metrics = fontloader.to_table(font)

-     fontloader.close(font)

-  end

-  return metrics

-end

-

-myfont = load_font('/opt/tex/texmf/fonts/data/arial.ttf')

-\stoptyping

-

-The main function call is

-

-\startfunctioncall

-<userdata> f, <table> w = fontloader.open(<string> filename)

-<userdata> f, <table> w = fontloader.open(<string> filename, <string> fontname)

-\stopfunctioncall

-

-The first return value is a userdata representation of the font. The second

-return value is a table containing any warnings and errors reported by fontloader

-while opening the font. In normal typesetting, you would probably ignore the

-second argument, but it can be useful for debugging purposes.

-

-For \TRUETYPE\ collections (when filename ends in 'ttc') and \DFONT\ collections,

-you have to use a second string argument to specify which font you want from the

-collection. Use the \type {fontname} strings that are returned by \type

-{fontloader.info} for that.

-

-To turn the font into a table, \type {fontloader.to_table} is used on the font

-returned by \type {fontloader.open}.

-

-\startfunctioncall

-<table> f = fontloader.to_table(<userdata> font)

-\stopfunctioncall

-

-This table cannot be used directly by \LUATEX\ and should be turned into another

-one as described in~\in {chapter} [fonts]. Do not forget to store the \type

-{fontname} value in the \type {psname} field of the metrics table to be returned

-to \LUATEX, otherwise the font inclusion backend will not be able to find the

-correct font in the collection.

-

-See \in {section} [fontloadertables] for details on the userdata object returned

-by \type {fontloader.open} and the layout of the \type {metrics} table returned

-by \type {fontloader.to_table}.

-

-The font file is parsed and partially interpreted by the font loading routines

-from \FONTFORGE. The file format can be \OPENTYPE, \TRUETYPE, \TRUETYPE\

-Collection, \CFF, or \TYPEONE.

-

-There are a few advantages to this approach compared to reading the actual font

-file ourselves:

-

-\startitemize

-

-\startitem

-    The font is automatically re|-|encoded, so that the \type {metrics} table for

-    \TRUETYPE\ and \OPENTYPE\ fonts is using \UNICODE\ for the character indices.

-\stopitem

-

-\startitem

-    Many features are pre|-|processed into a format that is easier to handle than

-    just the bare tables would be.

-\stopitem

-

-\startitem

-    \POSTSCRIPT|-|based \OPENTYPE\ fonts do not store the character height and

-    depth in the font file, so the character boundingbox has to be calculated in

-    some way.

-\stopitem

-

-\stopitemize

-

-A loaded font is discarded with:

-

-\startfunctioncall

-fontloader.close(<userdata> font)

-\stopfunctioncall

-

-\stopsection

-

-\startsection[title={Applying a \quote{feature file}}][library=fontloader]

-

-\libindex{apply_featurefile}

-

-You can apply a \quote{feature file} to a loaded font:

-

-\startfunctioncall

-<table> errors = fontloader.apply_featurefile(<userdata> font, <string> filename)

-\stopfunctioncall

-

-A \quote {feature file} is a textual representation of the features in an

-\OPENTYPE\ font. See

-

-\starttyping

-http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html

-\stoptyping

-

-and

-

-\starttyping

-http://fontforge.sourceforge.net/featurefile.html

-\stoptyping

-

-for a more detailed description of feature files.

-

-If the function fails, the return value is a table containing any errors reported

-by fontloader while applying the feature file. On success, \type {nil} is

-returned.

-

-\stopsection

-

-\startsection[title={Applying an \quote{\AFM\ file}}][library=fontloader]

-

-\topicindex {\TYPEONE}

-

-\libindex{apply_afmfile}

-

-You can apply an \quote {\AFM\ file} to a loaded font:

-

-\startfunctioncall

-<table> errors = fontloader.apply_afmfile(<userdata> font, <string> filename)

-\stopfunctioncall

-

-An \AFM\ file is a textual representation of (some of) the meta information

-in a \TYPEONE\ font. See

-

-\starttyping

-ftp://ftp.math.utah.edu/u/ma/hohn/linux/postscript/5004.AFM_Spec.pdf

-\stoptyping

-

-for more information about \AFM\ files.

-

-Note: If you \type {fontloader.open} a \TYPEONE\ file named \type {font.pfb},

-the library will automatically search for and apply \type {font.afm} if it exists

-in the same directory as the file \type {font.pfb}. In that case, there is no

-need for an explicit call to \type {apply_afmfile()}.

-

-If the function fails, the return value is a table containing any errors reported

-by fontloader while applying the AFM file. On success, \type {nil} is returned.

-

-\stopsection

-

-\startsection[title={Fontloader font tables},reference=fontloadertables][library=fontloader]

-

-\topicindex {fontloader+tables}

-

-\libindex{fields}

-

-As mentioned earlier, the return value of \type {fontloader.open} is a userdata

-object. One way to have access to the actual metrics is to call \type

-{fontloader.to_table} on this object, returning the table structure that is

-explained in the following sections. In teh following sections we will not

-explain each field in detail. Most fields are self descriptive and for the more

-technical aspects you need to consult the relevant font references.

-

-It turns out that the result from \type {fontloader.to_table} sometimes needs

-very large amounts of memory (depending on the font's complexity and size) so it

-is possible to access the userdata object directly.

-

-\startitemize

-\startitem

-    All top|-|level keys that would be returned by \type {to_table()}

-    can also be accessed directly.

-\stopitem

-\startitem

-    The top|-|level key \quote {glyphs} returns a {\it virtual\/} array that

-    allows indices from \type {f.glyphmin} to (\type {f.glyphmax}).

-\stopitem

-\startitem

-    The items in that virtual array (the actual glyphs) are themselves also

-    userdata objects, and each has accessors for all of the keys explained in the

-    section \quote {Glyph items} below.

-\stopitem

-\startitem

-    The top|-|level key \quote {subfonts} returns an {\it actual} array of userdata

-    objects, one for each of the subfonts (or nil, if there are no subfonts).

-\stopitem

-\stopitemize

-

-A short example may be helpful. This code generates a printout of all

-the glyph names in the font \type {PunkNova.kern.otf}:

-

-\starttyping

-local f = fontloader.open('PunkNova.kern.otf')

-print (f.fontname)

-local i = 0

-if f.glyphcnt > 0 then

-    for i=f.glyphmin,f.glyphmax do

-       local g = f.glyphs[i]

-       if g then

-          print(g.name)

-       end

-       i = i + 1

-    end

-end

-fontloader.close(f)

-\stoptyping

-

-In this case, the \LUATEX\ memory requirement stays below 100MB on the test

-computer, while the internal structure generated by \type {to_table()} needs more

-than 2GB of memory (the font itself is 6.9MB in disk size).

-

-Only the top|-|level font, the subfont table entries, and the glyphs are virtual

-objects, everything else still produces normal \LUA\ values and tables.

-

-If you want to know the valid fields in a font or glyph structure, call the \type

-{fields} function on an object of a particular type (either glyph or font):

-

-\startfunctioncall

-<table> fields = fontloader.fields(<userdata> font)

-<table> fields = fontloader.fields(<userdata> font_glyph)

-\stopfunctioncall

-

-For instance:

-

-\startfunctioncall

-local fields = fontloader.fields(f)

-local fields = fontloader.fields(f.glyphs[0])

-\stopfunctioncall

-

-\stopsection

-

-\startsection[title={Table types}][library=fontloader]

-

-\startsubsection[title={The main table}]

-

-The top|-|level keys in the returned table are (the explanations in this part of

-the documentation are not yet finished):

-

-\starttabulate[|l|l|p|]

-\DB key                                 \BC type     \NC explanation \NC \NR

-\TB

-\NC \type{table_version}                \NC number   \NC indicates the metrics version (currently~0.3)\NC \NR

-\NC \type{fontname}                     \NC string   \NC \POSTSCRIPT\ font name\NC \NR

-\NC \type{fullname}                     \NC string   \NC official (human-oriented) font name\NC \NR

-\NC \type{familyname}                   \NC string   \NC family name\NC \NR

-\NC \type{weight}                       \NC string   \NC weight indicator\NC \NR

-\NC \type{copyright}                    \NC string   \NC copyright information\NC \NR

-\NC \type{filename}                     \NC string   \NC the file name\NC \NR

-\NC \type{version}                      \NC string   \NC font version\NC \NR

-\NC \type{italicangle}                  \NC float    \NC slant angle\NC \NR

-\NC \type{units_per_em}                 \NC number   \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR

-\NC \type{ascent}                       \NC number   \NC height of ascender in \type {units_per_em}\NC \NR

-\NC \type{descent}                      \NC number   \NC depth of descender in \type {units_per_em}\NC \NR

-\NC \type{upos}                         \NC float    \NC \NC \NR

-\NC \type{uwidth}                       \NC float    \NC \NC \NR

-\NC \type{uniqueid}                     \NC number   \NC \NC \NR

-\NC \type{glyphs}                       \NC array    \NC \NC \NR

-\NC \type{glyphcnt}                     \NC number   \NC number of included glyphs\NC \NR

-\NC \type{glyphmax}                     \NC number   \NC maximum used index the glyphs array\NC \NR

-\NC \type{glyphmin}                     \NC number   \NC minimum used index the glyphs array\NC \NR

-\NC \type{notdef_loc}                   \NC number   \NC location of the \type {.notdef} glyph

-                                                         or \type {-1} when not present \NC \NR

-\NC \type{hasvmetrics}                  \NC number   \NC \NC \NR

-\NC \type{onlybitmaps}                  \NC number   \NC \NC \NR

-\NC \type{serifcheck}                   \NC number   \NC \NC \NR

-\NC \type{isserif}                      \NC number   \NC \NC \NR

-\NC \type{issans}                       \NC number   \NC \NC \NR

-\NC \type{encodingchanged}              \NC number   \NC \NC \NR

-\NC \type{strokedfont}                  \NC number   \NC \NC \NR

-\NC \type{use_typo_metrics}             \NC number   \NC \NC \NR

-\NC \type{weight_width_slope_only}      \NC number   \NC \NC \NR

-\NC \type{head_optimized_for_cleartype} \NC number   \NC \NC \NR

-\NC \type{uni_interp}                   \NC enum     \NC \nod {unset}, \type {none}, \type {adobe},

-                                                         \type {greek}, \type {japanese}, \type {trad_chinese},

-                                                         \type {simp_chinese}, \type {korean}, \type {ams}\NC \NR

-\NC \type{origname}                     \NC string   \NC the file name, as supplied by the user\NC \NR

-\NC \type{map}                          \NC table    \NC \NC \NR

-\NC \type{private}                      \NC table    \NC \NC \NR

-\NC \type{xuid}                         \NC string   \NC \NC \NR

-\NC \type{pfminfo}                      \NC table    \NC \NC \NR

-\NC \type{names}                        \NC table    \NC \NC \NR

-\NC \type{cidinfo}                      \NC table    \NC \NC \NR

-\NC \type{subfonts}                     \NC array    \NC \NC \NR

-\NC \type{commments}                    \NC string   \NC \NC \NR

-\NC \type{fontlog}                      \NC string   \NC \NC \NR

-\NC \type{cvt_names}                    \NC string   \NC \NC \NR

-\NC \type{anchor_classes}               \NC table    \NC \NC \NR

-\NC \type{ttf_tables}                   \NC table    \NC \NC \NR

-\NC \type{ttf_tab_saved}                \NC table    \NC \NC \NR

-\NC \type{kerns}                        \NC table    \NC \NC \NR

-\NC \type{vkerns}                       \NC table    \NC \NC \NR

-\NC \type{texdata}                      \NC table    \NC \NC \NR

-\NC \type{lookups}                      \NC table    \NC \NC \NR

-\NC \type{gpos}                         \NC table    \NC \NC \NR

-\NC \type{gsub}                         \NC table    \NC \NC \NR

-\NC \type{mm}                           \NC table    \NC \NC \NR

-\NC \type{chosenname}                   \NC string   \NC \NC \NR

-\NC \type{macstyle}                     \NC number   \NC \NC \NR

-\NC \type{fondname}                     \NC string   \NC \NC \NR

-%NC \type{design_size}                  \NC number   \NC \NC \NR

-\NC \type{fontstyle_id}                 \NC number   \NC \NC \NR

-\NC \type{fontstyle_name}               \NC table    \NC \NC \NR

-%NC \type{design_range_bottom}          \NC number   \NC \NC \NR

-%NC \type{design_range_top}             \NC number   \NC \NC \NR

-\NC \type{strokewidth}                  \NC float    \NC \NC \NR

-\NC \type{mark_classes}                 \NC table    \NC \NC \NR

-\NC \type{creationtime}                 \NC number   \NC \NC \NR

-\NC \type{modificationtime}             \NC number   \NC \NC \NR

-\NC \type{os2_version}                  \NC number   \NC \NC \NR

-\NC \type{math}                         \NC table    \NC \NC \NR

-\NC \type{validation_state}             \NC table    \NC \NC \NR

-\NC \type{horiz_base}                   \NC table    \NC \NC \NR

-\NC \type{vert_base}                    \NC table    \NC \NC \NR

-\NC \type{extrema_bound}                \NC number   \NC \NC \NR

-\NC \type{truetype}                     \NC boolean  \NC signals a \TRUETYPE\ font \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {glyphs}}]

-

-The \type {glyphs} is an array containing the per|-|character

-information (quite a few of these are only present if non|-|zero).

-

-\starttabulate[|l|l|p|]

-\DB key                      \BC type     \BC explanation \NC \NR

-\TB

-\NC \type{name}              \NC string   \NC the glyph name \NC \NR

-\NC \type{unicode}           \NC number   \NC unicode code point, or -1 \NC \NR

-\NC \type{boundingbox}       \NC array    \NC array of four numbers, see note below \NC \NR

-\NC \type{width}             \NC number   \NC only for horizontal fonts \NC \NR

-\NC \type{vwidth}            \NC number   \NC only for vertical fonts \NC \NR

-\NC \type{tsidebearing}      \NC number   \NC only for vertical ttf/otf fonts, and only if non|-|zero \NC \NR

-\NC \type{lsidebearing}      \NC number   \NC only if non|-|zero and not equal to boundingbox[1] \NC \NR

-\NC \type{class}             \NC string   \NC one of "none", "base", "ligature", "mark", "component"

-                                              (if not present, the glyph class is \quote {automatic}) \NC \NR

-\NC \type{kerns}             \NC array    \NC only for horizontal fonts, if set \NC \NR

-\NC \type{vkerns}            \NC array    \NC only for vertical fonts, if set \NC \NR

-\NC \type{dependents}        \NC array    \NC linear array of glyph name strings, only if nonempty\NC \NR

-\NC \type{lookups}           \NC table    \NC only if nonempty \NC \NR

-\NC \type{ligatures}         \NC table    \NC only if nonempty \NC \NR

-\NC \type{anchors}           \NC table    \NC only if set \NC \NR

-\NC \type{comment}           \NC string   \NC only if set \NC \NR

-\NC \type{tex_height}        \NC number   \NC only if set \NC \NR

-\NC \type{tex_depth}         \NC number   \NC only if set \NC \NR

-\NC \type{italic_correction} \NC number   \NC only if set \NC \NR

-\NC \type{top_accent}        \NC number   \NC only if set \NC \NR

-\NC \type{is_extended_shape} \NC number   \NC only if this character is part of a math extension list \NC \NR

-\NC \type{altuni}            \NC table    \NC alternate \UNICODE\ items \NC \NR

-\NC \type{vert_variants}     \NC table    \NC \NC \NR

-\NC \type{horiz_variants}    \NC table    \NC \NC \NR

-\NC \type{mathkern}          \NC table    \NC \NC \NR

-\LL

-\stoptabulate

-

-On \type {boundingbox}: The boundingbox information for \TRUETYPE\ fonts and

-\TRUETYPE-based \OTF\ fonts is read directly from the font file.

-\POSTSCRIPT-based fonts do not have this information, so the boundingbox of

-traditional \POSTSCRIPT\ fonts is generated by interpreting the actual bezier

-curves to find the exact boundingbox. This can be a slow process, so the

-boundingboxes of \POSTSCRIPT-based \OTF\ fonts (and raw \CFF\ fonts) are

-calculated using an approximation of the glyph shape based on the actual glyph

-points only, instead of taking the whole curve into account. This means that

-glyphs that have missing points at extrema will have a too|-|tight boundingbox,

-but the processing is so much faster that in our opinion the tradeoff is worth

-it.

-

-The \type {kerns} and \type {vkerns} are linear arrays of small hashes:

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{char}   \NC string \NC \NC \NR

-\NC \type{off}    \NC number \NC \NC \NR

-\NC \type{lookup} \NC string \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {lookups} is a hash, based on lookup subtable names, with

-the value of each key inside that a linear array of small hashes:

-

-% TODO: fix this description

-

-\starttabulate[|l|l|p|]

-\DB key                  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{type}          \NC enum \NC \type {position}, \type {pair}, \type

-                                      {substitution}, \type {alternate}, \type

-                                      {multiple}, \type {ligature}, \type

-                                      {lcaret}, \cbk {kerning}, \type {vkerning},

-                                      \type {anchors}, \type {contextpos}, \type

-                                      {contextsub}, \type {chainpos}, \type

-                                      {chainsub}, \type {reversesub}, \type

-                                      {max}, \type {kernback}, \type {vkernback}

-                                      \NC \NR

-\NC \type{specification} \NC table \NC extra data \NC \NR

-\LL

-\stoptabulate

-

-For the first seven values of \type {type}, there can be additional

-sub|-|information, stored in the sub-table \type {specification}:

-

-\starttabulate[|l|l|p|]

-\DB value               \BC type     \BC explanation \NC \NR

-\TB

-\NC \type{position}     \NC table    \NC a table of the \type {offset_specs} type \NC \NR

-\NC \type{pair}         \NC table    \NC one string: \type {paired}, and an array of one

-                                         or two \type {offset_specs} tables: \type {offsets} \NC \NR

-\NC \type{substitution} \NC table    \NC one string: \type {variant} \NC \NR

-\NC \type{alternate}    \NC table    \NC one string: \type {components} \NC \NR

-\NC \type{multiple}     \NC table    \NC one string: \type {components} \NC \NR

-\NC \type{ligature}     \NC table    \NC two strings: \type {components}, \type {char} \NC \NR

-\NC \type{lcaret}       \NC array    \NC linear array of numbers \NC \NR

-\LL

-\stoptabulate

-

-Tables for \type {offset_specs} contain up to four number|-|valued fields: \type

-{x} (a horizontal offset), \type {y} (a vertical offset), \type {h} (an advance

-width correction) and \type {v} (an advance height correction).

-

-The \type {ligatures} is a linear array of small hashes:

-

-\starttabulate[|l|l|p|]

-\DB key               \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{lig}        \NC table  \NC uses the same substructure as a single item in

-                                     the \type {lookups} table explained above \NC \NR

-\NC \type{char}       \NC string \NC \NC \NR

-\NC \type{components} \NC array  \NC linear array of named components \NC \NR

-\NC \type{ccnt}       \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {anchor} table is indexed by a string signifying the anchor type, which

-is one of:

-

-\starttabulate[|l|l|p|]

-\DB key             \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{mark}     \NC table \NC placement mark \NC \NR

-\NC \type{basechar} \NC table \NC mark for attaching combining items to a base char \NC \NR

-\NC \type{baselig}  \NC table \NC mark for attaching combining items to a ligature \NC \NR

-\NC \type{basemark} \NC table \NC generic mark for attaching combining items to connect to \NC \NR

-\NC \type{centry}   \NC table \NC cursive entry point \NC \NR

-\NC \type{cexit}    \NC table \NC cursive exit point \NC \NR

-\LL

-\stoptabulate

-

-The content of these is a short array of defined anchors, with the

-entry keys being the anchor names. For all except \type {baselig}, the

-value is a single table with this definition:

-

-\starttabulate[|l|l|p|]

-\DB key                 \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{x}            \NC number \NC x location \NC \NR

-\NC \type{y}            \NC number \NC y location \NC \NR

-\NC \type{ttf_pt_index} \NC number \NC truetype point index, only if given \NC \NR

-\LL

-\stoptabulate

-

-For \type {baselig}, the value is a small array of such anchor sets sets, one for

-each constituent item of the ligature.

-

-For clarification, an anchor table could for example look like this :

-

-\starttyping

-['anchor'] = {

-    ['basemark'] = {

-        ['Anchor-7'] = { ['x']=170, ['y']=1080 }

-    },

-    ['mark'] ={

-        ['Anchor-1'] = { ['x']=160, ['y']=810 },

-        ['Anchor-4'] = { ['x']=160, ['y']=800 }

-    },

-    ['baselig'] = {

-        [1] = { ['Anchor-2'] = { ['x']=160, ['y']=650 } },

-        [2] = { ['Anchor-2'] = { ['x']=460, ['y']=640 } }

-        }

-    }

-\stoptyping

-

-Note: The \type {baselig} table can be sparse!

-

-\stopsubsection

-

-\startsubsection[title={\type {map}}]

-

-The top|-|level map is a list of encoding mappings. Each of those is a table

-itself.

-

-\starttabulate[|l|l|p|]

-\DB key             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{enccount} \NC number \NC \NC \NR

-\NC \type{encmax}   \NC number \NC \NC \NR

-\NC \type{backmax}  \NC number \NC \NC \NR

-\NC \type{remap}    \NC table  \NC \NC \NR

-\NC \type{map}      \NC array  \NC non|-|linear array of mappings\NC \NR

-\NC \type{backmap}  \NC array  \NC non|-|linear array of backward mappings\NC \NR

-\NC \type{enc}      \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {remap} table is very small:

-

-\starttabulate[|l|l|p|]

-\DB key             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{firstenc} \NC number \NC \NC \NR

-\NC \type{lastenc}  \NC number \NC \NC \NR

-\NC \type{infont}   \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {enc} table is a bit more verbose:

-

-\starttabulate[|l|l|p|]

-\DB key                     \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{enc_name}         \NC string \NC \NC \NR

-\NC \type{char_cnt}         \NC number \NC \NC \NR

-\NC \type{char_max}         \NC number \NC \NC \NR

-\NC \type{unicode}          \NC array  \NC of \UNICODE\ position numbers\NC \NR

-\NC \type{psnames}          \NC array  \NC of \POSTSCRIPT\ glyph names\NC \NR

-\NC \type{builtin}          \NC number \NC \NC \NR

-\NC \type{hidden}           \NC number \NC \NC \NR

-\NC \type{only_1byte}       \NC number \NC \NC \NR

-\NC \type{has_1byte}        \NC number \NC \NC \NR

-\NC \type{has_2byte}        \NC number \NC \NC \NR

-\NC \type{is_unicodebmp}    \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_unicodefull}   \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_custom}        \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_original}      \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_compact}       \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_japanese}      \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_korean}        \NC number \NC only if non|-|zero\NC \NR

-\NC \type{is_tradchinese}   \NC number \NC only if non|-|zero [name?]\NC \NR

-\NC \type{is_simplechinese} \NC number \NC only if non|-|zero\NC \NR

-\NC \type{low_page}         \NC number \NC \NC \NR

-\NC \type{high_page}        \NC number \NC \NC \NR

-\NC \type{iconv_name}       \NC string \NC \NC \NR

-\NC \type{iso_2022_escape}  \NC string \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {private}}]

-

-This is the font's private \POSTSCRIPT\ dictionary, if any. Keys and values are

-both strings.

-

-\stopsubsection

-

-\startsubsection[title={\type {cidinfo}}]

-

-\starttabulate[|l|l|p|]

-\DB key               \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{registry}   \NC string \NC \NC \NR

-\NC \type{ordering}   \NC string \NC \NC \NR

-\NC \type{supplement} \NC number \NC \NC \NR

-\NC \type{version}    \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[reference=fontloaderpfminfotable,title={\type {pfminfo}}]

-

-The \type {pfminfo} table contains most of the OS/2 information:

-

-\starttabulate[|l|l|p|]

-\DB key                     \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{pfmset}           \NC number \NC \NC \NR

-\NC \type{winascent_add}    \NC number \NC \NC \NR

-\NC \type{windescent_add}   \NC number \NC \NC \NR

-\NC \type{hheadascent_add}  \NC number \NC \NC \NR

-\NC \type{hheaddescent_add} \NC number \NC \NC \NR

-\NC \type{typoascent_add}   \NC number \NC \NC \NR

-\NC \type{typodescent_add}  \NC number \NC \NC \NR

-\NC \type{subsuper_set}     \NC number \NC \NC \NR

-\NC \type{panose_set}       \NC number \NC \NC \NR

-\NC \type{hheadset}         \NC number \NC \NC \NR

-\NC \type{vheadset}         \NC number \NC \NC \NR

-\NC \type{pfmfamily}        \NC number \NC \NC \NR

-\NC \type{weight}           \NC number \NC \NC \NR

-\NC \type{width}            \NC number \NC \NC \NR

-\NC \type{avgwidth}         \NC number \NC \NC \NR

-\NC \type{firstchar}        \NC number \NC \NC \NR

-\NC \type{lastchar}         \NC number \NC \NC \NR

-\NC \type{fstype}           \NC number \NC \NC \NR

-\NC \type{linegap}          \NC number \NC \NC \NR

-\NC \type{vlinegap}         \NC number \NC \NC \NR

-\NC \type{hhead_ascent}     \NC number \NC \NC \NR

-\NC \type{hhead_descent}    \NC number \NC \NC \NR

-\NC \type{os2_typoascent}   \NC number \NC \NC \NR

-\NC \type{os2_typodescent}  \NC number \NC \NC \NR

-\NC \type{os2_typolinegap}  \NC number \NC \NC \NR

-\NC \type{os2_winascent}    \NC number \NC \NC \NR

-\NC \type{os2_windescent}   \NC number \NC \NC \NR

-\NC \type{os2_subxsize}     \NC number \NC \NC \NR

-\NC \type{os2_subysize}     \NC number \NC \NC \NR

-\NC \type{os2_subxoff}      \NC number \NC \NC \NR

-\NC \type{os2_subyoff}      \NC number \NC \NC \NR

-\NC \type{os2_supxsize}     \NC number \NC \NC \NR

-\NC \type{os2_supysize}     \NC number \NC \NC \NR

-\NC \type{os2_supxoff}      \NC number \NC \NC \NR

-\NC \type{os2_supyoff}      \NC number \NC \NC \NR

-\NC \type{os2_strikeysize}  \NC number \NC \NC \NR

-\NC \type{os2_strikeypos}   \NC number \NC \NC \NR

-\NC \type{os2_family_class} \NC number \NC \NC \NR

-\NC \type{os2_xheight}      \NC number \NC \NC \NR

-\NC \type{os2_capheight}    \NC number \NC \NC \NR

-\NC \type{os2_defaultchar}  \NC number \NC \NC \NR

-\NC \type{os2_breakchar}    \NC number \NC \NC \NR

-\NC \type{os2_vendor}       \NC string \NC \NC \NR

-\NC \type{codepages}        \NC table  \NC A two-number array of encoded code pages \NC \NR

-\NC \type{unicoderages}     \NC table  \NC A four-number array of encoded unicode ranges \NC \NR

-\NC \type{panose}           \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {panose} subtable has exactly 10 string keys:

-

-\starttabulate[|l|l|p|]

-\DB key                    \BC type    \BC explanation \NC \NR

-\TB

-\NC \type{familytype}      \NC string  \NC Values as in the \OPENTYPE\ font

-                                           specification: \type {Any}, \type {No Fit},

-                                           \type {Text and Display}, \type {Script},

-                                           \type {Decorative}, \type {Pictorial} \NC

-                                           \NR

-\NC \type{serifstyle}      \NC string  \NC See the \OPENTYPE\ font specification for

-                                           values \NC \NR

-\NC \type{weight}          \NC string  \NC idem \NC \NR

-\NC \type{proportion}      \NC string  \NC idem \NC \NR

-\NC \type{contrast}        \NC string  \NC idem \NC \NR

-\NC \type{strokevariation} \NC string  \NC idem \NC \NR

-\NC \type{armstyle}        \NC string  \NC idem \NC \NR

-\NC \type{letterform}      \NC string  \NC idem \NC \NR

-\NC \type{midline}         \NC string  \NC idem \NC \NR

-\NC \type{xheight}         \NC string  \NC idem \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[reference=fontloadernamestable,title={\type {names}}]

-

-Each item has two top|-|level keys:

-

-\starttabulate[|l|l|p|]

-\DB key          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{lang}  \NC string \NC language for this entry \NC \NR

-\NC \type{names} \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {names} keys are the actual \TRUETYPE\ name strings. The possible keys

-are: \type {copyright}, \type {family}, \type {subfamily}, \type {uniqueid},

-\type {fullname}, \type {version}, \type {postscriptname}, \type {trademark},

-\type {manufacturer}, \type {designer}, \type {descriptor}, \type {venderurl},

-\type {designerurl}, \type {license}, \type {licenseurl}, \type {idontknow},

-\type {preffamilyname}, \type {prefmodifiers}, \type {compatfull}, \type

-{sampletext}, \type {cidfindfontname}, \type {wwsfamily} and \type

-{wwssubfamily}.

-

-\stopsubsection

-

-\startsubsection[title={\type {anchor_classes}}]

-

-The anchor_classes classes:

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{name}   \NC string \NC a descriptive id of this anchor class\NC \NR

-\NC \type{lookup} \NC string \NC \NC \NR

-\NC \type{type}   \NC string \NC one of \nod {mark}, \type {mkmk}, \type {curs}, \type {mklg} \NC \NR

-\LL

-\stoptabulate

-

-% type is actually a lookup subtype, not a feature name. Officially, these

-% strings should be gpos_mark2mark etc.

-

-\stopsubsection

-

-\startsubsection[title={\type {gpos}}]

-

-The \type {gpos} table has one array entry for each lookup. (The \type {gpos_}

-prefix is somewhat redundant.)

-

-\starttabulate[|l|l|p|]

-\DB key              \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{type}      \NC string \NC one of \type {gpos_single}, \type {gpos_pair},

-                                    \type {gpos_cursive}, \type {gpos_mark2base},\crlf

-                                    \type {gpos_mark2ligature}, \type {gpos_mark2mark}, \type {gpos_context},\crlf \type {gpos_contextchain} \NC \NR

-\NC \type{flags}     \NC table  \NC \NC \NR

-\NC \type{name}      \NC string \NC \NC \NR

-\NC \type{features}  \NC array  \NC \NC \NR

-\NC \type{subtables} \NC array  \NC \NC \NR

-\LL

-\stoptabulate

-

-The flags table has a true value for each of the lookup flags that is actually

-set:

-

-\starttabulate[|l|l|p|]

-\DB key                         \BC type    \BC explanation \NC \NR

-\TB

-\NC \type{r2l}                  \NC boolean \NC \NC \NR

-\NC \type{ignorebaseglyphs}     \NC boolean \NC \NC \NR

-\NC \type{ignoreligatures}      \NC boolean \NC \NC \NR

-\NC \type{ignorecombiningmarks} \NC boolean \NC \NC \NR

-\NC \type{mark_class}           \NC string  \NC \NC \NR

-\LL

-\stoptabulate

-

-The features subtable items of gpos have:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{tag}     \NC string \NC \NC \NR

-\NC \type{scripts} \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The scripts table within features has:

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type             \BC explanation \NC \NR

-\TB

-\NC \type{script} \NC string           \NC \NC \NR

-\NC \type{langs}  \NC array of strings \NC \NC \NR

-\LL

-\stoptabulate

-

-The subtables table has:

-

-\starttabulate[|l|l|p|]

-\DB key                     \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{name}             \NC string \NC \NC \NR

-\NC \type{suffix}           \NC string \NC (only if used)\NC \NR % used by gpos_single to get a default

-\NC \type{anchor_classes}   \NC number \NC (only if used)\NC \NR

-\NC \type{vertical_kerning} \NC number \NC (only if used)\NC \NR

-\NC \type{kernclass}        \NC table  \NC (only if used)\NC \NR

-\LL

-\stoptabulate

-

-The kernclass with subtables table has:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type             \BC explanation \NC \NR

-\TB

-\NC \type{firsts}  \NC array of strings \NC \NC \NR

-\NC \type{seconds} \NC array of strings \NC \NC \NR

-\NC \type{lookup}  \NC string or array  \NC associated lookup(s) \NC \NR

-\NC \type{offsets} \NC array of numbers \NC \NC \NR

-\LL

-\stoptabulate

-

-Note: the kernclass (as far as we can see) always has one entry so it could be one level

-deep instead. Also the seconds start at \type {[2]} which is close to the fontforge

-internals so we keep that too.

-

-\stopsubsection

-

-\startsubsection[title={\type {gsub}}]

-

-This has identical layout to the \type {gpos} table, except for the

-type:

-

-\starttabulate[|l|l|p|]

-\DB key         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{type} \NC string \NC one of \type {gsub_single}, \type {gsub_multiple},

-                               \type {gsub_alternate}, \type {gsub_ligature},\crlf

-                               \type {gsub_context}, \type {gsub_contextchain},

-                               \type {gsub_reversecontextchain} \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {ttf_tables} and \type {ttf_tab_saved}}]

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{tag}    \NC string \NC \NC \NR

-\NC \type{len}    \NC number \NC \NC \NR

-\NC \type{maxlen} \NC number \NC \NC \NR

-\NC \type{data}   \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {mm}}]

-

-\starttabulate[|l|l|p|]

-\DB key                   \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{axes}           \NC table  \NC array of axis names \NC \NR

-\NC \type{instance_count} \NC number \NC \NC \NR

-\NC \type{positions}      \NC table  \NC array of instance positions

-                                         (\#axes * instances )\NC \NR

-\NC \type{defweights}     \NC table  \NC array of default weights for instances \NC \NR

-\NC \type{cdv}            \NC string \NC \NC \NR

-\NC \type{ndv}            \NC string \NC \NC \NR

-\NC \type{axismaps}       \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {axismaps}:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{blends}  \NC table  \NC an array of blend points \NC \NR

-\NC \type{designs} \NC table  \NC an array of design values \NC \NR

-\NC \type{min}     \NC number \NC \NC \NR

-\NC \type{def}     \NC number \NC \NC \NR

-\NC \type{max}     \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {mark_classes}}]

-

-The keys in this table are mark class names, and the values are a

-space|-|separated string of glyph names in this class.

-

-\stopsubsection

-

-\startsubsection[title={\type {math}}]

-

-The math table has the variables that are also discussed in the chapter aboout

-math: \type {ScriptPercentScaleDown}, \type {ScriptScriptPercentScaleDown}, \type

-{DelimitedSubFormulaMinHeight}, \type {DisplayOperatorMinHeight}, \type

-{MathLeading}, \type {AxisHeight}, \type {AccentBaseHeight}, \type

-{FlattenedAccentBaseHeight}, \type {SubscriptShiftDown}, \type {SubscriptTopMax},

-\type {SubscriptBaselineDropMin}, \type {SuperscriptShiftUp}, \type

-{SuperscriptShiftUpCramped}, \type {SuperscriptBottomMin}, \type

-{SuperscriptBaselineDropMax}, \type {SubSuperscriptGapMin}, \type

-{SuperscriptBottomMaxWithSubscript}, \type {SpaceAfterScript}, \type

-{UpperLimitGapMin}, \type {UpperLimitBaselineRiseMin}, \type {LowerLimitGapMin},

-\type {LowerLimitBaselineDropMin}, \type {StackTopShiftUp}, \type

-{StackTopDisplayStyleShiftUp}, \type {StackBottomShiftDown}, \type

-{StackBottomDisplayStyleShiftDown}, \type {StackGapMin}, \type

-{StackDisplayStyleGapMin}, \type {StretchStackTopShiftUp}, \type

-{StretchStackBottomShiftDown}, \type {StretchStackGapAboveMin}, \type

-{StretchStackGapBelowMin}, \type {FractionNumeratorShiftUp}, \type

-{FractionNumeratorDisplayStyleShiftUp}, \type {FractionDenominatorShiftDown},

-\type {FractionDenominatorDisplayStyleShiftDown}, \type

-{FractionNumeratorGapMin}, \type {FractionNumeratorDisplayStyleGapMin} \type

-{FractionRuleThickness}, \type {FractionDenominatorGapMin}, \type

-{FractionDenominatorDisplayStyleGapMin}, \type {SkewedFractionHorizontalGap},

-\type {SkewedFractionVerticalGap}, \type {OverbarVerticalGap}, \type

-{OverbarRuleThickness}, \type {OverbarExtraAscender}, \type

-{UnderbarVerticalGap}, \type {UnderbarRuleThickness}, \type

-{UnderbarExtraDescender}, \type {RadicalVerticalGap}, \type

-{RadicalDisplayStyleVerticalGap}, \type {RadicalRuleThickness}, \type

-{RadicalExtraAscender}, \type {RadicalKernBeforeDegree}, \type

-{RadicalKernAfterDegree}, \type {RadicalDegreeBottomRaisePercent}, \type

-{MinConnectorOverlap}, \type {FractionDelimiterSize} and \type

-{FractionDelimiterDisplayStyleSize}.

-

-\stopsubsection

-

-\startsubsection[title={\type {validation_state}}]

-

-This is just a bonus table with keys: \type {bad_ps_fontname}, \type {bad_glyph_table}, \type {bad_cff_table}, \type {bad_metrics_table}, \type {bad_cmap_table}, \type {bad_bitmaps_table}, \type {bad_gx_table}, \type {bad_ot_table}, \type {bad_os2_version} and \type {bad_sfnt_header}.

-

-\stopsubsection

-

-\startsubsection[title={\type {horiz_base} and \type {vert_base}}]

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{tags}    \NC table \NC an array of script list tags\NC \NR

-\NC \type{scripts} \NC table \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {scripts} subtable:

-

-\starttabulate[|l|l|p|]

-\DB key                     \BC type    \BC explanation \NC \NR

-\TB

-\NC \type{baseline}         \NC table   \NC \NC \NR

-\NC \type{default_baseline} \NC number  \NC \NC \NR

-\NC \type{lang}             \NC table   \NC \NC \NR

-\LL

-\stoptabulate

-

-

-The \type {lang} subtable:

-

-\starttabulate[|l|l|p|]

-\DB key             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{tag}      \NC string \NC a script tag \NC \NR

-\NC \type{ascent}   \NC number \NC \NC \NR

-\NC \type{descent}  \NC number \NC \NC \NR

-\NC \type{features} \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {features} points to an array of tables with the same layout except

-that in those nested tables, the tag represents a language.

-

-\stopsubsection

-

-\startsubsection[title={\type {altuni}}]

-

-An array of alternate \UNICODE\ values. Inside that array are hashes with:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{unicode} \NC number \NC this glyph is also used for this unicode \NC \NR

-\NC \type{variant} \NC number \NC the alternative is driven by this unicode selector \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {vert_variants} and \type {horiz_variants}}]

-

-\starttabulate[|l|l|p|]

-\DB key                      \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{variants}          \NC string \NC \NC \NR

-\NC \type{italic_correction} \NC number \NC \NC \NR

-\NC \type{parts}             \NC table  \NC \NC \NR

-\LL

-\stoptabulate

-

-The \type {parts} table is an array of smaller tables:

-

-\starttabulate[|l|l|p|]

-\DB key              \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{component} \NC string \NC \NC \NR

-\NC \type{extender}  \NC number \NC \NC \NR

-\NC \type{start}     \NC number \NC \NC \NR

-\NC \type{end}       \NC number \NC \NC \NR

-\NC \type{advance}   \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {mathkern}}]

-

-\starttabulate[|l|l|p|]

-\DB key                 \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{top_right}    \NC table \NC \NC \NR

-\NC \type{bottom_right} \NC table \NC \NC \NR

-\NC \type{top_left}     \NC table \NC \NC \NR

-\NC \type{bottom_left}  \NC table \NC \NC \NR

-\LL

-\stoptabulate

-

-Each of the subtables is an array of small hashes with two keys:

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{height} \NC number \NC \NC \NR

-\NC \type{kern}   \NC number \NC \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {kerns}}]

-

-Substructure is identical to the per|-|glyph subtable.

-

-\stopsubsection

-

-\startsubsection[title={\type {vkerns}}]

-

-Substructure is identical to the per|-|glyph subtable.

-

-\stopsubsection

-

-\startsubsection[title={\type {texdata}}]

-

-\starttabulate[|l|l|p|]

-\DB key           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{type}   \NC string \NC \nod {unset}, \type {text}, \nod {math}, \type {mathext} \NC \NR

-\NC \type{params} \NC array  \NC 22 font numeric parameters \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {lookups}}]

-

-Top|-|level \type {lookups} is quite different from the ones at character level.

-The keys in this hash are strings, the values the actual lookups, represented as

-dictionary tables.

-

-\starttabulate[|l|l|p|]

-\DB key                  \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{type}          \NC string \NC \NC \NR

-\NC \type{format}        \NC enum   \NC one of \type {glyphs}, \type {class}, \type {coverage},

-                                        \type {reversecoverage} \NC \NR

-\NC \type{tag}           \NC string \NC \NC \NR

-\NC \type{current_class} \NC array  \NC \NC \NR

-\NC \type{before_class}  \NC array  \NC \NC \NR

-\NC \type{after_class}   \NC array  \NC \NC \NR

-\NC \type{rules}         \NC array  \NC an array of rule items\NC \NR

-\LL

-\stoptabulate

-

-Rule items have one common item and one specialized item:

-

-\starttabulate[|l|l|p|]

-\DB key                    \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{lookups}         \NC array \NC a linear array of lookup names                         \NC \NR

-\NC \type{glyphs}          \NC array \NC only if the parent's format is \type {glyphs}          \NC \NR

-\NC \type{class}           \NC array \NC only if the parent's format is \type {class}           \NC \NR

-\NC \type{coverage}        \NC array \NC only if the parent's format is \type {coverage}        \NC \NR

-\NC \type{reversecoverage} \NC array \NC only if the parent's format is \type {reversecoverage} \NC \NR

-\LL

-\stoptabulate

-

-A glyph table is:

-

-\starttabulate[|l|l|p|]

-\DB key          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{names} \NC string \NC \NC \NR

-\NC \type{back}  \NC string \NC \NC \NR

-\NC \type{fore}  \NC string \NC \NC \NR

-\LL

-\stoptabulate

-

-A class table is:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{current} \NC array \NC of numbers  \NC \NR

-\NC \type{before}  \NC array \NC of numbers  \NC \NR

-\NC \type{after}   \NC array \NC of numbers  \NC \NR

-\LL

-\stoptabulate

-

-for coverage:

-

-\starttabulate[|l|l|p|]

-\DB key            \BC type  \BC explanation \NC \NR

-\TB

-\NC \type{current} \NC array \NC of strings \NC \NR

-\NC \type{before}  \NC array \NC of strings \NC \NR

-\NC \type{after}   \NC array \NC of strings \NC \NR

-\LL

-\stoptabulate

-

-and for reverse coverage:

-

-\starttabulate[|l|l|p|]

-\DB key                 \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{current}      \NC array  \NC of strings  \NC \NR

-\NC \type{before}       \NC array  \NC of strings  \NC \NR

-\NC \type{after}        \NC array  \NC of strings  \NC \NR

-\NC \type{replacements} \NC string \NC             \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-fontloader
+
+\startchapter[reference=fontloader,title={The fontloader}]
+
+\topicindex {fonts+loading}
+
+The fontloader library is sort of independent of the rest in the sense that it
+can load font into a \LUA\ table that then can be converted into a table suitable
+for \TEX. The library is an adapted subset of \FONTFORGE\ and as such gives a
+similar view on a font (which has advantages when you want to debug). We will not
+discuss \OPENTYPE\ in detail here as the \MICROSOFT\ website offers enough
+information about it. The tables returned by the loader are not that far from the
+standard. We have no plans to extend the loader (it may even become an external
+module at some time).
+
+\startsection[title={Getting quick information on a font}][library=fontloader]
+
+\topicindex {fonts+information}
+
+\libindex{info}
+
+When you want to locate font by name you need some basic information that is
+hidden in the font files. For that reason we provide an efficient helper that
+gets the basic information without loading all of the font. Normally this helper
+is used to create a font (name) database.
+
+\startfunctioncall
+<table> info =
+    fontloader.info(<string> filename)
+\stopfunctioncall
+
+This function returns either \type {nil}, or a \type {table}, or an array of
+small tables (in the case of a \TRUETYPE\ collection). The returned table(s) will
+contain some fairly interesting information items from the font(s) defined by the
+file:
+
+\starttabulate[|l|l|p|]
+\DB key                 \BC type     \BC explanation \NC \NR
+\TB
+\NC \type{fontname}     \NC string   \NC the \POSTSCRIPT\ name of the font\NC \NR
+\NC \type{fullname}     \NC string   \NC the formal name of the font\NC \NR
+\NC \type{familyname}   \NC string   \NC the family name this font belongs to\NC \NR
+\NC \type{weight}       \NC string   \NC a string indicating the color value of the font\NC \NR
+\NC \type{version}      \NC string   \NC the internal font version\NC \NR
+\NC \type{italicangle}  \NC float    \NC the slant angle\NC \NR
+\NC \type{units_per_em} \NC number   \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR
+\NC \type{pfminfo}      \NC table    \NC (see \in{section}[fontloaderpfminfotable])\NC \NR
+\LL
+\stoptabulate
+
+Getting information through this function is (sometimes much) more efficient than
+loading the font properly, and is therefore handy when you want to create a
+dictionary of available fonts based on a directory contents.
+
+\stopsection
+
+\startsection[title={Loading an \OPENTYPE\ or \TRUETYPE\ file}][library=fontloader]
+
+\topicindex {\OPENTYPE}
+\topicindex {\TRUETYPE}
+
+\libindex{open}
+\libindex{close}
+\libindex{to_table}
+
+If you want to use an \OPENTYPE\ font, you have to get the metric information
+from somewhere. Using the \type {fontloader} library, the simplest way to get
+that information is thus:
+
+\starttyping
+function load_font (filename)
+  local metrics = nil
+  local font = fontloader.open(filename)
+  if font then
+     metrics = fontloader.to_table(font)
+     fontloader.close(font)
+  end
+  return metrics
+end
+
+myfont = load_font('/opt/tex/texmf/fonts/data/arial.ttf')
+\stoptyping
+
+The main function call is
+
+\startfunctioncall
+<userdata> f, <table> w = fontloader.open(<string> filename)
+<userdata> f, <table> w = fontloader.open(<string> filename, <string> fontname)
+\stopfunctioncall
+
+The first return value is a userdata representation of the font. The second
+return value is a table containing any warnings and errors reported by fontloader
+while opening the font. In normal typesetting, you would probably ignore the
+second argument, but it can be useful for debugging purposes.
+
+For \TRUETYPE\ collections (when filename ends in 'ttc') and \DFONT\ collections,
+you have to use a second string argument to specify which font you want from the
+collection. Use the \type {fontname} strings that are returned by \type
+{fontloader.info} for that.
+
+To turn the font into a table, \type {fontloader.to_table} is used on the font
+returned by \type {fontloader.open}.
+
+\startfunctioncall
+<table> f = fontloader.to_table(<userdata> font)
+\stopfunctioncall
+
+This table cannot be used directly by \LUATEX\ and should be turned into another
+one as described in~\in {chapter} [fonts]. Do not forget to store the \type
+{fontname} value in the \type {psname} field of the metrics table to be returned
+to \LUATEX, otherwise the font inclusion backend will not be able to find the
+correct font in the collection.
+
+See \in {section} [fontloadertables] for details on the userdata object returned
+by \type {fontloader.open} and the layout of the \type {metrics} table returned
+by \type {fontloader.to_table}.
+
+The font file is parsed and partially interpreted by the font loading routines
+from \FONTFORGE. The file format can be \OPENTYPE, \TRUETYPE, \TRUETYPE\
+Collection, \CFF, or \TYPEONE.
+
+There are a few advantages to this approach compared to reading the actual font
+file ourselves:
+
+\startitemize
+
+\startitem
+    The font is automatically re|-|encoded, so that the \type {metrics} table for
+    \TRUETYPE\ and \OPENTYPE\ fonts is using \UNICODE\ for the character indices.
+\stopitem
+
+\startitem
+    Many features are pre|-|processed into a format that is easier to handle than
+    just the bare tables would be.
+\stopitem
+
+\startitem
+    \POSTSCRIPT|-|based \OPENTYPE\ fonts do not store the character height and
+    depth in the font file, so the character boundingbox has to be calculated in
+    some way.
+\stopitem
+
+\stopitemize
+
+A loaded font is discarded with:
+
+\startfunctioncall
+fontloader.close(<userdata> font)
+\stopfunctioncall
+
+\stopsection
+
+\startsection[title={Applying a \quote{feature file}}][library=fontloader]
+
+\libindex{apply_featurefile}
+
+You can apply a \quote{feature file} to a loaded font:
+
+\startfunctioncall
+<table> errors = fontloader.apply_featurefile(<userdata> font, <string> filename)
+\stopfunctioncall
+
+A \quote {feature file} is a textual representation of the features in an
+\OPENTYPE\ font. See
+
+\starttyping
+http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html
+\stoptyping
+
+and
+
+\starttyping
+http://fontforge.sourceforge.net/featurefile.html
+\stoptyping
+
+for a more detailed description of feature files.
+
+If the function fails, the return value is a table containing any errors reported
+by fontloader while applying the feature file. On success, \type {nil} is
+returned.
+
+\stopsection
+
+\startsection[title={Applying an \quote{\AFM\ file}}][library=fontloader]
+
+\topicindex {\TYPEONE}
+
+\libindex{apply_afmfile}
+
+You can apply an \quote {\AFM\ file} to a loaded font:
+
+\startfunctioncall
+<table> errors = fontloader.apply_afmfile(<userdata> font, <string> filename)
+\stopfunctioncall
+
+An \AFM\ file is a textual representation of (some of) the meta information
+in a \TYPEONE\ font. See
+
+\starttyping
+ftp://ftp.math.utah.edu/u/ma/hohn/linux/postscript/5004.AFM_Spec.pdf
+\stoptyping
+
+for more information about \AFM\ files.
+
+Note: If you \type {fontloader.open} a \TYPEONE\ file named \type {font.pfb},
+the library will automatically search for and apply \type {font.afm} if it exists
+in the same directory as the file \type {font.pfb}. In that case, there is no
+need for an explicit call to \type {apply_afmfile()}.
+
+If the function fails, the return value is a table containing any errors reported
+by fontloader while applying the AFM file. On success, \type {nil} is returned.
+
+\stopsection
+
+\startsection[title={Fontloader font tables},reference=fontloadertables][library=fontloader]
+
+\topicindex {fontloader+tables}
+
+\libindex{fields}
+
+As mentioned earlier, the return value of \type {fontloader.open} is a userdata
+object. One way to have access to the actual metrics is to call \type
+{fontloader.to_table} on this object, returning the table structure that is
+explained in the following sections. In teh following sections we will not
+explain each field in detail. Most fields are self descriptive and for the more
+technical aspects you need to consult the relevant font references.
+
+It turns out that the result from \type {fontloader.to_table} sometimes needs
+very large amounts of memory (depending on the font's complexity and size) so it
+is possible to access the userdata object directly.
+
+\startitemize
+\startitem
+    All top|-|level keys that would be returned by \type {to_table()}
+    can also be accessed directly.
+\stopitem
+\startitem
+    The top|-|level key \quote {glyphs} returns a {\it virtual\/} array that
+    allows indices from \type {f.glyphmin} to (\type {f.glyphmax}).
+\stopitem
+\startitem
+    The items in that virtual array (the actual glyphs) are themselves also
+    userdata objects, and each has accessors for all of the keys explained in the
+    section \quote {Glyph items} below.
+\stopitem
+\startitem
+    The top|-|level key \quote {subfonts} returns an {\it actual} array of userdata
+    objects, one for each of the subfonts (or nil, if there are no subfonts).
+\stopitem
+\stopitemize
+
+A short example may be helpful. This code generates a printout of all
+the glyph names in the font \type {PunkNova.kern.otf}:
+
+\starttyping
+local f = fontloader.open('PunkNova.kern.otf')
+print (f.fontname)
+local i = 0
+if f.glyphcnt > 0 then
+    for i=f.glyphmin,f.glyphmax do
+       local g = f.glyphs[i]
+       if g then
+          print(g.name)
+       end
+       i = i + 1
+    end
+end
+fontloader.close(f)
+\stoptyping
+
+In this case, the \LUATEX\ memory requirement stays below 100MB on the test
+computer, while the internal structure generated by \type {to_table()} needs more
+than 2GB of memory (the font itself is 6.9MB in disk size).
+
+Only the top|-|level font, the subfont table entries, and the glyphs are virtual
+objects, everything else still produces normal \LUA\ values and tables.
+
+If you want to know the valid fields in a font or glyph structure, call the \type
+{fields} function on an object of a particular type (either glyph or font):
+
+\startfunctioncall
+<table> fields = fontloader.fields(<userdata> font)
+<table> fields = fontloader.fields(<userdata> font_glyph)
+\stopfunctioncall
+
+For instance:
+
+\startfunctioncall
+local fields = fontloader.fields(f)
+local fields = fontloader.fields(f.glyphs[0])
+\stopfunctioncall
+
+\stopsection
+
+\startsection[title={Table types}][library=fontloader]
+
+\startsubsection[title={The main table}]
+
+The top|-|level keys in the returned table are (the explanations in this part of
+the documentation are not yet finished):
+
+\starttabulate[|l|l|p|]
+\DB key                                 \BC type     \NC explanation \NC \NR
+\TB
+\NC \type{table_version}                \NC number   \NC indicates the metrics version (currently~0.3)\NC \NR
+\NC \type{fontname}                     \NC string   \NC \POSTSCRIPT\ font name\NC \NR
+\NC \type{fullname}                     \NC string   \NC official (human-oriented) font name\NC \NR
+\NC \type{familyname}                   \NC string   \NC family name\NC \NR
+\NC \type{weight}                       \NC string   \NC weight indicator\NC \NR
+\NC \type{copyright}                    \NC string   \NC copyright information\NC \NR
+\NC \type{filename}                     \NC string   \NC the file name\NC \NR
+\NC \type{version}                      \NC string   \NC font version\NC \NR
+\NC \type{italicangle}                  \NC float    \NC slant angle\NC \NR
+\NC \type{units_per_em}                 \NC number   \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR
+\NC \type{ascent}                       \NC number   \NC height of ascender in \type {units_per_em}\NC \NR
+\NC \type{descent}                      \NC number   \NC depth of descender in \type {units_per_em}\NC \NR
+\NC \type{upos}                         \NC float    \NC \NC \NR
+\NC \type{uwidth}                       \NC float    \NC \NC \NR
+\NC \type{uniqueid}                     \NC number   \NC \NC \NR
+\NC \type{glyphs}                       \NC array    \NC \NC \NR
+\NC \type{glyphcnt}                     \NC number   \NC number of included glyphs\NC \NR
+\NC \type{glyphmax}                     \NC number   \NC maximum used index the glyphs array\NC \NR
+\NC \type{glyphmin}                     \NC number   \NC minimum used index the glyphs array\NC \NR
+\NC \type{notdef_loc}                   \NC number   \NC location of the \type {.notdef} glyph
+                                                         or \type {-1} when not present \NC \NR
+\NC \type{hasvmetrics}                  \NC number   \NC \NC \NR
+\NC \type{onlybitmaps}                  \NC number   \NC \NC \NR
+\NC \type{serifcheck}                   \NC number   \NC \NC \NR
+\NC \type{isserif}                      \NC number   \NC \NC \NR
+\NC \type{issans}                       \NC number   \NC \NC \NR
+\NC \type{encodingchanged}              \NC number   \NC \NC \NR
+\NC \type{strokedfont}                  \NC number   \NC \NC \NR
+\NC \type{use_typo_metrics}             \NC number   \NC \NC \NR
+\NC \type{weight_width_slope_only}      \NC number   \NC \NC \NR
+\NC \type{head_optimized_for_cleartype} \NC number   \NC \NC \NR
+\NC \type{uni_interp}                   \NC enum     \NC \nod {unset}, \type {none}, \type {adobe},
+                                                         \type {greek}, \type {japanese}, \type {trad_chinese},
+                                                         \type {simp_chinese}, \type {korean}, \type {ams}\NC \NR
+\NC \type{origname}                     \NC string   \NC the file name, as supplied by the user\NC \NR
+\NC \type{map}                          \NC table    \NC \NC \NR
+\NC \type{private}                      \NC table    \NC \NC \NR
+\NC \type{xuid}                         \NC string   \NC \NC \NR
+\NC \type{pfminfo}                      \NC table    \NC \NC \NR
+\NC \type{names}                        \NC table    \NC \NC \NR
+\NC \type{cidinfo}                      \NC table    \NC \NC \NR
+\NC \type{subfonts}                     \NC array    \NC \NC \NR
+\NC \type{commments}                    \NC string   \NC \NC \NR
+\NC \type{fontlog}                      \NC string   \NC \NC \NR
+\NC \type{cvt_names}                    \NC string   \NC \NC \NR
+\NC \type{anchor_classes}               \NC table    \NC \NC \NR
+\NC \type{ttf_tables}                   \NC table    \NC \NC \NR
+\NC \type{ttf_tab_saved}                \NC table    \NC \NC \NR
+\NC \type{kerns}                        \NC table    \NC \NC \NR
+\NC \type{vkerns}                       \NC table    \NC \NC \NR
+\NC \type{texdata}                      \NC table    \NC \NC \NR
+\NC \type{lookups}                      \NC table    \NC \NC \NR
+\NC \type{gpos}                         \NC table    \NC \NC \NR
+\NC \type{gsub}                         \NC table    \NC \NC \NR
+\NC \type{mm}                           \NC table    \NC \NC \NR
+\NC \type{chosenname}                   \NC string   \NC \NC \NR
+\NC \type{macstyle}                     \NC number   \NC \NC \NR
+\NC \type{fondname}                     \NC string   \NC \NC \NR
+%NC \type{design_size}                  \NC number   \NC \NC \NR
+\NC \type{fontstyle_id}                 \NC number   \NC \NC \NR
+\NC \type{fontstyle_name}               \NC table    \NC \NC \NR
+%NC \type{design_range_bottom}          \NC number   \NC \NC \NR
+%NC \type{design_range_top}             \NC number   \NC \NC \NR
+\NC \type{strokewidth}                  \NC float    \NC \NC \NR
+\NC \type{mark_classes}                 \NC table    \NC \NC \NR
+\NC \type{creationtime}                 \NC number   \NC \NC \NR
+\NC \type{modificationtime}             \NC number   \NC \NC \NR
+\NC \type{os2_version}                  \NC number   \NC \NC \NR
+\NC \type{math}                         \NC table    \NC \NC \NR
+\NC \type{validation_state}             \NC table    \NC \NC \NR
+\NC \type{horiz_base}                   \NC table    \NC \NC \NR
+\NC \type{vert_base}                    \NC table    \NC \NC \NR
+\NC \type{extrema_bound}                \NC number   \NC \NC \NR
+\NC \type{truetype}                     \NC boolean  \NC signals a \TRUETYPE\ font \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {glyphs}}]
+
+The \type {glyphs} is an array containing the per|-|character
+information (quite a few of these are only present if non|-|zero).
+
+\starttabulate[|l|l|p|]
+\DB key                      \BC type     \BC explanation \NC \NR
+\TB
+\NC \type{name}              \NC string   \NC the glyph name \NC \NR
+\NC \type{unicode}           \NC number   \NC unicode code point, or -1 \NC \NR
+\NC \type{boundingbox}       \NC array    \NC array of four numbers, see note below \NC \NR
+\NC \type{width}             \NC number   \NC only for horizontal fonts \NC \NR
+\NC \type{vwidth}            \NC number   \NC only for vertical fonts \NC \NR
+\NC \type{tsidebearing}      \NC number   \NC only for vertical ttf/otf fonts, and only if non|-|zero \NC \NR
+\NC \type{lsidebearing}      \NC number   \NC only if non|-|zero and not equal to boundingbox[1] \NC \NR
+\NC \type{class}             \NC string   \NC one of "none", "base", "ligature", "mark", "component"
+                                              (if not present, the glyph class is \quote {automatic}) \NC \NR
+\NC \type{kerns}             \NC array    \NC only for horizontal fonts, if set \NC \NR
+\NC \type{vkerns}            \NC array    \NC only for vertical fonts, if set \NC \NR
+\NC \type{dependents}        \NC array    \NC linear array of glyph name strings, only if nonempty\NC \NR
+\NC \type{lookups}           \NC table    \NC only if nonempty \NC \NR
+\NC \type{ligatures}         \NC table    \NC only if nonempty \NC \NR
+\NC \type{anchors}           \NC table    \NC only if set \NC \NR
+\NC \type{comment}           \NC string   \NC only if set \NC \NR
+\NC \type{tex_height}        \NC number   \NC only if set \NC \NR
+\NC \type{tex_depth}         \NC number   \NC only if set \NC \NR
+\NC \type{italic_correction} \NC number   \NC only if set \NC \NR
+\NC \type{top_accent}        \NC number   \NC only if set \NC \NR
+\NC \type{is_extended_shape} \NC number   \NC only if this character is part of a math extension list \NC \NR
+\NC \type{altuni}            \NC table    \NC alternate \UNICODE\ items \NC \NR
+\NC \type{vert_variants}     \NC table    \NC \NC \NR
+\NC \type{horiz_variants}    \NC table    \NC \NC \NR
+\NC \type{mathkern}          \NC table    \NC \NC \NR
+\LL
+\stoptabulate
+
+On \type {boundingbox}: The boundingbox information for \TRUETYPE\ fonts and
+\TRUETYPE-based \OTF\ fonts is read directly from the font file.
+\POSTSCRIPT-based fonts do not have this information, so the boundingbox of
+traditional \POSTSCRIPT\ fonts is generated by interpreting the actual bezier
+curves to find the exact boundingbox. This can be a slow process, so the
+boundingboxes of \POSTSCRIPT-based \OTF\ fonts (and raw \CFF\ fonts) are
+calculated using an approximation of the glyph shape based on the actual glyph
+points only, instead of taking the whole curve into account. This means that
+glyphs that have missing points at extrema will have a too|-|tight boundingbox,
+but the processing is so much faster that in our opinion the tradeoff is worth
+it.
+
+The \type {kerns} and \type {vkerns} are linear arrays of small hashes:
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{char}   \NC string \NC \NC \NR
+\NC \type{off}    \NC number \NC \NC \NR
+\NC \type{lookup} \NC string \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {lookups} is a hash, based on lookup subtable names, with
+the value of each key inside that a linear array of small hashes:
+
+% TODO: fix this description
+
+\starttabulate[|l|l|p|]
+\DB key                  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{type}          \NC enum \NC \type {position}, \type {pair}, \type
+                                      {substitution}, \type {alternate}, \type
+                                      {multiple}, \type {ligature}, \type
+                                      {lcaret}, \cbk {kerning}, \type {vkerning},
+                                      \type {anchors}, \type {contextpos}, \type
+                                      {contextsub}, \type {chainpos}, \type
+                                      {chainsub}, \type {reversesub}, \type
+                                      {max}, \type {kernback}, \type {vkernback}
+                                      \NC \NR
+\NC \type{specification} \NC table \NC extra data \NC \NR
+\LL
+\stoptabulate
+
+For the first seven values of \type {type}, there can be additional
+sub|-|information, stored in the sub-table \type {specification}:
+
+\starttabulate[|l|l|p|]
+\DB value               \BC type     \BC explanation \NC \NR
+\TB
+\NC \type{position}     \NC table    \NC a table of the \type {offset_specs} type \NC \NR
+\NC \type{pair}         \NC table    \NC one string: \type {paired}, and an array of one
+                                         or two \type {offset_specs} tables: \type {offsets} \NC \NR
+\NC \type{substitution} \NC table    \NC one string: \type {variant} \NC \NR
+\NC \type{alternate}    \NC table    \NC one string: \type {components} \NC \NR
+\NC \type{multiple}     \NC table    \NC one string: \type {components} \NC \NR
+\NC \type{ligature}     \NC table    \NC two strings: \type {components}, \type {char} \NC \NR
+\NC \type{lcaret}       \NC array    \NC linear array of numbers \NC \NR
+\LL
+\stoptabulate
+
+Tables for \type {offset_specs} contain up to four number|-|valued fields: \type
+{x} (a horizontal offset), \type {y} (a vertical offset), \type {h} (an advance
+width correction) and \type {v} (an advance height correction).
+
+The \type {ligatures} is a linear array of small hashes:
+
+\starttabulate[|l|l|p|]
+\DB key               \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{lig}        \NC table  \NC uses the same substructure as a single item in
+                                     the \type {lookups} table explained above \NC \NR
+\NC \type{char}       \NC string \NC \NC \NR
+\NC \type{components} \NC array  \NC linear array of named components \NC \NR
+\NC \type{ccnt}       \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {anchor} table is indexed by a string signifying the anchor type, which
+is one of:
+
+\starttabulate[|l|l|p|]
+\DB key             \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{mark}     \NC table \NC placement mark \NC \NR
+\NC \type{basechar} \NC table \NC mark for attaching combining items to a base char \NC \NR
+\NC \type{baselig}  \NC table \NC mark for attaching combining items to a ligature \NC \NR
+\NC \type{basemark} \NC table \NC generic mark for attaching combining items to connect to \NC \NR
+\NC \type{centry}   \NC table \NC cursive entry point \NC \NR
+\NC \type{cexit}    \NC table \NC cursive exit point \NC \NR
+\LL
+\stoptabulate
+
+The content of these is a short array of defined anchors, with the
+entry keys being the anchor names. For all except \type {baselig}, the
+value is a single table with this definition:
+
+\starttabulate[|l|l|p|]
+\DB key                 \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{x}            \NC number \NC x location \NC \NR
+\NC \type{y}            \NC number \NC y location \NC \NR
+\NC \type{ttf_pt_index} \NC number \NC truetype point index, only if given \NC \NR
+\LL
+\stoptabulate
+
+For \type {baselig}, the value is a small array of such anchor sets sets, one for
+each constituent item of the ligature.
+
+For clarification, an anchor table could for example look like this :
+
+\starttyping
+['anchor'] = {
+    ['basemark'] = {
+        ['Anchor-7'] = { ['x']=170, ['y']=1080 }
+    },
+    ['mark'] ={
+        ['Anchor-1'] = { ['x']=160, ['y']=810 },
+        ['Anchor-4'] = { ['x']=160, ['y']=800 }
+    },
+    ['baselig'] = {
+        [1] = { ['Anchor-2'] = { ['x']=160, ['y']=650 } },
+        [2] = { ['Anchor-2'] = { ['x']=460, ['y']=640 } }
+        }
+    }
+\stoptyping
+
+Note: The \type {baselig} table can be sparse!
+
+\stopsubsection
+
+\startsubsection[title={\type {map}}]
+
+The top|-|level map is a list of encoding mappings. Each of those is a table
+itself.
+
+\starttabulate[|l|l|p|]
+\DB key             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{enccount} \NC number \NC \NC \NR
+\NC \type{encmax}   \NC number \NC \NC \NR
+\NC \type{backmax}  \NC number \NC \NC \NR
+\NC \type{remap}    \NC table  \NC \NC \NR
+\NC \type{map}      \NC array  \NC non|-|linear array of mappings\NC \NR
+\NC \type{backmap}  \NC array  \NC non|-|linear array of backward mappings\NC \NR
+\NC \type{enc}      \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {remap} table is very small:
+
+\starttabulate[|l|l|p|]
+\DB key             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{firstenc} \NC number \NC \NC \NR
+\NC \type{lastenc}  \NC number \NC \NC \NR
+\NC \type{infont}   \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {enc} table is a bit more verbose:
+
+\starttabulate[|l|l|p|]
+\DB key                     \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{enc_name}         \NC string \NC \NC \NR
+\NC \type{char_cnt}         \NC number \NC \NC \NR
+\NC \type{char_max}         \NC number \NC \NC \NR
+\NC \type{unicode}          \NC array  \NC of \UNICODE\ position numbers\NC \NR
+\NC \type{psnames}          \NC array  \NC of \POSTSCRIPT\ glyph names\NC \NR
+\NC \type{builtin}          \NC number \NC \NC \NR
+\NC \type{hidden}           \NC number \NC \NC \NR
+\NC \type{only_1byte}       \NC number \NC \NC \NR
+\NC \type{has_1byte}        \NC number \NC \NC \NR
+\NC \type{has_2byte}        \NC number \NC \NC \NR
+\NC \type{is_unicodebmp}    \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_unicodefull}   \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_custom}        \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_original}      \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_compact}       \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_japanese}      \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_korean}        \NC number \NC only if non|-|zero\NC \NR
+\NC \type{is_tradchinese}   \NC number \NC only if non|-|zero [name?]\NC \NR
+\NC \type{is_simplechinese} \NC number \NC only if non|-|zero\NC \NR
+\NC \type{low_page}         \NC number \NC \NC \NR
+\NC \type{high_page}        \NC number \NC \NC \NR
+\NC \type{iconv_name}       \NC string \NC \NC \NR
+\NC \type{iso_2022_escape}  \NC string \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {private}}]
+
+This is the font's private \POSTSCRIPT\ dictionary, if any. Keys and values are
+both strings.
+
+\stopsubsection
+
+\startsubsection[title={\type {cidinfo}}]
+
+\starttabulate[|l|l|p|]
+\DB key               \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{registry}   \NC string \NC \NC \NR
+\NC \type{ordering}   \NC string \NC \NC \NR
+\NC \type{supplement} \NC number \NC \NC \NR
+\NC \type{version}    \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[reference=fontloaderpfminfotable,title={\type {pfminfo}}]
+
+The \type {pfminfo} table contains most of the OS/2 information:
+
+\starttabulate[|l|l|p|]
+\DB key                     \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{pfmset}           \NC number \NC \NC \NR
+\NC \type{winascent_add}    \NC number \NC \NC \NR
+\NC \type{windescent_add}   \NC number \NC \NC \NR
+\NC \type{hheadascent_add}  \NC number \NC \NC \NR
+\NC \type{hheaddescent_add} \NC number \NC \NC \NR
+\NC \type{typoascent_add}   \NC number \NC \NC \NR
+\NC \type{typodescent_add}  \NC number \NC \NC \NR
+\NC \type{subsuper_set}     \NC number \NC \NC \NR
+\NC \type{panose_set}       \NC number \NC \NC \NR
+\NC \type{hheadset}         \NC number \NC \NC \NR
+\NC \type{vheadset}         \NC number \NC \NC \NR
+\NC \type{pfmfamily}        \NC number \NC \NC \NR
+\NC \type{weight}           \NC number \NC \NC \NR
+\NC \type{width}            \NC number \NC \NC \NR
+\NC \type{avgwidth}         \NC number \NC \NC \NR
+\NC \type{firstchar}        \NC number \NC \NC \NR
+\NC \type{lastchar}         \NC number \NC \NC \NR
+\NC \type{fstype}           \NC number \NC \NC \NR
+\NC \type{linegap}          \NC number \NC \NC \NR
+\NC \type{vlinegap}         \NC number \NC \NC \NR
+\NC \type{hhead_ascent}     \NC number \NC \NC \NR
+\NC \type{hhead_descent}    \NC number \NC \NC \NR
+\NC \type{os2_typoascent}   \NC number \NC \NC \NR
+\NC \type{os2_typodescent}  \NC number \NC \NC \NR
+\NC \type{os2_typolinegap}  \NC number \NC \NC \NR
+\NC \type{os2_winascent}    \NC number \NC \NC \NR
+\NC \type{os2_windescent}   \NC number \NC \NC \NR
+\NC \type{os2_subxsize}     \NC number \NC \NC \NR
+\NC \type{os2_subysize}     \NC number \NC \NC \NR
+\NC \type{os2_subxoff}      \NC number \NC \NC \NR
+\NC \type{os2_subyoff}      \NC number \NC \NC \NR
+\NC \type{os2_supxsize}     \NC number \NC \NC \NR
+\NC \type{os2_supysize}     \NC number \NC \NC \NR
+\NC \type{os2_supxoff}      \NC number \NC \NC \NR
+\NC \type{os2_supyoff}      \NC number \NC \NC \NR
+\NC \type{os2_strikeysize}  \NC number \NC \NC \NR
+\NC \type{os2_strikeypos}   \NC number \NC \NC \NR
+\NC \type{os2_family_class} \NC number \NC \NC \NR
+\NC \type{os2_xheight}      \NC number \NC \NC \NR
+\NC \type{os2_capheight}    \NC number \NC \NC \NR
+\NC \type{os2_defaultchar}  \NC number \NC \NC \NR
+\NC \type{os2_breakchar}    \NC number \NC \NC \NR
+\NC \type{os2_vendor}       \NC string \NC \NC \NR
+\NC \type{codepages}        \NC table  \NC A two-number array of encoded code pages \NC \NR
+\NC \type{unicoderages}     \NC table  \NC A four-number array of encoded unicode ranges \NC \NR
+\NC \type{panose}           \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {panose} subtable has exactly 10 string keys:
+
+\starttabulate[|l|l|p|]
+\DB key                    \BC type    \BC explanation \NC \NR
+\TB
+\NC \type{familytype}      \NC string  \NC Values as in the \OPENTYPE\ font
+                                           specification: \type {Any}, \type {No Fit},
+                                           \type {Text and Display}, \type {Script},
+                                           \type {Decorative}, \type {Pictorial} \NC
+                                           \NR
+\NC \type{serifstyle}      \NC string  \NC See the \OPENTYPE\ font specification for
+                                           values \NC \NR
+\NC \type{weight}          \NC string  \NC idem \NC \NR
+\NC \type{proportion}      \NC string  \NC idem \NC \NR
+\NC \type{contrast}        \NC string  \NC idem \NC \NR
+\NC \type{strokevariation} \NC string  \NC idem \NC \NR
+\NC \type{armstyle}        \NC string  \NC idem \NC \NR
+\NC \type{letterform}      \NC string  \NC idem \NC \NR
+\NC \type{midline}         \NC string  \NC idem \NC \NR
+\NC \type{xheight}         \NC string  \NC idem \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[reference=fontloadernamestable,title={\type {names}}]
+
+Each item has two top|-|level keys:
+
+\starttabulate[|l|l|p|]
+\DB key          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{lang}  \NC string \NC language for this entry \NC \NR
+\NC \type{names} \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {names} keys are the actual \TRUETYPE\ name strings. The possible keys
+are: \type {copyright}, \type {family}, \type {subfamily}, \type {uniqueid},
+\type {fullname}, \type {version}, \type {postscriptname}, \type {trademark},
+\type {manufacturer}, \type {designer}, \type {descriptor}, \type {venderurl},
+\type {designerurl}, \type {license}, \type {licenseurl}, \type {idontknow},
+\type {preffamilyname}, \type {prefmodifiers}, \type {compatfull}, \type
+{sampletext}, \type {cidfindfontname}, \type {wwsfamily} and \type
+{wwssubfamily}.
+
+\stopsubsection
+
+\startsubsection[title={\type {anchor_classes}}]
+
+The anchor_classes classes:
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{name}   \NC string \NC a descriptive id of this anchor class\NC \NR
+\NC \type{lookup} \NC string \NC \NC \NR
+\NC \type{type}   \NC string \NC one of \nod {mark}, \type {mkmk}, \type {curs}, \type {mklg} \NC \NR
+\LL
+\stoptabulate
+
+% type is actually a lookup subtype, not a feature name. Officially, these
+% strings should be gpos_mark2mark etc.
+
+\stopsubsection
+
+\startsubsection[title={\type {gpos}}]
+
+The \type {gpos} table has one array entry for each lookup. (The \type {gpos_}
+prefix is somewhat redundant.)
+
+\starttabulate[|l|l|p|]
+\DB key              \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{type}      \NC string \NC one of \type {gpos_single}, \type {gpos_pair},
+                                    \type {gpos_cursive}, \type {gpos_mark2base},\crlf
+                                    \type {gpos_mark2ligature}, \type {gpos_mark2mark}, \type {gpos_context},\crlf \type {gpos_contextchain} \NC \NR
+\NC \type{flags}     \NC table  \NC \NC \NR
+\NC \type{name}      \NC string \NC \NC \NR
+\NC \type{features}  \NC array  \NC \NC \NR
+\NC \type{subtables} \NC array  \NC \NC \NR
+\LL
+\stoptabulate
+
+The flags table has a true value for each of the lookup flags that is actually
+set:
+
+\starttabulate[|l|l|p|]
+\DB key                         \BC type    \BC explanation \NC \NR
+\TB
+\NC \type{r2l}                  \NC boolean \NC \NC \NR
+\NC \type{ignorebaseglyphs}     \NC boolean \NC \NC \NR
+\NC \type{ignoreligatures}      \NC boolean \NC \NC \NR
+\NC \type{ignorecombiningmarks} \NC boolean \NC \NC \NR
+\NC \type{mark_class}           \NC string  \NC \NC \NR
+\LL
+\stoptabulate
+
+The features subtable items of gpos have:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{tag}     \NC string \NC \NC \NR
+\NC \type{scripts} \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The scripts table within features has:
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type             \BC explanation \NC \NR
+\TB
+\NC \type{script} \NC string           \NC \NC \NR
+\NC \type{langs}  \NC array of strings \NC \NC \NR
+\LL
+\stoptabulate
+
+The subtables table has:
+
+\starttabulate[|l|l|p|]
+\DB key                     \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{name}             \NC string \NC \NC \NR
+\NC \type{suffix}           \NC string \NC (only if used)\NC \NR % used by gpos_single to get a default
+\NC \type{anchor_classes}   \NC number \NC (only if used)\NC \NR
+\NC \type{vertical_kerning} \NC number \NC (only if used)\NC \NR
+\NC \type{kernclass}        \NC table  \NC (only if used)\NC \NR
+\LL
+\stoptabulate
+
+The kernclass with subtables table has:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type             \BC explanation \NC \NR
+\TB
+\NC \type{firsts}  \NC array of strings \NC \NC \NR
+\NC \type{seconds} \NC array of strings \NC \NC \NR
+\NC \type{lookup}  \NC string or array  \NC associated lookup(s) \NC \NR
+\NC \type{offsets} \NC array of numbers \NC \NC \NR
+\LL
+\stoptabulate
+
+Note: the kernclass (as far as we can see) always has one entry so it could be one level
+deep instead. Also the seconds start at \type {[2]} which is close to the fontforge
+internals so we keep that too.
+
+\stopsubsection
+
+\startsubsection[title={\type {gsub}}]
+
+This has identical layout to the \type {gpos} table, except for the
+type:
+
+\starttabulate[|l|l|p|]
+\DB key         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{type} \NC string \NC one of \type {gsub_single}, \type {gsub_multiple},
+                               \type {gsub_alternate}, \type {gsub_ligature},\crlf
+                               \type {gsub_context}, \type {gsub_contextchain},
+                               \type {gsub_reversecontextchain} \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {ttf_tables} and \type {ttf_tab_saved}}]
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{tag}    \NC string \NC \NC \NR
+\NC \type{len}    \NC number \NC \NC \NR
+\NC \type{maxlen} \NC number \NC \NC \NR
+\NC \type{data}   \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {mm}}]
+
+\starttabulate[|l|l|p|]
+\DB key                   \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{axes}           \NC table  \NC array of axis names \NC \NR
+\NC \type{instance_count} \NC number \NC \NC \NR
+\NC \type{positions}      \NC table  \NC array of instance positions
+                                         (\#axes * instances )\NC \NR
+\NC \type{defweights}     \NC table  \NC array of default weights for instances \NC \NR
+\NC \type{cdv}            \NC string \NC \NC \NR
+\NC \type{ndv}            \NC string \NC \NC \NR
+\NC \type{axismaps}       \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {axismaps}:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{blends}  \NC table  \NC an array of blend points \NC \NR
+\NC \type{designs} \NC table  \NC an array of design values \NC \NR
+\NC \type{min}     \NC number \NC \NC \NR
+\NC \type{def}     \NC number \NC \NC \NR
+\NC \type{max}     \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {mark_classes}}]
+
+The keys in this table are mark class names, and the values are a
+space|-|separated string of glyph names in this class.
+
+\stopsubsection
+
+\startsubsection[title={\type {math}}]
+
+The math table has the variables that are also discussed in the chapter aboout
+math: \type {ScriptPercentScaleDown}, \type {ScriptScriptPercentScaleDown}, \type
+{DelimitedSubFormulaMinHeight}, \type {DisplayOperatorMinHeight}, \type
+{MathLeading}, \type {AxisHeight}, \type {AccentBaseHeight}, \type
+{FlattenedAccentBaseHeight}, \type {SubscriptShiftDown}, \type {SubscriptTopMax},
+\type {SubscriptBaselineDropMin}, \type {SuperscriptShiftUp}, \type
+{SuperscriptShiftUpCramped}, \type {SuperscriptBottomMin}, \type
+{SuperscriptBaselineDropMax}, \type {SubSuperscriptGapMin}, \type
+{SuperscriptBottomMaxWithSubscript}, \type {SpaceAfterScript}, \type
+{UpperLimitGapMin}, \type {UpperLimitBaselineRiseMin}, \type {LowerLimitGapMin},
+\type {LowerLimitBaselineDropMin}, \type {StackTopShiftUp}, \type
+{StackTopDisplayStyleShiftUp}, \type {StackBottomShiftDown}, \type
+{StackBottomDisplayStyleShiftDown}, \type {StackGapMin}, \type
+{StackDisplayStyleGapMin}, \type {StretchStackTopShiftUp}, \type
+{StretchStackBottomShiftDown}, \type {StretchStackGapAboveMin}, \type
+{StretchStackGapBelowMin}, \type {FractionNumeratorShiftUp}, \type
+{FractionNumeratorDisplayStyleShiftUp}, \type {FractionDenominatorShiftDown},
+\type {FractionDenominatorDisplayStyleShiftDown}, \type
+{FractionNumeratorGapMin}, \type {FractionNumeratorDisplayStyleGapMin} \type
+{FractionRuleThickness}, \type {FractionDenominatorGapMin}, \type
+{FractionDenominatorDisplayStyleGapMin}, \type {SkewedFractionHorizontalGap},
+\type {SkewedFractionVerticalGap}, \type {OverbarVerticalGap}, \type
+{OverbarRuleThickness}, \type {OverbarExtraAscender}, \type
+{UnderbarVerticalGap}, \type {UnderbarRuleThickness}, \type
+{UnderbarExtraDescender}, \type {RadicalVerticalGap}, \type
+{RadicalDisplayStyleVerticalGap}, \type {RadicalRuleThickness}, \type
+{RadicalExtraAscender}, \type {RadicalKernBeforeDegree}, \type
+{RadicalKernAfterDegree}, \type {RadicalDegreeBottomRaisePercent}, \type
+{MinConnectorOverlap}, \type {FractionDelimiterSize} and \type
+{FractionDelimiterDisplayStyleSize}.
+
+\stopsubsection
+
+\startsubsection[title={\type {validation_state}}]
+
+This is just a bonus table with keys: \type {bad_ps_fontname}, \type {bad_glyph_table}, \type {bad_cff_table}, \type {bad_metrics_table}, \type {bad_cmap_table}, \type {bad_bitmaps_table}, \type {bad_gx_table}, \type {bad_ot_table}, \type {bad_os2_version} and \type {bad_sfnt_header}.
+
+\stopsubsection
+
+\startsubsection[title={\type {horiz_base} and \type {vert_base}}]
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{tags}    \NC table \NC an array of script list tags\NC \NR
+\NC \type{scripts} \NC table \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {scripts} subtable:
+
+\starttabulate[|l|l|p|]
+\DB key                     \BC type    \BC explanation \NC \NR
+\TB
+\NC \type{baseline}         \NC table   \NC \NC \NR
+\NC \type{default_baseline} \NC number  \NC \NC \NR
+\NC \type{lang}             \NC table   \NC \NC \NR
+\LL
+\stoptabulate
+
+
+The \type {lang} subtable:
+
+\starttabulate[|l|l|p|]
+\DB key             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{tag}      \NC string \NC a script tag \NC \NR
+\NC \type{ascent}   \NC number \NC \NC \NR
+\NC \type{descent}  \NC number \NC \NC \NR
+\NC \type{features} \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {features} points to an array of tables with the same layout except
+that in those nested tables, the tag represents a language.
+
+\stopsubsection
+
+\startsubsection[title={\type {altuni}}]
+
+An array of alternate \UNICODE\ values. Inside that array are hashes with:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{unicode} \NC number \NC this glyph is also used for this unicode \NC \NR
+\NC \type{variant} \NC number \NC the alternative is driven by this unicode selector \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {vert_variants} and \type {horiz_variants}}]
+
+\starttabulate[|l|l|p|]
+\DB key                      \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{variants}          \NC string \NC \NC \NR
+\NC \type{italic_correction} \NC number \NC \NC \NR
+\NC \type{parts}             \NC table  \NC \NC \NR
+\LL
+\stoptabulate
+
+The \type {parts} table is an array of smaller tables:
+
+\starttabulate[|l|l|p|]
+\DB key              \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{component} \NC string \NC \NC \NR
+\NC \type{extender}  \NC number \NC \NC \NR
+\NC \type{start}     \NC number \NC \NC \NR
+\NC \type{end}       \NC number \NC \NC \NR
+\NC \type{advance}   \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {mathkern}}]
+
+\starttabulate[|l|l|p|]
+\DB key                 \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{top_right}    \NC table \NC \NC \NR
+\NC \type{bottom_right} \NC table \NC \NC \NR
+\NC \type{top_left}     \NC table \NC \NC \NR
+\NC \type{bottom_left}  \NC table \NC \NC \NR
+\LL
+\stoptabulate
+
+Each of the subtables is an array of small hashes with two keys:
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{height} \NC number \NC \NC \NR
+\NC \type{kern}   \NC number \NC \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {kerns}}]
+
+Substructure is identical to the per|-|glyph subtable.
+
+\stopsubsection
+
+\startsubsection[title={\type {vkerns}}]
+
+Substructure is identical to the per|-|glyph subtable.
+
+\stopsubsection
+
+\startsubsection[title={\type {texdata}}]
+
+\starttabulate[|l|l|p|]
+\DB key           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{type}   \NC string \NC \nod {unset}, \type {text}, \nod {math}, \type {mathext} \NC \NR
+\NC \type{params} \NC array  \NC 22 font numeric parameters \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {lookups}}]
+
+Top|-|level \type {lookups} is quite different from the ones at character level.
+The keys in this hash are strings, the values the actual lookups, represented as
+dictionary tables.
+
+\starttabulate[|l|l|p|]
+\DB key                  \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{type}          \NC string \NC \NC \NR
+\NC \type{format}        \NC enum   \NC one of \type {glyphs}, \type {class}, \type {coverage},
+                                        \type {reversecoverage} \NC \NR
+\NC \type{tag}           \NC string \NC \NC \NR
+\NC \type{current_class} \NC array  \NC \NC \NR
+\NC \type{before_class}  \NC array  \NC \NC \NR
+\NC \type{after_class}   \NC array  \NC \NC \NR
+\NC \type{rules}         \NC array  \NC an array of rule items\NC \NR
+\LL
+\stoptabulate
+
+Rule items have one common item and one specialized item:
+
+\starttabulate[|l|l|p|]
+\DB key                    \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{lookups}         \NC array \NC a linear array of lookup names                         \NC \NR
+\NC \type{glyphs}          \NC array \NC only if the parent's format is \type {glyphs}          \NC \NR
+\NC \type{class}           \NC array \NC only if the parent's format is \type {class}           \NC \NR
+\NC \type{coverage}        \NC array \NC only if the parent's format is \type {coverage}        \NC \NR
+\NC \type{reversecoverage} \NC array \NC only if the parent's format is \type {reversecoverage} \NC \NR
+\LL
+\stoptabulate
+
+A glyph table is:
+
+\starttabulate[|l|l|p|]
+\DB key          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{names} \NC string \NC \NC \NR
+\NC \type{back}  \NC string \NC \NC \NR
+\NC \type{fore}  \NC string \NC \NC \NR
+\LL
+\stoptabulate
+
+A class table is:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{current} \NC array \NC of numbers  \NC \NR
+\NC \type{before}  \NC array \NC of numbers  \NC \NR
+\NC \type{after}   \NC array \NC of numbers  \NC \NR
+\LL
+\stoptabulate
+
+for coverage:
+
+\starttabulate[|l|l|p|]
+\DB key            \BC type  \BC explanation \NC \NR
+\TB
+\NC \type{current} \NC array \NC of strings \NC \NR
+\NC \type{before}  \NC array \NC of strings \NC \NR
+\NC \type{after}   \NC array \NC of strings \NC \NR
+\LL
+\stoptabulate
+
+and for reverse coverage:
+
+\starttabulate[|l|l|p|]
+\DB key                 \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{current}      \NC array  \NC of strings  \NC \NR
+\NC \type{before}       \NC array  \NC of strings  \NC \NR
+\NC \type{after}        \NC array  \NC of strings  \NC \NR
+\NC \type{replacements} \NC string \NC             \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-fonts.tex b/systems/doc/luatex/luatex-fonts.tex
index 0e1cc8cc5a..d49c63afec 100644
--- a/systems/doc/luatex/luatex-fonts.tex
+++ b/systems/doc/luatex/luatex-fonts.tex
@@ -1,858 +1,858 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-fonts

-

-\startchapter[reference=fonts,title={Font structure}]

-

-\startsection[title={The font tables}]

-

-\topicindex {fonts}

-\topicindex {fonts+tables}

-

-All \TEX\ fonts are represented to \LUA\ code as tables, and internally as

-\CCODE~structures. All keys in the table below are saved in the internal font

-structure if they are present in the table returned by the \cbk {define_font}

-callback, or if they result from the normal \TFM|/|\VF\ reading routines if there

-is no \cbk {define_font} callback defined.

-

-The column \quote {\VF} means that this key will be created by the \type

-{font.read_vf()} routine, \quote {\TFM} means that the key will be created by the

-\type {font.read_tfm()} routine, and \quote {used} means whether or not the

-\LUATEX\ engine itself will do something with the key. The top|-|level keys in

-the table are as follows:

-

-\starttabulate[|l|c|c|c|l|pl|]

-\DB key                     \BC vf  \BC tfm \BC used \BC value type \BC description \NC \NR

-\TB

-\NC \type{name}             \NC yes \NC yes \NC yes  \NC string     \NC metric (file) name \NC \NR

-\NC \type{area}             \NC no  \NC yes \NC yes  \NC string     \NC (directory) location, typically empty \NC \NR

-\NC \type{used}             \NC no  \NC yes \NC yes  \NC boolean    \NC indicates usage (initial: false) \NC \NR

-\NC \type{characters}       \NC yes \NC yes \NC yes  \NC table      \NC the defined glyphs of this font \NC \NR

-\NC \type{checksum}         \NC yes \NC yes \NC no   \NC number     \NC default: 0 \NC \NR

-\NC \type{designsize}       \NC no  \NC yes \NC yes  \NC number     \NC expected size (default: 655360 == 10pt) \NC \NR

-\NC \type{direction}        \NC no  \NC yes \NC yes  \NC number     \NC default: 0 \NC \NR

-\NC \type{encodingbytes}    \NC no  \NC no  \NC yes  \NC number     \NC default: depends on \type {format} \NC \NR

-\NC \type{encodingname}     \NC no  \NC no  \NC yes  \NC string     \NC encoding name \NC \NR

-\NC \type{fonts}            \NC yes \NC no  \NC yes  \NC table      \NC locally used fonts \NC \NR

-\NC \type{psname}           \NC no  \NC no  \NC yes  \NC string     \NC This is the \POSTSCRIPT\ fontname in the incoming font

-                                                                        source, and it's used as fontname identifier in the \PDF\

-                                                                        output. This has to be a valid string, e.g.\ no spaces

-                                                                        and such, as the backend will not do a cleanup. This gives

-                                                                        complete control to the loader. \NC \NR

-\NC \type{fullname}         \NC no  \NC no  \NC yes  \NC string     \NC output font name, used as a fallback in the \PDF\ output

-                                                                        if the \type {psname} is not set \NC \NR

-\NC \type{header}           \NC yes \NC no  \NC no   \NC string     \NC header comments, if any \NC \NR

-\NC \type{hyphenchar}       \NC no  \NC no  \NC yes  \NC number     \NC default: \TEX's \prm {hyphenchar} \NC \NR

-\NC \type{parameters}       \NC no  \NC yes \NC yes  \NC hash       \NC default: 7 parameters, all zero \NC \NR

-\NC \type{size}             \NC no  \NC yes \NC yes  \NC number     \NC the required scaling (by default the same as designsize) \NC \NR

-\NC \type{skewchar}         \NC no  \NC no  \NC yes  \NC number     \NC default: \TEX's \prm {skewchar} \NC \NR

-\NC \type{type}             \NC yes \NC no  \NC yes  \NC string     \NC basic type of this font \NC \NR

-\NC \type{format}           \NC no  \NC no  \NC yes  \NC string     \NC disk format type \NC \NR

-\NC \type{embedding}        \NC no  \NC no  \NC yes  \NC string     \NC \PDF\ inclusion  \NC \NR

-\NC \type{filename}         \NC no  \NC no  \NC yes  \NC string     \NC the name of the font on disk \NC \NR

-\NC \type{tounicode}        \NC no  \NC yes \NC yes  \NC number     \NC When this is set to~1 \LUATEX\ assumes per|-|glyph

-                                                                        tounicode entries are present in the font. \NC \NR

-\NC \type{stretch}          \NC no  \NC no  \NC yes  \NC number     \NC the \quote {stretch} value from \lpr {expandglyphsinfont} \NC \NR

-\NC \type{shrink}           \NC no  \NC no  \NC yes  \NC number     \NC the \quote {shrink} value from \lpr {expandglyphsinfont} \NC \NR

-\NC \type{step}             \NC no  \NC no  \NC yes  \NC number     \NC the \quote {step} value from \lpr {expandglyphsinfont} \NC \NR

-\NC \type{expansion_factor} \NC no  \NC no  \NC no   \NC number     \NC the actual expansion factor of an expanded font \NC \NR

-\NC \type{attributes}       \NC no  \NC no  \NC yes  \NC string     \NC the \orm {pdffontattr} \NC \NR

-\NC \type{cache}            \NC no  \NC no  \NC yes  \NC string     \NC This key controls caching of the \LUA\ table on the

-                                                                        \TEX\ end where \type {yes} means: use a reference to

-                                                                        the table that is passed to \LUATEX\ (this is the

-                                                                        default), and \type {no} means: don't store the

-                                                                        table reference, don't cache any \LUA\ data for this

-                                                                        font while \type {renew} means: don't store the table

-                                                                        reference, but save a reference to the table that is

-                                                                        created at the first access to one of its fields in the

-                                                                        font. \NC \NR

-\NC \type{nomath}           \NC no  \NC no  \NC yes  \NC boolean    \NC This key allows a minor speedup for text fonts. If it

-                                                                        is present and true, then \LUATEX\ will not check the

-                                                                        character entries for math|-|specific keys. \NC \NR

-\NC \type{oldmath}          \NC no  \NC no  \NC yes  \NC boolean    \NC This key flags a font as representing an old school \TEX\

-                                                                        math font and disables the \OPENTYPE\ code path. \NC \NR

-\NC \type{slant}            \NC no  \NC no  \NC yes  \NC number     \NC This parameter will tilt the font and

-                                                                        does the same as \type {SlantFont} in the map file for

-                                                                        \TYPEONE\ fonts. \NC \NR

-\NC \type{extend}           \NC no  \NC no  \NC yes  \NC number     \NC This parameter will scale the font horizontally and

-                                                                        does the same as \type {ExtendFont} in the map file for

-                                                                        \TYPEONE\ fonts. \NC \NR

-\NC \type{squeeze}          \NC no  \NC no  \NC yes  \NC number     \NC This parameter will scale the font vertically and has

-                                                                        no equivalent in the map file. \NC \NR

-\NC \type{width}            \NC no  \NC no  \NC yes  \NC number     \NC The backend will inject \PDF\ operators that set the

-                                                                        penwidth. The value is (as usual in \TEX) divided by 1000.

-                                                                        It works with the \type {mode} file. \NC \NR

-\NC \type{mode}             \NC no  \NC no  \NC yes  \NC number     \NC The backend will inject \PDF\ operators that relate to the

-                                                                        drawing mode with 0~being a fill, 1~being an outline,

-                                                                        2~both draw and fill and 3~no painting at all. \NC \NR

-\LL

-\stoptabulate

-

-The saved reference in the \type {cache} option is thread|-|local, so be careful

-when you are using coroutines: an error will be thrown if the table has been

-cached in one thread, but you reference it from another thread.

-

-The key \type {name} is always required. The keys \type {stretch}, \type

-{shrink}, \type {step} only have meaning when used together: they can be used to

-replace a post|-|loading \lpr {expandglyphsinfont} command. The \type

-{auto_expand} option is not supported in \LUATEX. In fact, the primitives that

-create expanded or protruding copies are probably only useful when used with

-traditional fonts because all these extra \OPENTYPE\ properties are kept out of

-the picture. The \type {expansion_factor} is value that can be present inside a

-font in \type {font.fonts}. It is the actual expansion factor (a value between

-\type {-shrink} and \type {stretch}, with step \type {step}) of a font that was

-automatically generated by the font expansion algorithm.

-

-Because we store the actual state of expansion with each glyph and don't have

-special font instances, we can change some font related parameters before lines

-are constructed, like:

-

-\starttyping

-font.setexpansion(font.current(),100,100,20)

-\stoptyping

-

-This is mostly meant for experiments (or an optimizing routing written in \LUA)

-so there is no primitive.

-

-The key \type {attributes} can be used to set font attributes in the \PDF\ file.

-The key \type {used} is set by the engine when a font is actively in use, this

-makes sure that the font's definition is written to the output file (\DVI\ or

-\PDF). The \TFM\ reader sets it to false. The \type {direction} is a number

-signalling the \quote {normal} direction for this font. There are sixteen

-possibilities:

-

-\starttabulate[|Tc|c|Tc|c|Tc|c|Tc|c|]

-\DB \# \BC dir \BC \# \BC dir \BC \# \BC dir \BC \# \BC dir \NC \NR

-\TB

-\NC  0 \NC LT  \NC  4 \NC RT  \NC  8 \NC TT  \NC 12 \NC BT  \NC \NR

-\NC  1 \NC LL  \NC  5 \NC RL  \NC  9 \NC TL  \NC 13 \NC BL  \NC \NR

-\NC  2 \NC LB  \NC  6 \NC RB  \NC 10 \NC TB  \NC 14 \NC BB  \NC \NR

-\NC  3 \NC LR  \NC  7 \NC RR  \NC 11 \NC TR  \NC 15 \NC BR  \NC \NR

-\LL

-\stoptabulate

-

-These are \OMEGA|-|style direction abbreviations: the first character indicates

-the \quote {first} edge of the character glyphs (the edge that is seen first in

-the writing direction), the second the \quote {top} side. Keep in mind that

-\LUATEX\ has a bit different directional model so these values are not used for

-anything.

-

-The \type {parameters} is a hash with mixed key types. There are seven possible

-string keys, as well as a number of integer indices (these start from 8 up). The

-seven strings are actually used instead of the bottom seven indices, because that

-gives a nicer user interface.

-

-The names and their internal remapping are:

-

-\starttabulate[|l|c|]

-\DB name                  \BC remapping \NC \NR

-\TB

-\NC \type {slant}         \NC 1 \NC \NR

-\NC \type {space}         \NC 2 \NC \NR

-\NC \type {space_stretch} \NC 3 \NC \NR

-\NC \type {space_shrink}  \NC 4 \NC \NR

-\NC \type {x_height}      \NC 5 \NC \NR

-\NC \type {quad}          \NC 6 \NC \NR

-\NC \type {extra_space}   \NC 7 \NC \NR

-\LL

-\stoptabulate

-

-The keys \type {type}, \type {format}, \type {embedding}, \type {fullname} and

-\type {filename} are used to embed \OPENTYPE\ fonts in the result \PDF.

-

-The \type {characters} table is a list of character hashes indexed by an integer

-number. The number is the \quote {internal code} \TEX\ knows this character by.

-

-Two very special string indexes can be used also: \type {left_boundary} is a

-virtual character whose ligatures and kerns are used to handle word boundary

-processing. \type {right_boundary} is similar but not actually used for anything

-(yet).

-

-Each character hash itself is a hash. For example, here is the character \quote

-{f} (decimal 102) in the font \type {cmr10 at 10pt}. The numbers that represent

-dimensions are in scaled points.

-

-\starttyping

-[102] = {

-    ["width"]  = 200250,

-    ["height"] = 455111,

-    ["depth"]  = 0,

-    ["italic"] = 50973,

-    ["kerns"]  = {

-        [63] = 50973,

-        [93] = 50973,

-        [39] = 50973,

-        [33] = 50973,

-        [41] = 50973

-    },

-    ["ligatures"] = {

-        [102] = { ["char"] = 11, ["type"] = 0 },

-        [108] = { ["char"] = 13, ["type"] = 0 },

-        [105] = { ["char"] = 12, ["type"] = 0 }

-    }

-}

-\stoptyping

-

-The following top|-|level keys can be present inside a character hash:

-

-\starttabulate[|l|c|c|c|l|p|]

-\DB key                     \BC vf  \BC tfm \BC used  \BC type    \BC description \NC\NR

-\TB

-\NC \type{width}            \NC yes \NC yes \NC yes   \NC number  \NC character's width, in sp (default 0) \NC\NR

-\NC \type{height}           \NC no  \NC yes \NC yes   \NC number  \NC character's height, in sp (default 0) \NC\NR

-\NC \type{depth}            \NC no  \NC yes \NC yes   \NC number  \NC character's depth, in sp (default 0) \NC\NR

-\NC \type{italic}           \NC no  \NC yes \NC yes   \NC number  \NC character's italic correction, in sp (default zero) \NC\NR

-\NC \type{top_accent}       \NC no  \NC no  \NC maybe \NC number  \NC character's top accent alignment place, in sp (default zero) \NC\NR

-\NC \type{bot_accent}       \NC no  \NC no  \NC maybe \NC number  \NC character's bottom accent alignment place, in sp (default zero) \NC\NR

-\NC \type{left_protruding}  \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {lpcode} \NC\NR

-\NC \type{right_protruding} \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {rpcode} \NC\NR

-\NC \type{expansion_factor} \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {efcode} \NC\NR

-\NC \type{tounicode}        \NC no  \NC no  \NC maybe \NC string  \NC character's \UNICODE\ equivalent(s), in \UTF|-|16BE hexadecimal format \NC\NR

-\NC \type{next}             \NC no  \NC yes \NC yes   \NC number  \NC the \quote {next larger} character index \NC\NR

-\NC \type{extensible}       \NC no  \NC yes \NC yes   \NC table   \NC the constituent parts of an extensible recipe \NC\NR

-\NC \type{vert_variants}    \NC no  \NC no  \NC yes   \NC table   \NC constituent parts of a vertical variant set \NC \NR

-\NC \type{horiz_variants}   \NC no  \NC no  \NC yes   \NC table   \NC constituent parts of a horizontal variant set \NC \NR

-\NC \type{kerns}            \NC no  \NC yes \NC yes   \NC table   \NC kerning information \NC\NR

-\NC \type{ligatures}        \NC no  \NC yes \NC yes   \NC table   \NC ligaturing information \NC\NR

-\NC \type{commands}         \NC yes \NC no  \NC yes   \NC array   \NC virtual font commands \NC\NR

-\NC \type{name}             \NC no  \NC no  \NC no    \NC string  \NC the character (\POSTSCRIPT) name \NC\NR

-\NC \type{index}            \NC no  \NC no  \NC yes   \NC number  \NC the (\OPENTYPE\ or \TRUETYPE) font glyph index \NC\NR

-\NC \type{used}             \NC no  \NC yes \NC yes   \NC boolean \NC typeset already (default: false) \NC\NR

-\NC \type{mathkern}         \NC no  \NC no  \NC yes   \NC table   \NC math cut-in specifications \NC\NR

-\LL

-\stoptabulate

-

-The values of \type {top_accent}, \type {bot_accent} and \type {mathkern} are

-used only for math accent and superscript placement, see \at {page} [math] in

-this manual for details. The values of \type {left_protruding} and \type

-{right_protruding} are used only when \lpr {protrudechars} is non-zero. Whether

-or not \type {expansion_factor} is used depends on the font's global expansion

-settings, as well as on the value of \lpr {adjustspacing}.

-

-The usage of \type {tounicode} is this: if this font specifies a \type

-{tounicode=1} at the top level, then \LUATEX\ will construct a \type {/ToUnicode}

-entry for the \PDF\ font (or font subset) based on the character|-|level \type

-{tounicode} strings, where they are available. If a character does not have a

-sensible \UNICODE\ equivalent, do not provide a string either (no empty strings).

-

-If the font level \type {tounicode} is not set, then \LUATEX\ will build up \type

-{/ToUnicode} based on the \TEX\ code points you used, and any character-level

-\type {tounicodes} will be ignored. The string format is exactly the format that

-is expected by Adobe \CMAP\ files (\UTF-16BE in hexadecimal encoding), minus the

-enclosing angle brackets. For instance the \type {tounicode} for a \type {fi}

-ligature would be \type {00660069}. When you pass a number the conversion will be

-done for you.

-

-A math character can have a \type {next} field that points to a next larger

-shape. However, the presence of \type {extensible} will overrule \type {next}, if

-that is also present. The \type {extensible} field in turn can be overruled by

-\type {vert_variants}, the \OPENTYPE\ version. The \type {extensible} table is

-very simple:

-

-\starttabulate[|l|l|p|]

-\DB key        \BC type   \BC description                \NC\NR

-\TB

-\NC \type{top} \NC number \NC top character index        \NC\NR

-\NC \type{mid} \NC number \NC middle character index     \NC\NR

-\NC \type{bot} \NC number \NC bottom character index     \NC\NR

-\NC \type{rep} \NC number \NC repeatable character index \NC\NR

-\LL

-\stoptabulate

-

-The \type {horiz_variants} and \type {vert_variants} are arrays of components.

-Each of those components is itself a hash of up to five keys:

-

-\starttabulate[|l|l|p|]

-\DB key             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{glyph}    \NC number \NC The character index. Note that this is an encoding number, not a name. \NC \NR

-\NC \type{extender} \NC number \NC One (1) if this part is repeatable, zero (0) otherwise. \NC \NR

-\NC \type{start}    \NC number \NC The maximum overlap at the starting side (in scaled points). \NC \NR

-\NC \type{end}      \NC number \NC The maximum overlap at the ending side (in scaled points). \NC \NR

-\NC \type{advance}  \NC number \NC The total advance width of this item. It can be zero or missing,

-                                   then the natural size of the glyph for character \type {component}

-                                   is used. \NC \NR

-\LL

-\stoptabulate

-

-The \type {kerns} table is a hash indexed by character index (and \quote

-{character index} is defined as either a non|-|negative integer or the string

-value \type {right_boundary}), with the values of the kerning to be applied, in

-scaled points.

-

-The \type {ligatures} table is a hash indexed by character index (and \quote

-{character index} is defined as either a non|-|negative integer or the string

-value \type {right_boundary}), with the values being yet another small hash, with

-two fields:

-

-\starttabulate[|l|l|p|]

-\DB key         \BC type   \BC description \NC \NR

-\TB

-\NC \type{type} \NC number \NC the type of this ligature command, default 0 \NC \NR

-\NC \type{char} \NC number \NC the character index of the resultant ligature \NC \NR

-\LL

-\stoptabulate

-

-The \type {char} field in a ligature is required. The \type {type} field inside a

-ligature is the numerical or string value of one of the eight possible ligature

-types supported by \TEX. When \TEX\ inserts a new ligature, it puts the new glyph

-in the middle of the left and right glyphs. The original left and right glyphs

-can optionally be retained, and when at least one of them is kept, it is also

-possible to move the new \quote {insertion point} forward one or two places. The

-glyph that ends up to the right of the insertion point will become the next

-\quote {left}.

-

-\starttabulate[|l|c|l|l|]

-\DB textual (Knuth)       \BC number \BC string        \BC result      \NC\NR

-\TB

-\NC \type{l + r =: n}     \NC 0      \NC \type{=:}     \NC \type{|n}   \NC\NR

-\NC \type{l + r =:| n}    \NC 1      \NC \type{=:|}    \NC \type{|nr}  \NC\NR

-\NC \type{l + r |=: n}    \NC 2      \NC \type{|=:}    \NC \type{|ln}  \NC\NR

-\NC \type{l + r |=:| n}   \NC 3      \NC \type{|=:|}   \NC \type{|lnr} \NC\NR

-\NC \type{l + r  =:|> n}  \NC 5      \NC \type{=:|>}   \NC \type{n|r}  \NC\NR

-\NC \type{l + r |=:> n}   \NC 6      \NC \type{|=:>}   \NC \type{l|n}  \NC\NR

-\NC \type{l + r |=:|> n}  \NC 7      \NC \type{|=:|>}  \NC \type{l|nr} \NC\NR

-\NC \type{l + r |=:|>> n} \NC 11     \NC \type{|=:|>>} \NC \type{ln|r} \NC\NR

-\LL

-\stoptabulate

-

-The default value is~0, and can be left out. That signifies a \quote {normal}

-ligature where the ligature replaces both original glyphs. In this table the~\type {|}

-indicates the final insertion point.

-

-The \type {commands} array is explained below.

-

-\stopsection

-

-\startsection[title={Real fonts}]

-

-\topicindex {fonts+real}

-\topicindex {fonts+virtual}

-

-Whether or not a \TEX\ font is a \quote {real} font that should be written to the

-\PDF\ document is decided by the \type {type} value in the top|-|level font

-structure. If the value is \type {real}, then this is a proper font, and the

-inclusion mechanism will attempt to add the needed font object definitions to the

-\PDF. Values for \type {type} are:

-

-\starttabulate[|l|p|]

-\DB value          \BC description            \NC\NR

-\TB

-\NC \type{real}    \NC this is a base font    \NC\NR

-\NC \type{virtual} \NC this is a virtual font \NC\NR

-\LL

-\stoptabulate

-

-The actions to be taken depend on a number of different variables:

-

-\startitemize[packed]

-\startitem

-    Whether the used font fits in an 8-bit encoding scheme or not. This is true for

-    traditional \TEX\ fonts that communicate via \TFM\ files.

-\stopitem

-\startitem

-    The type of the disk font file, for instance a bitmap file or an outline

-    \TYPEONE, \TRUETYPE\ or \OPENTYPE\ font.

-\stopitem

-\startitem

-    The level of embedding requested, although in most cases a subset of

-    characters is embedded. The times when nothing got embedded are (in our

-    opinion at least) basically gone.

-\stopitem

-\stopitemize

-

-A font that uses anything other than an 8-bit encoding vector has to be written

-to the \PDF\ in a different way. When the font table has \type {encodingbytes}

-set to~2, then it is a wide font, in all other cases it isn't. The value~2 is the

-default for \OPENTYPE\ and \TRUETYPE\ fonts loaded via \LUA. For \TYPEONE\ fonts,

-you have to set \type {encodingbytes} to~2 explicitly. For \PK\ bitmap fonts,

-wide font encoding is not supported at all.

-

-If no special care is needed, \LUATEX\ falls back to the mapfile|-|based solution

-used by \PDFTEX\ and \DVIPS, so that legacy fonts are supported transparently. If

-a \quote {wide} font is used, the new subsystem kicks in, and some extra fields

-have to be present in the font structure. In this case, \LUATEX\ does not use a

-map file at all. These extra fields are: \type {format}, \type {embedding}, \type

-{fullname}, \type {cidinfo} (as explained above), \type {filename}, and the \type

-{index} key in the separate characters.

-

-The \type {format} variable can have the following values. \type {type3} fonts

-are provided for backward compatibility only, and do not support the new wide

-encoding options.

-

-\starttabulate[|l|p|]

-\DB value           \BC description                                               \NC \NR

-\TB

-\NC \type{type1}    \NC this is a \POSTSCRIPT\ \TYPEONE\ font                     \NC \NR

-\NC \type{type3}    \NC this is a bitmapped (\PK) font                            \NC \NR

-\NC \type{truetype} \NC this is a \TRUETYPE\ or \TRUETYPE|-|based \OPENTYPE\ font \NC \NR

-\NC \type{opentype} \NC this is a \POSTSCRIPT|-|based \OPENTYPE\ font             \NC \NR

-\LL

-\stoptabulate

-

-Valid values for the \type {embedding} variable are:

-

-\starttabulate[|l|p|]

-\DB value         \BC description                             \NC \NR

-\TB

-\NC \type{no}     \NC don't embed the font at all             \NC \NR

-\NC \type{subset} \NC include and atttempt to subset the font \NC \NR

-\NC \type{full}   \NC include this font in its entirety       \NC \NR

-\LL

-\stoptabulate

-

-The other fields are used as follows. The \type {fullname} will be the

-\POSTSCRIPT|/|\PDF\ font name. The \type {cidinfo} will be used as the character

-set: the CID \type {/Ordering} and \type {/Registry} keys. The \type {filename}

-points to the actual font file. If you include the full path in the \type

-{filename} or if the file is in the local directory, \LUATEX\ will run a little

-bit more efficient because it will not have to re|-|run the \type {find_*_file}

-callback in that case.

-

-Be careful: when mixing old and new fonts in one document, it is possible to

-create \POSTSCRIPT\ name clashes that can result in printing errors. When this

-happens, you have to change the \type {fullname} of the font to a more unique

-one.

-

-Typeset strings are written out in a wide format using 2~bytes per glyph, using

-the \type {index} key in the character information as value. The overall effect

-is like having an encoding based on numbers instead of traditional (\POSTSCRIPT)

-name|-|based reencoding. One way to get the correct \type {index} numbers for

-\TYPEONE\ fonts is by loading the font via \type {fontloader.open} and use the

-table indices as \type {index} fields.

-

-In order to make sure that cut and paste of the final document works okay you can

-best make sure that there is a \type {tounicode} vector enforced. Not all \PDF\

-viewers handle this right so take \ACROBAT\ as reference.

-

-\stopsection

-

-\startsection[reference=virtualfonts,title={Virtual fonts}]

-

-\subsection{The structure}

-

-\topicindex {fonts+virtual}

-

-You have to take the following steps if you want \LUATEX\ to treat the returned

-table from \cbk {define_font} as a virtual font:

-

-\startitemize[packed]

-\startitem

-    Set the top|-|level key \type {type} to \type {virtual}. In most cases it's

-    optional because we look at the \type {commands} entry anyway.

-\stopitem

-\startitem

-    Make sure there is at least one valid entry in \type {fonts} (see below),

-    although recent versions of \LUATEX\ add a default entry when this table is

-    missing.

-\stopitem

-\startitem

-    Add a \type {commands} array to those characters that matter. A virtual

-    character can itself point to virtual characters but be careful with nesting

-    as you can create loops and overflow the stack (which often indicates an

-    error anyway).

-\stopitem

-\stopitemize

-

-The presence of the toplevel \type {type} key with the specific value \type

-{virtual} will trigger handling of the rest of the special virtual font fields in

-the table, but the mere existence of 'type' is enough to prevent \LUATEX\ from

-looking for a virtual font on its own. This also works \quote {in reverse}: if

-you are absolutely certain that a font is not a virtual font, assigning the value

-\type {real} to \type {type} will inhibit \LUATEX\ from looking for a virtual

-font file, thereby saving you a disk search. This only matters when we load a

-\TFM\ file.

-

-The \type {fonts} is an (indexed) \LUA\ table. The values are one- or two|-|key

-hashes themselves, each entry indicating one of the base fonts in a virtual font.

-In case your font is referring to itself, you can use the \type {font.nextid()}

-function which returns the index of the next to be defined font which is probably

-the currently defined one. So, a table looks like this:

-

-\starttyping

-fonts = {

-  { name = "ptmr8a", size = 655360 },

-  { name = "psyr", size = 600000 },

-  { id = 38 }

-}

-\stoptyping

-

-The first referenced font (at index~1) in this virtual font is \type {ptrmr8a}

-loaded at 10pt, and the second is \type {psyr} loaded at a little over 9pt. The

-third one is a previously defined font that is known to \LUATEX\ as font id~38.

-The array index numbers are used by the character command definitions that are

-part of each character.

-

-The \type {commands} array is a hash where each item is another small array,

-with the first entry representing a command and the extra items being the

-parameters to that command. The allowed commands and their arguments are:

-

-\starttabulate[|l|l|l|p|]

-\DB command        \BC arguments \BC type      \BC description \NC \NR

-\TB

-\NC \type{font}    \NC 1         \NC number    \NC select a new font from the local \type {fonts} table \NC \NR

-\NC \type{char}    \NC 1         \NC number    \NC typeset this character number from the current font,

-                                                   and move right by the character's width \NC \NR

-\NC \type{node}    \NC 1         \NC node      \NC output this node (list), and move right

-                                                   by the width of this list\NC \NR

-\NC \type{slot}    \NC 2         \NC 2 numbers \NC a shortcut for the combination of a font and char command\NC \NR

-\NC \type{push}    \NC 0         \NC           \NC save current position\NC \NR

-\NC \type{nop}     \NC 0         \NC           \NC do nothing \NC \NR

-\NC \type{pop}     \NC 0         \NC           \NC pop position \NC \NR

-\NC \type{rule}    \NC 2         \NC 2 numbers \NC output a rule $ht*wd$, and move right. \NC \NR

-\NC \type{down}    \NC 1         \NC number    \NC move down on the page \NC \NR

-\NC \type{right}   \NC 1         \NC number    \NC move right on the page \NC \NR

-\NC \type{special} \NC 1         \NC string    \NC output a \prm {special} command \NC \NR

-\NC \type{pdf}     \NC 2         \NC 2 strings \NC output a \PDF\ literal, the first string is one of \type {origin},

-                                                   \type {page}, \type {text}, \type {font}, \type {direct} or \type {raw}; if you

-                                                   have one string only \type {origin} is assumed \NC \NR

-\NC \type{lua}     \NC 1         \NC string,

-                                     function  \NC execute a \LUA\ script when the glyph is embedded; in case of a

-                                                   function it gets the font id and character code passed \NC \NR

-\NC \type{image}   \NC 1         \NC image     \NC output an image (the argument can be either an \type {<image>} variable or an \type {image_spec} table) \NC \NR

-\NC \type{comment} \NC any       \NC any       \NC the arguments of this command are ignored \NC \NR

-\LL

-\stoptabulate

-

-When a font id is set to~0 then it will be replaced by the currently assigned

-font id. This prevents the need for hackery with future id's. Normally one could

-use \type {font.nextid} but when more complex fonts are built in the meantime

-other instances could have been loaded.

-

-The \type {pdf} option also accepts a \type {mode} keyword in which case the

-third argument sets the mode. That option will change the mode in an efficient

-way (passing an empty string would result in an extra empty lines in the \PDF\

-file. This option only makes sense for virtual fonts. The \type {font} mode only

-makes sense in virtual fonts. Modes are somewhat fuzzy and partially inherited

-from \PDFTEX.

-

-\starttabulate[|l|p|]

-\DB mode           \BC description \NC \NR

-\TB

-\NC \type {origin} \NC enter page mode and set the position \NC \NR

-\NC \type {page}   \NC enter page mode \NC \NR

-\NC \type {text}   \NC enter text mode \NC \NR

-\NC \type {font}   \NC enter font mode (kind of text mode, only in virtual fonts) \NC \NR

-\NC \type {always} \NC finish the current string and force a transform if needed \NC \NR

-\NC \type {raw}    \NC finish the current string \NC \NR

-\LL

-\stoptabulate

-

-You always need to check what \PDF\ code is generated because there can be all

-kind of interferences with optimization in the backend and fonts are complicated

-anyway. Here is a rather elaborate glyph commands example using such keys:

-

-\starttyping

-...

-commands = {

-    { "push" },                     -- remember where we are

-    { "right", 5000 },              -- move right about 0.08pt

-    { "font", 3 },                  -- select the fonts[3] entry

-    { "char", 97 },                 -- place character 97 (ASCII 'a')

- -- { "slot", 2, 97 },              -- an alternative for the previous two

-    { "pop" },                      -- go all the way back

-    { "down", -200000 },            -- move upwards by about 3pt

-    { "special", "pdf: 1 0 0 rg" }  -- switch to red color

- -- { "pdf", "origin", "1 0 0 rg" } -- switch to red color (alternative)

-    { "rule", 500000, 20000 }       -- draw a bar

-    { "special", "pdf: 0 g" }       -- back to black

- -- { "pdf", "origin", "0 g" }      -- back to black (alternative)

-}

-...

-\stoptyping

-

-The default value for \type {font} is always~1 at the start of the

-\type {commands} array. Therefore, if the virtual font is essentially only a

-re|-|encoding, then you do usually not have created an explicit \quote {font}

-command in the array.

-

-Rules inside of \type {commands} arrays are built up using only two dimensions:

-they do not have depth. For correct vertical placement, an extra \type {down}

-command may be needed.

-

-Regardless of the amount of movement you create within the \type {commands}, the

-output pointer will always move by exactly the width that was given in the \type

-{width} key of the character hash. Any movements that take place inside the \type

-{commands} array are ignored on the upper level.

-

-The special can have a \type {pdf:}, \type {pdf:origin:},  \type {pdf:page:},

-\type {pdf:direct:} or  \type {pdf:raw:} prefix. When you have to concatenate

-strings using the \type {pdf} command might be more efficient.

-

-\subsection{Artificial fonts}

-

-Even in a \quote {real} font, there can be virtual characters. When \LUATEX\

-encounters a \type {commands} field inside a character when it becomes time to

-typeset the character, it will interpret the commands, just like for a true

-virtual character. In this case, if you have created no \quote {fonts} array,

-then the default (and only) \quote {base} font is taken to be the current font

-itself. In practice, this means that you can create virtual duplicates of

-existing characters which is useful if you want to create composite characters.

-

-Note: this feature does {\it not\/} work the other way around. There can not be

-\quote {real} characters in a virtual font! You cannot use this technique for

-font re-encoding either; you need a truly virtual font for that (because

-characters that are already present cannot be altered).

-

-\subsection{Example virtual font}

-

-\topicindex {fonts+virtual}

-

-Finally, here is a plain \TEX\ input file with a virtual font demonstration:

-

-\startbuffer

-\directlua {

-  callback.register('define_font',

-    function (name,size)

-      if name == 'cmr10-red' then

-        local f = font.read_tfm('cmr10',size)

-        f.name  = 'cmr10-red'

-        f.type  = 'virtual'

-        f.fonts = {

-          { name = 'cmr10', size = size }

-        }

-        for i,v in pairs(f.characters) do

-          if string.char(i):find('[tacohanshartmut]') then

-             v.commands = {

-               { "special", "pdf: 1 0 0 rg" },

-               { "char", i },

-               { "special", "pdf: 0 g" },

-              }

-          end

-        end

-        return f

-      else

-        return font.read_tfm(name,size)

-      end

-    end

-  )

-}

-

-\font\myfont  = cmr10-red at 10pt \myfont  This is a line of text \par

-\font\myfontx = cmr10     at 10pt \myfontx Here is another line of text \par

-\stopbuffer

-

-\typebuffer

-

-\stopsection

-

-\startsection[title={The \type {vf} library}]

-

-The \type {vf} library can be used when \LUA\ code, as defined in the \type

-{commands} of the font, is executed. The functions provided are similar as the

-commands: \type {char}, \type {down}, \type {fontid}, \type {image}, \type

-{node}, \type {nop}, \type {pop}, \type {push}, \type {right}, \nod {rule}, \type

-{special} and \type {pdf}. This library has been present for a while but not been

-advertised and tested much, if only because it's easy to define an invalid font

-(or mess up the \PDF\ stream). Keep in mind that the \LUA\ snippets are executed

-each time when a character is output.

-

-\stopsection

-

-\startsection[title={The \type {font} library}]

-

-\topicindex {fonts+library}

-

-The font library provides the interface into the internals of the font system,

-and it also contains helper functions to load traditional \TEX\ font metrics

-formats. Other font loading functionality is provided by the \type {fontloader}

-library that will be discussed in the next section.

-

-\subsection{Loading a \TFM\ file}

-

-\topicindex {fonts+tfm}

-

-The behaviour documented in this subsection is considered stable in the sense that

-there will not be backward|-|incompatible changes any more.

-

-\startfunctioncall

-<table> fnt =

-    font.read_tfm(<string> name, <number> s)

-\stopfunctioncall

-

-The number is a bit special:

-

-\startitemize

-\startitem

-    If it is positive, it specifies an \quote {at size} in scaled points.

-\stopitem

-\startitem

-    If it is negative, its absolute value represents a \quote {scaled}

-    setting relative to the designsize of the font.

-\stopitem

-\stopitemize

-

-\subsection{Loading a \VF\ file}

-

-\topicindex {fonts+vf}

-

-The behavior documented in this subsection is considered stable in the sense that

-there will not be backward-incompatible changes any more.

-

-\startfunctioncall

-<table> vf_fnt =

-    font.read_vf(<string> name, <number> s)

-\stopfunctioncall

-

-The meaning of the number \type {s} and the format of the returned table are

-similar to the ones in the \type {read_tfm} function.

-

-\subsection{The fonts array}

-

-\topicindex {fonts+virtual}

-

-The whole table of \TEX\ fonts is accessible from \LUA\ using a virtual array.

-

-\starttyping

-font.fonts[n] = { ... }

-<table> f = font.fonts[n]

-\stoptyping

-

-Because this is a virtual array, you cannot call \type {pairs} on it, but see

-below for the \type {font.each} iterator.

-

-The two metatable functions implementing the virtual array are:

-

-\startfunctioncall

-<table> f = font.getfont(<number> n)

-font.setfont(<number> n, <table> f)

-\stopfunctioncall

-

-Note that at the moment, each access to the \type {font.fonts} or call to \type

-{font.getfont} creates a \LUA\ table for the whole font unless you cached it.

-This process can be quite slow.

-

-\startfunctioncall

-<table> p = font.getparameters(<number> n)

-\stopfunctioncall

-

-This one will return a table of the parameters as known to \TEX. These can be

-different from the ones in the cached table.

-

-Also note the following: assignments can only be made to fonts that have already

-been defined in \TEX, but have not been accessed {\it at all\/} since that

-definition. This limits the usability of the write access to \type {font.fonts}

-quite a lot, a less stringent ruleset will likely be implemented later.

-

-\subsection{Checking a font's status}

-

-You can test for the status of a font by calling this function:

-

-\startfunctioncall

-<boolean> f =

-    font.frozen(<number> n)

-\stopfunctioncall

-

-The return value is one of \type {true} (unassignable), \type {false} (can be

-changed) or \type {nil} (not a valid font at all).

-

-\subsection{Defining a font directly}

-

-\topicindex {fonts+define}

-

-You can define your own font into \type {font.fonts} by calling this function:

-

-\startfunctioncall

-<number> i =

-    font.define(<table> f)

-\stopfunctioncall

-

-The return value is the internal id number of the defined font (the index into

-\type {font.fonts}). If the font creation fails, an error is raised. The table is

-a font structure. An alternative call is:

-

-\startfunctioncall

-<number> i =

-    font.define(<number> n, <table> f)

-\stopfunctioncall

-

-Where the first argument is a reserved font id (see below).

-

-\subsection{Extending a font}

-

-\topicindex {fonts+extend}

-

-Within reasonable bounds you can extend a font after it has been defined. Because

-some properties are best left unchanged this is limited to adding characters.

-

-\startfunctioncall

-font.addcharacters(<number n>, <table> f)

-\stopfunctioncall

-

-The table passed can have the fields \type {characters} which is a (sub)table

-like the one used in define, and for virtual fonts a \type {fonts} table can be

-added. The characters defined in the \type {characters} table are added (when not

-yet present) or replace an existing entry. Keep in mind that replacing can have

-side effects because a character already can have been used. Instead of posing

-restrictions we expect the user to be careful. (The \type {setfont} helper is

-a more drastic replacer.)

-

-\subsection{Projected next font id}

-

-\topicindex {fonts+id}

-

-\startfunctioncall

-<number> i =

-    font.nextid()

-\stopfunctioncall

-

-This returns the font id number that would be returned by a \type {font.define}

-call if it was executed at this spot in the code flow. This is useful for virtual

-fonts that need to reference themselves. If you pass \type {true} as argument,

-the id gets reserved and you can pass to \type {font.define} as first argument.

-This can be handy when you create complex virtual fonts.

-

-\startfunctioncall

-<number> i =

-    font.nextid(true)

-\stopfunctioncall

-

-\subsection{Font ids}

-

-\topicindex {fonts+id}

-\topicindex {fonts+current}

-

-\startfunctioncall

-<number> i =

-    font.id(<string> csname)

-\stopfunctioncall

-

-This returns the font id associated with \type {csname}, or $-1$ if \type

-{csname} is not defined.

-

-\startfunctioncall

-<number> i =

-    font.max()

-\stopfunctioncall

-

-This is the largest used index in \type {font.fonts}.

-

-\startfunctioncall

-<number> i = font.current()

-font.current(<number> i)

-\stopfunctioncall

-

-This gets or sets the currently used font number.

-

-\subsection{Iterating over all fonts}

-

-\topicindex {fonts+iterate}

-

-\startfunctioncall

-for i,v in font.each() do

-  ...

-end

-\stopfunctioncall

-

-This is an iterator over each of the defined \TEX\ fonts. The first returned

-value is the index in \type {font.fonts}, the second the font itself, as a \LUA\

-table. The indices are listed incrementally, but they do not always form an array

-of consecutive numbers: in some cases there can be holes in the sequence.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-fonts
+
+\startchapter[reference=fonts,title={Font structure}]
+
+\startsection[title={The font tables}]
+
+\topicindex {fonts}
+\topicindex {fonts+tables}
+
+All \TEX\ fonts are represented to \LUA\ code as tables, and internally as
+\CCODE~structures. All keys in the table below are saved in the internal font
+structure if they are present in the table returned by the \cbk {define_font}
+callback, or if they result from the normal \TFM|/|\VF\ reading routines if there
+is no \cbk {define_font} callback defined.
+
+The column \quote {\VF} means that this key will be created by the \type
+{font.read_vf()} routine, \quote {\TFM} means that the key will be created by the
+\type {font.read_tfm()} routine, and \quote {used} means whether or not the
+\LUATEX\ engine itself will do something with the key. The top|-|level keys in
+the table are as follows:
+
+\starttabulate[|l|c|c|c|l|pl|]
+\DB key                     \BC vf  \BC tfm \BC used \BC value type \BC description \NC \NR
+\TB
+\NC \type{name}             \NC yes \NC yes \NC yes  \NC string     \NC metric (file) name \NC \NR
+\NC \type{area}             \NC no  \NC yes \NC yes  \NC string     \NC (directory) location, typically empty \NC \NR
+\NC \type{used}             \NC no  \NC yes \NC yes  \NC boolean    \NC indicates usage (initial: false) \NC \NR
+\NC \type{characters}       \NC yes \NC yes \NC yes  \NC table      \NC the defined glyphs of this font \NC \NR
+\NC \type{checksum}         \NC yes \NC yes \NC no   \NC number     \NC default: 0 \NC \NR
+\NC \type{designsize}       \NC no  \NC yes \NC yes  \NC number     \NC expected size (default: 655360 == 10pt) \NC \NR
+\NC \type{direction}        \NC no  \NC yes \NC yes  \NC number     \NC default: 0 \NC \NR
+\NC \type{encodingbytes}    \NC no  \NC no  \NC yes  \NC number     \NC default: depends on \type {format} \NC \NR
+\NC \type{encodingname}     \NC no  \NC no  \NC yes  \NC string     \NC encoding name \NC \NR
+\NC \type{fonts}            \NC yes \NC no  \NC yes  \NC table      \NC locally used fonts \NC \NR
+\NC \type{psname}           \NC no  \NC no  \NC yes  \NC string     \NC This is the \POSTSCRIPT\ fontname in the incoming font
+                                                                        source, and it's used as fontname identifier in the \PDF\
+                                                                        output. This has to be a valid string, e.g.\ no spaces
+                                                                        and such, as the backend will not do a cleanup. This gives
+                                                                        complete control to the loader. \NC \NR
+\NC \type{fullname}         \NC no  \NC no  \NC yes  \NC string     \NC output font name, used as a fallback in the \PDF\ output
+                                                                        if the \type {psname} is not set \NC \NR
+\NC \type{header}           \NC yes \NC no  \NC no   \NC string     \NC header comments, if any \NC \NR
+\NC \type{hyphenchar}       \NC no  \NC no  \NC yes  \NC number     \NC default: \TEX's \prm {hyphenchar} \NC \NR
+\NC \type{parameters}       \NC no  \NC yes \NC yes  \NC hash       \NC default: 7 parameters, all zero \NC \NR
+\NC \type{size}             \NC no  \NC yes \NC yes  \NC number     \NC the required scaling (by default the same as designsize) \NC \NR
+\NC \type{skewchar}         \NC no  \NC no  \NC yes  \NC number     \NC default: \TEX's \prm {skewchar} \NC \NR
+\NC \type{type}             \NC yes \NC no  \NC yes  \NC string     \NC basic type of this font \NC \NR
+\NC \type{format}           \NC no  \NC no  \NC yes  \NC string     \NC disk format type \NC \NR
+\NC \type{embedding}        \NC no  \NC no  \NC yes  \NC string     \NC \PDF\ inclusion  \NC \NR
+\NC \type{filename}         \NC no  \NC no  \NC yes  \NC string     \NC the name of the font on disk \NC \NR
+\NC \type{tounicode}        \NC no  \NC yes \NC yes  \NC number     \NC When this is set to~1 \LUATEX\ assumes per|-|glyph
+                                                                        tounicode entries are present in the font. \NC \NR
+\NC \type{stretch}          \NC no  \NC no  \NC yes  \NC number     \NC the \quote {stretch} value from \lpr {expandglyphsinfont} \NC \NR
+\NC \type{shrink}           \NC no  \NC no  \NC yes  \NC number     \NC the \quote {shrink} value from \lpr {expandglyphsinfont} \NC \NR
+\NC \type{step}             \NC no  \NC no  \NC yes  \NC number     \NC the \quote {step} value from \lpr {expandglyphsinfont} \NC \NR
+\NC \type{expansion_factor} \NC no  \NC no  \NC no   \NC number     \NC the actual expansion factor of an expanded font \NC \NR
+\NC \type{attributes}       \NC no  \NC no  \NC yes  \NC string     \NC the \orm {pdffontattr} \NC \NR
+\NC \type{cache}            \NC no  \NC no  \NC yes  \NC string     \NC This key controls caching of the \LUA\ table on the
+                                                                        \TEX\ end where \type {yes} means: use a reference to
+                                                                        the table that is passed to \LUATEX\ (this is the
+                                                                        default), and \type {no} means: don't store the
+                                                                        table reference, don't cache any \LUA\ data for this
+                                                                        font while \type {renew} means: don't store the table
+                                                                        reference, but save a reference to the table that is
+                                                                        created at the first access to one of its fields in the
+                                                                        font. \NC \NR
+\NC \type{nomath}           \NC no  \NC no  \NC yes  \NC boolean    \NC This key allows a minor speedup for text fonts. If it
+                                                                        is present and true, then \LUATEX\ will not check the
+                                                                        character entries for math|-|specific keys. \NC \NR
+\NC \type{oldmath}          \NC no  \NC no  \NC yes  \NC boolean    \NC This key flags a font as representing an old school \TEX\
+                                                                        math font and disables the \OPENTYPE\ code path. \NC \NR
+\NC \type{slant}            \NC no  \NC no  \NC yes  \NC number     \NC This parameter will tilt the font and
+                                                                        does the same as \type {SlantFont} in the map file for
+                                                                        \TYPEONE\ fonts. \NC \NR
+\NC \type{extend}           \NC no  \NC no  \NC yes  \NC number     \NC This parameter will scale the font horizontally and
+                                                                        does the same as \type {ExtendFont} in the map file for
+                                                                        \TYPEONE\ fonts. \NC \NR
+\NC \type{squeeze}          \NC no  \NC no  \NC yes  \NC number     \NC This parameter will scale the font vertically and has
+                                                                        no equivalent in the map file. \NC \NR
+\NC \type{width}            \NC no  \NC no  \NC yes  \NC number     \NC The backend will inject \PDF\ operators that set the
+                                                                        penwidth. The value is (as usual in \TEX) divided by 1000.
+                                                                        It works with the \type {mode} file. \NC \NR
+\NC \type{mode}             \NC no  \NC no  \NC yes  \NC number     \NC The backend will inject \PDF\ operators that relate to the
+                                                                        drawing mode with 0~being a fill, 1~being an outline,
+                                                                        2~both draw and fill and 3~no painting at all. \NC \NR
+\LL
+\stoptabulate
+
+The saved reference in the \type {cache} option is thread|-|local, so be careful
+when you are using coroutines: an error will be thrown if the table has been
+cached in one thread, but you reference it from another thread.
+
+The key \type {name} is always required. The keys \type {stretch}, \type
+{shrink}, \type {step} only have meaning when used together: they can be used to
+replace a post|-|loading \lpr {expandglyphsinfont} command. The \type
+{auto_expand} option is not supported in \LUATEX. In fact, the primitives that
+create expanded or protruding copies are probably only useful when used with
+traditional fonts because all these extra \OPENTYPE\ properties are kept out of
+the picture. The \type {expansion_factor} is value that can be present inside a
+font in \type {font.fonts}. It is the actual expansion factor (a value between
+\type {-shrink} and \type {stretch}, with step \type {step}) of a font that was
+automatically generated by the font expansion algorithm.
+
+Because we store the actual state of expansion with each glyph and don't have
+special font instances, we can change some font related parameters before lines
+are constructed, like:
+
+\starttyping
+font.setexpansion(font.current(),100,100,20)
+\stoptyping
+
+This is mostly meant for experiments (or an optimizing routing written in \LUA)
+so there is no primitive.
+
+The key \type {attributes} can be used to set font attributes in the \PDF\ file.
+The key \type {used} is set by the engine when a font is actively in use, this
+makes sure that the font's definition is written to the output file (\DVI\ or
+\PDF). The \TFM\ reader sets it to false. The \type {direction} is a number
+signalling the \quote {normal} direction for this font. There are sixteen
+possibilities:
+
+\starttabulate[|Tc|c|Tc|c|Tc|c|Tc|c|]
+\DB \# \BC dir \BC \# \BC dir \BC \# \BC dir \BC \# \BC dir \NC \NR
+\TB
+\NC  0 \NC LT  \NC  4 \NC RT  \NC  8 \NC TT  \NC 12 \NC BT  \NC \NR
+\NC  1 \NC LL  \NC  5 \NC RL  \NC  9 \NC TL  \NC 13 \NC BL  \NC \NR
+\NC  2 \NC LB  \NC  6 \NC RB  \NC 10 \NC TB  \NC 14 \NC BB  \NC \NR
+\NC  3 \NC LR  \NC  7 \NC RR  \NC 11 \NC TR  \NC 15 \NC BR  \NC \NR
+\LL
+\stoptabulate
+
+These are \OMEGA|-|style direction abbreviations: the first character indicates
+the \quote {first} edge of the character glyphs (the edge that is seen first in
+the writing direction), the second the \quote {top} side. Keep in mind that
+\LUATEX\ has a bit different directional model so these values are not used for
+anything.
+
+The \type {parameters} is a hash with mixed key types. There are seven possible
+string keys, as well as a number of integer indices (these start from 8 up). The
+seven strings are actually used instead of the bottom seven indices, because that
+gives a nicer user interface.
+
+The names and their internal remapping are:
+
+\starttabulate[|l|c|]
+\DB name                  \BC remapping \NC \NR
+\TB
+\NC \type {slant}         \NC 1 \NC \NR
+\NC \type {space}         \NC 2 \NC \NR
+\NC \type {space_stretch} \NC 3 \NC \NR
+\NC \type {space_shrink}  \NC 4 \NC \NR
+\NC \type {x_height}      \NC 5 \NC \NR
+\NC \type {quad}          \NC 6 \NC \NR
+\NC \type {extra_space}   \NC 7 \NC \NR
+\LL
+\stoptabulate
+
+The keys \type {type}, \type {format}, \type {embedding}, \type {fullname} and
+\type {filename} are used to embed \OPENTYPE\ fonts in the result \PDF.
+
+The \type {characters} table is a list of character hashes indexed by an integer
+number. The number is the \quote {internal code} \TEX\ knows this character by.
+
+Two very special string indexes can be used also: \type {left_boundary} is a
+virtual character whose ligatures and kerns are used to handle word boundary
+processing. \type {right_boundary} is similar but not actually used for anything
+(yet).
+
+Each character hash itself is a hash. For example, here is the character \quote
+{f} (decimal 102) in the font \type {cmr10 at 10pt}. The numbers that represent
+dimensions are in scaled points.
+
+\starttyping
+[102] = {
+    ["width"]  = 200250,
+    ["height"] = 455111,
+    ["depth"]  = 0,
+    ["italic"] = 50973,
+    ["kerns"]  = {
+        [63] = 50973,
+        [93] = 50973,
+        [39] = 50973,
+        [33] = 50973,
+        [41] = 50973
+    },
+    ["ligatures"] = {
+        [102] = { ["char"] = 11, ["type"] = 0 },
+        [108] = { ["char"] = 13, ["type"] = 0 },
+        [105] = { ["char"] = 12, ["type"] = 0 }
+    }
+}
+\stoptyping
+
+The following top|-|level keys can be present inside a character hash:
+
+\starttabulate[|l|c|c|c|l|p|]
+\DB key                     \BC vf  \BC tfm \BC used  \BC type    \BC description \NC\NR
+\TB
+\NC \type{width}            \NC yes \NC yes \NC yes   \NC number  \NC character's width, in sp (default 0) \NC\NR
+\NC \type{height}           \NC no  \NC yes \NC yes   \NC number  \NC character's height, in sp (default 0) \NC\NR
+\NC \type{depth}            \NC no  \NC yes \NC yes   \NC number  \NC character's depth, in sp (default 0) \NC\NR
+\NC \type{italic}           \NC no  \NC yes \NC yes   \NC number  \NC character's italic correction, in sp (default zero) \NC\NR
+\NC \type{top_accent}       \NC no  \NC no  \NC maybe \NC number  \NC character's top accent alignment place, in sp (default zero) \NC\NR
+\NC \type{bot_accent}       \NC no  \NC no  \NC maybe \NC number  \NC character's bottom accent alignment place, in sp (default zero) \NC\NR
+\NC \type{left_protruding}  \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {lpcode} \NC\NR
+\NC \type{right_protruding} \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {rpcode} \NC\NR
+\NC \type{expansion_factor} \NC no  \NC no  \NC maybe \NC number  \NC character's \lpr {efcode} \NC\NR
+\NC \type{tounicode}        \NC no  \NC no  \NC maybe \NC string  \NC character's \UNICODE\ equivalent(s), in \UTF|-|16BE hexadecimal format \NC\NR
+\NC \type{next}             \NC no  \NC yes \NC yes   \NC number  \NC the \quote {next larger} character index \NC\NR
+\NC \type{extensible}       \NC no  \NC yes \NC yes   \NC table   \NC the constituent parts of an extensible recipe \NC\NR
+\NC \type{vert_variants}    \NC no  \NC no  \NC yes   \NC table   \NC constituent parts of a vertical variant set \NC \NR
+\NC \type{horiz_variants}   \NC no  \NC no  \NC yes   \NC table   \NC constituent parts of a horizontal variant set \NC \NR
+\NC \type{kerns}            \NC no  \NC yes \NC yes   \NC table   \NC kerning information \NC\NR
+\NC \type{ligatures}        \NC no  \NC yes \NC yes   \NC table   \NC ligaturing information \NC\NR
+\NC \type{commands}         \NC yes \NC no  \NC yes   \NC array   \NC virtual font commands \NC\NR
+\NC \type{name}             \NC no  \NC no  \NC no    \NC string  \NC the character (\POSTSCRIPT) name \NC\NR
+\NC \type{index}            \NC no  \NC no  \NC yes   \NC number  \NC the (\OPENTYPE\ or \TRUETYPE) font glyph index \NC\NR
+\NC \type{used}             \NC no  \NC yes \NC yes   \NC boolean \NC typeset already (default: false) \NC\NR
+\NC \type{mathkern}         \NC no  \NC no  \NC yes   \NC table   \NC math cut-in specifications \NC\NR
+\LL
+\stoptabulate
+
+The values of \type {top_accent}, \type {bot_accent} and \type {mathkern} are
+used only for math accent and superscript placement, see \at {page} [math] in
+this manual for details. The values of \type {left_protruding} and \type
+{right_protruding} are used only when \lpr {protrudechars} is non-zero. Whether
+or not \type {expansion_factor} is used depends on the font's global expansion
+settings, as well as on the value of \lpr {adjustspacing}.
+
+The usage of \type {tounicode} is this: if this font specifies a \type
+{tounicode=1} at the top level, then \LUATEX\ will construct a \type {/ToUnicode}
+entry for the \PDF\ font (or font subset) based on the character|-|level \type
+{tounicode} strings, where they are available. If a character does not have a
+sensible \UNICODE\ equivalent, do not provide a string either (no empty strings).
+
+If the font level \type {tounicode} is not set, then \LUATEX\ will build up \type
+{/ToUnicode} based on the \TEX\ code points you used, and any character-level
+\type {tounicodes} will be ignored. The string format is exactly the format that
+is expected by Adobe \CMAP\ files (\UTF-16BE in hexadecimal encoding), minus the
+enclosing angle brackets. For instance the \type {tounicode} for a \type {fi}
+ligature would be \type {00660069}. When you pass a number the conversion will be
+done for you.
+
+A math character can have a \type {next} field that points to a next larger
+shape. However, the presence of \type {extensible} will overrule \type {next}, if
+that is also present. The \type {extensible} field in turn can be overruled by
+\type {vert_variants}, the \OPENTYPE\ version. The \type {extensible} table is
+very simple:
+
+\starttabulate[|l|l|p|]
+\DB key        \BC type   \BC description                \NC\NR
+\TB
+\NC \type{top} \NC number \NC top character index        \NC\NR
+\NC \type{mid} \NC number \NC middle character index     \NC\NR
+\NC \type{bot} \NC number \NC bottom character index     \NC\NR
+\NC \type{rep} \NC number \NC repeatable character index \NC\NR
+\LL
+\stoptabulate
+
+The \type {horiz_variants} and \type {vert_variants} are arrays of components.
+Each of those components is itself a hash of up to five keys:
+
+\starttabulate[|l|l|p|]
+\DB key             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{glyph}    \NC number \NC The character index. Note that this is an encoding number, not a name. \NC \NR
+\NC \type{extender} \NC number \NC One (1) if this part is repeatable, zero (0) otherwise. \NC \NR
+\NC \type{start}    \NC number \NC The maximum overlap at the starting side (in scaled points). \NC \NR
+\NC \type{end}      \NC number \NC The maximum overlap at the ending side (in scaled points). \NC \NR
+\NC \type{advance}  \NC number \NC The total advance width of this item. It can be zero or missing,
+                                   then the natural size of the glyph for character \type {component}
+                                   is used. \NC \NR
+\LL
+\stoptabulate
+
+The \type {kerns} table is a hash indexed by character index (and \quote
+{character index} is defined as either a non|-|negative integer or the string
+value \type {right_boundary}), with the values of the kerning to be applied, in
+scaled points.
+
+The \type {ligatures} table is a hash indexed by character index (and \quote
+{character index} is defined as either a non|-|negative integer or the string
+value \type {right_boundary}), with the values being yet another small hash, with
+two fields:
+
+\starttabulate[|l|l|p|]
+\DB key         \BC type   \BC description \NC \NR
+\TB
+\NC \type{type} \NC number \NC the type of this ligature command, default 0 \NC \NR
+\NC \type{char} \NC number \NC the character index of the resultant ligature \NC \NR
+\LL
+\stoptabulate
+
+The \type {char} field in a ligature is required. The \type {type} field inside a
+ligature is the numerical or string value of one of the eight possible ligature
+types supported by \TEX. When \TEX\ inserts a new ligature, it puts the new glyph
+in the middle of the left and right glyphs. The original left and right glyphs
+can optionally be retained, and when at least one of them is kept, it is also
+possible to move the new \quote {insertion point} forward one or two places. The
+glyph that ends up to the right of the insertion point will become the next
+\quote {left}.
+
+\starttabulate[|l|c|l|l|]
+\DB textual (Knuth)       \BC number \BC string        \BC result      \NC\NR
+\TB
+\NC \type{l + r =: n}     \NC 0      \NC \type{=:}     \NC \type{|n}   \NC\NR
+\NC \type{l + r =:| n}    \NC 1      \NC \type{=:|}    \NC \type{|nr}  \NC\NR
+\NC \type{l + r |=: n}    \NC 2      \NC \type{|=:}    \NC \type{|ln}  \NC\NR
+\NC \type{l + r |=:| n}   \NC 3      \NC \type{|=:|}   \NC \type{|lnr} \NC\NR
+\NC \type{l + r  =:|> n}  \NC 5      \NC \type{=:|>}   \NC \type{n|r}  \NC\NR
+\NC \type{l + r |=:> n}   \NC 6      \NC \type{|=:>}   \NC \type{l|n}  \NC\NR
+\NC \type{l + r |=:|> n}  \NC 7      \NC \type{|=:|>}  \NC \type{l|nr} \NC\NR
+\NC \type{l + r |=:|>> n} \NC 11     \NC \type{|=:|>>} \NC \type{ln|r} \NC\NR
+\LL
+\stoptabulate
+
+The default value is~0, and can be left out. That signifies a \quote {normal}
+ligature where the ligature replaces both original glyphs. In this table the~\type {|}
+indicates the final insertion point.
+
+The \type {commands} array is explained below.
+
+\stopsection
+
+\startsection[title={Real fonts}]
+
+\topicindex {fonts+real}
+\topicindex {fonts+virtual}
+
+Whether or not a \TEX\ font is a \quote {real} font that should be written to the
+\PDF\ document is decided by the \type {type} value in the top|-|level font
+structure. If the value is \type {real}, then this is a proper font, and the
+inclusion mechanism will attempt to add the needed font object definitions to the
+\PDF. Values for \type {type} are:
+
+\starttabulate[|l|p|]
+\DB value          \BC description            \NC\NR
+\TB
+\NC \type{real}    \NC this is a base font    \NC\NR
+\NC \type{virtual} \NC this is a virtual font \NC\NR
+\LL
+\stoptabulate
+
+The actions to be taken depend on a number of different variables:
+
+\startitemize[packed]
+\startitem
+    Whether the used font fits in an 8-bit encoding scheme or not. This is true for
+    traditional \TEX\ fonts that communicate via \TFM\ files.
+\stopitem
+\startitem
+    The type of the disk font file, for instance a bitmap file or an outline
+    \TYPEONE, \TRUETYPE\ or \OPENTYPE\ font.
+\stopitem
+\startitem
+    The level of embedding requested, although in most cases a subset of
+    characters is embedded. The times when nothing got embedded are (in our
+    opinion at least) basically gone.
+\stopitem
+\stopitemize
+
+A font that uses anything other than an 8-bit encoding vector has to be written
+to the \PDF\ in a different way. When the font table has \type {encodingbytes}
+set to~2, then it is a wide font, in all other cases it isn't. The value~2 is the
+default for \OPENTYPE\ and \TRUETYPE\ fonts loaded via \LUA. For \TYPEONE\ fonts,
+you have to set \type {encodingbytes} to~2 explicitly. For \PK\ bitmap fonts,
+wide font encoding is not supported at all.
+
+If no special care is needed, \LUATEX\ falls back to the mapfile|-|based solution
+used by \PDFTEX\ and \DVIPS, so that legacy fonts are supported transparently. If
+a \quote {wide} font is used, the new subsystem kicks in, and some extra fields
+have to be present in the font structure. In this case, \LUATEX\ does not use a
+map file at all. These extra fields are: \type {format}, \type {embedding}, \type
+{fullname}, \type {cidinfo} (as explained above), \type {filename}, and the \type
+{index} key in the separate characters.
+
+The \type {format} variable can have the following values. \type {type3} fonts
+are provided for backward compatibility only, and do not support the new wide
+encoding options.
+
+\starttabulate[|l|p|]
+\DB value           \BC description                                               \NC \NR
+\TB
+\NC \type{type1}    \NC this is a \POSTSCRIPT\ \TYPEONE\ font                     \NC \NR
+\NC \type{type3}    \NC this is a bitmapped (\PK) font                            \NC \NR
+\NC \type{truetype} \NC this is a \TRUETYPE\ or \TRUETYPE|-|based \OPENTYPE\ font \NC \NR
+\NC \type{opentype} \NC this is a \POSTSCRIPT|-|based \OPENTYPE\ font             \NC \NR
+\LL
+\stoptabulate
+
+Valid values for the \type {embedding} variable are:
+
+\starttabulate[|l|p|]
+\DB value         \BC description                             \NC \NR
+\TB
+\NC \type{no}     \NC don't embed the font at all             \NC \NR
+\NC \type{subset} \NC include and atttempt to subset the font \NC \NR
+\NC \type{full}   \NC include this font in its entirety       \NC \NR
+\LL
+\stoptabulate
+
+The other fields are used as follows. The \type {fullname} will be the
+\POSTSCRIPT|/|\PDF\ font name. The \type {cidinfo} will be used as the character
+set: the CID \type {/Ordering} and \type {/Registry} keys. The \type {filename}
+points to the actual font file. If you include the full path in the \type
+{filename} or if the file is in the local directory, \LUATEX\ will run a little
+bit more efficient because it will not have to re|-|run the \type {find_*_file}
+callback in that case.
+
+Be careful: when mixing old and new fonts in one document, it is possible to
+create \POSTSCRIPT\ name clashes that can result in printing errors. When this
+happens, you have to change the \type {fullname} of the font to a more unique
+one.
+
+Typeset strings are written out in a wide format using 2~bytes per glyph, using
+the \type {index} key in the character information as value. The overall effect
+is like having an encoding based on numbers instead of traditional (\POSTSCRIPT)
+name|-|based reencoding. One way to get the correct \type {index} numbers for
+\TYPEONE\ fonts is by loading the font via \type {fontloader.open} and use the
+table indices as \type {index} fields.
+
+In order to make sure that cut and paste of the final document works okay you can
+best make sure that there is a \type {tounicode} vector enforced. Not all \PDF\
+viewers handle this right so take \ACROBAT\ as reference.
+
+\stopsection
+
+\startsection[reference=virtualfonts,title={Virtual fonts}]
+
+\subsection{The structure}
+
+\topicindex {fonts+virtual}
+
+You have to take the following steps if you want \LUATEX\ to treat the returned
+table from \cbk {define_font} as a virtual font:
+
+\startitemize[packed]
+\startitem
+    Set the top|-|level key \type {type} to \type {virtual}. In most cases it's
+    optional because we look at the \type {commands} entry anyway.
+\stopitem
+\startitem
+    Make sure there is at least one valid entry in \type {fonts} (see below),
+    although recent versions of \LUATEX\ add a default entry when this table is
+    missing.
+\stopitem
+\startitem
+    Add a \type {commands} array to those characters that matter. A virtual
+    character can itself point to virtual characters but be careful with nesting
+    as you can create loops and overflow the stack (which often indicates an
+    error anyway).
+\stopitem
+\stopitemize
+
+The presence of the toplevel \type {type} key with the specific value \type
+{virtual} will trigger handling of the rest of the special virtual font fields in
+the table, but the mere existence of 'type' is enough to prevent \LUATEX\ from
+looking for a virtual font on its own. This also works \quote {in reverse}: if
+you are absolutely certain that a font is not a virtual font, assigning the value
+\type {real} to \type {type} will inhibit \LUATEX\ from looking for a virtual
+font file, thereby saving you a disk search. This only matters when we load a
+\TFM\ file.
+
+The \type {fonts} is an (indexed) \LUA\ table. The values are one- or two|-|key
+hashes themselves, each entry indicating one of the base fonts in a virtual font.
+In case your font is referring to itself, you can use the \type {font.nextid()}
+function which returns the index of the next to be defined font which is probably
+the currently defined one. So, a table looks like this:
+
+\starttyping
+fonts = {
+  { name = "ptmr8a", size = 655360 },
+  { name = "psyr", size = 600000 },
+  { id = 38 }
+}
+\stoptyping
+
+The first referenced font (at index~1) in this virtual font is \type {ptrmr8a}
+loaded at 10pt, and the second is \type {psyr} loaded at a little over 9pt. The
+third one is a previously defined font that is known to \LUATEX\ as font id~38.
+The array index numbers are used by the character command definitions that are
+part of each character.
+
+The \type {commands} array is a hash where each item is another small array,
+with the first entry representing a command and the extra items being the
+parameters to that command. The allowed commands and their arguments are:
+
+\starttabulate[|l|l|l|p|]
+\DB command        \BC arguments \BC type      \BC description \NC \NR
+\TB
+\NC \type{font}    \NC 1         \NC number    \NC select a new font from the local \type {fonts} table \NC \NR
+\NC \type{char}    \NC 1         \NC number    \NC typeset this character number from the current font,
+                                                   and move right by the character's width \NC \NR
+\NC \type{node}    \NC 1         \NC node      \NC output this node (list), and move right
+                                                   by the width of this list\NC \NR
+\NC \type{slot}    \NC 2         \NC 2 numbers \NC a shortcut for the combination of a font and char command\NC \NR
+\NC \type{push}    \NC 0         \NC           \NC save current position\NC \NR
+\NC \type{nop}     \NC 0         \NC           \NC do nothing \NC \NR
+\NC \type{pop}     \NC 0         \NC           \NC pop position \NC \NR
+\NC \type{rule}    \NC 2         \NC 2 numbers \NC output a rule $ht*wd$, and move right. \NC \NR
+\NC \type{down}    \NC 1         \NC number    \NC move down on the page \NC \NR
+\NC \type{right}   \NC 1         \NC number    \NC move right on the page \NC \NR
+\NC \type{special} \NC 1         \NC string    \NC output a \prm {special} command \NC \NR
+\NC \type{pdf}     \NC 2         \NC 2 strings \NC output a \PDF\ literal, the first string is one of \type {origin},
+                                                   \type {page}, \type {text}, \type {font}, \type {direct} or \type {raw}; if you
+                                                   have one string only \type {origin} is assumed \NC \NR
+\NC \type{lua}     \NC 1         \NC string,
+                                     function  \NC execute a \LUA\ script when the glyph is embedded; in case of a
+                                                   function it gets the font id and character code passed \NC \NR
+\NC \type{image}   \NC 1         \NC image     \NC output an image (the argument can be either an \type {<image>} variable or an \type {image_spec} table) \NC \NR
+\NC \type{comment} \NC any       \NC any       \NC the arguments of this command are ignored \NC \NR
+\LL
+\stoptabulate
+
+When a font id is set to~0 then it will be replaced by the currently assigned
+font id. This prevents the need for hackery with future id's. Normally one could
+use \type {font.nextid} but when more complex fonts are built in the meantime
+other instances could have been loaded.
+
+The \type {pdf} option also accepts a \type {mode} keyword in which case the
+third argument sets the mode. That option will change the mode in an efficient
+way (passing an empty string would result in an extra empty lines in the \PDF\
+file. This option only makes sense for virtual fonts. The \type {font} mode only
+makes sense in virtual fonts. Modes are somewhat fuzzy and partially inherited
+from \PDFTEX.
+
+\starttabulate[|l|p|]
+\DB mode           \BC description \NC \NR
+\TB
+\NC \type {origin} \NC enter page mode and set the position \NC \NR
+\NC \type {page}   \NC enter page mode \NC \NR
+\NC \type {text}   \NC enter text mode \NC \NR
+\NC \type {font}   \NC enter font mode (kind of text mode, only in virtual fonts) \NC \NR
+\NC \type {always} \NC finish the current string and force a transform if needed \NC \NR
+\NC \type {raw}    \NC finish the current string \NC \NR
+\LL
+\stoptabulate
+
+You always need to check what \PDF\ code is generated because there can be all
+kind of interferences with optimization in the backend and fonts are complicated
+anyway. Here is a rather elaborate glyph commands example using such keys:
+
+\starttyping
+...
+commands = {
+    { "push" },                     -- remember where we are
+    { "right", 5000 },              -- move right about 0.08pt
+    { "font", 3 },                  -- select the fonts[3] entry
+    { "char", 97 },                 -- place character 97 (ASCII 'a')
+ -- { "slot", 2, 97 },              -- an alternative for the previous two
+    { "pop" },                      -- go all the way back
+    { "down", -200000 },            -- move upwards by about 3pt
+    { "special", "pdf: 1 0 0 rg" }  -- switch to red color
+ -- { "pdf", "origin", "1 0 0 rg" } -- switch to red color (alternative)
+    { "rule", 500000, 20000 }       -- draw a bar
+    { "special", "pdf: 0 g" }       -- back to black
+ -- { "pdf", "origin", "0 g" }      -- back to black (alternative)
+}
+...
+\stoptyping
+
+The default value for \type {font} is always~1 at the start of the
+\type {commands} array. Therefore, if the virtual font is essentially only a
+re|-|encoding, then you do usually not have created an explicit \quote {font}
+command in the array.
+
+Rules inside of \type {commands} arrays are built up using only two dimensions:
+they do not have depth. For correct vertical placement, an extra \type {down}
+command may be needed.
+
+Regardless of the amount of movement you create within the \type {commands}, the
+output pointer will always move by exactly the width that was given in the \type
+{width} key of the character hash. Any movements that take place inside the \type
+{commands} array are ignored on the upper level.
+
+The special can have a \type {pdf:}, \type {pdf:origin:},  \type {pdf:page:},
+\type {pdf:direct:} or  \type {pdf:raw:} prefix. When you have to concatenate
+strings using the \type {pdf} command might be more efficient.
+
+\subsection{Artificial fonts}
+
+Even in a \quote {real} font, there can be virtual characters. When \LUATEX\
+encounters a \type {commands} field inside a character when it becomes time to
+typeset the character, it will interpret the commands, just like for a true
+virtual character. In this case, if you have created no \quote {fonts} array,
+then the default (and only) \quote {base} font is taken to be the current font
+itself. In practice, this means that you can create virtual duplicates of
+existing characters which is useful if you want to create composite characters.
+
+Note: this feature does {\it not\/} work the other way around. There can not be
+\quote {real} characters in a virtual font! You cannot use this technique for
+font re-encoding either; you need a truly virtual font for that (because
+characters that are already present cannot be altered).
+
+\subsection{Example virtual font}
+
+\topicindex {fonts+virtual}
+
+Finally, here is a plain \TEX\ input file with a virtual font demonstration:
+
+\startbuffer
+\directlua {
+  callback.register('define_font',
+    function (name,size)
+      if name == 'cmr10-red' then
+        local f = font.read_tfm('cmr10',size)
+        f.name  = 'cmr10-red'
+        f.type  = 'virtual'
+        f.fonts = {
+          { name = 'cmr10', size = size }
+        }
+        for i,v in pairs(f.characters) do
+          if string.char(i):find('[tacohanshartmut]') then
+             v.commands = {
+               { "special", "pdf: 1 0 0 rg" },
+               { "char", i },
+               { "special", "pdf: 0 g" },
+              }
+          end
+        end
+        return f
+      else
+        return font.read_tfm(name,size)
+      end
+    end
+  )
+}
+
+\font\myfont  = cmr10-red at 10pt \myfont  This is a line of text \par
+\font\myfontx = cmr10     at 10pt \myfontx Here is another line of text \par
+\stopbuffer
+
+\typebuffer
+
+\stopsection
+
+\startsection[title={The \type {vf} library}]
+
+The \type {vf} library can be used when \LUA\ code, as defined in the \type
+{commands} of the font, is executed. The functions provided are similar as the
+commands: \type {char}, \type {down}, \type {fontid}, \type {image}, \type
+{node}, \type {nop}, \type {pop}, \type {push}, \type {right}, \nod {rule}, \type
+{special} and \type {pdf}. This library has been present for a while but not been
+advertised and tested much, if only because it's easy to define an invalid font
+(or mess up the \PDF\ stream). Keep in mind that the \LUA\ snippets are executed
+each time when a character is output.
+
+\stopsection
+
+\startsection[title={The \type {font} library}]
+
+\topicindex {fonts+library}
+
+The font library provides the interface into the internals of the font system,
+and it also contains helper functions to load traditional \TEX\ font metrics
+formats. Other font loading functionality is provided by the \type {fontloader}
+library that will be discussed in the next section.
+
+\subsection{Loading a \TFM\ file}
+
+\topicindex {fonts+tfm}
+
+The behaviour documented in this subsection is considered stable in the sense that
+there will not be backward|-|incompatible changes any more.
+
+\startfunctioncall
+<table> fnt =
+    font.read_tfm(<string> name, <number> s)
+\stopfunctioncall
+
+The number is a bit special:
+
+\startitemize
+\startitem
+    If it is positive, it specifies an \quote {at size} in scaled points.
+\stopitem
+\startitem
+    If it is negative, its absolute value represents a \quote {scaled}
+    setting relative to the designsize of the font.
+\stopitem
+\stopitemize
+
+\subsection{Loading a \VF\ file}
+
+\topicindex {fonts+vf}
+
+The behavior documented in this subsection is considered stable in the sense that
+there will not be backward-incompatible changes any more.
+
+\startfunctioncall
+<table> vf_fnt =
+    font.read_vf(<string> name, <number> s)
+\stopfunctioncall
+
+The meaning of the number \type {s} and the format of the returned table are
+similar to the ones in the \type {read_tfm} function.
+
+\subsection{The fonts array}
+
+\topicindex {fonts+virtual}
+
+The whole table of \TEX\ fonts is accessible from \LUA\ using a virtual array.
+
+\starttyping
+font.fonts[n] = { ... }
+<table> f = font.fonts[n]
+\stoptyping
+
+Because this is a virtual array, you cannot call \type {pairs} on it, but see
+below for the \type {font.each} iterator.
+
+The two metatable functions implementing the virtual array are:
+
+\startfunctioncall
+<table> f = font.getfont(<number> n)
+font.setfont(<number> n, <table> f)
+\stopfunctioncall
+
+Note that at the moment, each access to the \type {font.fonts} or call to \type
+{font.getfont} creates a \LUA\ table for the whole font unless you cached it.
+This process can be quite slow.
+
+\startfunctioncall
+<table> p = font.getparameters(<number> n)
+\stopfunctioncall
+
+This one will return a table of the parameters as known to \TEX. These can be
+different from the ones in the cached table.
+
+Also note the following: assignments can only be made to fonts that have already
+been defined in \TEX, but have not been accessed {\it at all\/} since that
+definition. This limits the usability of the write access to \type {font.fonts}
+quite a lot, a less stringent ruleset will likely be implemented later.
+
+\subsection{Checking a font's status}
+
+You can test for the status of a font by calling this function:
+
+\startfunctioncall
+<boolean> f =
+    font.frozen(<number> n)
+\stopfunctioncall
+
+The return value is one of \type {true} (unassignable), \type {false} (can be
+changed) or \type {nil} (not a valid font at all).
+
+\subsection{Defining a font directly}
+
+\topicindex {fonts+define}
+
+You can define your own font into \type {font.fonts} by calling this function:
+
+\startfunctioncall
+<number> i =
+    font.define(<table> f)
+\stopfunctioncall
+
+The return value is the internal id number of the defined font (the index into
+\type {font.fonts}). If the font creation fails, an error is raised. The table is
+a font structure. An alternative call is:
+
+\startfunctioncall
+<number> i =
+    font.define(<number> n, <table> f)
+\stopfunctioncall
+
+Where the first argument is a reserved font id (see below).
+
+\subsection{Extending a font}
+
+\topicindex {fonts+extend}
+
+Within reasonable bounds you can extend a font after it has been defined. Because
+some properties are best left unchanged this is limited to adding characters.
+
+\startfunctioncall
+font.addcharacters(<number n>, <table> f)
+\stopfunctioncall
+
+The table passed can have the fields \type {characters} which is a (sub)table
+like the one used in define, and for virtual fonts a \type {fonts} table can be
+added. The characters defined in the \type {characters} table are added (when not
+yet present) or replace an existing entry. Keep in mind that replacing can have
+side effects because a character already can have been used. Instead of posing
+restrictions we expect the user to be careful. (The \type {setfont} helper is
+a more drastic replacer.)
+
+\subsection{Projected next font id}
+
+\topicindex {fonts+id}
+
+\startfunctioncall
+<number> i =
+    font.nextid()
+\stopfunctioncall
+
+This returns the font id number that would be returned by a \type {font.define}
+call if it was executed at this spot in the code flow. This is useful for virtual
+fonts that need to reference themselves. If you pass \type {true} as argument,
+the id gets reserved and you can pass to \type {font.define} as first argument.
+This can be handy when you create complex virtual fonts.
+
+\startfunctioncall
+<number> i =
+    font.nextid(true)
+\stopfunctioncall
+
+\subsection{Font ids}
+
+\topicindex {fonts+id}
+\topicindex {fonts+current}
+
+\startfunctioncall
+<number> i =
+    font.id(<string> csname)
+\stopfunctioncall
+
+This returns the font id associated with \type {csname}, or $-1$ if \type
+{csname} is not defined.
+
+\startfunctioncall
+<number> i =
+    font.max()
+\stopfunctioncall
+
+This is the largest used index in \type {font.fonts}.
+
+\startfunctioncall
+<number> i = font.current()
+font.current(<number> i)
+\stopfunctioncall
+
+This gets or sets the currently used font number.
+
+\subsection{Iterating over all fonts}
+
+\topicindex {fonts+iterate}
+
+\startfunctioncall
+for i,v in font.each() do
+  ...
+end
+\stopfunctioncall
+
+This is an iterator over each of the defined \TEX\ fonts. The first returned
+value is the index in \type {font.fonts}, the second the font itself, as a \LUA\
+table. The indices are listed incrementally, but they do not always form an array
+of consecutive numbers: in some cases there can be holes in the sequence.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-graphics.tex b/systems/doc/luatex/luatex-graphics.tex
index 038710cd58..3f12762b68 100644
--- a/systems/doc/luatex/luatex-graphics.tex
+++ b/systems/doc/luatex/luatex-graphics.tex
@@ -1,831 +1,831 @@
-% language=uk

-

-% mp solve_path

-

-\environment luatex-style

-

-\startcomponent luatex-graphics

-

-\startchapter[reference=graphics,title={The graphic libraries}]

-

-\startsection[title={The \type {img} library}][library=img]

-

-\topicindex {images}

-\topicindex {images+library}

-\topicindex {graphics}

-

-The \type {img} library can be used as an alternative to \orm {pdfximage} and

-\orm {pdfrefximage}, and the associated \quote {satellite} commands like \type

-{\pdfximagebbox}. Image objects can also be used within virtual fonts via the

-\type {image} command listed in~\in {section} [virtualfonts].

-

-\subsection{\type {new}}

-

-\libindex{new}

-

-\startfunctioncall

-<image> var = img.new()

-<image> var = img.new(<table> image_spec)

-\stopfunctioncall

-

-This function creates a userdata object of type \quote {image}. The \type

-{image_spec} argument is optional. If it is given, it must be a table, and that

-table must contain a \type {filename} key. A number of other keys can also be

-useful, these are explained below.

-

-You can either say

-

-\starttyping

-a = img.new()

-\stoptyping

-

-followed by

-

-\starttyping

-a.filename = "foo.png"

-\stoptyping

-

-or you can put the file name (and some or all of the other keys) into a table

-directly, like so:

-

-\starttyping

-a = img.new({filename='foo.pdf', page=1})

-\stoptyping

-

-The generated \type {<image>} userdata object allows access to a set of

-user|-|specified values as well as a set of values that are normally filled in

-and updated automatically by \LUATEX\ itself. Some of those are derived from the

-actual image file, others are updated to reflect the \PDF\ output status of the

-object.

-

-There is one required user-specified field: the file name (\type {filename}). It

-can optionally be augmented by the requested image dimensions (\type {width},

-\type {depth}, \type {height}), user|-|specified image attributes (\type {attr}),

-the requested \PDF\ page identifier (\type {page}), the requested boundingbox

-(\type {pagebox}) for \PDF\ inclusion, the requested color space object (\type

-{colorspace}).

-

-The function \type {img.new} does not access the actual image file, it just

-creates the \type {<image>} userdata object and initializes some memory

-structures. The \type {<image>} object and its internal structures are

-automatically garbage collected.

-

-Once the image is scanned, all the values in the \type {<image>} except \type

-{width}, \type {height} and \type {depth}, become frozen, and you cannot change

-them any more.

-

-You can use \type {pdf.setignoreunknownimages(1)} (or at the \TEX\ end the \lpr

-{pdfvariable} \type {ignoreunknownimages}) to get around a quit when no known

-image type is found (based on name or preamble). Beware: this will not catch

-invalid images and we cannot guarantee side effects. A zero dimension image is

-still included when requested. No special flags are set. A proper workflow will

-not rely in such a catch but make sure that images are valid.

-

-\subsection{\type {fields}}

-

-\libindex{fields}

-

-\startfunctioncall

-<table> keys = img.fields()

-\stopfunctioncall

-

-This function returns a list of all the possible \type {image_spec} keys, both

-user-supplied and automatic ones.

-

-\starttabulate[|l|l|p|]

-\DB field name             \BC type     \BC description \NC \NR

-\TB

-\NC \type{attr}            \NC string   \NC the image attributes for \LUATEX \NC \NR

-\NC \type{bbox}            \NC table    \NC table with 4 boundingbox dimensions \type

-                                            {llx}, \type {lly}, \type {urx} and \type

-                                            {ury} overruling the \type {pagebox} entry \NC \NR

-\NC \type{colordepth}      \NC number   \NC the number of bits used by the color space \NC \NR

-\NC \type{colorspace}      \NC number   \NC the color space object number \NC \NR

-\NC \type{depth}           \NC number   \NC the image depth for \LUATEX \NC \NR

-\NC \type{filename}        \NC string   \NC the image file name \NC \NR

-\NC \type{filepath}        \NC string   \NC the full (expanded) file name of the image\NC \NR

-\NC \type{height}          \NC number   \NC the image height for \LUATEX \NC \NR

-\NC \type{imagetype}       \NC string   \NC one of \type {pdf}, \type {png}, \type {jpg},

-                                            \type {jp2} or \type {jbig2} \NC \NR

-\NC \type{index}           \NC number   \NC the \PDF\ image name suffix \NC \NR

-\NC \type{objnum}          \NC number   \NC the \PDF\ image object number \NC \NR

-\NC \type{page}            \NC number   \NC the identifier for the requested image page \NC \NR

-\NC \type{pagebox}         \NC string   \NC the requested bounding box, one of

-                                            \type {none}, \type {media}, \type {crop},

-                                            \type {bleed}, \type {trim}, \type {art} \NC \NR

-\NC \type{pages}           \NC number   \NC the total number of available pages \NC \NR

-\NC \type{rotation}        \NC number   \NC the image rotation from included \PDF\ file,

-                                            in multiples of 90~deg. \NC \NR

-\NC \type{stream}          \NC string   \NC the raw stream data for an \type {/Xobject}

-                                            \type {/Form} object\NC \NR

-\NC \type{transform}       \NC number   \NC the image transform, integer number 0..7 \NC \NR

-\NC \type{orientation}     \NC number   \NC the (jpeg) image orientation, integer number 1..8

-                                            (0 for unset) \NC \NR

-\NC \type{width}           \NC number   \NC the image width for \LUATEX \NC \NR

-\NC \type{xres}            \NC number   \NC the horizontal natural image resolution

-                                            (in \DPI) \NC \NR

-\NC \type{xsize}           \NC number   \NC the natural image width \NC \NR

-\NC \type{yres}            \NC number   \NC the vertical natural image resolution

-                                            (in \DPI) \NC \NR

-\NC \type{ysize}           \NC number   \NC the natural image height \NC \NR

-\NC \type{visiblefilename} \NC string   \NC when set, this name will find its way in the

-                                            \PDF\ file as \type {PTEX} specification; when

-                                            an empty string is assigned nothing is written

-                                            to file; otherwise the natural filename is

-                                            taken \NC \NR

-\NC \type{userpassword}   \NC string   \NC  the userpassword needed for opening a \PDF\ file \NC \NR

-\NC \type{ownerpassword}  \NC string   \NC  the ownerpassword needed for opening a \PDF\ file \NC \NR

-\NC \type{keepopen}       \NC boolean  \NC  keep the \PDF\ file open \NC \NR

-\NC \type{nobbox}         \NC boolean  \NC  don't add a boundingbox specification for streams \NC \NR

-\NC \type{nolength}       \NC boolean  \NC  don't add length key nor compress for streams \NC \NR

-\NC \type{nosize}         \NC boolean  \NC  don't add size fields for streams \NC \NR

-\LL

-\stoptabulate

-

-A running (undefined) dimension in \type {width}, \type {height}, or \type

-{depth} is represented as \type {nil} in \LUA, so if you want to load an image at

-its \quote {natural} size, you do not have to specify any of those three fields.

-

-The \type {stream} parameter allows to fabricate an \type {/XObject} \type

-{/Form} object from a string giving the stream contents, e.g., for a filled

-rectangle:

-

-\startfunctioncall

-a.stream = "0 0 20 10 re f"

-\stopfunctioncall

-

-When writing the image, an \type {/Xobject} \type {/Form} object is created, like

-with embedded \PDF\ file writing. The object is written out only once. The \type

-{stream} key requires that also the \type {bbox} table is given. The \type

-{stream} key conflicts with the \type {filename} key. The \type {transform} key

-works as usual also with \type {stream}.

-

-The \type {bbox} key needs a table with four boundingbox values, e.g.:

-

-\startfunctioncall

-a.bbox = { "30bp", 0, "225bp", "200bp" }

-\stopfunctioncall

-

-This replaces and overrules any given \type {pagebox} value; with given \type

-{bbox} the box dimensions coming with an embedded \PDF\ file are ignored. The

-\type {xsize} and \type {ysize} dimensions are set accordingly, when the image is

-scaled. The \type {bbox} parameter is ignored for non-\PDF\ images.

-

-The \type {transform} allows to mirror and rotate the image in steps of 90~deg.

-The default value~$0$ gives an unmirrored, unrotated image. Values $1-3$ give

-counterclockwise rotation by $90$, $180$, or $270$~degrees, whereas with values

-$4-7$ the image is first mirrored and then rotated counterclockwise by $90$,

-$180$, or $270$~degrees. The \type {transform} operation gives the same visual

-result as if you would externally preprocess the image by a graphics tool and

-then use it by \LUATEX. If a \PDF\ file to be embedded already contains a \type

-{/Rotate} specification, the rotation result is the combination of the \type

-{/Rotate} rotation followed by the \type {transform} operation.

-

-\subsection{\type {scan}}

-

-\libindex{scan}

-

-\startfunctioncall

-<image> var = img.scan(<image> var)

-<image> var = img.scan(<table> image_spec)

-\stopfunctioncall

-

-When you say \type {img.scan(a)} for a new image, the file is scanned, and

-variables such as \type {xsize}, \type {ysize}, image \type {type}, number of

-\type {pages}, and the resolution are extracted. Each of the \type {width}, \type

-{height}, \type {depth} fields are set up according to the image dimensions, if

-they were not given an explicit value already. An image file will never be

-scanned more than once for a given image variable. With all subsequent \type

-{img.scan(a)} calls only the dimensions are again set up (if they have been

-changed by the user in the meantime).

-

-For ease of use, you can do right-away a

-

-\starttyping

-<image> a = img.scan { filename = "foo.png" }

-\stoptyping

-

-without a prior \type {img.new}.

-

-Nothing is written yet at this point, so you can do \type {a=img.scan}, retrieve

-the available info like image width and height, and then throw away \type {a}

-again by saying \type {a=nil}. In that case no image object will be reserved in

-the PDF, and the used memory will be cleaned up automatically.

-

-\subsection{\type {copy}}

-

-\libindex{copy}

-

-\startfunctioncall

-<image> var = img.copy(<image> var)

-<image> var = img.copy(<table> image_spec)

-\stopfunctioncall

-

-If you say \type {a = b}, then both variables point to the same \type {<image>}

-object. if you want to write out an image with different sizes, you can do

-\type {b = img.copy(a)}.

-

-Afterwards, \type {a} and \type {b} still reference the same actual image

-dictionary, but the dimensions for \type {b} can now be changed from their

-initial values that were just copies from \type {a}.

-

-\subsection{\type {write}, \type {immediatewrite}, \type {immediatewriteobject}}

-

-\topicindex {images+injection}

-\topicindex {images+immediate}

-\topicindex {images+object}

-

-\libindex{write}

-\libindex{immediatewrite}

-\libindex{immediatewriteobject}

-

-\startfunctioncall

-<image> var = img.write(<image> var)

-<image> var = img.write(<table> image_spec)

-\stopfunctioncall

-

-By \type {img.write(a)} a \PDF\ object number is allocated, and a rule node of

-subtype \type {image} is generated and put into the output list. By this the

-image \type {a} is placed into the page stream, and the image file is written out

-into an image stream object after the shipping of the current page is finished.

-

-Again you can do a terse call like

-

-\starttyping

-img.write { filename = "foo.png" }

-\stoptyping

-

-The \type {<image>} variable is returned in case you want it for later

-processing. You can also write an object.

-

-By \type {img.immediatewrite(a)} a \PDF\ object number is allocated, and the

-image file for image \type {a} is written out immediately into the \PDF\ file as

-an image stream object (like with \prm {immediate}\orm {pdfximage}). The object

-number of the image stream dictionary is then available by the \type {objnum}

-key. No \type {pdf_refximage} whatsit node is generated. You will need an

-\type {img.write(a)} or \type {img.node(a)} call to let the image appear on the

-page, or reference it by another trick; else you will have a dangling image

-object in the \PDF\ file.

-

-\startfunctioncall

-<image> var = img.immediatewrite(<image> var)

-<image> var = img.immediatewrite(<table> image_spec)

-\stopfunctioncall

-

-Also here you can do a terse call like

-

-\starttyping

-a = img.immediatewrite { filename = "foo.png" }

-\stoptyping

-

-The \type {<image>} variable is returned and you will most likely need it.

-

-The next function is kind of special as it copies an object from a (\PDF) image

-file. This features is experimental and might disappear.

-

-\startfunctioncall

-<integer> objnum = img.immediatewriteobject(<image> var, <integer> objnum)

-<integer> objnum = img.immediatewriteobject(<table> image_spec, <integer> objnum)

-\stopfunctioncall

-

-\subsection{\type {node}}

-

-\libindex{node}

-

-\startfunctioncall

-<node> n = img.node(<image> var)

-<node> n = img.node(<table> image_spec)

-\stopfunctioncall

-

-This function allocates a \PDF\ object number and returns a whatsit node of

-subtype \type {pdf_refximage}, filled with the image parameters \type {width},

-\type {height}, \type {depth}, and \type {objnum}. Also here you can do a terse

-call like:

-

-\starttyping

-n = img.node ({ filename = "foo.png" })

-\stoptyping

-

-This example outputs an image:

-

-\starttyping

-node.write(img.node{filename="foo.png"})

-\stoptyping

-

-\subsection{\type {types}}

-

-\topicindex {images+types}

-

-\libindex{types}

-

-\startfunctioncall

-<table> types = img.types()

-\stopfunctioncall

-

-This function returns a list with the supported image file type names, currently

-these are \type {pdf}, \type {png}, \type {jpg}, \type {jp2} (JPEG~2000), and

-\type {jbig2}.

-

-\subsection{\type {boxes}}

-

-\libindex{boxes}

-

-\startfunctioncall

-<table> boxes = img.boxes()

-\stopfunctioncall

-

-This function returns a list with the supported \PDF\ page box names, currently

-these are \type {media}, \type {crop}, \type {bleed}, \type {trim}, and \type

-{art}, all in lowercase.

-

-The \PDF\ file is kept open after its properties are determined. After inclusion,

-which happens when the page that references the image is flushed, the file is

-closed. This means that when you have thousands of images on one page, your

-operating system might decide to abort the run. When you include more than one

-page from a \PDF\ file you can set the \type {keepopen} flag when you allocate an

-image object, or pass the \type {keepopen} directive when you refer to the image

-with \lpr {useimageresource}. This only makes sense when you embed many pages.

-An \prm {immediate} applied to \lpr {saveimageresource} will also force a

-close after inclusion.

-

-\starttyping

-\immediate\useimageresource{foo.pdf}%

-          \saveimageresource         \lastsavedimageresourceindex % closed

-          \useimageresource{foo.pdf}%

-          \saveimageresource         \lastsavedimageresourceindex % kept open

-          \useimageresource{foo.pdf}%

-          \saveimageresource keepopen\lastsavedimageresourceindex % kept open

-

-\directlua{img.write(img.scan{ file = "foo.pdf" })}                  % closed

-\directlua{img.write(img.scan{ file = "foo.pdf", keepopen = true })} % kept open

-\stoptyping

-

-\stopsection

-

-\startsection[title={The \type {mplib} library}][library=mplib]

-

-\topicindex {\METAPOST}

-\topicindex {\METAPOST+mplib}

-\topicindex {images+mplib}

-\topicindex {images+\METAPOST}

-

-\libindex{version}

-

-The \MP\ library interface registers itself in the table \type {mplib}. It is

-based on \MPLIB\ version \ctxlua {context(mplib.version())}.

-

-\subsection{\type {new}}

-

-\libindex{new}

-

-To create a new \METAPOST\ instance, call

-

-\startfunctioncall

-<mpinstance> mp = mplib.new({...})

-\stopfunctioncall

-

-This creates the \type {mp} instance object. The argument hash can have a number

-of different fields, as follows:

-

-\starttabulate[|l|l|pl|pl|]

-\DB name               \BC type     \BC description              \BC default           \NC \NR

-\TB

-\NC \type{error_line}  \NC number   \NC error line width         \NC 79                \NC \NR

-\NC \type{print_line}  \NC number   \NC line length in ps output \NC 100               \NC \NR

-\NC \type{random_seed} \NC number   \NC the initial random seed  \NC variable          \NC \NR

-\NC \type{math_mode}   \NC string   \NC the number system to use:

-                                        \type {scaled},

-                                        \type {double} or

-                                      % \type {binary} or

-                                        \type {decimal}          \NC \type {scaled}    \NC \NR

-\NC \type{interaction} \NC string   \NC the interaction mode:

-                                        \type {batch},

-                                        \type {nonstop},

-                                        \type {scroll} or

-                                        \type {errorstop}        \NC \type {errorstop} \NC \NR

-\NC \type{job_name}    \NC string   \NC \type {--jobname}        \NC \type {mpout}     \NC \NR

-\NC \type{find_file}   \NC function \NC a function to find files \NC only local files  \NC \NR

-\LL

-\stoptabulate

-

-The binary mode is no longer available in the \LUATEX\ version of \MPLIB. It

-offers no real advantage and brings a ton of extra libraries with platform

-specific properties that we can now avoid. We might introduce a high resolution

-scaled variant at some point but only when it pays of performance wise.

-

-The \type {find_file} function should be of this form:

-

-\starttyping

-<string> found = finder (<string> name, <string> mode, <string> type)

-\stoptyping

-

-with:

-

-\starttabulate[|l|p|]

-\DB name        \BC the requested file \NC \NR

-\TB

-\NC \type{mode} \NC the file mode: \type {r} or \type {w} \NC \NR

-\NC \type{type} \NC the kind of file, one of: \type {mp}, \type {tfm}, \type {map},

-                    \type {pfb}, \type {enc} \NC \NR

-\LL

-\stoptabulate

-

-Return either the full path name of the found file, or \type {nil} if the file

-cannot be found.

-

-Note that the new version of \MPLIB\ no longer uses binary mem files, so the way

-to preload a set of macros is simply to start off with an \type {input} command

-in the first \type {execute} call.

-

-When you are processing a snippet of text starting with \type {btex} and

-ending with either \type {etex} or \type {verbatimtex}, the \METAPOST\

-\type {texscriptmode} parameter controls how spaces and newlines get honoured.

-The default value is~1. Possible values are:

-

-\starttabulate[|l|p|]

-\DB name      \BC meaning \NC \NR

-\TB

-\NC \type {0} \NC no newlines \NC \NR

-\NC \type {1} \NC newlines in \type {verbatimtex} \NC \NR

-\NC \type {2} \NC newlines in \type {verbatimtex} and \type {etex} \NC \NR

-\NC \type {3} \NC no leading and trailing strip in \type {verbatimtex} \NC \NR

-\NC \type {4} \NC no leading and trailing strip in \type {verbatimtex} and \type {btex} \NC \NR

-\LL

-\stoptabulate

-

-That way the \LUA\ handler (assigned to \type {make_text}) can do what it likes.

-An \type {etex} has to be followed by a space or \type {;} or be at the end of a

-line and preceded by a space or at the beginning of a line.

-

-\subsection{\type {statistics}}

-

-\libindex{statistics}

-

-You can request statistics with:

-

-\startfunctioncall

-<table> stats = mp:statistics()

-\stopfunctioncall

-

-This function returns the vital statistics for an \MPLIB\ instance. There are

-four fields, giving the maximum number of used items in each of four allocated

-object classes:

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{main_memory} \NC number \NC memory size \NC \NR

-\NC \type{hash_size}   \NC number \NC hash size\NC \NR

-\NC \type{param_size}  \NC number \NC simultaneous macro parameters\NC \NR

-\NC \type{max_in_open} \NC number \NC input file nesting levels\NC \NR

-\LL

-\stoptabulate

-

-Note that in the new version of \MPLIB, this is informational only. The objects

-are all allocated dynamically, so there is no chance of running out of space

-unless the available system memory is exhausted.

-

-\subsection{\type {execute}}

-

-\libindex{execute}

-

-You can ask the \METAPOST\ interpreter to run a chunk of code by calling

-

-\startfunctioncall

-<table> rettable = execute(mp,"metapost code")

-\stopfunctioncall

-

-for various bits of \METAPOST\ language input. Be sure to check the \type

-{rettable.status} (see below) because when a fatal \METAPOST\ error occurs the

-\MPLIB\ instance will become unusable thereafter.

-

-Generally speaking, it is best to keep your chunks small, but beware that all

-chunks have to obey proper syntax, like each of them is a small file. For

-instance, you cannot split a single statement over multiple chunks.

-

-In contrast with the normal stand alone \type {mpost} command, there is

-\notabene {no} implied \quote{input} at the start of the first chunk.

-

-\subsection{\type {finish}}

-

-\libindex{finish}

-

-\startfunctioncall

-<table> rettable = finish(mp)

-\stopfunctioncall

-

-If for some reason you want to stop using an \MPLIB\ instance while processing is

-not yet actually done, you can call \type finish}. Eventually, used memory

-will be freed and open files will be closed by the \LUA\ garbage collector, but

-an explicit \type finish} is the only way to capture the final part of the

-output streams.

-

-\subsection{Result table}

-

-\libindex {fields}

-

-The return value of \type {execute} and \type {finish} is a table with a

-few possible keys (only \type {status} is always guaranteed to be present).

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{log}    \NC string \NC output to the \quote {log} stream \NC \NR

-\NC \type{term}   \NC string \NC output to the \quote {term} stream \NC \NR

-\NC \type{error}  \NC string \NC output to the \quote {error} stream

-                                 (only used for \quote {out of memory}) \NC \NR

-\NC \type{status} \NC number \NC the return value:

-                                 \type {0} = good,

-                                 \type {1} = warning,

-                                 \type {2} = errors,

-                                 \type {3} = fatal error \NC \NR

-\NC \type{fig}    \NC table  \NC an array of generated figures (if any) \NC \NR

-\LL

-\stoptabulate

-

-When \type {status} equals~3, you should stop using this \MPLIB\ instance

-immediately, it is no longer capable of processing input.

-

-If it is present, each of the entries in the \type {fig} array is a userdata

-representing a figure object, and each of those has a number of object methods

-you can call:

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{boundingbox}  \NC function \NC returns the bounding box, as an array of 4

-                                         values \NC \NR

-\NC \type{postscript}   \NC function \NC returns a string that is the ps output of the

-                                         \type {fig}. this function accepts two optional

-                                         integer arguments for specifying the values of

-                                         \type {prologues} (first argument) and \type

-                                         {procset} (second argument) \NC \NR

-\NC \type{svg}          \NC function \NC returns a string that is the svg output of the

-                                         \type {fig}. This function accepts an optional

-                                         integer argument for specifying the value of

-                                         \type {prologues} \NC \NR

-\NC \type{objects}      \NC function \NC returns the actual array of graphic objects in

-                                         this \type {fig} \NC \NR

-\NC \type{copy_objects} \NC function \NC returns a deep copy of the array of graphic

-                                         objects in this \type {fig} \NC \NR

-\NC \type{filename}     \NC function \NC the filename this \type {fig}'s \POSTSCRIPT\

-                                         output would have written to in stand alone

-                                         mode \NC \NR

-\NC \type{width}        \NC function \NC the \type {fontcharwd} value \NC \NR

-\NC \type{height}       \NC function \NC the \type {fontcharht} value \NC \NR

-\NC \type{depth}        \NC function \NC the \type {fontchardp} value \NC \NR

-\NC \type{italcorr}     \NC function \NC the \type {fontcharit} value \NC \NR

-\NC \type{charcode}     \NC function \NC the (rounded) \type {charcode} value \NC \NR

-\LL

-\stoptabulate

-

-Note: you can call \type {fig:objects()} only once for any one \type {fig}

-object!

-

-When the boundingbox represents a \quote {negated rectangle}, i.e.\ when the

-first set of coordinates is larger than the second set, the picture is empty.

-

-Graphical objects come in various types that each has a different list of

-accessible values. The types are: \type {fill}, \type {outline}, \type {text},

-\type {start_clip}, \type {stop_clip}, \type {start_bounds}, \type {stop_bounds},

-\type {special}.

-

-There is a helper function (\type {mplib.fields(obj)}) to get the list of

-accessible values for a particular object, but you can just as easily use the

-tables given below.

-

-All graphical objects have a field \type {type} that gives the object type as a

-string value; it is not explicit mentioned in the following tables. In the

-following, \type {number}s are \POSTSCRIPT\ points represented as a floating

-point number, unless stated otherwise. Field values that are of type \type

-{table} are explained in the next section.

-

-\subsubsection{fill}

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{path}       \NC table  \NC the list of knots \NC \NR

-\NC \type{htap}       \NC table  \NC the list of knots for the reversed trajectory \NC \NR

-\NC \type{pen}        \NC table  \NC knots of the pen \NC \NR

-\NC \type{color}      \NC table  \NC the object's color \NC \NR

-\NC \type{linejoin}   \NC number \NC line join style (bare number)\NC \NR

-\NC \type{miterlimit} \NC number \NC miterlimit\NC \NR

-\NC \type{prescript}  \NC string \NC the prescript text \NC \NR

-\NC \type{postscript} \NC string \NC the postscript text \NC \NR

-\LL

-\stoptabulate

-

-The entries \type {htap} and \type {pen} are optional.

-

-\subsubsection{outline}

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{path}       \NC table  \NC the list of knots \NC \NR

-\NC \type{pen}        \NC table  \NC knots of the pen \NC \NR

-\NC \type{color}      \NC table  \NC the object's color \NC \NR

-\NC \type{linejoin}   \NC number \NC line join style (bare number) \NC \NR

-\NC \type{miterlimit} \NC number \NC miterlimit \NC \NR

-\NC \type{linecap}    \NC number \NC line cap style (bare number) \NC \NR

-\NC \type{dash}       \NC table  \NC representation of a dash list \NC \NR

-\NC \type{prescript}  \NC string \NC the prescript text \NC \NR

-\NC \type{postscript} \NC string \NC the postscript text \NC \NR

-\LL

-\stoptabulate

-

-The entry \type {dash} is optional.

-

-\subsubsection{text}

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{text}       \NC string \NC the text \NC \NR

-\NC \type{font}       \NC string \NC font tfm name \NC \NR

-\NC \type{dsize}      \NC number \NC font size \NC \NR

-\NC \type{color}      \NC table  \NC the object's color \NC \NR

-\NC \type{width}      \NC number \NC \NC \NR

-\NC \type{height}     \NC number \NC \NC \NR

-\NC \type{depth}      \NC number \NC \NC \NR

-\NC \type{transform}  \NC table  \NC a text transformation \NC \NR

-\NC \type{prescript}  \NC string \NC the prescript text \NC \NR

-\NC \type{postscript} \NC string \NC the postscript text \NC \NR

-\LL

-\stoptabulate

-

-\subsubsection{special}

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{prescript} \NC string \NC special text \NC \NR

-\LL

-\stoptabulate

-

-\subsubsection{start_bounds, start_clip}

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{path} \NC table \NC the list of knots \NC \NR

-\LL

-\stoptabulate

-

-\subsubsection{stop_bounds, stop_clip}

-

-Here are no fields available.

-

-\subsection{Subsidiary table formats}

-

-\subsubsection{Paths and pens}

-

-Paths and pens (that are really just a special type of paths as far as \MPLIB\ is

-concerned) are represented by an array where each entry is a table that

-represents a knot.

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{left_type}  \NC string \NC when present: endpoint, but usually absent \NC \NR

-\NC \type{right_type} \NC string \NC like \type {left_type} \NC \NR

-\NC \type{x_coord}    \NC number \NC X coordinate of this knot \NC \NR

-\NC \type{y_coord}    \NC number \NC Y coordinate of this knot \NC \NR

-\NC \type{left_x}     \NC number \NC X coordinate of the precontrol point of this knot \NC \NR

-\NC \type{left_y}     \NC number \NC Y coordinate of the precontrol point of this knot \NC \NR

-\NC \type{right_x}    \NC number \NC X coordinate of the postcontrol point of this knot \NC \NR

-\NC \type{right_y}    \NC number \NC Y coordinate of the postcontrol point of this knot \NC \NR

-\LL

-\stoptabulate

-

-There is one special case: pens that are (possibly transformed) ellipses have an

-extra string-valued key \type {type} with value \type {elliptical} besides the

-array part containing the knot list.

-

-\subsubsection{Colors}

-

-A color is an integer array with 0, 1, 3 or 4 values:

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{0} \NC marking only \NC no values                                                     \NC \NR

-\NC \type{1} \NC greyscale    \NC one value in the range $(0,1)$, \quote {black} is $0$         \NC \NR

-\NC \type{3} \NC \RGB         \NC three values in the range $(0,1)$, \quote {black} is $0,0,0$  \NC \NR

-\NC \type{4} \NC \CMYK        \NC four values in the range $(0,1)$, \quote {black} is $0,0,0,1$ \NC \NR

-\LL

-\stoptabulate

-

-If the color model of the internal object was \type {uninitialized}, then it was

-initialized to the values representing \quote {black} in the colorspace \type

-{defaultcolormodel} that was in effect at the time of the \type {shipout}.

-

-\subsubsection{Transforms}

-

-Each transform is a six|-|item array.

-

-\starttabulate[|l|l|p|]

-\DB index  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{1} \NC number \NC represents x  \NC \NR

-\NC \type{2} \NC number \NC represents y  \NC \NR

-\NC \type{3} \NC number \NC represents xx \NC \NR

-\NC \type{4} \NC number \NC represents yx \NC \NR

-\NC \type{5} \NC number \NC represents xy \NC \NR

-\NC \type{6} \NC number \NC represents yy \NC \NR

-\LL

-\stoptabulate

-

-Note that the translation (index 1 and 2) comes first. This differs from the

-ordering in \POSTSCRIPT, where the translation comes last.

-

-\subsubsection{Dashes}

-

-Each \type {dash} is two-item hash, using the same model as \POSTSCRIPT\ for the

-representation of the dashlist. \type {dashes} is an array of \quote {on} and

-\quote {off}, values, and \type {offset} is the phase of the pattern.

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{dashes} \NC hash   \NC an array of on-off numbers \NC \NR

-\NC \type{offset} \NC number \NC the starting offset value  \NC \NR

-\LL

-\stoptabulate

-

-\subsection{Pens and \type {pen_info}}

-

-\libindex{pen_info}

-

-There is helper function (\type {pen_info(obj)}) that returns a table containing

-a bunch of vital characteristics of the used pen (all values are floats):

-

-\starttabulate[|l|l|p|]

-\DB field  \BC type \BC explanation \NC \NR

-\TB

-\NC \type{width} \NC number \NC width of the pen \NC \NR

-\NC \type{sx}    \NC number \NC $x$ scale        \NC \NR

-\NC \type{rx}    \NC number \NC $xy$ multiplier  \NC \NR

-\NC \type{ry}    \NC number \NC $yx$ multiplier  \NC \NR

-\NC \type{sy}    \NC number \NC $y$ scale        \NC \NR

-\NC \type{tx}    \NC number \NC $x$ offset       \NC \NR

-\NC \type{ty}    \NC number \NC $y$ offset       \NC \NR

-\LL

-\stoptabulate

-

-\subsection{Character size information}

-

-These functions find the size of a glyph in a defined font. The \type {fontname}

-is the same name as the argument to \type {infont}; the \type {char} is a glyph

-id in the range 0 to 255; the returned \type {w} is in AFM units.

-

-\subsubsection{\type {char_width}}

-

-\libindex{char_width}

-

-\startfunctioncall

-<number> w = char_width(mp,<string> fontname, <number> char)

-\stopfunctioncall

-

-\subsubsection{\type {char_height}}

-

-\libindex{char_height}

-

-\startfunctioncall

-<number> w = char_height(mp,<string> fontname, <number> char)

-\stopfunctioncall

-

-\subsubsection{\type {char_depth}}

-

-\libindex{char_depth}

-

-\startfunctioncall

-<number> w = char_depth(mp,<string> fontname, <number> char)

-\stopfunctioncall

-

-\subsubsection{\type {get_[boolean|numeric|string|path]}}

-

-\libindex{get_boolean}

-\libindex{get_numeric}

-\libindex{get_path}

-\libindex{get_string}

-

-When a script call brings you from the \METAPOST\ run (temporarily) back to

-\LUA\ you can access variables, but only if they are known (so for instance

-anonymous capsules like loop variables are not accessible).

-

-\startfunctioncall

-<boolean> w = get_boolean(mp,<string> name)

-<number>  n = get_numeric(mp,<string> name)

-<string>  s = get_string (mp,<string> name)

-<table>   p = get_path   (mp,<string> name)

-\stopfunctioncall

-

-The path is returned a a table with subtables that have six numbers: the

-coordinates of the point, pre- and postcontrol. A \type {cycle} fields indicates

-if a path is cyclic.

-

-\stopsection

-

-\stopchapter

+% language=uk
+
+% mp solve_path
+
+\environment luatex-style
+
+\startcomponent luatex-graphics
+
+\startchapter[reference=graphics,title={The graphic libraries}]
+
+\startsection[title={The \type {img} library}][library=img]
+
+\topicindex {images}
+\topicindex {images+library}
+\topicindex {graphics}
+
+The \type {img} library can be used as an alternative to \orm {pdfximage} and
+\orm {pdfrefximage}, and the associated \quote {satellite} commands like \type
+{\pdfximagebbox}. Image objects can also be used within virtual fonts via the
+\type {image} command listed in~\in {section} [virtualfonts].
+
+\subsection{\type {new}}
+
+\libindex{new}
+
+\startfunctioncall
+<image> var = img.new()
+<image> var = img.new(<table> image_spec)
+\stopfunctioncall
+
+This function creates a userdata object of type \quote {image}. The \type
+{image_spec} argument is optional. If it is given, it must be a table, and that
+table must contain a \type {filename} key. A number of other keys can also be
+useful, these are explained below.
+
+You can either say
+
+\starttyping
+a = img.new()
+\stoptyping
+
+followed by
+
+\starttyping
+a.filename = "foo.png"
+\stoptyping
+
+or you can put the file name (and some or all of the other keys) into a table
+directly, like so:
+
+\starttyping
+a = img.new({filename='foo.pdf', page=1})
+\stoptyping
+
+The generated \type {<image>} userdata object allows access to a set of
+user|-|specified values as well as a set of values that are normally filled in
+and updated automatically by \LUATEX\ itself. Some of those are derived from the
+actual image file, others are updated to reflect the \PDF\ output status of the
+object.
+
+There is one required user-specified field: the file name (\type {filename}). It
+can optionally be augmented by the requested image dimensions (\type {width},
+\type {depth}, \type {height}), user|-|specified image attributes (\type {attr}),
+the requested \PDF\ page identifier (\type {page}), the requested boundingbox
+(\type {pagebox}) for \PDF\ inclusion, the requested color space object (\type
+{colorspace}).
+
+The function \type {img.new} does not access the actual image file, it just
+creates the \type {<image>} userdata object and initializes some memory
+structures. The \type {<image>} object and its internal structures are
+automatically garbage collected.
+
+Once the image is scanned, all the values in the \type {<image>} except \type
+{width}, \type {height} and \type {depth}, become frozen, and you cannot change
+them any more.
+
+You can use \type {pdf.setignoreunknownimages(1)} (or at the \TEX\ end the \lpr
+{pdfvariable} \type {ignoreunknownimages}) to get around a quit when no known
+image type is found (based on name or preamble). Beware: this will not catch
+invalid images and we cannot guarantee side effects. A zero dimension image is
+still included when requested. No special flags are set. A proper workflow will
+not rely in such a catch but make sure that images are valid.
+
+\subsection{\type {fields}}
+
+\libindex{fields}
+
+\startfunctioncall
+<table> keys = img.fields()
+\stopfunctioncall
+
+This function returns a list of all the possible \type {image_spec} keys, both
+user-supplied and automatic ones.
+
+\starttabulate[|l|l|p|]
+\DB field name             \BC type     \BC description \NC \NR
+\TB
+\NC \type{attr}            \NC string   \NC the image attributes for \LUATEX \NC \NR
+\NC \type{bbox}            \NC table    \NC table with 4 boundingbox dimensions \type
+                                            {llx}, \type {lly}, \type {urx} and \type
+                                            {ury} overruling the \type {pagebox} entry \NC \NR
+\NC \type{colordepth}      \NC number   \NC the number of bits used by the color space \NC \NR
+\NC \type{colorspace}      \NC number   \NC the color space object number \NC \NR
+\NC \type{depth}           \NC number   \NC the image depth for \LUATEX \NC \NR
+\NC \type{filename}        \NC string   \NC the image file name \NC \NR
+\NC \type{filepath}        \NC string   \NC the full (expanded) file name of the image\NC \NR
+\NC \type{height}          \NC number   \NC the image height for \LUATEX \NC \NR
+\NC \type{imagetype}       \NC string   \NC one of \type {pdf}, \type {png}, \type {jpg},
+                                            \type {jp2} or \type {jbig2} \NC \NR
+\NC \type{index}           \NC number   \NC the \PDF\ image name suffix \NC \NR
+\NC \type{objnum}          \NC number   \NC the \PDF\ image object number \NC \NR
+\NC \type{page}            \NC number   \NC the identifier for the requested image page \NC \NR
+\NC \type{pagebox}         \NC string   \NC the requested bounding box, one of
+                                            \type {none}, \type {media}, \type {crop},
+                                            \type {bleed}, \type {trim}, \type {art} \NC \NR
+\NC \type{pages}           \NC number   \NC the total number of available pages \NC \NR
+\NC \type{rotation}        \NC number   \NC the image rotation from included \PDF\ file,
+                                            in multiples of 90~deg. \NC \NR
+\NC \type{stream}          \NC string   \NC the raw stream data for an \type {/Xobject}
+                                            \type {/Form} object\NC \NR
+\NC \type{transform}       \NC number   \NC the image transform, integer number 0..7 \NC \NR
+\NC \type{orientation}     \NC number   \NC the (jpeg) image orientation, integer number 1..8
+                                            (0 for unset) \NC \NR
+\NC \type{width}           \NC number   \NC the image width for \LUATEX \NC \NR
+\NC \type{xres}            \NC number   \NC the horizontal natural image resolution
+                                            (in \DPI) \NC \NR
+\NC \type{xsize}           \NC number   \NC the natural image width \NC \NR
+\NC \type{yres}            \NC number   \NC the vertical natural image resolution
+                                            (in \DPI) \NC \NR
+\NC \type{ysize}           \NC number   \NC the natural image height \NC \NR
+\NC \type{visiblefilename} \NC string   \NC when set, this name will find its way in the
+                                            \PDF\ file as \type {PTEX} specification; when
+                                            an empty string is assigned nothing is written
+                                            to file; otherwise the natural filename is
+                                            taken \NC \NR
+\NC \type{userpassword}   \NC string   \NC  the userpassword needed for opening a \PDF\ file \NC \NR
+\NC \type{ownerpassword}  \NC string   \NC  the ownerpassword needed for opening a \PDF\ file \NC \NR
+\NC \type{keepopen}       \NC boolean  \NC  keep the \PDF\ file open \NC \NR
+\NC \type{nobbox}         \NC boolean  \NC  don't add a boundingbox specification for streams \NC \NR
+\NC \type{nolength}       \NC boolean  \NC  don't add length key nor compress for streams \NC \NR
+\NC \type{nosize}         \NC boolean  \NC  don't add size fields for streams \NC \NR
+\LL
+\stoptabulate
+
+A running (undefined) dimension in \type {width}, \type {height}, or \type
+{depth} is represented as \type {nil} in \LUA, so if you want to load an image at
+its \quote {natural} size, you do not have to specify any of those three fields.
+
+The \type {stream} parameter allows to fabricate an \type {/XObject} \type
+{/Form} object from a string giving the stream contents, e.g., for a filled
+rectangle:
+
+\startfunctioncall
+a.stream = "0 0 20 10 re f"
+\stopfunctioncall
+
+When writing the image, an \type {/Xobject} \type {/Form} object is created, like
+with embedded \PDF\ file writing. The object is written out only once. The \type
+{stream} key requires that also the \type {bbox} table is given. The \type
+{stream} key conflicts with the \type {filename} key. The \type {transform} key
+works as usual also with \type {stream}.
+
+The \type {bbox} key needs a table with four boundingbox values, e.g.:
+
+\startfunctioncall
+a.bbox = { "30bp", 0, "225bp", "200bp" }
+\stopfunctioncall
+
+This replaces and overrules any given \type {pagebox} value; with given \type
+{bbox} the box dimensions coming with an embedded \PDF\ file are ignored. The
+\type {xsize} and \type {ysize} dimensions are set accordingly, when the image is
+scaled. The \type {bbox} parameter is ignored for non-\PDF\ images.
+
+The \type {transform} allows to mirror and rotate the image in steps of 90~deg.
+The default value~$0$ gives an unmirrored, unrotated image. Values $1-3$ give
+counterclockwise rotation by $90$, $180$, or $270$~degrees, whereas with values
+$4-7$ the image is first mirrored and then rotated counterclockwise by $90$,
+$180$, or $270$~degrees. The \type {transform} operation gives the same visual
+result as if you would externally preprocess the image by a graphics tool and
+then use it by \LUATEX. If a \PDF\ file to be embedded already contains a \type
+{/Rotate} specification, the rotation result is the combination of the \type
+{/Rotate} rotation followed by the \type {transform} operation.
+
+\subsection{\type {scan}}
+
+\libindex{scan}
+
+\startfunctioncall
+<image> var = img.scan(<image> var)
+<image> var = img.scan(<table> image_spec)
+\stopfunctioncall
+
+When you say \type {img.scan(a)} for a new image, the file is scanned, and
+variables such as \type {xsize}, \type {ysize}, image \type {type}, number of
+\type {pages}, and the resolution are extracted. Each of the \type {width}, \type
+{height}, \type {depth} fields are set up according to the image dimensions, if
+they were not given an explicit value already. An image file will never be
+scanned more than once for a given image variable. With all subsequent \type
+{img.scan(a)} calls only the dimensions are again set up (if they have been
+changed by the user in the meantime).
+
+For ease of use, you can do right-away a
+
+\starttyping
+<image> a = img.scan { filename = "foo.png" }
+\stoptyping
+
+without a prior \type {img.new}.
+
+Nothing is written yet at this point, so you can do \type {a=img.scan}, retrieve
+the available info like image width and height, and then throw away \type {a}
+again by saying \type {a=nil}. In that case no image object will be reserved in
+the PDF, and the used memory will be cleaned up automatically.
+
+\subsection{\type {copy}}
+
+\libindex{copy}
+
+\startfunctioncall
+<image> var = img.copy(<image> var)
+<image> var = img.copy(<table> image_spec)
+\stopfunctioncall
+
+If you say \type {a = b}, then both variables point to the same \type {<image>}
+object. if you want to write out an image with different sizes, you can do
+\type {b = img.copy(a)}.
+
+Afterwards, \type {a} and \type {b} still reference the same actual image
+dictionary, but the dimensions for \type {b} can now be changed from their
+initial values that were just copies from \type {a}.
+
+\subsection{\type {write}, \type {immediatewrite}, \type {immediatewriteobject}}
+
+\topicindex {images+injection}
+\topicindex {images+immediate}
+\topicindex {images+object}
+
+\libindex{write}
+\libindex{immediatewrite}
+\libindex{immediatewriteobject}
+
+\startfunctioncall
+<image> var = img.write(<image> var)
+<image> var = img.write(<table> image_spec)
+\stopfunctioncall
+
+By \type {img.write(a)} a \PDF\ object number is allocated, and a rule node of
+subtype \type {image} is generated and put into the output list. By this the
+image \type {a} is placed into the page stream, and the image file is written out
+into an image stream object after the shipping of the current page is finished.
+
+Again you can do a terse call like
+
+\starttyping
+img.write { filename = "foo.png" }
+\stoptyping
+
+The \type {<image>} variable is returned in case you want it for later
+processing. You can also write an object.
+
+By \type {img.immediatewrite(a)} a \PDF\ object number is allocated, and the
+image file for image \type {a} is written out immediately into the \PDF\ file as
+an image stream object (like with \prm {immediate}\orm {pdfximage}). The object
+number of the image stream dictionary is then available by the \type {objnum}
+key. No \type {pdf_refximage} whatsit node is generated. You will need an
+\type {img.write(a)} or \type {img.node(a)} call to let the image appear on the
+page, or reference it by another trick; else you will have a dangling image
+object in the \PDF\ file.
+
+\startfunctioncall
+<image> var = img.immediatewrite(<image> var)
+<image> var = img.immediatewrite(<table> image_spec)
+\stopfunctioncall
+
+Also here you can do a terse call like
+
+\starttyping
+a = img.immediatewrite { filename = "foo.png" }
+\stoptyping
+
+The \type {<image>} variable is returned and you will most likely need it.
+
+The next function is kind of special as it copies an object from a (\PDF) image
+file. This features is experimental and might disappear.
+
+\startfunctioncall
+<integer> objnum = img.immediatewriteobject(<image> var, <integer> objnum)
+<integer> objnum = img.immediatewriteobject(<table> image_spec, <integer> objnum)
+\stopfunctioncall
+
+\subsection{\type {node}}
+
+\libindex{node}
+
+\startfunctioncall
+<node> n = img.node(<image> var)
+<node> n = img.node(<table> image_spec)
+\stopfunctioncall
+
+This function allocates a \PDF\ object number and returns a whatsit node of
+subtype \type {pdf_refximage}, filled with the image parameters \type {width},
+\type {height}, \type {depth}, and \type {objnum}. Also here you can do a terse
+call like:
+
+\starttyping
+n = img.node ({ filename = "foo.png" })
+\stoptyping
+
+This example outputs an image:
+
+\starttyping
+node.write(img.node{filename="foo.png"})
+\stoptyping
+
+\subsection{\type {types}}
+
+\topicindex {images+types}
+
+\libindex{types}
+
+\startfunctioncall
+<table> types = img.types()
+\stopfunctioncall
+
+This function returns a list with the supported image file type names, currently
+these are \type {pdf}, \type {png}, \type {jpg}, \type {jp2} (JPEG~2000), and
+\type {jbig2}.
+
+\subsection{\type {boxes}}
+
+\libindex{boxes}
+
+\startfunctioncall
+<table> boxes = img.boxes()
+\stopfunctioncall
+
+This function returns a list with the supported \PDF\ page box names, currently
+these are \type {media}, \type {crop}, \type {bleed}, \type {trim}, and \type
+{art}, all in lowercase.
+
+The \PDF\ file is kept open after its properties are determined. After inclusion,
+which happens when the page that references the image is flushed, the file is
+closed. This means that when you have thousands of images on one page, your
+operating system might decide to abort the run. When you include more than one
+page from a \PDF\ file you can set the \type {keepopen} flag when you allocate an
+image object, or pass the \type {keepopen} directive when you refer to the image
+with \lpr {useimageresource}. This only makes sense when you embed many pages.
+An \prm {immediate} applied to \lpr {saveimageresource} will also force a
+close after inclusion.
+
+\starttyping
+\immediate\useimageresource{foo.pdf}%
+          \saveimageresource         \lastsavedimageresourceindex % closed
+          \useimageresource{foo.pdf}%
+          \saveimageresource         \lastsavedimageresourceindex % kept open
+          \useimageresource{foo.pdf}%
+          \saveimageresource keepopen\lastsavedimageresourceindex % kept open
+
+\directlua{img.write(img.scan{ file = "foo.pdf" })}                  % closed
+\directlua{img.write(img.scan{ file = "foo.pdf", keepopen = true })} % kept open
+\stoptyping
+
+\stopsection
+
+\startsection[title={The \type {mplib} library}][library=mplib]
+
+\topicindex {\METAPOST}
+\topicindex {\METAPOST+mplib}
+\topicindex {images+mplib}
+\topicindex {images+\METAPOST}
+
+\libindex{version}
+
+The \MP\ library interface registers itself in the table \type {mplib}. It is
+based on \MPLIB\ version \ctxlua {context(mplib.version())}.
+
+\subsection{\type {new}}
+
+\libindex{new}
+
+To create a new \METAPOST\ instance, call
+
+\startfunctioncall
+<mpinstance> mp = mplib.new({...})
+\stopfunctioncall
+
+This creates the \type {mp} instance object. The argument hash can have a number
+of different fields, as follows:
+
+\starttabulate[|l|l|pl|pl|]
+\DB name               \BC type     \BC description              \BC default           \NC \NR
+\TB
+\NC \type{error_line}  \NC number   \NC error line width         \NC 79                \NC \NR
+\NC \type{print_line}  \NC number   \NC line length in ps output \NC 100               \NC \NR
+\NC \type{random_seed} \NC number   \NC the initial random seed  \NC variable          \NC \NR
+\NC \type{math_mode}   \NC string   \NC the number system to use:
+                                        \type {scaled},
+                                        \type {double} or
+                                      % \type {binary} or
+                                        \type {decimal}          \NC \type {scaled}    \NC \NR
+\NC \type{interaction} \NC string   \NC the interaction mode:
+                                        \type {batch},
+                                        \type {nonstop},
+                                        \type {scroll} or
+                                        \type {errorstop}        \NC \type {errorstop} \NC \NR
+\NC \type{job_name}    \NC string   \NC \type {--jobname}        \NC \type {mpout}     \NC \NR
+\NC \type{find_file}   \NC function \NC a function to find files \NC only local files  \NC \NR
+\LL
+\stoptabulate
+
+The binary mode is no longer available in the \LUATEX\ version of \MPLIB. It
+offers no real advantage and brings a ton of extra libraries with platform
+specific properties that we can now avoid. We might introduce a high resolution
+scaled variant at some point but only when it pays of performance wise.
+
+The \type {find_file} function should be of this form:
+
+\starttyping
+<string> found = finder (<string> name, <string> mode, <string> type)
+\stoptyping
+
+with:
+
+\starttabulate[|l|p|]
+\DB name        \BC the requested file \NC \NR
+\TB
+\NC \type{mode} \NC the file mode: \type {r} or \type {w} \NC \NR
+\NC \type{type} \NC the kind of file, one of: \type {mp}, \type {tfm}, \type {map},
+                    \type {pfb}, \type {enc} \NC \NR
+\LL
+\stoptabulate
+
+Return either the full path name of the found file, or \type {nil} if the file
+cannot be found.
+
+Note that the new version of \MPLIB\ no longer uses binary mem files, so the way
+to preload a set of macros is simply to start off with an \type {input} command
+in the first \type {execute} call.
+
+When you are processing a snippet of text starting with \type {btex} and
+ending with either \type {etex} or \type {verbatimtex}, the \METAPOST\
+\type {texscriptmode} parameter controls how spaces and newlines get honoured.
+The default value is~1. Possible values are:
+
+\starttabulate[|l|p|]
+\DB name      \BC meaning \NC \NR
+\TB
+\NC \type {0} \NC no newlines \NC \NR
+\NC \type {1} \NC newlines in \type {verbatimtex} \NC \NR
+\NC \type {2} \NC newlines in \type {verbatimtex} and \type {etex} \NC \NR
+\NC \type {3} \NC no leading and trailing strip in \type {verbatimtex} \NC \NR
+\NC \type {4} \NC no leading and trailing strip in \type {verbatimtex} and \type {btex} \NC \NR
+\LL
+\stoptabulate
+
+That way the \LUA\ handler (assigned to \type {make_text}) can do what it likes.
+An \type {etex} has to be followed by a space or \type {;} or be at the end of a
+line and preceded by a space or at the beginning of a line.
+
+\subsection{\type {statistics}}
+
+\libindex{statistics}
+
+You can request statistics with:
+
+\startfunctioncall
+<table> stats = mp:statistics()
+\stopfunctioncall
+
+This function returns the vital statistics for an \MPLIB\ instance. There are
+four fields, giving the maximum number of used items in each of four allocated
+object classes:
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{main_memory} \NC number \NC memory size \NC \NR
+\NC \type{hash_size}   \NC number \NC hash size\NC \NR
+\NC \type{param_size}  \NC number \NC simultaneous macro parameters\NC \NR
+\NC \type{max_in_open} \NC number \NC input file nesting levels\NC \NR
+\LL
+\stoptabulate
+
+Note that in the new version of \MPLIB, this is informational only. The objects
+are all allocated dynamically, so there is no chance of running out of space
+unless the available system memory is exhausted.
+
+\subsection{\type {execute}}
+
+\libindex{execute}
+
+You can ask the \METAPOST\ interpreter to run a chunk of code by calling
+
+\startfunctioncall
+<table> rettable = execute(mp,"metapost code")
+\stopfunctioncall
+
+for various bits of \METAPOST\ language input. Be sure to check the \type
+{rettable.status} (see below) because when a fatal \METAPOST\ error occurs the
+\MPLIB\ instance will become unusable thereafter.
+
+Generally speaking, it is best to keep your chunks small, but beware that all
+chunks have to obey proper syntax, like each of them is a small file. For
+instance, you cannot split a single statement over multiple chunks.
+
+In contrast with the normal stand alone \type {mpost} command, there is
+\notabene {no} implied \quote{input} at the start of the first chunk.
+
+\subsection{\type {finish}}
+
+\libindex{finish}
+
+\startfunctioncall
+<table> rettable = finish(mp)
+\stopfunctioncall
+
+If for some reason you want to stop using an \MPLIB\ instance while processing is
+not yet actually done, you can call \type finish}. Eventually, used memory
+will be freed and open files will be closed by the \LUA\ garbage collector, but
+an explicit \type finish} is the only way to capture the final part of the
+output streams.
+
+\subsection{Result table}
+
+\libindex {fields}
+
+The return value of \type {execute} and \type {finish} is a table with a
+few possible keys (only \type {status} is always guaranteed to be present).
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{log}    \NC string \NC output to the \quote {log} stream \NC \NR
+\NC \type{term}   \NC string \NC output to the \quote {term} stream \NC \NR
+\NC \type{error}  \NC string \NC output to the \quote {error} stream
+                                 (only used for \quote {out of memory}) \NC \NR
+\NC \type{status} \NC number \NC the return value:
+                                 \type {0} = good,
+                                 \type {1} = warning,
+                                 \type {2} = errors,
+                                 \type {3} = fatal error \NC \NR
+\NC \type{fig}    \NC table  \NC an array of generated figures (if any) \NC \NR
+\LL
+\stoptabulate
+
+When \type {status} equals~3, you should stop using this \MPLIB\ instance
+immediately, it is no longer capable of processing input.
+
+If it is present, each of the entries in the \type {fig} array is a userdata
+representing a figure object, and each of those has a number of object methods
+you can call:
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{boundingbox}  \NC function \NC returns the bounding box, as an array of 4
+                                         values \NC \NR
+\NC \type{postscript}   \NC function \NC returns a string that is the ps output of the
+                                         \type {fig}. this function accepts two optional
+                                         integer arguments for specifying the values of
+                                         \type {prologues} (first argument) and \type
+                                         {procset} (second argument) \NC \NR
+\NC \type{svg}          \NC function \NC returns a string that is the svg output of the
+                                         \type {fig}. This function accepts an optional
+                                         integer argument for specifying the value of
+                                         \type {prologues} \NC \NR
+\NC \type{objects}      \NC function \NC returns the actual array of graphic objects in
+                                         this \type {fig} \NC \NR
+\NC \type{copy_objects} \NC function \NC returns a deep copy of the array of graphic
+                                         objects in this \type {fig} \NC \NR
+\NC \type{filename}     \NC function \NC the filename this \type {fig}'s \POSTSCRIPT\
+                                         output would have written to in stand alone
+                                         mode \NC \NR
+\NC \type{width}        \NC function \NC the \type {fontcharwd} value \NC \NR
+\NC \type{height}       \NC function \NC the \type {fontcharht} value \NC \NR
+\NC \type{depth}        \NC function \NC the \type {fontchardp} value \NC \NR
+\NC \type{italcorr}     \NC function \NC the \type {fontcharit} value \NC \NR
+\NC \type{charcode}     \NC function \NC the (rounded) \type {charcode} value \NC \NR
+\LL
+\stoptabulate
+
+Note: you can call \type {fig:objects()} only once for any one \type {fig}
+object!
+
+When the boundingbox represents a \quote {negated rectangle}, i.e.\ when the
+first set of coordinates is larger than the second set, the picture is empty.
+
+Graphical objects come in various types that each has a different list of
+accessible values. The types are: \type {fill}, \type {outline}, \type {text},
+\type {start_clip}, \type {stop_clip}, \type {start_bounds}, \type {stop_bounds},
+\type {special}.
+
+There is a helper function (\type {mplib.fields(obj)}) to get the list of
+accessible values for a particular object, but you can just as easily use the
+tables given below.
+
+All graphical objects have a field \type {type} that gives the object type as a
+string value; it is not explicit mentioned in the following tables. In the
+following, \type {number}s are \POSTSCRIPT\ points represented as a floating
+point number, unless stated otherwise. Field values that are of type \type
+{table} are explained in the next section.
+
+\subsubsection{fill}
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{path}       \NC table  \NC the list of knots \NC \NR
+\NC \type{htap}       \NC table  \NC the list of knots for the reversed trajectory \NC \NR
+\NC \type{pen}        \NC table  \NC knots of the pen \NC \NR
+\NC \type{color}      \NC table  \NC the object's color \NC \NR
+\NC \type{linejoin}   \NC number \NC line join style (bare number)\NC \NR
+\NC \type{miterlimit} \NC number \NC miterlimit\NC \NR
+\NC \type{prescript}  \NC string \NC the prescript text \NC \NR
+\NC \type{postscript} \NC string \NC the postscript text \NC \NR
+\LL
+\stoptabulate
+
+The entries \type {htap} and \type {pen} are optional.
+
+\subsubsection{outline}
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{path}       \NC table  \NC the list of knots \NC \NR
+\NC \type{pen}        \NC table  \NC knots of the pen \NC \NR
+\NC \type{color}      \NC table  \NC the object's color \NC \NR
+\NC \type{linejoin}   \NC number \NC line join style (bare number) \NC \NR
+\NC \type{miterlimit} \NC number \NC miterlimit \NC \NR
+\NC \type{linecap}    \NC number \NC line cap style (bare number) \NC \NR
+\NC \type{dash}       \NC table  \NC representation of a dash list \NC \NR
+\NC \type{prescript}  \NC string \NC the prescript text \NC \NR
+\NC \type{postscript} \NC string \NC the postscript text \NC \NR
+\LL
+\stoptabulate
+
+The entry \type {dash} is optional.
+
+\subsubsection{text}
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{text}       \NC string \NC the text \NC \NR
+\NC \type{font}       \NC string \NC font tfm name \NC \NR
+\NC \type{dsize}      \NC number \NC font size \NC \NR
+\NC \type{color}      \NC table  \NC the object's color \NC \NR
+\NC \type{width}      \NC number \NC \NC \NR
+\NC \type{height}     \NC number \NC \NC \NR
+\NC \type{depth}      \NC number \NC \NC \NR
+\NC \type{transform}  \NC table  \NC a text transformation \NC \NR
+\NC \type{prescript}  \NC string \NC the prescript text \NC \NR
+\NC \type{postscript} \NC string \NC the postscript text \NC \NR
+\LL
+\stoptabulate
+
+\subsubsection{special}
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{prescript} \NC string \NC special text \NC \NR
+\LL
+\stoptabulate
+
+\subsubsection{start_bounds, start_clip}
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{path} \NC table \NC the list of knots \NC \NR
+\LL
+\stoptabulate
+
+\subsubsection{stop_bounds, stop_clip}
+
+Here are no fields available.
+
+\subsection{Subsidiary table formats}
+
+\subsubsection{Paths and pens}
+
+Paths and pens (that are really just a special type of paths as far as \MPLIB\ is
+concerned) are represented by an array where each entry is a table that
+represents a knot.
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{left_type}  \NC string \NC when present: endpoint, but usually absent \NC \NR
+\NC \type{right_type} \NC string \NC like \type {left_type} \NC \NR
+\NC \type{x_coord}    \NC number \NC X coordinate of this knot \NC \NR
+\NC \type{y_coord}    \NC number \NC Y coordinate of this knot \NC \NR
+\NC \type{left_x}     \NC number \NC X coordinate of the precontrol point of this knot \NC \NR
+\NC \type{left_y}     \NC number \NC Y coordinate of the precontrol point of this knot \NC \NR
+\NC \type{right_x}    \NC number \NC X coordinate of the postcontrol point of this knot \NC \NR
+\NC \type{right_y}    \NC number \NC Y coordinate of the postcontrol point of this knot \NC \NR
+\LL
+\stoptabulate
+
+There is one special case: pens that are (possibly transformed) ellipses have an
+extra string-valued key \type {type} with value \type {elliptical} besides the
+array part containing the knot list.
+
+\subsubsection{Colors}
+
+A color is an integer array with 0, 1, 3 or 4 values:
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{0} \NC marking only \NC no values                                                     \NC \NR
+\NC \type{1} \NC greyscale    \NC one value in the range $(0,1)$, \quote {black} is $0$         \NC \NR
+\NC \type{3} \NC \RGB         \NC three values in the range $(0,1)$, \quote {black} is $0,0,0$  \NC \NR
+\NC \type{4} \NC \CMYK        \NC four values in the range $(0,1)$, \quote {black} is $0,0,0,1$ \NC \NR
+\LL
+\stoptabulate
+
+If the color model of the internal object was \type {uninitialized}, then it was
+initialized to the values representing \quote {black} in the colorspace \type
+{defaultcolormodel} that was in effect at the time of the \type {shipout}.
+
+\subsubsection{Transforms}
+
+Each transform is a six|-|item array.
+
+\starttabulate[|l|l|p|]
+\DB index  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{1} \NC number \NC represents x  \NC \NR
+\NC \type{2} \NC number \NC represents y  \NC \NR
+\NC \type{3} \NC number \NC represents xx \NC \NR
+\NC \type{4} \NC number \NC represents yx \NC \NR
+\NC \type{5} \NC number \NC represents xy \NC \NR
+\NC \type{6} \NC number \NC represents yy \NC \NR
+\LL
+\stoptabulate
+
+Note that the translation (index 1 and 2) comes first. This differs from the
+ordering in \POSTSCRIPT, where the translation comes last.
+
+\subsubsection{Dashes}
+
+Each \type {dash} is two-item hash, using the same model as \POSTSCRIPT\ for the
+representation of the dashlist. \type {dashes} is an array of \quote {on} and
+\quote {off}, values, and \type {offset} is the phase of the pattern.
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{dashes} \NC hash   \NC an array of on-off numbers \NC \NR
+\NC \type{offset} \NC number \NC the starting offset value  \NC \NR
+\LL
+\stoptabulate
+
+\subsection{Pens and \type {pen_info}}
+
+\libindex{pen_info}
+
+There is helper function (\type {pen_info(obj)}) that returns a table containing
+a bunch of vital characteristics of the used pen (all values are floats):
+
+\starttabulate[|l|l|p|]
+\DB field  \BC type \BC explanation \NC \NR
+\TB
+\NC \type{width} \NC number \NC width of the pen \NC \NR
+\NC \type{sx}    \NC number \NC $x$ scale        \NC \NR
+\NC \type{rx}    \NC number \NC $xy$ multiplier  \NC \NR
+\NC \type{ry}    \NC number \NC $yx$ multiplier  \NC \NR
+\NC \type{sy}    \NC number \NC $y$ scale        \NC \NR
+\NC \type{tx}    \NC number \NC $x$ offset       \NC \NR
+\NC \type{ty}    \NC number \NC $y$ offset       \NC \NR
+\LL
+\stoptabulate
+
+\subsection{Character size information}
+
+These functions find the size of a glyph in a defined font. The \type {fontname}
+is the same name as the argument to \type {infont}; the \type {char} is a glyph
+id in the range 0 to 255; the returned \type {w} is in AFM units.
+
+\subsubsection{\type {char_width}}
+
+\libindex{char_width}
+
+\startfunctioncall
+<number> w = char_width(mp,<string> fontname, <number> char)
+\stopfunctioncall
+
+\subsubsection{\type {char_height}}
+
+\libindex{char_height}
+
+\startfunctioncall
+<number> w = char_height(mp,<string> fontname, <number> char)
+\stopfunctioncall
+
+\subsubsection{\type {char_depth}}
+
+\libindex{char_depth}
+
+\startfunctioncall
+<number> w = char_depth(mp,<string> fontname, <number> char)
+\stopfunctioncall
+
+\subsubsection{\type {get_[boolean|numeric|string|path]}}
+
+\libindex{get_boolean}
+\libindex{get_numeric}
+\libindex{get_path}
+\libindex{get_string}
+
+When a script call brings you from the \METAPOST\ run (temporarily) back to
+\LUA\ you can access variables, but only if they are known (so for instance
+anonymous capsules like loop variables are not accessible).
+
+\startfunctioncall
+<boolean> w = get_boolean(mp,<string> name)
+<number>  n = get_numeric(mp,<string> name)
+<string>  s = get_string (mp,<string> name)
+<table>   p = get_path   (mp,<string> name)
+\stopfunctioncall
+
+The path is returned a a table with subtables that have six numbers: the
+coordinates of the point, pre- and postcontrol. A \type {cycle} fields indicates
+if a path is cyclic.
+
+\stopsection
+
+\stopchapter
diff --git a/systems/doc/luatex/luatex-introduction.tex b/systems/doc/luatex/luatex-introduction.tex
index c03725357b..93d0215a82 100644
--- a/systems/doc/luatex/luatex-introduction.tex
+++ b/systems/doc/luatex/luatex-introduction.tex
@@ -1,174 +1,174 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-introduction

-

-\startchapter[title=Introduction]

-

-This is the reference manual of \LUATEX. We don't claim it is complete and we

-assume that the reader knows about \TEX\ as described in \quotation {The \TEX\

-Book}, the \quotation {\ETEX\ manual}, the \quotation {\PDFTEX\ manual}, etc.

-Additional reference material is published in journals of user groups and

-\CONTEXT\ related documentation.

-

-It took about a decade to reach stable version 1.0, but for good reason.

-Successive versions brought new functionality, more control, some cleanup of

-internals. Experimental features evolved into stable ones or were dropped.

-Already quite early \LUATEX\ could be used for production and it was used on a

-daily basis by the authors. Successive versions sometimes demanded an adaption to

-the \LUA\ interfacing, but the concepts were unchanged. The current version can

-be considered stable in functionality and there will be no fundamental changes.

-Of course we then can decide to move towards version 2.00 with different

-properties.

-

-Don't expect \LUATEX\ to behave the same as \PDFTEX ! Although the core

-functionality of that 8 bit engine was starting point, it has been combined with

-the directional support of \OMEGA\ (\ALEPH). But, \LUATEX\ can behave different

-due to its wide (32 bit) characters, many registers and large memory support. The

-\PDF\ code produced differs from \PDFTEX\ but users will normally not notice

-that. There is native \UTF\ input, support for large (more than 8 bit) fonts, and

-the math machinery is tuned for \OPENTYPE\ math. There is support for directional

-typesetting too. The log output can differ from other engines and will likely

-differ more as we move forward. When you run plain \TEX\ for sure \LUATEX\ runs

-slower than \PDFTEX\ but when you run for instance \CONTEXT\ \MKIV\ in many cases

-it runs faster, especially when you have a bit more complex documents or input.

-Anyway, 32 bit all||over combined with more features has a price, but on a modern

-machine this is no real problem.

-

-Testing is done with \CONTEXT, but \LUATEX\ should work fine with other macro

-packages too. For that purpose we provide generic font handlers that are mostly

-the same as used in \CONTEXT. Discussing specific implementations is beyond this

-manual. Even when we keep \LUATEX\ lean and mean, we already have enough to

-discuss here.

-

-\LUATEX\ consists of a number of interrelated but (still) distinguishable parts.

-The organization of the source code is adapted so that it can glue all these

-components together. We continue cleaning up side effects of the accumulated

-code in \TEX\ engines (especially code that is not needed any longer).

-

-\startitemize [unpacked]

-    \startitem

-        We started out with most of \PDFTEX\ version 1.40.9. The code base was

-        converted to \CCODE\ and split in modules. Experimental features were

-        removed and utility macros are not inherited because their functionality

-        can be programmed in \LUA. The number of backend interface commands has

-        been reduced to a few. The so called extensions are separated from the

-        core (which we try to keep close to the original \TEX\ core). Some

-        mechanisms like expansion and protrusion can behave different from the

-        original due to some cleanup and optimization. Some whatsit based

-        functionality (image support and reusable content) is now core

-        functionality. We don't stay in sync with \PDFTEX\ development.

-    \stopitem

-    \startitem

-        The direction model from \ALEPH\ RC4 (which is derived from \OMEGA) is

-        included. The related primitives are part of core \LUATEX\ but at the

-        node level directional support is no longer based on so called whatsits

-        but on real nodes with relevant properties. The number of directions is

-        limited to the useful set and the backend has been made direction aware.

-    \stopitem

-    \startitem

-        Neither \ALEPH's I/O translation processes, nor tcx files, nor \ENCTEX\

-        are available. These encoding|-|related functions are superseded by a

-        \LUA|-|based solution (reader callbacks). In a similar fashion all file

-        \IO\ can be intercepted.

-    \stopitem

-    \startitem

-        We currently use \LUA\ 5.3.*. There are few \LUA\ libraries that we

-        consider part of the core \LUA\ machinery, for instance \type {lpeg}.

-        There are additional \LUA\ libraries that interface to the internals of

-        \TEX. We also keep the \LUA\ 5.2 \type {bit32} library around.

-    \stopitem

-    \startitem

-        There are various \TEX\ extensions but only those that cannot be done

-        using the \LUA\ interfaces. The math machinery often has two code paths:

-        one traditional and the other more suitable for wide \OPENTYPE\ fonts. Here

-        we follow the \MICROSOFT\ specifications as much as possible.  Some math

-        functionality has been opened up a bit so that users have more control.

-    \stopitem

-    \startitem

-        The fontloader uses parts of \FONTFORGE\ 2008.11.17 combined with

-        additional code specific for usage in a \TEX\ engine. We try to minimize

-        specific font support to what \TEX\ needs: character references and

-        dimensions and delegate everything else to \LUA. That way we keep \TEX\

-        open for extensions without touching the core. In order to minimize

-        dependencies at some point we may decide to make this an optional

-        library.

-    \stopitem

-    \startitem

-        The \METAPOST\ library is integral part of \LUATEX. This gives \TEX\ some

-        graphical capabilities using a relative high speed graphical subsystem.

-        Again \LUA\ is used as glue between the frontend and backend. Further

-        development of \METAPOST\ is closely related to \LUATEX.

-    \stopitem

-    \startitem

-        The virtual font technology that comes with \TEX\ has been integrated

-        into the font machinery in a way that permits creating virtual fonts

-        at runtime. Because \LUATEX\ can also act as a \LUA\ interpreter this

-        means that a complete \TEX\ workflow can be built without the need for

-        additional programs.

-    \stopitem

-    \startitem

-        The versions starting from 1.09 no longer use the poppler library for

-        inclusion but a lightweight dedicated one. This removes a dependency but

-        also makes the inclusion code of \LUATEX\ different from \PDFTEX. In fact

-        it was already much different due to the \LUA\ image interfacing.

-    \stopitem

-\stopitemize

-

-We try to keep upcoming versions compatible but intermediate releases can contain

-experimental features. A general rule is that versions that end up on \TEXLIVE\

-and|/|or are released around \CONTEXT\ meetings are stable. Any version between

-the yearly \TEXLIVE\ releases are to be considered beta and in the repository end

-up as trunk releases. We have an experimental branch that we use for development

-but there is no support for any of its experimental features. Intermediate

-releases (from trunk) are normally available via the \CONTEXT\ distribution

-channels (the garden and so called minimals).

-

-Version 1.10 is more or less an endpoint in development: this is what you get.

-Because not only \CONTEXT, that we can adapt rather easily, uses \LUATEX, we

-cannot change fundamentals without unforeseen consequences. By now it has been

-proven that \LUA\ can be used to extend the core functionality so there is no

-need to add more, and definitely no hard coded solutions for (not so) common

-problems. Of course there will be bug fixes, maybe some optimization, and there

-might even be some additions or non|-|intrusive improvements, but only after

-testing outside the stable release. After all, the binary is already more than

-large enough and there is not that much to gain.

-

-You might find \LUA\ helpers that are not yet documented. These are considered

-experimental, although when you encounter them in a \CONTEXT\ version that has

-been around for a while you can assume that they will stay. Of course it can just

-be that we forgot to document them yet.

-

-A manual like this is not really meant as tutorial, for that we refer to

-documents that ship with \CONTEXT, articles, etc. It is also never complete

-enough for all readers. We try to keep up but the reader needs to realize that

-it's all volunteer work done in spare time. And for sure, complaining about a bad

-manual or crappy documentation will not really motivate us to spend more time on

-it. That being said, we hope that this document is useful.

-

-\blank[big]

-

-\testpage[5]

-

-\startlines

-Hans Hagen

-Harmut Henkel

-Taco Hoekwater

-Luigi Scarso

-\stoplines

-

-\blank[3*big]

-

-\starttabulate[|||]

-\NC Version  \EQ \currentdate \NC \NR

-\NC \LUATEX  \EQ \cldcontext{LUATEXENGINE} %

-                 \cldcontext{"\letterpercent 0.2f",LUATEXVERSION} / %

-                 \cldcontext{LUATEXFUNCTIONALITY}

-                 \NC \NR

-\NC \CONTEXT \EQ MkIV \contextversion \NC \NR

-\stoptabulate

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-introduction
+
+\startchapter[title=Introduction]
+
+This is the reference manual of \LUATEX. We don't claim it is complete and we
+assume that the reader knows about \TEX\ as described in \quotation {The \TEX\
+Book}, the \quotation {\ETEX\ manual}, the \quotation {\PDFTEX\ manual}, etc.
+Additional reference material is published in journals of user groups and
+\CONTEXT\ related documentation.
+
+It took about a decade to reach stable version 1.0, but for good reason.
+Successive versions brought new functionality, more control, some cleanup of
+internals. Experimental features evolved into stable ones or were dropped.
+Already quite early \LUATEX\ could be used for production and it was used on a
+daily basis by the authors. Successive versions sometimes demanded an adaption to
+the \LUA\ interfacing, but the concepts were unchanged. The current version can
+be considered stable in functionality and there will be no fundamental changes.
+Of course we then can decide to move towards version 2.00 with different
+properties.
+
+Don't expect \LUATEX\ to behave the same as \PDFTEX ! Although the core
+functionality of that 8 bit engine was starting point, it has been combined with
+the directional support of \OMEGA\ (\ALEPH). But, \LUATEX\ can behave different
+due to its wide (32 bit) characters, many registers and large memory support. The
+\PDF\ code produced differs from \PDFTEX\ but users will normally not notice
+that. There is native \UTF\ input, support for large (more than 8 bit) fonts, and
+the math machinery is tuned for \OPENTYPE\ math. There is support for directional
+typesetting too. The log output can differ from other engines and will likely
+differ more as we move forward. When you run plain \TEX\ for sure \LUATEX\ runs
+slower than \PDFTEX\ but when you run for instance \CONTEXT\ \MKIV\ in many cases
+it runs faster, especially when you have a bit more complex documents or input.
+Anyway, 32 bit all||over combined with more features has a price, but on a modern
+machine this is no real problem.
+
+Testing is done with \CONTEXT, but \LUATEX\ should work fine with other macro
+packages too. For that purpose we provide generic font handlers that are mostly
+the same as used in \CONTEXT. Discussing specific implementations is beyond this
+manual. Even when we keep \LUATEX\ lean and mean, we already have enough to
+discuss here.
+
+\LUATEX\ consists of a number of interrelated but (still) distinguishable parts.
+The organization of the source code is adapted so that it can glue all these
+components together. We continue cleaning up side effects of the accumulated
+code in \TEX\ engines (especially code that is not needed any longer).
+
+\startitemize [unpacked]
+    \startitem
+        We started out with most of \PDFTEX\ version 1.40.9. The code base was
+        converted to \CCODE\ and split in modules. Experimental features were
+        removed and utility macros are not inherited because their functionality
+        can be programmed in \LUA. The number of backend interface commands has
+        been reduced to a few. The so called extensions are separated from the
+        core (which we try to keep close to the original \TEX\ core). Some
+        mechanisms like expansion and protrusion can behave different from the
+        original due to some cleanup and optimization. Some whatsit based
+        functionality (image support and reusable content) is now core
+        functionality. We don't stay in sync with \PDFTEX\ development.
+    \stopitem
+    \startitem
+        The direction model from \ALEPH\ RC4 (which is derived from \OMEGA) is
+        included. The related primitives are part of core \LUATEX\ but at the
+        node level directional support is no longer based on so called whatsits
+        but on real nodes with relevant properties. The number of directions is
+        limited to the useful set and the backend has been made direction aware.
+    \stopitem
+    \startitem
+        Neither \ALEPH's I/O translation processes, nor tcx files, nor \ENCTEX\
+        are available. These encoding|-|related functions are superseded by a
+        \LUA|-|based solution (reader callbacks). In a similar fashion all file
+        \IO\ can be intercepted.
+    \stopitem
+    \startitem
+        We currently use \LUA\ 5.3.*. There are few \LUA\ libraries that we
+        consider part of the core \LUA\ machinery, for instance \type {lpeg}.
+        There are additional \LUA\ libraries that interface to the internals of
+        \TEX. We also keep the \LUA\ 5.2 \type {bit32} library around.
+    \stopitem
+    \startitem
+        There are various \TEX\ extensions but only those that cannot be done
+        using the \LUA\ interfaces. The math machinery often has two code paths:
+        one traditional and the other more suitable for wide \OPENTYPE\ fonts. Here
+        we follow the \MICROSOFT\ specifications as much as possible.  Some math
+        functionality has been opened up a bit so that users have more control.
+    \stopitem
+    \startitem
+        The fontloader uses parts of \FONTFORGE\ 2008.11.17 combined with
+        additional code specific for usage in a \TEX\ engine. We try to minimize
+        specific font support to what \TEX\ needs: character references and
+        dimensions and delegate everything else to \LUA. That way we keep \TEX\
+        open for extensions without touching the core. In order to minimize
+        dependencies at some point we may decide to make this an optional
+        library.
+    \stopitem
+    \startitem
+        The \METAPOST\ library is integral part of \LUATEX. This gives \TEX\ some
+        graphical capabilities using a relative high speed graphical subsystem.
+        Again \LUA\ is used as glue between the frontend and backend. Further
+        development of \METAPOST\ is closely related to \LUATEX.
+    \stopitem
+    \startitem
+        The virtual font technology that comes with \TEX\ has been integrated
+        into the font machinery in a way that permits creating virtual fonts
+        at runtime. Because \LUATEX\ can also act as a \LUA\ interpreter this
+        means that a complete \TEX\ workflow can be built without the need for
+        additional programs.
+    \stopitem
+    \startitem
+        The versions starting from 1.09 no longer use the poppler library for
+        inclusion but a lightweight dedicated one. This removes a dependency but
+        also makes the inclusion code of \LUATEX\ different from \PDFTEX. In fact
+        it was already much different due to the \LUA\ image interfacing.
+    \stopitem
+\stopitemize
+
+We try to keep upcoming versions compatible but intermediate releases can contain
+experimental features. A general rule is that versions that end up on \TEXLIVE\
+and|/|or are released around \CONTEXT\ meetings are stable. Any version between
+the yearly \TEXLIVE\ releases are to be considered beta and in the repository end
+up as trunk releases. We have an experimental branch that we use for development
+but there is no support for any of its experimental features. Intermediate
+releases (from trunk) are normally available via the \CONTEXT\ distribution
+channels (the garden and so called minimals).
+
+Version 1.10 is more or less an endpoint in development: this is what you get.
+Because not only \CONTEXT, that we can adapt rather easily, uses \LUATEX, we
+cannot change fundamentals without unforeseen consequences. By now it has been
+proven that \LUA\ can be used to extend the core functionality so there is no
+need to add more, and definitely no hard coded solutions for (not so) common
+problems. Of course there will be bug fixes, maybe some optimization, and there
+might even be some additions or non|-|intrusive improvements, but only after
+testing outside the stable release. After all, the binary is already more than
+large enough and there is not that much to gain.
+
+You might find \LUA\ helpers that are not yet documented. These are considered
+experimental, although when you encounter them in a \CONTEXT\ version that has
+been around for a while you can assume that they will stay. Of course it can just
+be that we forgot to document them yet.
+
+A manual like this is not really meant as tutorial, for that we refer to
+documents that ship with \CONTEXT, articles, etc. It is also never complete
+enough for all readers. We try to keep up but the reader needs to realize that
+it's all volunteer work done in spare time. And for sure, complaining about a bad
+manual or crappy documentation will not really motivate us to spend more time on
+it. That being said, we hope that this document is useful.
+
+\blank[big]
+
+\testpage[5]
+
+\startlines
+Hans Hagen
+Harmut Henkel
+Taco Hoekwater
+Luigi Scarso
+\stoplines
+
+\blank[3*big]
+
+\starttabulate[|||]
+\NC Version  \EQ \currentdate \NC \NR
+\NC \LUATEX  \EQ \cldcontext{LUATEXENGINE} %
+                 \cldcontext{"\letterpercent 0.2f",LUATEXVERSION} / %
+                 \cldcontext{LUATEXFUNCTIONALITY}
+                 \NC \NR
+\NC \CONTEXT \EQ MkIV \contextversion \NC \NR
+\stoptabulate
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-languages.tex b/systems/doc/luatex/luatex-languages.tex
index 98960aa65d..d4a7bda607 100644
--- a/systems/doc/luatex/luatex-languages.tex
+++ b/systems/doc/luatex/luatex-languages.tex
@@ -1,1113 +1,1113 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-languages

-

-\startchapter[reference=languages,title={Languages, characters, fonts and glyphs}]

-

-\startsection[title={Introduction}]

-

-\topicindex {languages}

-

-\LUATEX's internal handling of the characters and glyphs that eventually become

-typeset is quite different from the way \TEX82 handles those same objects. The

-easiest way to explain the difference is to focus on unrestricted horizontal mode

-(i.e.\ paragraphs) and hyphenation first. Later on, it will be easy to deal

-with the differences that occur in horizontal and math modes.

-

-In \TEX82, the characters you type are converted into \type {char} node records

-when they are encountered by the main control loop. \TEX\ attaches and processes

-the font information while creating those records, so that the resulting \quote

-{horizontal list} contains the final forms of ligatures and implicit kerning.

-This packaging is needed because we may want to get the effective width of for

-instance a horizontal box.

-

-When it becomes necessary to hyphenate words in a paragraph, \TEX\ converts (one

-word at time) the \type {char} node records into a string by replacing ligatures

-with their components and ignoring the kerning. Then it runs the hyphenation

-algorithm on this string, and converts the hyphenated result back into a \quote

-{horizontal list} that is consecutively spliced back into the paragraph stream.

-Keep in mind that the paragraph may contain unboxed horizontal material, which

-then already contains ligatures and kerns and the words therein are part of the

-hyphenation process.

-

-Those \type {char} node records are somewhat misnamed, as they are glyph

-positions in specific fonts, and therefore not really \quote {characters} in the

-linguistic sense. There is no language information inside the \type {char} node

-records at all. Instead, language information is passed along using \type

-{language whatsit} nodes inside the horizontal list.

-

-In \LUATEX, the situation is quite different. The characters you type are always

-converted into \nod {glyph} node records with a special subtype to identify them

-as being intended as linguistic characters. \LUATEX\ stores the needed language

-information in those records, but does not do any font|-|related processing at

-the time of node creation. It only stores the index of the current font and a

-reference to a character in that font.

-

-When it becomes necessary to typeset a paragraph, \LUATEX\ first inserts all

-hyphenation points right into the whole node list. Next, it processes all the

-font information in the whole list (creating ligatures and adjusting kerning),

-and finally it adjusts all the subtype identifiers so that the records are \quote

-{glyph nodes} from now on.

-

-\stopsection

-

-\startsection[title={Characters, glyphs and discretionaries},reference=charsandglyphs]

-

-\topicindex {characters}

-\topicindex {glyphs}

-\topicindex {hyphenation}

-

-\TEX82 (including \PDFTEX) differentiates between \type {char} nodes and \type

-{lig} nodes. The former are simple items that contained nothing but a \quote

-{character} and a \quote {font} field, and they lived in the same memory as

-tokens did. The latter also contained a list of components, and a subtype

-indicating whether this ligature was the result of a word boundary, and it was

-stored in the same place as other nodes like boxes and kerns and glues.

-

-In \LUATEX, these two types are merged into one, somewhat larger structure called

-a \nod {glyph} node. Besides having the old character, font, and component

-fields there are a few more, like \quote {attr} that we will see in \in {section}

-[glyphnodes], these nodes also contain a subtype, that codes four main types and

-two additional ghost types. For ligatures, multiple bits can be set at the same

-time (in case of a single|-|glyph word).

-

-\startitemize

-    \startitem

-        \type {character}, for characters to be hyphenated: the lowest bit

-        (bit 0) is set to 1.

-    \stopitem

-    \startitem

-        \nod {glyph}, for specific font glyphs: the lowest bit (bit 0) is

-        not set.

-    \stopitem

-    \startitem

-        \type {ligature}, for constructed ligatures bit 1 is set.

-    \stopitem

-    \startitem

-        \type {ghost}, for so called \quote {ghost objects} bit 2 is set.

-    \stopitem

-    \startitem

-        \type {left}, for ligatures created from a left word boundary and for

-        ghosts created from \lpr {leftghost} bit 3 gets set.

-    \stopitem

-    \startitem

-        \type {right}, for ligatures created from a right word boundary and

-        for ghosts created from \lpr {rightghost} bit 4 is set.

-    \stopitem

-\stopitemize

-

-The \nod {glyph} nodes also contain language data, split into four items that

-were current when the node was created: the \prm {setlanguage} (15~bits), \prm

-{lefthyphenmin} (8~bits), \prm {righthyphenmin} (8~bits), and \prm {uchyph}

-(1~bit).

-

-Incidentally, \LUATEX\ allows 16383 separate languages, and words can be 256

-characters long. The language is stored with each character. You can set

-\prm {firstvalidlanguage} to for instance~1 and make thereby language~0

-an ignored hyphenation language.

-

-The new primitive \lpr {hyphenationmin} can be used to signal the minimal length

-of a word. This value is stored with the (current) language.

-

-Because the \prm {uchyph} value is saved in the actual nodes, its handling is

-subtly different from \TEX82: changes to \prm {uchyph} become effective

-immediately, not at the end of the current partial paragraph.

-

-Typeset boxes now always have their language information embedded in the nodes

-themselves, so there is no longer a possible dependency on the surrounding

-language settings. In \TEX82, a mid|-|paragraph statement like \type {\unhbox0}

-would process the box using the current paragraph language unless there was a

-\prm {setlanguage} issued inside the box. In \LUATEX, all language variables

-are already frozen.

-

-In traditional \TEX\ the process of hyphenation is driven by \type {lccode}s. In

-\LUATEX\ we made this dependency less strong. There are several strategies

-possible. When you do nothing, the currently used \type {lccode}s are used, when

-loading patterns, setting exceptions or hyphenating a list.

-

-When you set \prm {savinghyphcodes} to a value greater than zero the current set

-of \type {lccode}s will be saved with the language. In that case changing a \type

-{lccode} afterwards has no effect. However, you can adapt the set with:

-

-\starttyping

-\hjcode`a=`a

-\stoptyping

-

-This change is global which makes sense if you keep in mind that the moment that

-hyphenation happens is (normally) when the paragraph or a horizontal box is

-constructed. When \prm {savinghyphcodes} was zero when the language got

-initialized you start out with nothing, otherwise you already have a set.

-

-When a \lpr {hjcode} is greater than 0 but less than 32 is indicates the

-to be used length. In the following example we map a character (\type {x}) onto

-another one in the patterns and tell the engine that \type {œ} counts as one

-character. Because traditionally zero itself is reserved for inhibiting

-hyphenation, a value of 32 counts as zero.

-

-Here are some examples (we assume that French patterns are used):

-

-\starttabulate[||||]

-\NC                                  \NC \type{foobar} \NC \type{foo-bar} \NC \NR

-\NC \type{\hjcode`x=`o}              \NC \type{fxxbar} \NC \type{fxx-bar} \NC \NR

-\NC \type{\lefthyphenmin3}           \NC \type{œdipus} \NC \type{œdi-pus} \NC \NR

-\NC \type{\lefthyphenmin4}           \NC \type{œdipus} \NC \type{œdipus}  \NC \NR

-\NC \type{\hjcode`œ=2}               \NC \type{œdipus} \NC \type{œdi-pus} \NC \NR

-\NC \type{\hjcode`i=32 \hjcode`d=32} \NC \type{œdipus} \NC \type{œdipus}  \NC \NR

-\NC

-\stoptabulate

-

-Carrying all this information with each glyph would give too much overhead and

-also make the process of setting up these codes more complex. A solution with

-\type {hjcode} sets was considered but rejected because in practice the current

-approach is sufficient and it would not be compatible anyway.

-

-Beware: the values are always saved in the format, independent of the setting

-of \prm {savinghyphcodes} at the moment the format is dumped.

-

-A boundary node normally would mark the end of a word which interferes with for

-instance discretionary injection. For this you can use the \prm {wordboundary}

-as a trigger. Here are a few examples of usage:

-

-\startbuffer

-    discrete---discrete

-\stopbuffer

-\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower

-\startbuffer

-    discrete\discretionary{}{}{---}discrete

-\stopbuffer

-\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower

-\startbuffer

-    discrete\wordboundary\discretionary{}{}{---}discrete

-\stopbuffer

-\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower

-\startbuffer

-    discrete\wordboundary\discretionary{}{}{---}\wordboundary discrete

-\stopbuffer

-\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower

-\startbuffer

-    discrete\wordboundary\discretionary{---}{}{}\wordboundary discrete

-\stopbuffer

-\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower

-

-We only accept an explicit hyphen when there is a preceding glyph and we skip a

-sequence of explicit hyphens since that normally indicates a \type {--} or \type

-{---} ligature in which case we can in a worse case usage get bad node lists

-later on due to messed up ligature building as these dashes are ligatures in base

-fonts. This is a side effect of separating the hyphenation, ligaturing and

-kerning steps.

-

-The start and end of a sequence of characters is signalled by a \nod {glue}, \nod

-{penalty}, \nod {kern} or \nod {boundary} node. But by default also a \nod

-{hlist}, \nod {vlist}, \nod {rule}, \nod {dir}, \nod {whatsit}, \nod {ins}, and

-\nod {adjust} node indicate a start or end. You can omit the last set from the

-test by setting \lpr {hyphenationbounds} to a non|-|zero value:

-

-\starttabulate[|c|l|]

-\DB value    \BC behaviour \NC \NR

-\TB

-\NC \type{0} \NC not strict \NC \NR

-\NC \type{1} \NC strict start \NC \NR

-\NC \type{2} \NC strict end \NC \NR

-\NC \type{3} \NC strict start and strict end \NC \NR

-\LL

-\stoptabulate

-

-The word start is determined as follows:

-

-\starttabulate[|l|l|]

-\DB node      \BC behaviour \NC \NR

-\TB

-\BC boundary  \NC yes when wordboundary \NC \NR

-\BC hlist     \NC when hyphenationbounds 1 or 3 \NC \NR

-\BC vlist     \NC when hyphenationbounds 1 or 3 \NC \NR

-\BC rule      \NC when hyphenationbounds 1 or 3 \NC \NR

-\BC dir       \NC when hyphenationbounds 1 or 3 \NC \NR

-\BC whatsit   \NC when hyphenationbounds 1 or 3 \NC \NR

-\BC glue      \NC yes \NC \NR

-\BC math      \NC skipped \NC \NR

-\BC glyph     \NC exhyphenchar (one only) : yes (so no -- ---) \NC \NR

-\BC otherwise \NC yes \NC \NR

-\LL

-\stoptabulate

-

-The word end is determined as follows:

-

-\starttabulate[|l|l|]

-\DB node      \BC behaviour \NC \NR

-\TB

-\BC boundary  \NC yes \NC \NR

-\BC glyph     \NC yes when different language \NC \NR

-\BC glue      \NC yes \NC \NR

-\BC penalty   \NC yes \NC \NR

-\BC kern      \NC yes when not italic (for some historic reason) \NC \NR

-\BC hlist     \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC vlist     \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC rule      \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC dir       \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC whatsit   \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC ins       \NC when hyphenationbounds 2 or 3 \NC \NR

-\BC adjust    \NC when hyphenationbounds 2 or 3 \NC \NR

-\LL

-\stoptabulate

-

-\in {Figures} [hb:1] upto \in [hb:5] show some examples. In all cases we set the

-min values to 1 and make sure that the words hyphenate at each character.

-

-\hyphenation{o-n-e t-w-o}

-

-\def\SomeTest#1#2%

-  {\lefthyphenmin  \plusone

-   \righthyphenmin \plusone

-   \parindent      \zeropoint

-   \everypar       \emptytoks

-   \dontcomplain

-   \hbox to 2cm {%

-     \vtop {%

-       \hsize 1pt

-       \hyphenationbounds#1

-       #2

-       \par}}}

-

-\startplacefigure[reference=hb:1,title={\type{one}}]

-    \startcombination[4*1]

-        {\SomeTest{0}{one}} {\type{0}}

-        {\SomeTest{1}{one}} {\type{1}}

-        {\SomeTest{2}{one}} {\type{2}}

-        {\SomeTest{3}{one}} {\type{3}}

-    \stopcombination

-\stopplacefigure

-

-\startplacefigure[reference=hb:2,title={\type{one\null two}}]

-    \startcombination[4*1]

-        {\SomeTest{0}{one\null two}} {\type{0}}

-        {\SomeTest{1}{one\null two}} {\type{1}}

-        {\SomeTest{2}{one\null two}} {\type{2}}

-        {\SomeTest{3}{one\null two}} {\type{3}}

-    \stopcombination

-\stopplacefigure

-

-\startplacefigure[reference=hb:3,title={\type{\null one\null two}}]

-    \startcombination[4*1]

-        {\SomeTest{0}{\null one\null two}} {\type{0}}

-        {\SomeTest{1}{\null one\null two}} {\type{1}}

-        {\SomeTest{2}{\null one\null two}} {\type{2}}

-        {\SomeTest{3}{\null one\null two}} {\type{3}}

-    \stopcombination

-\stopplacefigure

-

-\startplacefigure[reference=hb:4,title={\type{one\null two\null}}]

-    \startcombination[4*1]

-        {\SomeTest{0}{one\null two\null}} {\type{0}}

-        {\SomeTest{1}{one\null two\null}} {\type{1}}

-        {\SomeTest{2}{one\null two\null}} {\type{2}}

-        {\SomeTest{3}{one\null two\null}} {\type{3}}

-    \stopcombination

-\stopplacefigure

-

-\startplacefigure[reference=hb:5,title={\type{\null one\null two\null}}]

-    \startcombination[4*1]

-        {\SomeTest{0}{\null one\null two\null}} {\type{0}}

-        {\SomeTest{1}{\null one\null two\null}} {\type{1}}

-        {\SomeTest{2}{\null one\null two\null}} {\type{2}}

-        {\SomeTest{3}{\null one\null two\null}} {\type{3}}

-    \stopcombination

-\stopplacefigure

-

-% (Future versions of \LUATEX\ might provide more granularity.)

-

-In traditional \TEX\ ligature building and hyphenation are interwoven with the

-line break mechanism. In \LUATEX\ these phases are isolated. As a consequence we

-deal differently with (a sequence of) explicit hyphens. We already have added

-some control over aspects of the hyphenation and yet another one concerns

-automatic hyphens (e.g.\ \type {-} characters in the input).

-

-When \lpr {automatichyphenmode} has a value of 0, a hyphen will be turned into

-an automatic discretionary. The snippets before and after it will not be

-hyphenated. A side effect is that a leading hyphen can lead to a split but one

-will seldom run into that situation. Setting a pre and post character makes this

-more prominent. A value of 1 will prevent this side effect and a value of 2 will

-not turn the hyphen into a discretionary. Experiments with other options, like

-permitting hyphenation of the words on both sides were discarded.

-

-\startbuffer[a]

-before-after \par

-before--after \par

-before---after \par

-\stopbuffer

-

-\startbuffer[b]

--before \par

-after- \par

---before \par

-after-- \par

----before \par

-after--- \par

-\stopbuffer

-

-\startbuffer[c]

-before-after \par

-before--after \par

-before---after \par

-\stopbuffer

-

-\startbuffer[demo]

-\startcombination[nx=4,ny=3,location=top]

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[a]}} {A~0~6em}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[a]}} {A~0~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[a]}} {A~1~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[a]}} {A~2~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[b]}} {B~0~6em}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[b]}} {B~0~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[b]}} {B~1~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[b]}} {B~2~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[c]}} {C~0~6em}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[c]}} {C~0~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[c]}} {C~1~2pt}

-    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[c]}} {C~2~2pt}

-\stopcombination

-\stopbuffer

-

-\startplacefigure[locationreference=automatichyphenmode:1,title={The automatic modes \type {0} (default), \type {1} and \type {2}, with a \prm {hsize}

-of 6em and 2pt (which triggers a linebreak).}]

-    \dontcomplain \tt \getbuffer[demo]

-\stopplacefigure

-

-\startplacefigure[reference=automatichyphenmode:2,title={The automatic modes \type {0} (default), \type {1} and \type {2}, with \lpr {preexhyphenchar} and \lpr {postexhyphenchar} set to characters \type {A} and \type {B}.}]

-    \postexhyphenchar`A\relax

-    \preexhyphenchar `B\relax

-    \dontcomplain \tt \getbuffer[demo]

-\stopplacefigure

-

-In \in {figure} [automatichyphenmode:1] \in {and} [automatichyphenmode:2] we show

-what happens with three samples:

-

-Input A: \typebuffer[a]

-Input B: \typebuffer[b]

-Input C: \typebuffer[c]

-

-As with primitive companions of other single character commands, the \prm {-}

-command has a more verbose primitive version in \lpr {explicitdiscretionary}

-and the normally intercepted in the hyphenator character \type {-} (or whatever

-is configured) is available as \lpr {automaticdiscretionary}.

-

-\stopsection

-

-\startsection[title={The main control loop}]

-

-\topicindex {main loop}

-\topicindex {hyphenation}

-

-In \LUATEX's main loop, almost all input characters that are to be typeset are

-converted into \nod {glyph} node records with subtype \quote {character}, but

-there are a few exceptions.

-

-\startitemize[n]

-

-\startitem

-    The \prm {accent} primitive creates nodes with subtype \quote {glyph}

-    instead of \quote {character}: one for the actual accent and one for the

-    accentee. The primary reason for this is that \prm {accent} in \TEX82 is

-    explicitly dependent on the current font encoding, so it would not make much

-    sense to attach a new meaning to the primitive's name, as that would

-    invalidate many old documents and macro packages. A secondary reason is that

-    in \TEX82, \prm {accent} prohibits hyphenation of the current word. Since

-    in \LUATEX\ hyphenation only takes place on \quote {character} nodes, it is

-    possible to achieve the same effect. Of course, modern \UNICODE\ aware macro

-    packages will not use the \prm {accent} primitive at all but try to map

-    directly on composed characters.

-

-    This change of meaning did happen with \prm {char}, that now generates

-    \quote {glyph} nodes with a character subtype. In traditional \TEX\ there was

-    a strong relationship between the 8|-|bit input encoding, hyphenation and

-    glyphs taken from a font. In \LUATEX\ we have \UTF\ input, and in most cases

-    this maps directly to a character in a font, apart from glyph replacement in

-    the font engine. If you want to access arbitrary glyphs in a font directly

-    you can always use \LUA\ to do so, because fonts are available as \LUA\

-    table.

-\stopitem

-

-\startitem

-    All the results of processing in math mode eventually become nodes with

-    \quote {glyph} subtypes. In fact, the result of processing math is just

-    a regular list of glyphs, kerns, glue, penalties, boxes etc.

-\stopitem

-

-\startitem

-    The \ALEPH|-|derived commands \lpr {leftghost} and \lpr {rightghost}

-    create nodes of a third subtype: \quote {ghost}. These nodes are ignored

-    completely by all further processing until the stage where inter|-|glyph

-    kerning is added.

-\stopitem

-

-\startitem

-    Automatic discretionaries are handled differently. \TEX82 inserts an empty

-    discretionary after sensing an input character that matches the \prm

-    {hyphenchar} in the current font. This test is wrong in our opinion: whether

-    or not hyphenation takes place should not depend on the current font, it is a

-    language property. \footnote {When \TEX\ showed up we didn't have \UNICODE\

-    yet and being limited to eight bits meant that one sometimes had to

-    compromise between supporting character input, glyph rendering, hyphenation.}

-

-    In \LUATEX, it works like this: if \LUATEX\ senses a string of input

-    characters that matches the value of the new integer parameter \prm

-    {exhyphenchar}, it will insert an explicit discretionary after that series of

-    nodes. Initially \TEX\ sets the \type {\exhyphenchar=`\-}. Incidentally, this

-    is a global parameter instead of a language-specific one because it may be

-    useful to change the value depending on the document structure instead of the

-    text language.

-

-    The insertion of discretionaries after a sequence of explicit hyphens happens

-    at the same time as the other hyphenation processing, {\it not\/} inside the

-    main control loop.

-

-    The only use \LUATEX\ has for \prm {hyphenchar} is at the check whether a

-    word should be considered for hyphenation at all. If the \prm {hyphenchar}

-    of the font attached to the first character node in a word is negative, then

-    hyphenation of that word is abandoned immediately. This behaviour is added

-    for backward compatibility only, and the use of \type {\hyphenchar=-1} as a

-    means of preventing hyphenation should not be used in new \LUATEX\ documents.

-\stopitem

-

-\startitem

-    The \prm {setlanguage} command no longer creates whatsits. The meaning of

-    \prm {setlanguage} is changed so that it is now an integer parameter like all

-    others. That integer parameter is used in \type {\glyph_node} creation to add

-    language information to the glyph nodes. In conjunction, the \prm {language}

-    primitive is extended so that it always also updates the value of \prm

-    {setlanguage}.

-\stopitem

-

-\startitem

-    The \prm {noboundary} command (that prohibits word boundary processing

-    where that would normally take place) now does create nodes. These nodes are

-    needed because the exact place of the \prm {noboundary} command in the

-    input stream has to be retained until after the ligature and font processing

-    stages.

-\stopitem

-

-\startitem

-    There is no longer a \type {main_loop} label in the code. Remember that

-    \TEX82 did quite a lot of processing while adding \type {char_nodes} to the

-    horizontal list? For speed reasons, it handled that processing code outside

-    of the \quote {main control} loop, and only the first character of any \quote

-    {word} was handled by that \quote {main control} loop. In \LUATEX, there is

-    no longer a need for that (all hard work is done later), and the (now very

-    small) bits of character|-|handling code have been moved back inline. When

-    \prm {tracingcommands} is on, this is visible because the full word is

-    reported, instead of just the initial character.

-\stopitem

-

-\stopitemize

-

-Because we tend to make hard coded behaviour configurable a few new primitives

-have been added:

-

-\starttyping

-\hyphenpenaltymode

-\automatichyphenpenalty

-\explicithyphenpenalty

-\stoptyping

-

-The first parameter has the following consequences for automatic discs (the ones

-resulting from an \prm {exhyphenchar}:

-

-\starttabulate[|c|l|l|]

-\DB mode     \BC automatic disc \type {-}      \BC explicit disc \prm{-}         \NC \NR

-\TB

-\NC \type{0} \NC \prm {exhyphenpenalty}        \NC \prm {exhyphenpenalty}        \NC \NR

-\NC \type{1} \NC \prm {hyphenpenalty}          \NC \prm {hyphenpenalty}          \NC \NR

-\NC \type{2} \NC \prm {exhyphenpenalty}        \NC \prm {hyphenpenalty}          \NC \NR

-\NC \type{3} \NC \prm {hyphenpenalty}          \NC \prm {exhyphenpenalty}        \NC \NR

-\NC \type{4} \NC \lpr {automatichyphenpenalty} \NC \lpr {explicithyphenpenalty}  \NC \NR

-\NC \type{5} \NC \prm {exhyphenpenalty}        \NC \lpr {explicithyphenpenalty}  \NC \NR

-\NC \type{6} \NC \prm {hyphenpenalty}          \NC \lpr {explicithyphenpenalty}  \NC \NR

-\NC \type{7} \NC \lpr {automatichyphenpenalty} \NC \prm {exhyphenpenalty}        \NC \NR

-\NC \type{8} \NC \lpr {automatichyphenpenalty} \NC \prm {hyphenpenalty}          \NC \NR

-\LL

-\stoptabulate

-

-other values do what we always did in \LUATEX: insert \prm {exhyphenpenalty}.

-

-\stopsection

-

-\startsection[title={Loading patterns and exceptions},reference=patternsexceptions]

-

-\topicindex {hyphenation}

-\topicindex {hyphenation+patterns}

-\topicindex {hyphenation+exceptions}

-\topicindex {patterns}

-\topicindex {exceptions}

-

-Although we keep the traditional approach towards hyphenation (which is still

-superior) the implementation of the hyphenation algorithm in \LUATEX\ is quite

-different from the one in \TEX82.

-

-After expansion, the argument for \prm {patterns} has to be proper \UTF8 with

-individual patterns separated by spaces, no \prm {char} or \prm {chardef}d

-commands are allowed. The current implementation is quite strict and will reject

-all non|-|\UNICODE\ characters. Likewise, the expanded argument for \prm

-{hyphenation} also has to be proper \UTF8, but here a bit of extra syntax is

-provided:

-

-\startitemize[n]

-\startitem

-    Three sets of arguments in curly braces (\type {{}{}{}}) indicate a desired

-    complex discretionary, with arguments as in \prm {discretionary}'s command in

-    normal document input.

-\stopitem

-\startitem

-    A \type {-} indicates a desired simple discretionary, cf.\ \type {\-} and

-    \type {\discretionary{-}{}{}} in normal document input.

-\stopitem

-\startitem

-    Internal command names are ignored. This rule is provided especially for \prm

-    {discretionary}, but it also helps to deal with \prm {relax} commands that

-    may sneak in.

-\stopitem

-\startitem

-    An \type {=} indicates a (non|-|discretionary) hyphen in the document input.

-\stopitem

-\stopitemize

-

-The expanded argument is first converted back to a space|-|separated string while

-dropping the internal command names. This string is then converted into a

-dictionary by a routine that creates key|-|value pairs by converting the other

-listed items. It is important to note that the keys in an exception dictionary

-can always be generated from the values. Here are a few examples:

-

-\starttabulate[|l|l|l|]

-\DB value                  \BC implied key (input) \BC effect \NC\NR

-\TB

-\NC \type {ta-ble}         \NC table               \NC \type {ta\-ble} ($=$ \type {ta\discretionary{-}{}{}ble}) \NC\NR

-\NC \type {ba{k-}{}{c}ken} \NC backen              \NC \type {ba\discretionary{k-}{}{c}ken} \NC\NR

-\LL

-\stoptabulate

-

-The resultant patterns and exception dictionary will be stored under the language

-code that is the present value of \prm {language}.

-

-In the last line of the table, you see there is no \prm {discretionary} command

-in the value: the command is optional in the \TEX-based input syntax. The

-underlying reason for that is that it is conceivable that a whole dictionary of

-words is stored as a plain text file and loaded into \LUATEX\ using one of the

-functions in the \LUA\ \type {lang} library. This loading method is quite a bit

-faster than going through the \TEX\ language primitives, but some (most?) of that

-speed gain would be lost if it had to interpret command sequences while doing so.

-

-It is possible to specify extra hyphenation points in compound words by using

-\type {{-}{}{-}} for the explicit hyphen character (replace \type {-} by the

-actual explicit hyphen character if needed). For example, this matches the word

-\quote {multi|-|word|-|boundaries} and allows an extra break inbetween \quote

-{boun} and \quote {daries}:

-

-\starttyping

-\hyphenation{multi{-}{}{-}word{-}{}{-}boun-daries}

-\stoptyping

-

-The motivation behind the \ETEX\ extension \prm {savinghyphcodes} was that

-hyphenation heavily depended on font encodings. This is no longer true in

-\LUATEX, and the corresponding primitive is basically ignored. Because we now

-have \lpr {hjcode}, the case relate codes can be used exclusively for \prm

-{uppercase} and \prm {lowercase}.

-

-The three curly brace pair pattern in an exception can be somewhat unexpected so

-we will try to explain it by example. The pattern \type {foo{}{}{x}bar} pattern

-creates a lookup \type {fooxbar} and the pattern \type {foo{}{}{}bar} creates

-\type {foobar}. Then, when a hit happens there is a replacement text (\type {x})

-or none. Because we introduced penalties in discretionary nodes, the exception

-syntax now also can take a penalty specification. The value between square brackets

-is a multiplier for \lpr {exceptionpenalty}. Here we have set it to 10000 so

-effectively we get 30000 in the example.

-

-\def\ShowSample#1#2%

-  {\startlinecorrection[blank]

-   \hyphenation{#1}%

-   \exceptionpenalty=10000

-   \bTABLE[foregroundstyle=type]

-     \bTR

-       \bTD[align=middle,nx=4] \type{#1} \eTD

-     \eTR

-     \bTR

-       \bTD[align=middle] \type{10em} \eTD

-       \bTD[align=middle] \type {3em} \eTD

-       \bTD[align=middle] \type {0em} \eTD

-       \bTD[align=middle] \type {6em} \eTD

-     \eTR

-     \bTR

-       \bTD[width=10em]\vtop{\hsize 10em 123 #2 123\par}\eTD

-       \bTD[width=10em]\vtop{\hsize  3em 123 #2 123\par}\eTD

-       \bTD[width=10em]\vtop{\hsize  0em 123 #2 123\par}\eTD

-       \bTD[width=10em]\vtop{\setupalign[verytolerant,stretch]\rmtf\hsize 6em 123 #2 #2 #2 #2 123\par}\eTD

-     \eTR

-   \eTABLE

-   \stoplinecorrection}

-

-\ShowSample{x{a-}{-b}{}x{a-}{-b}{}x{a-}{-b}{}x{a-}{-b}{}xx}{xxxxxx}

-\ShowSample{x{a-}{-b}{}x{a-}{-b}{}[3]x{a-}{-b}{}[1]x{a-}{-b}{}xx}{xxxxxx}

-

-\ShowSample{z{a-}{-b}{z}{a-}{-b}{z}{a-}{-b}{z}{a-}{-b}{z}z}{zzzzzz}

-\ShowSample{z{a-}{-b}{z}{a-}{-b}{z}[3]{a-}{-b}{z}[1]{a-}{-b}{z}z}{zzzzzz}

-

-\stopsection

-

-\startsection[title={Applying hyphenation}]

-

-\topicindex {hyphenation+how it works}

-\topicindex {hyphenation+discretionaries}

-\topicindex {discretionaries}

-

-The internal structures \LUATEX\ uses for the insertion of discretionaries in

-words is very different from the ones in \TEX82, and that means there are some

-noticeable differences in handling as well.

-

-First and foremost, there is no \quote {compressed trie} involved in hyphenation.

-The algorithm still reads pattern files generated by \PATGEN, but \LUATEX\ uses a

-finite state hash to match the patterns against the word to be hyphenated. This

-algorithm is based on the \quote {libhnj} library used by \OPENOFFICE, which in

-turn is inspired by \TEX.

-

-There are a few differences between \LUATEX\ and \TEX82 that are a direct result

-of the implementation:

-

-\startitemize

-\startitem

-    \LUATEX\ happily hyphenates the full \UNICODE\ character range.

-\stopitem

-\startitem

-    Pattern and exception dictionary size is limited by the available memory

-    only, all allocations are done dynamically. The trie|-|related settings in

-    \type {texmf.cnf} are ignored.

-\stopitem

-\startitem

-    Because there is no \quote {trie preparation} stage, language patterns never

-    become frozen. This means that the primitive \prm {patterns} (and its \LUA\

-    counterpart \type {lang.patterns}) can be used at any time, not only in

-    ini\TEX.

-\stopitem

-\startitem

-    Only the string representation of \prm {patterns} and \prm {hyphenation} is

-    stored in the format file. At format load time, they are simply

-    re|-|evaluated. It follows that there is no real reason to preload languages

-    in the format file. In fact, it is usually not a good idea to do so. It is

-    much smarter to load patterns no sooner than the first time they are actually

-    needed.

-\stopitem

-\startitem

-    \LUATEX\ uses the language-specific variables \lpr {prehyphenchar} and \lpr

-    {posthyphenchar} in the creation of implicit discretionaries, instead of

-    \TEX82's \prm {hyphenchar}, and the values of the language|-|specific

-    variables \lpr {preexhyphenchar} and \lpr {postexhyphenchar} for explicit

-    discretionaries (instead of \TEX82's empty discretionary).

-\stopitem

-\startitem

-    The value of the two counters related to hyphenation, \prm {hyphenpenalty}

-    and \prm {exhyphenpenalty}, are now stored in the discretionary nodes. This

-    permits a local overload for explicit \prm {discretionary} commands. The

-    value current when the hyphenation pass is applied is used. When no callbacks

-    are used this is compatible with traditional \TEX. When you apply the \LUA\

-    \type {lang.hyphenate} function the current values are used.

-\stopitem

-\startitem

-    The hyphenation exception dictionary is maintained as key|-|value hash, and

-    that is also dynamic, so the \type {hyph_size} setting is not used either.

-\stopitem

-\stopitemize

-

-Because we store penalties in the disc node the \prm {discretionary} command has

-been extended to accept an optional penalty specification, so you can do the

-following:

-

-\startbuffer

-\hsize1mm

-1:foo{\hyphenpenalty 10000\discretionary{}{}{}}bar\par

-2:foo\discretionary penalty 10000 {}{}{}bar\par

-3:foo\discretionary{}{}{}bar\par

-\stopbuffer

-

-\typebuffer

-

-This results in:

-

-\blank \start \getbuffer \stop \blank

-

-Inserted characters and ligatures inherit their attributes from the nearest glyph

-node item (usually the preceding one, but the following one for the items

-inserted at the left-hand side of a word).

-

-Word boundaries are no longer implied by font switches, but by language switches.

-One word can have two separate fonts and still be hyphenated correctly (but it

-can not have two different languages, the \prm {setlanguage} command forces a

-word boundary).

-

-All languages start out with \type {\prehyphenchar=`\-}, \type {\posthyphenchar=0},

-\type {\preexhyphenchar=0} and \type {\postexhyphenchar=0}. When you assign the

-values of one of these four parameters, you are actually changing the settings

-for the current \prm {language}, this behaviour is compatible with \prm {patterns}

-and \prm {hyphenation}.

-

-\LUATEX\ also hyphenates the first word in a paragraph. Words can be up to 256

-characters long (up from 64 in \TEX82). Longer words are ignored right now, but

-eventually either the limitation will be removed or perhaps it will become

-possible to silently ignore the excess characters (this is what happens in

-\TEX82, but there the behaviour cannot be controlled).

-

-If you are using the \LUA\ function \type {lang.hyphenate}, you should be aware

-that this function expects to receive a list of \quote {character} nodes. It will

-not operate properly in the presence of \quote {glyph}, \quote {ligature}, or

-\quote {ghost} nodes, nor does it know how to deal with kerning.

-

-\stopsection

-

-\startsection[title={Applying ligatures and kerning}]

-

-\topicindex {ligatures}

-\topicindex {kerning}

-

-After all possible hyphenation points have been inserted in the list, \LUATEX\

-will process the list to convert the \quote {character} nodes into \quote {glyph}

-and \quote {ligature} nodes. This is actually done in two stages: first all

-ligatures are processed, then all kerning information is applied to the result

-list. But those two stages are somewhat dependent on each other: If the used font

-makes it possible to do so, the ligaturing stage adds virtual \quote {character}

-nodes to the word boundaries in the list. While doing so, it removes and

-interprets \prm {noboundary} nodes. The kerning stage deletes those word

-boundary items after it is done with them, and it does the same for \quote

-{ghost} nodes. Finally, at the end of the kerning stage, all remaining \quote

-{character} nodes are converted to \quote {glyph} nodes.

-

-This word separation is worth mentioning because, if you overrule from \LUA\ only

-one of the two callbacks related to font handling, then you have to make sure you

-perform the tasks normally done by \LUATEX\ itself in order to make sure that the

-other, non|-|overruled, routine continues to function properly.

-

-Although we could improve the situation the reality is that in modern \OPENTYPE\

-fonts ligatures can be constructed in many ways: by replacing a sequence of

-characters by one glyph, or by selectively replacing individual glyphs, or by

-kerning, or any combination of this. Add to that contextual analysis and it will

-be clear that we have to let \LUA\ do that job instead. The generic font handler

-that we provide (which is part of \CONTEXT) distinguishes between base mode

-(which essentially is what we describe here and which delegates the task to \TEX)

-and node mode (which deals with more complex fonts.

-

-Let's look at an example. Take the word \type {office}, hyphenated \type

-{of-fice}, using a \quote {normal} font with all the \type {f}-\type {f} and

-\type {f}-\type {i} type ligatures:

-

-\starttabulate[|l|l|]

-\NC initial              \NC \type {{o}{f}{f}{i}{c}{e}}             \NC\NR

-\NC after hyphenation    \NC \type {{o}{f}{{-},{},{}}{f}{i}{c}{e}}  \NC\NR

-\NC first ligature stage \NC \type {{o}{{f-},{f},{<ff>}}{i}{c}{e}}  \NC\NR

-\NC final result         \NC \type {{o}{{f-},{<fi>},{<ffi>}}{c}{e}} \NC\NR

-\stoptabulate

-

-That's bad enough, but let us assume that there is also a hyphenation point

-between the \type {f} and the \type {i}, to create \type {of-f-ice}. Then the

-final result should be:

-

-\starttyping

-{o}{{f-},

-    {{f-},

-     {i},

-     {<fi>}},

-    {{<ff>-},

-     {i},

-     {<ffi>}}}{c}{e}

-\stoptyping

-

-with discretionaries in the post-break text as well as in the replacement text of

-the top-level discretionary that resulted from the first hyphenation point.

-

-Here is that nested solution again, in a different representation:

-

-\testpage[4]

-

-\starttabulate[|l|c|c|c|c|c|c|]

-\DB         \BC pre           \BC     \BC post      \BC       \BC replace       \BC       \NC \NR

-\TB

-\NC topdisc \NC \type {f-}    \NC (1) \NC           \NC sub 1 \NC               \NC sub 2 \NC \NR

-\NC sub 1   \NC \type {f-}    \NC (2) \NC \type {i} \NC (3)   \NC \type {<fi>}  \NC (4)   \NC \NR

-\NC sub 2   \NC \type {<ff>-} \NC (5) \NC \type {i} \NC (6)   \NC \type {<ffi>} \NC (7)   \NC \NR

-\LL

-\stoptabulate

-

-When line breaking is choosing its breakpoints, the following fields will

-eventually be selected:

-

-\starttabulate[|l|c|c|]

-\NC \type {of-f-ice} \NC \type {f-}    \NC (1) \NC \NR

-\NC                  \NC \type {f-}    \NC (2) \NC \NR

-\NC                  \NC \type {i}     \NC (3) \NC \NR

-\NC \type {of-fice}  \NC \type {f-}    \NC (1) \NC \NR

-\NC                  \NC \type {<fi>}  \NC (4) \NC \NR

-\NC \type {off-ice}  \NC \type {<ff>-} \NC (5) \NC \NR

-\NC                  \NC \type {i}     \NC (6) \NC \NR

-\NC \type {office}   \NC \type {<ffi>} \NC (7) \NC \NR

-\stoptabulate

-

-The current solution in \LUATEX\ is not able to handle nested discretionaries,

-but it is in fact smart enough to handle this fictional \type {of-f-ice} example.

-It does so by combining two sequential discretionary nodes as if they were a

-single object (where the second discretionary node is treated as an extension of

-the first node).

-

-One can observe that the \type {of-f-ice} and \type {off-ice} cases both end with

-the same actual post replacement list (\type {i}), and that this would be the

-case even if \type {i} was the first item of a potential following ligature like

-\type {ic}. This allows \LUATEX\ to do away with one of the fields, and thus make

-the whole stuff fit into just two discretionary nodes.

-

-The mapping of the seven list fields to the six fields in this discretionary node

-pair is as follows:

-

-\starttabulate[|l|c|c|]

-\DB field                 \BC description   \NC       \NC \NR

-\TB

-\NC \type {disc1.pre}     \NC \type {f-}    \NC (1)   \NC \NR

-\NC \type {disc1.post}    \NC \type {<fi>}  \NC (4)   \NC \NR

-\NC \type {disc1.replace} \NC \type {<ffi>} \NC (7)   \NC \NR

-\NC \type {disc2.pre}     \NC \type {f-}    \NC (2)   \NC \NR

-\NC \type {disc2.post}    \NC \type {i}     \NC (3,6) \NC \NR

-\NC \type {disc2.replace} \NC \type {<ff>-} \NC (5)   \NC \NR

-\LL

-\stoptabulate

-

-What is actually generated after ligaturing has been applied is therefore:

-

-\starttyping

-{o}{{f-},

-    {<fi>},

-    {<ffi>}}

-   {{f-},

-    {i},

-    {<ff>-}}{c}{e}

-\stoptyping

-

-The two discretionaries have different subtypes from a discretionary appearing on

-its own: the first has subtype 4, and the second has subtype 5. The need for

-these special subtypes stems from the fact that not all of the fields appear in

-their \quote {normal} location. The second discretionary especially looks odd,

-with things like the \type {<ff>-} appearing in \type {disc2.replace}. The fact

-that some of the fields have different meanings (and different processing code

-internally) is what makes it necessary to have different subtypes: this enables

-\LUATEX\ to distinguish this sequence of two joined discretionary nodes from the

-case of two standalone discretionaries appearing in a row.

-

-Of course there is still that relationship with fonts: ligatures can be implemented by

-mapping a sequence of glyphs onto one glyph, but also by selective replacement and

-kerning. This means that the above examples are just representing the traditional

-approach.

-

-\stopsection

-

-\startsection[title={Breaking paragraphs into lines}]

-

-\topicindex {linebreaks}

-\topicindex {paragraphs}

-\topicindex {discretionaries}

-

-This code is almost unchanged, but because of the above|-|mentioned changes

-with respect to discretionaries and ligatures, line breaking will potentially be

-different from traditional \TEX. The actual line breaking code is still based on

-the \TEX82 algorithms, and it does not expect there to be discretionaries inside

-of discretionaries. But, as patterns evolve and font handling can influence

-discretionaries, you need to be aware of the fact that long term consistency is not

-an engine matter only.

-

-But that situation is now fairly common in \LUATEX, due to the changes to the

-ligaturing mechanism. And also, the \LUATEX\ discretionary nodes are implemented

-slightly different from the \TEX82 nodes: the \type {no_break} text is now

-embedded inside the disc node, where previously these nodes kept their place in

-the horizontal list. In traditional \TEX\ the discretionary node contains a

-counter indicating how many nodes to skip, but in \LUATEX\ we store the pre, post

-and replace text in the discretionary node.

-

-The combined effect of these two differences is that \LUATEX\ does not always use

-all of the potential breakpoints in a paragraph, especially when fonts with many

-ligatures are used. Of course kerning also complicates matters here.

-

-\stopsection

-

-\startsection[title={The \type {lang} library}][library=lang]

-

-\subsection {\type {new} and \type {id}}

-

-\topicindex {languages+library}

-

-\libindex {new}

-\libindex {id}

-

-This library provides the interface to \LUATEX's structure representing a

-language, and the associated functions.

-

-\startfunctioncall

-<language> l = lang.new()

-<language> l = lang.new(<number> id)

-\stopfunctioncall

-

-This function creates a new userdata object. An object of type \type {<language>}

-is the first argument to most of the other functions in the \type {lang} library.

-These functions can also be used as if they were object methods, using the colon

-syntax. Without an argument, the next available internal id number will be

-assigned to this object. With argument, an object will be created that links to

-the internal language with that id number.

-

-\startfunctioncall

-<number> n = lang.id(<language> l)

-\stopfunctioncall

-

-The number returned is the internal \prm {language} id number this object refers to.

-

-\subsection {\type {hyphenation}}

-

-\libindex {hyphenation}

-

-You can hyphenate a string directly with:

-

-\startfunctioncall

-<string> n = lang.hyphenation(<language> l)

-lang.hyphenation(<language> l, <string> n)

-\stopfunctioncall

-

-\subsection {\type {clear_hyphenation} and \type {clean}}

-

-\libindex {clear_hyphenation}

-\libindex {clean}

-

-This either returns the current hyphenation exceptions for this language, or adds

-new ones. The syntax of the string is explained in~\in {section}

-[patternsexceptions].

-

-\startfunctioncall

-lang.clear_hyphenation(<language> l)

-\stopfunctioncall

-

-This call clears the exception dictionary (string) for this language.

-

-\startfunctioncall

-<string> n = lang.clean(<language> l, <string> o)

-<string> n = lang.clean(<string> o)

-\stopfunctioncall

-

-This function creates a hyphenation key from the supplied hyphenation value. The

-syntax of the argument string is explained in \in {section} [patternsexceptions].

-This function is useful if you want to do something else based on the words in a

-dictionary file, like spell|-|checking.

-

-\subsection {\type {patterns} and \type {clear_patterns}}

-

-\libindex {patterns}

-\libindex {clear_patterns}

-

-\startfunctioncall

-<string> n = lang.patterns(<language> l)

-lang.patterns(<language> l, <string> n)

-\stopfunctioncall

-

-This adds additional patterns for this language object, or returns the current

-set. The syntax of this string is explained in \in {section}

-[patternsexceptions].

-

-\startfunctioncall

-lang.clear_patterns(<language> l)

-\stopfunctioncall

-

-This can be used to clear the pattern dictionary for a language.

-

-\subsection {\type {hyphenationmin}}

-

-\libindex {hyphenationmin}

-

-This function sets (or gets) the value of the \TEX\ parameter

-\type {\hyphenationmin}.

-

-\startfunctioncall

-n = lang.hyphenationmin(<language> l)

-lang.hyphenationmin(<language> l, <number> n)

-\stopfunctioncall

-

-\subsection {\type {[pre|post][ex|]hyphenchar}}

-

-\libindex {prehyphenchar}

-\libindex {posthyphenchar}

-\libindex {preexhyphenchar}

-\libindex {postexhyphenchar}

-

-\startfunctioncall

-<number> n = lang.prehyphenchar(<language> l)

-lang.prehyphenchar(<language> l, <number> n)

-

-<number> n = lang.posthyphenchar(<language> l)

-lang.posthyphenchar(<language> l, <number> n)

-\stopfunctioncall

-

-These two are used to get or set the \quote {pre|-|break} and \quote

-{post|-|break} hyphen characters for implicit hyphenation in this language. The

-intial values are decimal 45 (hyphen) and decimal~0 (indicating emptiness).

-

-\startfunctioncall

-<number> n = lang.preexhyphenchar(<language> l)

-lang.preexhyphenchar(<language> l, <number> n)

-

-<number> n = lang.postexhyphenchar(<language> l)

-lang.postexhyphenchar(<language> l, <number> n)

-\stopfunctioncall

-

-These gets or set the \quote {pre|-|break} and \quote {post|-|break} hyphen

-characters for explicit hyphenation in this language. Both are initially

-decimal~0 (indicating emptiness).

-

-\subsection {\type {hyphenate}}

-

-\libindex {hyphenate}

-

-The next call inserts hyphenation points (discretionary nodes) in a node list. If

-\type {tail} is given as argument, processing stops on that node. Currently,

-\type {success} is always true if \type {head} (and \type {tail}, if specified)

-are proper nodes, regardless of possible other errors.

-

-\startfunctioncall

-<boolean> success = lang.hyphenate(<node> head)

-<boolean> success = lang.hyphenate(<node> head, <node> tail)

-\stopfunctioncall

-

-Hyphenation works only on \quote {characters}, a special subtype of all the glyph

-nodes with the node subtype having the value \type {1}. Glyph modes with

-different subtypes are not processed. See \in {section} [charsandglyphs] for

-more details.

-

-\subsection {\type {[set|get]hjcode}}

-

-\libindex {sethjcode}

-\libindex {gethjcode}

-

-The following two commands can be used to set or query hj codes:

-

-\startfunctioncall

-lang.sethjcode(<language> l, <number> char, <number> usedchar)

-<number> usedchar = lang.gethjcode(<language> l, <number> char)

-\stopfunctioncall

-

-When you set a hjcode the current sets get initialized unless the set was already

-initialized due to \prm {savinghyphcodes} being larger than zero.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

-

-% \parindent0pt \hsize=1.1cm

-% 12-34-56 \par

-% 12-34-\hbox{56} \par

-% 12-34-\vrule width 1em height 1.5ex \par

-% 12-\hbox{34}-56 \par

-% 12-\vrule width 1em height 1.5ex-56 \par

-% \hjcode`\1=`\1 \hjcode`\2=`\2 \hjcode`\3=`\3 \hjcode`\4=`\4 \vskip.5cm

-% 12-34-56 \par

-% 12-34-\hbox{56} \par

-% 12-34-\vrule width 1em height 1.5ex \par

-% 12-\hbox{34}-56 \par

-% 12-\vrule width 1em height 1.5ex-56 \par

-

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-languages
+
+\startchapter[reference=languages,title={Languages, characters, fonts and glyphs}]
+
+\startsection[title={Introduction}]
+
+\topicindex {languages}
+
+\LUATEX's internal handling of the characters and glyphs that eventually become
+typeset is quite different from the way \TEX82 handles those same objects. The
+easiest way to explain the difference is to focus on unrestricted horizontal mode
+(i.e.\ paragraphs) and hyphenation first. Later on, it will be easy to deal
+with the differences that occur in horizontal and math modes.
+
+In \TEX82, the characters you type are converted into \type {char} node records
+when they are encountered by the main control loop. \TEX\ attaches and processes
+the font information while creating those records, so that the resulting \quote
+{horizontal list} contains the final forms of ligatures and implicit kerning.
+This packaging is needed because we may want to get the effective width of for
+instance a horizontal box.
+
+When it becomes necessary to hyphenate words in a paragraph, \TEX\ converts (one
+word at time) the \type {char} node records into a string by replacing ligatures
+with their components and ignoring the kerning. Then it runs the hyphenation
+algorithm on this string, and converts the hyphenated result back into a \quote
+{horizontal list} that is consecutively spliced back into the paragraph stream.
+Keep in mind that the paragraph may contain unboxed horizontal material, which
+then already contains ligatures and kerns and the words therein are part of the
+hyphenation process.
+
+Those \type {char} node records are somewhat misnamed, as they are glyph
+positions in specific fonts, and therefore not really \quote {characters} in the
+linguistic sense. There is no language information inside the \type {char} node
+records at all. Instead, language information is passed along using \type
+{language whatsit} nodes inside the horizontal list.
+
+In \LUATEX, the situation is quite different. The characters you type are always
+converted into \nod {glyph} node records with a special subtype to identify them
+as being intended as linguistic characters. \LUATEX\ stores the needed language
+information in those records, but does not do any font|-|related processing at
+the time of node creation. It only stores the index of the current font and a
+reference to a character in that font.
+
+When it becomes necessary to typeset a paragraph, \LUATEX\ first inserts all
+hyphenation points right into the whole node list. Next, it processes all the
+font information in the whole list (creating ligatures and adjusting kerning),
+and finally it adjusts all the subtype identifiers so that the records are \quote
+{glyph nodes} from now on.
+
+\stopsection
+
+\startsection[title={Characters, glyphs and discretionaries},reference=charsandglyphs]
+
+\topicindex {characters}
+\topicindex {glyphs}
+\topicindex {hyphenation}
+
+\TEX82 (including \PDFTEX) differentiates between \type {char} nodes and \type
+{lig} nodes. The former are simple items that contained nothing but a \quote
+{character} and a \quote {font} field, and they lived in the same memory as
+tokens did. The latter also contained a list of components, and a subtype
+indicating whether this ligature was the result of a word boundary, and it was
+stored in the same place as other nodes like boxes and kerns and glues.
+
+In \LUATEX, these two types are merged into one, somewhat larger structure called
+a \nod {glyph} node. Besides having the old character, font, and component
+fields there are a few more, like \quote {attr} that we will see in \in {section}
+[glyphnodes], these nodes also contain a subtype, that codes four main types and
+two additional ghost types. For ligatures, multiple bits can be set at the same
+time (in case of a single|-|glyph word).
+
+\startitemize
+    \startitem
+        \type {character}, for characters to be hyphenated: the lowest bit
+        (bit 0) is set to 1.
+    \stopitem
+    \startitem
+        \nod {glyph}, for specific font glyphs: the lowest bit (bit 0) is
+        not set.
+    \stopitem
+    \startitem
+        \type {ligature}, for constructed ligatures bit 1 is set.
+    \stopitem
+    \startitem
+        \type {ghost}, for so called \quote {ghost objects} bit 2 is set.
+    \stopitem
+    \startitem
+        \type {left}, for ligatures created from a left word boundary and for
+        ghosts created from \lpr {leftghost} bit 3 gets set.
+    \stopitem
+    \startitem
+        \type {right}, for ligatures created from a right word boundary and
+        for ghosts created from \lpr {rightghost} bit 4 is set.
+    \stopitem
+\stopitemize
+
+The \nod {glyph} nodes also contain language data, split into four items that
+were current when the node was created: the \prm {setlanguage} (15~bits), \prm
+{lefthyphenmin} (8~bits), \prm {righthyphenmin} (8~bits), and \prm {uchyph}
+(1~bit).
+
+Incidentally, \LUATEX\ allows 16383 separate languages, and words can be 256
+characters long. The language is stored with each character. You can set
+\prm {firstvalidlanguage} to for instance~1 and make thereby language~0
+an ignored hyphenation language.
+
+The new primitive \lpr {hyphenationmin} can be used to signal the minimal length
+of a word. This value is stored with the (current) language.
+
+Because the \prm {uchyph} value is saved in the actual nodes, its handling is
+subtly different from \TEX82: changes to \prm {uchyph} become effective
+immediately, not at the end of the current partial paragraph.
+
+Typeset boxes now always have their language information embedded in the nodes
+themselves, so there is no longer a possible dependency on the surrounding
+language settings. In \TEX82, a mid|-|paragraph statement like \type {\unhbox0}
+would process the box using the current paragraph language unless there was a
+\prm {setlanguage} issued inside the box. In \LUATEX, all language variables
+are already frozen.
+
+In traditional \TEX\ the process of hyphenation is driven by \type {lccode}s. In
+\LUATEX\ we made this dependency less strong. There are several strategies
+possible. When you do nothing, the currently used \type {lccode}s are used, when
+loading patterns, setting exceptions or hyphenating a list.
+
+When you set \prm {savinghyphcodes} to a value greater than zero the current set
+of \type {lccode}s will be saved with the language. In that case changing a \type
+{lccode} afterwards has no effect. However, you can adapt the set with:
+
+\starttyping
+\hjcode`a=`a
+\stoptyping
+
+This change is global which makes sense if you keep in mind that the moment that
+hyphenation happens is (normally) when the paragraph or a horizontal box is
+constructed. When \prm {savinghyphcodes} was zero when the language got
+initialized you start out with nothing, otherwise you already have a set.
+
+When a \lpr {hjcode} is greater than 0 but less than 32 is indicates the
+to be used length. In the following example we map a character (\type {x}) onto
+another one in the patterns and tell the engine that \type {œ} counts as one
+character. Because traditionally zero itself is reserved for inhibiting
+hyphenation, a value of 32 counts as zero.
+
+Here are some examples (we assume that French patterns are used):
+
+\starttabulate[||||]
+\NC                                  \NC \type{foobar} \NC \type{foo-bar} \NC \NR
+\NC \type{\hjcode`x=`o}              \NC \type{fxxbar} \NC \type{fxx-bar} \NC \NR
+\NC \type{\lefthyphenmin3}           \NC \type{œdipus} \NC \type{œdi-pus} \NC \NR
+\NC \type{\lefthyphenmin4}           \NC \type{œdipus} \NC \type{œdipus}  \NC \NR
+\NC \type{\hjcode`œ=2}               \NC \type{œdipus} \NC \type{œdi-pus} \NC \NR
+\NC \type{\hjcode`i=32 \hjcode`d=32} \NC \type{œdipus} \NC \type{œdipus}  \NC \NR
+\NC
+\stoptabulate
+
+Carrying all this information with each glyph would give too much overhead and
+also make the process of setting up these codes more complex. A solution with
+\type {hjcode} sets was considered but rejected because in practice the current
+approach is sufficient and it would not be compatible anyway.
+
+Beware: the values are always saved in the format, independent of the setting
+of \prm {savinghyphcodes} at the moment the format is dumped.
+
+A boundary node normally would mark the end of a word which interferes with for
+instance discretionary injection. For this you can use the \prm {wordboundary}
+as a trigger. Here are a few examples of usage:
+
+\startbuffer
+    discrete---discrete
+\stopbuffer
+\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower
+\startbuffer
+    discrete\discretionary{}{}{---}discrete
+\stopbuffer
+\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower
+\startbuffer
+    discrete\wordboundary\discretionary{}{}{---}discrete
+\stopbuffer
+\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower
+\startbuffer
+    discrete\wordboundary\discretionary{}{}{---}\wordboundary discrete
+\stopbuffer
+\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower
+\startbuffer
+    discrete\wordboundary\discretionary{---}{}{}\wordboundary discrete
+\stopbuffer
+\typebuffer \startnarrower \dontcomplain \hsize 1pt \getbuffer \par \stopnarrower
+
+We only accept an explicit hyphen when there is a preceding glyph and we skip a
+sequence of explicit hyphens since that normally indicates a \type {--} or \type
+{---} ligature in which case we can in a worse case usage get bad node lists
+later on due to messed up ligature building as these dashes are ligatures in base
+fonts. This is a side effect of separating the hyphenation, ligaturing and
+kerning steps.
+
+The start and end of a sequence of characters is signalled by a \nod {glue}, \nod
+{penalty}, \nod {kern} or \nod {boundary} node. But by default also a \nod
+{hlist}, \nod {vlist}, \nod {rule}, \nod {dir}, \nod {whatsit}, \nod {ins}, and
+\nod {adjust} node indicate a start or end. You can omit the last set from the
+test by setting \lpr {hyphenationbounds} to a non|-|zero value:
+
+\starttabulate[|c|l|]
+\DB value    \BC behaviour \NC \NR
+\TB
+\NC \type{0} \NC not strict \NC \NR
+\NC \type{1} \NC strict start \NC \NR
+\NC \type{2} \NC strict end \NC \NR
+\NC \type{3} \NC strict start and strict end \NC \NR
+\LL
+\stoptabulate
+
+The word start is determined as follows:
+
+\starttabulate[|l|l|]
+\DB node      \BC behaviour \NC \NR
+\TB
+\BC boundary  \NC yes when wordboundary \NC \NR
+\BC hlist     \NC when hyphenationbounds 1 or 3 \NC \NR
+\BC vlist     \NC when hyphenationbounds 1 or 3 \NC \NR
+\BC rule      \NC when hyphenationbounds 1 or 3 \NC \NR
+\BC dir       \NC when hyphenationbounds 1 or 3 \NC \NR
+\BC whatsit   \NC when hyphenationbounds 1 or 3 \NC \NR
+\BC glue      \NC yes \NC \NR
+\BC math      \NC skipped \NC \NR
+\BC glyph     \NC exhyphenchar (one only) : yes (so no -- ---) \NC \NR
+\BC otherwise \NC yes \NC \NR
+\LL
+\stoptabulate
+
+The word end is determined as follows:
+
+\starttabulate[|l|l|]
+\DB node      \BC behaviour \NC \NR
+\TB
+\BC boundary  \NC yes \NC \NR
+\BC glyph     \NC yes when different language \NC \NR
+\BC glue      \NC yes \NC \NR
+\BC penalty   \NC yes \NC \NR
+\BC kern      \NC yes when not italic (for some historic reason) \NC \NR
+\BC hlist     \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC vlist     \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC rule      \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC dir       \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC whatsit   \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC ins       \NC when hyphenationbounds 2 or 3 \NC \NR
+\BC adjust    \NC when hyphenationbounds 2 or 3 \NC \NR
+\LL
+\stoptabulate
+
+\in {Figures} [hb:1] upto \in [hb:5] show some examples. In all cases we set the
+min values to 1 and make sure that the words hyphenate at each character.
+
+\hyphenation{o-n-e t-w-o}
+
+\def\SomeTest#1#2%
+  {\lefthyphenmin  \plusone
+   \righthyphenmin \plusone
+   \parindent      \zeropoint
+   \everypar       \emptytoks
+   \dontcomplain
+   \hbox to 2cm {%
+     \vtop {%
+       \hsize 1pt
+       \hyphenationbounds#1
+       #2
+       \par}}}
+
+\startplacefigure[reference=hb:1,title={\type{one}}]
+    \startcombination[4*1]
+        {\SomeTest{0}{one}} {\type{0}}
+        {\SomeTest{1}{one}} {\type{1}}
+        {\SomeTest{2}{one}} {\type{2}}
+        {\SomeTest{3}{one}} {\type{3}}
+    \stopcombination
+\stopplacefigure
+
+\startplacefigure[reference=hb:2,title={\type{one\null two}}]
+    \startcombination[4*1]
+        {\SomeTest{0}{one\null two}} {\type{0}}
+        {\SomeTest{1}{one\null two}} {\type{1}}
+        {\SomeTest{2}{one\null two}} {\type{2}}
+        {\SomeTest{3}{one\null two}} {\type{3}}
+    \stopcombination
+\stopplacefigure
+
+\startplacefigure[reference=hb:3,title={\type{\null one\null two}}]
+    \startcombination[4*1]
+        {\SomeTest{0}{\null one\null two}} {\type{0}}
+        {\SomeTest{1}{\null one\null two}} {\type{1}}
+        {\SomeTest{2}{\null one\null two}} {\type{2}}
+        {\SomeTest{3}{\null one\null two}} {\type{3}}
+    \stopcombination
+\stopplacefigure
+
+\startplacefigure[reference=hb:4,title={\type{one\null two\null}}]
+    \startcombination[4*1]
+        {\SomeTest{0}{one\null two\null}} {\type{0}}
+        {\SomeTest{1}{one\null two\null}} {\type{1}}
+        {\SomeTest{2}{one\null two\null}} {\type{2}}
+        {\SomeTest{3}{one\null two\null}} {\type{3}}
+    \stopcombination
+\stopplacefigure
+
+\startplacefigure[reference=hb:5,title={\type{\null one\null two\null}}]
+    \startcombination[4*1]
+        {\SomeTest{0}{\null one\null two\null}} {\type{0}}
+        {\SomeTest{1}{\null one\null two\null}} {\type{1}}
+        {\SomeTest{2}{\null one\null two\null}} {\type{2}}
+        {\SomeTest{3}{\null one\null two\null}} {\type{3}}
+    \stopcombination
+\stopplacefigure
+
+% (Future versions of \LUATEX\ might provide more granularity.)
+
+In traditional \TEX\ ligature building and hyphenation are interwoven with the
+line break mechanism. In \LUATEX\ these phases are isolated. As a consequence we
+deal differently with (a sequence of) explicit hyphens. We already have added
+some control over aspects of the hyphenation and yet another one concerns
+automatic hyphens (e.g.\ \type {-} characters in the input).
+
+When \lpr {automatichyphenmode} has a value of 0, a hyphen will be turned into
+an automatic discretionary. The snippets before and after it will not be
+hyphenated. A side effect is that a leading hyphen can lead to a split but one
+will seldom run into that situation. Setting a pre and post character makes this
+more prominent. A value of 1 will prevent this side effect and a value of 2 will
+not turn the hyphen into a discretionary. Experiments with other options, like
+permitting hyphenation of the words on both sides were discarded.
+
+\startbuffer[a]
+before-after \par
+before--after \par
+before---after \par
+\stopbuffer
+
+\startbuffer[b]
+-before \par
+after- \par
+--before \par
+after-- \par
+---before \par
+after--- \par
+\stopbuffer
+
+\startbuffer[c]
+before-after \par
+before--after \par
+before---after \par
+\stopbuffer
+
+\startbuffer[demo]
+\startcombination[nx=4,ny=3,location=top]
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[a]}} {A~0~6em}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[a]}} {A~0~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[a]}} {A~1~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[a]}} {A~2~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[b]}} {B~0~6em}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[b]}} {B~0~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[b]}} {B~1~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[b]}} {B~2~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize6em \getbuffer[c]}} {C~0~6em}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\zerocount \hsize2pt \getbuffer[c]}} {C~0~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plusone   \hsize2pt \getbuffer[c]}} {C~1~2pt}
+    {\framed[align=normal,strut=no,top=\vskip.5ex,bottom=\vskip.5ex]{\automatichyphenmode\plustwo   \hsize2pt \getbuffer[c]}} {C~2~2pt}
+\stopcombination
+\stopbuffer
+
+\startplacefigure[locationreference=automatichyphenmode:1,title={The automatic modes \type {0} (default), \type {1} and \type {2}, with a \prm {hsize}
+of 6em and 2pt (which triggers a linebreak).}]
+    \dontcomplain \tt \getbuffer[demo]
+\stopplacefigure
+
+\startplacefigure[reference=automatichyphenmode:2,title={The automatic modes \type {0} (default), \type {1} and \type {2}, with \lpr {preexhyphenchar} and \lpr {postexhyphenchar} set to characters \type {A} and \type {B}.}]
+    \postexhyphenchar`A\relax
+    \preexhyphenchar `B\relax
+    \dontcomplain \tt \getbuffer[demo]
+\stopplacefigure
+
+In \in {figure} [automatichyphenmode:1] \in {and} [automatichyphenmode:2] we show
+what happens with three samples:
+
+Input A: \typebuffer[a]
+Input B: \typebuffer[b]
+Input C: \typebuffer[c]
+
+As with primitive companions of other single character commands, the \prm {-}
+command has a more verbose primitive version in \lpr {explicitdiscretionary}
+and the normally intercepted in the hyphenator character \type {-} (or whatever
+is configured) is available as \lpr {automaticdiscretionary}.
+
+\stopsection
+
+\startsection[title={The main control loop}]
+
+\topicindex {main loop}
+\topicindex {hyphenation}
+
+In \LUATEX's main loop, almost all input characters that are to be typeset are
+converted into \nod {glyph} node records with subtype \quote {character}, but
+there are a few exceptions.
+
+\startitemize[n]
+
+\startitem
+    The \prm {accent} primitive creates nodes with subtype \quote {glyph}
+    instead of \quote {character}: one for the actual accent and one for the
+    accentee. The primary reason for this is that \prm {accent} in \TEX82 is
+    explicitly dependent on the current font encoding, so it would not make much
+    sense to attach a new meaning to the primitive's name, as that would
+    invalidate many old documents and macro packages. A secondary reason is that
+    in \TEX82, \prm {accent} prohibits hyphenation of the current word. Since
+    in \LUATEX\ hyphenation only takes place on \quote {character} nodes, it is
+    possible to achieve the same effect. Of course, modern \UNICODE\ aware macro
+    packages will not use the \prm {accent} primitive at all but try to map
+    directly on composed characters.
+
+    This change of meaning did happen with \prm {char}, that now generates
+    \quote {glyph} nodes with a character subtype. In traditional \TEX\ there was
+    a strong relationship between the 8|-|bit input encoding, hyphenation and
+    glyphs taken from a font. In \LUATEX\ we have \UTF\ input, and in most cases
+    this maps directly to a character in a font, apart from glyph replacement in
+    the font engine. If you want to access arbitrary glyphs in a font directly
+    you can always use \LUA\ to do so, because fonts are available as \LUA\
+    table.
+\stopitem
+
+\startitem
+    All the results of processing in math mode eventually become nodes with
+    \quote {glyph} subtypes. In fact, the result of processing math is just
+    a regular list of glyphs, kerns, glue, penalties, boxes etc.
+\stopitem
+
+\startitem
+    The \ALEPH|-|derived commands \lpr {leftghost} and \lpr {rightghost}
+    create nodes of a third subtype: \quote {ghost}. These nodes are ignored
+    completely by all further processing until the stage where inter|-|glyph
+    kerning is added.
+\stopitem
+
+\startitem
+    Automatic discretionaries are handled differently. \TEX82 inserts an empty
+    discretionary after sensing an input character that matches the \prm
+    {hyphenchar} in the current font. This test is wrong in our opinion: whether
+    or not hyphenation takes place should not depend on the current font, it is a
+    language property. \footnote {When \TEX\ showed up we didn't have \UNICODE\
+    yet and being limited to eight bits meant that one sometimes had to
+    compromise between supporting character input, glyph rendering, hyphenation.}
+
+    In \LUATEX, it works like this: if \LUATEX\ senses a string of input
+    characters that matches the value of the new integer parameter \prm
+    {exhyphenchar}, it will insert an explicit discretionary after that series of
+    nodes. Initially \TEX\ sets the \type {\exhyphenchar=`\-}. Incidentally, this
+    is a global parameter instead of a language-specific one because it may be
+    useful to change the value depending on the document structure instead of the
+    text language.
+
+    The insertion of discretionaries after a sequence of explicit hyphens happens
+    at the same time as the other hyphenation processing, {\it not\/} inside the
+    main control loop.
+
+    The only use \LUATEX\ has for \prm {hyphenchar} is at the check whether a
+    word should be considered for hyphenation at all. If the \prm {hyphenchar}
+    of the font attached to the first character node in a word is negative, then
+    hyphenation of that word is abandoned immediately. This behaviour is added
+    for backward compatibility only, and the use of \type {\hyphenchar=-1} as a
+    means of preventing hyphenation should not be used in new \LUATEX\ documents.
+\stopitem
+
+\startitem
+    The \prm {setlanguage} command no longer creates whatsits. The meaning of
+    \prm {setlanguage} is changed so that it is now an integer parameter like all
+    others. That integer parameter is used in \type {\glyph_node} creation to add
+    language information to the glyph nodes. In conjunction, the \prm {language}
+    primitive is extended so that it always also updates the value of \prm
+    {setlanguage}.
+\stopitem
+
+\startitem
+    The \prm {noboundary} command (that prohibits word boundary processing
+    where that would normally take place) now does create nodes. These nodes are
+    needed because the exact place of the \prm {noboundary} command in the
+    input stream has to be retained until after the ligature and font processing
+    stages.
+\stopitem
+
+\startitem
+    There is no longer a \type {main_loop} label in the code. Remember that
+    \TEX82 did quite a lot of processing while adding \type {char_nodes} to the
+    horizontal list? For speed reasons, it handled that processing code outside
+    of the \quote {main control} loop, and only the first character of any \quote
+    {word} was handled by that \quote {main control} loop. In \LUATEX, there is
+    no longer a need for that (all hard work is done later), and the (now very
+    small) bits of character|-|handling code have been moved back inline. When
+    \prm {tracingcommands} is on, this is visible because the full word is
+    reported, instead of just the initial character.
+\stopitem
+
+\stopitemize
+
+Because we tend to make hard coded behaviour configurable a few new primitives
+have been added:
+
+\starttyping
+\hyphenpenaltymode
+\automatichyphenpenalty
+\explicithyphenpenalty
+\stoptyping
+
+The first parameter has the following consequences for automatic discs (the ones
+resulting from an \prm {exhyphenchar}:
+
+\starttabulate[|c|l|l|]
+\DB mode     \BC automatic disc \type {-}      \BC explicit disc \prm{-}         \NC \NR
+\TB
+\NC \type{0} \NC \prm {exhyphenpenalty}        \NC \prm {exhyphenpenalty}        \NC \NR
+\NC \type{1} \NC \prm {hyphenpenalty}          \NC \prm {hyphenpenalty}          \NC \NR
+\NC \type{2} \NC \prm {exhyphenpenalty}        \NC \prm {hyphenpenalty}          \NC \NR
+\NC \type{3} \NC \prm {hyphenpenalty}          \NC \prm {exhyphenpenalty}        \NC \NR
+\NC \type{4} \NC \lpr {automatichyphenpenalty} \NC \lpr {explicithyphenpenalty}  \NC \NR
+\NC \type{5} \NC \prm {exhyphenpenalty}        \NC \lpr {explicithyphenpenalty}  \NC \NR
+\NC \type{6} \NC \prm {hyphenpenalty}          \NC \lpr {explicithyphenpenalty}  \NC \NR
+\NC \type{7} \NC \lpr {automatichyphenpenalty} \NC \prm {exhyphenpenalty}        \NC \NR
+\NC \type{8} \NC \lpr {automatichyphenpenalty} \NC \prm {hyphenpenalty}          \NC \NR
+\LL
+\stoptabulate
+
+other values do what we always did in \LUATEX: insert \prm {exhyphenpenalty}.
+
+\stopsection
+
+\startsection[title={Loading patterns and exceptions},reference=patternsexceptions]
+
+\topicindex {hyphenation}
+\topicindex {hyphenation+patterns}
+\topicindex {hyphenation+exceptions}
+\topicindex {patterns}
+\topicindex {exceptions}
+
+Although we keep the traditional approach towards hyphenation (which is still
+superior) the implementation of the hyphenation algorithm in \LUATEX\ is quite
+different from the one in \TEX82.
+
+After expansion, the argument for \prm {patterns} has to be proper \UTF8 with
+individual patterns separated by spaces, no \prm {char} or \prm {chardef}d
+commands are allowed. The current implementation is quite strict and will reject
+all non|-|\UNICODE\ characters. Likewise, the expanded argument for \prm
+{hyphenation} also has to be proper \UTF8, but here a bit of extra syntax is
+provided:
+
+\startitemize[n]
+\startitem
+    Three sets of arguments in curly braces (\type {{}{}{}}) indicate a desired
+    complex discretionary, with arguments as in \prm {discretionary}'s command in
+    normal document input.
+\stopitem
+\startitem
+    A \type {-} indicates a desired simple discretionary, cf.\ \type {\-} and
+    \type {\discretionary{-}{}{}} in normal document input.
+\stopitem
+\startitem
+    Internal command names are ignored. This rule is provided especially for \prm
+    {discretionary}, but it also helps to deal with \prm {relax} commands that
+    may sneak in.
+\stopitem
+\startitem
+    An \type {=} indicates a (non|-|discretionary) hyphen in the document input.
+\stopitem
+\stopitemize
+
+The expanded argument is first converted back to a space|-|separated string while
+dropping the internal command names. This string is then converted into a
+dictionary by a routine that creates key|-|value pairs by converting the other
+listed items. It is important to note that the keys in an exception dictionary
+can always be generated from the values. Here are a few examples:
+
+\starttabulate[|l|l|l|]
+\DB value                  \BC implied key (input) \BC effect \NC\NR
+\TB
+\NC \type {ta-ble}         \NC table               \NC \type {ta\-ble} ($=$ \type {ta\discretionary{-}{}{}ble}) \NC\NR
+\NC \type {ba{k-}{}{c}ken} \NC backen              \NC \type {ba\discretionary{k-}{}{c}ken} \NC\NR
+\LL
+\stoptabulate
+
+The resultant patterns and exception dictionary will be stored under the language
+code that is the present value of \prm {language}.
+
+In the last line of the table, you see there is no \prm {discretionary} command
+in the value: the command is optional in the \TEX-based input syntax. The
+underlying reason for that is that it is conceivable that a whole dictionary of
+words is stored as a plain text file and loaded into \LUATEX\ using one of the
+functions in the \LUA\ \type {lang} library. This loading method is quite a bit
+faster than going through the \TEX\ language primitives, but some (most?) of that
+speed gain would be lost if it had to interpret command sequences while doing so.
+
+It is possible to specify extra hyphenation points in compound words by using
+\type {{-}{}{-}} for the explicit hyphen character (replace \type {-} by the
+actual explicit hyphen character if needed). For example, this matches the word
+\quote {multi|-|word|-|boundaries} and allows an extra break inbetween \quote
+{boun} and \quote {daries}:
+
+\starttyping
+\hyphenation{multi{-}{}{-}word{-}{}{-}boun-daries}
+\stoptyping
+
+The motivation behind the \ETEX\ extension \prm {savinghyphcodes} was that
+hyphenation heavily depended on font encodings. This is no longer true in
+\LUATEX, and the corresponding primitive is basically ignored. Because we now
+have \lpr {hjcode}, the case relate codes can be used exclusively for \prm
+{uppercase} and \prm {lowercase}.
+
+The three curly brace pair pattern in an exception can be somewhat unexpected so
+we will try to explain it by example. The pattern \type {foo{}{}{x}bar} pattern
+creates a lookup \type {fooxbar} and the pattern \type {foo{}{}{}bar} creates
+\type {foobar}. Then, when a hit happens there is a replacement text (\type {x})
+or none. Because we introduced penalties in discretionary nodes, the exception
+syntax now also can take a penalty specification. The value between square brackets
+is a multiplier for \lpr {exceptionpenalty}. Here we have set it to 10000 so
+effectively we get 30000 in the example.
+
+\def\ShowSample#1#2%
+  {\startlinecorrection[blank]
+   \hyphenation{#1}%
+   \exceptionpenalty=10000
+   \bTABLE[foregroundstyle=type]
+     \bTR
+       \bTD[align=middle,nx=4] \type{#1} \eTD
+     \eTR
+     \bTR
+       \bTD[align=middle] \type{10em} \eTD
+       \bTD[align=middle] \type {3em} \eTD
+       \bTD[align=middle] \type {0em} \eTD
+       \bTD[align=middle] \type {6em} \eTD
+     \eTR
+     \bTR
+       \bTD[width=10em]\vtop{\hsize 10em 123 #2 123\par}\eTD
+       \bTD[width=10em]\vtop{\hsize  3em 123 #2 123\par}\eTD
+       \bTD[width=10em]\vtop{\hsize  0em 123 #2 123\par}\eTD
+       \bTD[width=10em]\vtop{\setupalign[verytolerant,stretch]\rmtf\hsize 6em 123 #2 #2 #2 #2 123\par}\eTD
+     \eTR
+   \eTABLE
+   \stoplinecorrection}
+
+\ShowSample{x{a-}{-b}{}x{a-}{-b}{}x{a-}{-b}{}x{a-}{-b}{}xx}{xxxxxx}
+\ShowSample{x{a-}{-b}{}x{a-}{-b}{}[3]x{a-}{-b}{}[1]x{a-}{-b}{}xx}{xxxxxx}
+
+\ShowSample{z{a-}{-b}{z}{a-}{-b}{z}{a-}{-b}{z}{a-}{-b}{z}z}{zzzzzz}
+\ShowSample{z{a-}{-b}{z}{a-}{-b}{z}[3]{a-}{-b}{z}[1]{a-}{-b}{z}z}{zzzzzz}
+
+\stopsection
+
+\startsection[title={Applying hyphenation}]
+
+\topicindex {hyphenation+how it works}
+\topicindex {hyphenation+discretionaries}
+\topicindex {discretionaries}
+
+The internal structures \LUATEX\ uses for the insertion of discretionaries in
+words is very different from the ones in \TEX82, and that means there are some
+noticeable differences in handling as well.
+
+First and foremost, there is no \quote {compressed trie} involved in hyphenation.
+The algorithm still reads pattern files generated by \PATGEN, but \LUATEX\ uses a
+finite state hash to match the patterns against the word to be hyphenated. This
+algorithm is based on the \quote {libhnj} library used by \OPENOFFICE, which in
+turn is inspired by \TEX.
+
+There are a few differences between \LUATEX\ and \TEX82 that are a direct result
+of the implementation:
+
+\startitemize
+\startitem
+    \LUATEX\ happily hyphenates the full \UNICODE\ character range.
+\stopitem
+\startitem
+    Pattern and exception dictionary size is limited by the available memory
+    only, all allocations are done dynamically. The trie|-|related settings in
+    \type {texmf.cnf} are ignored.
+\stopitem
+\startitem
+    Because there is no \quote {trie preparation} stage, language patterns never
+    become frozen. This means that the primitive \prm {patterns} (and its \LUA\
+    counterpart \type {lang.patterns}) can be used at any time, not only in
+    ini\TEX.
+\stopitem
+\startitem
+    Only the string representation of \prm {patterns} and \prm {hyphenation} is
+    stored in the format file. At format load time, they are simply
+    re|-|evaluated. It follows that there is no real reason to preload languages
+    in the format file. In fact, it is usually not a good idea to do so. It is
+    much smarter to load patterns no sooner than the first time they are actually
+    needed.
+\stopitem
+\startitem
+    \LUATEX\ uses the language-specific variables \lpr {prehyphenchar} and \lpr
+    {posthyphenchar} in the creation of implicit discretionaries, instead of
+    \TEX82's \prm {hyphenchar}, and the values of the language|-|specific
+    variables \lpr {preexhyphenchar} and \lpr {postexhyphenchar} for explicit
+    discretionaries (instead of \TEX82's empty discretionary).
+\stopitem
+\startitem
+    The value of the two counters related to hyphenation, \prm {hyphenpenalty}
+    and \prm {exhyphenpenalty}, are now stored in the discretionary nodes. This
+    permits a local overload for explicit \prm {discretionary} commands. The
+    value current when the hyphenation pass is applied is used. When no callbacks
+    are used this is compatible with traditional \TEX. When you apply the \LUA\
+    \type {lang.hyphenate} function the current values are used.
+\stopitem
+\startitem
+    The hyphenation exception dictionary is maintained as key|-|value hash, and
+    that is also dynamic, so the \type {hyph_size} setting is not used either.
+\stopitem
+\stopitemize
+
+Because we store penalties in the disc node the \prm {discretionary} command has
+been extended to accept an optional penalty specification, so you can do the
+following:
+
+\startbuffer
+\hsize1mm
+1:foo{\hyphenpenalty 10000\discretionary{}{}{}}bar\par
+2:foo\discretionary penalty 10000 {}{}{}bar\par
+3:foo\discretionary{}{}{}bar\par
+\stopbuffer
+
+\typebuffer
+
+This results in:
+
+\blank \start \getbuffer \stop \blank
+
+Inserted characters and ligatures inherit their attributes from the nearest glyph
+node item (usually the preceding one, but the following one for the items
+inserted at the left-hand side of a word).
+
+Word boundaries are no longer implied by font switches, but by language switches.
+One word can have two separate fonts and still be hyphenated correctly (but it
+can not have two different languages, the \prm {setlanguage} command forces a
+word boundary).
+
+All languages start out with \type {\prehyphenchar=`\-}, \type {\posthyphenchar=0},
+\type {\preexhyphenchar=0} and \type {\postexhyphenchar=0}. When you assign the
+values of one of these four parameters, you are actually changing the settings
+for the current \prm {language}, this behaviour is compatible with \prm {patterns}
+and \prm {hyphenation}.
+
+\LUATEX\ also hyphenates the first word in a paragraph. Words can be up to 256
+characters long (up from 64 in \TEX82). Longer words are ignored right now, but
+eventually either the limitation will be removed or perhaps it will become
+possible to silently ignore the excess characters (this is what happens in
+\TEX82, but there the behaviour cannot be controlled).
+
+If you are using the \LUA\ function \type {lang.hyphenate}, you should be aware
+that this function expects to receive a list of \quote {character} nodes. It will
+not operate properly in the presence of \quote {glyph}, \quote {ligature}, or
+\quote {ghost} nodes, nor does it know how to deal with kerning.
+
+\stopsection
+
+\startsection[title={Applying ligatures and kerning}]
+
+\topicindex {ligatures}
+\topicindex {kerning}
+
+After all possible hyphenation points have been inserted in the list, \LUATEX\
+will process the list to convert the \quote {character} nodes into \quote {glyph}
+and \quote {ligature} nodes. This is actually done in two stages: first all
+ligatures are processed, then all kerning information is applied to the result
+list. But those two stages are somewhat dependent on each other: If the used font
+makes it possible to do so, the ligaturing stage adds virtual \quote {character}
+nodes to the word boundaries in the list. While doing so, it removes and
+interprets \prm {noboundary} nodes. The kerning stage deletes those word
+boundary items after it is done with them, and it does the same for \quote
+{ghost} nodes. Finally, at the end of the kerning stage, all remaining \quote
+{character} nodes are converted to \quote {glyph} nodes.
+
+This word separation is worth mentioning because, if you overrule from \LUA\ only
+one of the two callbacks related to font handling, then you have to make sure you
+perform the tasks normally done by \LUATEX\ itself in order to make sure that the
+other, non|-|overruled, routine continues to function properly.
+
+Although we could improve the situation the reality is that in modern \OPENTYPE\
+fonts ligatures can be constructed in many ways: by replacing a sequence of
+characters by one glyph, or by selectively replacing individual glyphs, or by
+kerning, or any combination of this. Add to that contextual analysis and it will
+be clear that we have to let \LUA\ do that job instead. The generic font handler
+that we provide (which is part of \CONTEXT) distinguishes between base mode
+(which essentially is what we describe here and which delegates the task to \TEX)
+and node mode (which deals with more complex fonts.
+
+Let's look at an example. Take the word \type {office}, hyphenated \type
+{of-fice}, using a \quote {normal} font with all the \type {f}-\type {f} and
+\type {f}-\type {i} type ligatures:
+
+\starttabulate[|l|l|]
+\NC initial              \NC \type {{o}{f}{f}{i}{c}{e}}             \NC\NR
+\NC after hyphenation    \NC \type {{o}{f}{{-},{},{}}{f}{i}{c}{e}}  \NC\NR
+\NC first ligature stage \NC \type {{o}{{f-},{f},{<ff>}}{i}{c}{e}}  \NC\NR
+\NC final result         \NC \type {{o}{{f-},{<fi>},{<ffi>}}{c}{e}} \NC\NR
+\stoptabulate
+
+That's bad enough, but let us assume that there is also a hyphenation point
+between the \type {f} and the \type {i}, to create \type {of-f-ice}. Then the
+final result should be:
+
+\starttyping
+{o}{{f-},
+    {{f-},
+     {i},
+     {<fi>}},
+    {{<ff>-},
+     {i},
+     {<ffi>}}}{c}{e}
+\stoptyping
+
+with discretionaries in the post-break text as well as in the replacement text of
+the top-level discretionary that resulted from the first hyphenation point.
+
+Here is that nested solution again, in a different representation:
+
+\testpage[4]
+
+\starttabulate[|l|c|c|c|c|c|c|]
+\DB         \BC pre           \BC     \BC post      \BC       \BC replace       \BC       \NC \NR
+\TB
+\NC topdisc \NC \type {f-}    \NC (1) \NC           \NC sub 1 \NC               \NC sub 2 \NC \NR
+\NC sub 1   \NC \type {f-}    \NC (2) \NC \type {i} \NC (3)   \NC \type {<fi>}  \NC (4)   \NC \NR
+\NC sub 2   \NC \type {<ff>-} \NC (5) \NC \type {i} \NC (6)   \NC \type {<ffi>} \NC (7)   \NC \NR
+\LL
+\stoptabulate
+
+When line breaking is choosing its breakpoints, the following fields will
+eventually be selected:
+
+\starttabulate[|l|c|c|]
+\NC \type {of-f-ice} \NC \type {f-}    \NC (1) \NC \NR
+\NC                  \NC \type {f-}    \NC (2) \NC \NR
+\NC                  \NC \type {i}     \NC (3) \NC \NR
+\NC \type {of-fice}  \NC \type {f-}    \NC (1) \NC \NR
+\NC                  \NC \type {<fi>}  \NC (4) \NC \NR
+\NC \type {off-ice}  \NC \type {<ff>-} \NC (5) \NC \NR
+\NC                  \NC \type {i}     \NC (6) \NC \NR
+\NC \type {office}   \NC \type {<ffi>} \NC (7) \NC \NR
+\stoptabulate
+
+The current solution in \LUATEX\ is not able to handle nested discretionaries,
+but it is in fact smart enough to handle this fictional \type {of-f-ice} example.
+It does so by combining two sequential discretionary nodes as if they were a
+single object (where the second discretionary node is treated as an extension of
+the first node).
+
+One can observe that the \type {of-f-ice} and \type {off-ice} cases both end with
+the same actual post replacement list (\type {i}), and that this would be the
+case even if \type {i} was the first item of a potential following ligature like
+\type {ic}. This allows \LUATEX\ to do away with one of the fields, and thus make
+the whole stuff fit into just two discretionary nodes.
+
+The mapping of the seven list fields to the six fields in this discretionary node
+pair is as follows:
+
+\starttabulate[|l|c|c|]
+\DB field                 \BC description   \NC       \NC \NR
+\TB
+\NC \type {disc1.pre}     \NC \type {f-}    \NC (1)   \NC \NR
+\NC \type {disc1.post}    \NC \type {<fi>}  \NC (4)   \NC \NR
+\NC \type {disc1.replace} \NC \type {<ffi>} \NC (7)   \NC \NR
+\NC \type {disc2.pre}     \NC \type {f-}    \NC (2)   \NC \NR
+\NC \type {disc2.post}    \NC \type {i}     \NC (3,6) \NC \NR
+\NC \type {disc2.replace} \NC \type {<ff>-} \NC (5)   \NC \NR
+\LL
+\stoptabulate
+
+What is actually generated after ligaturing has been applied is therefore:
+
+\starttyping
+{o}{{f-},
+    {<fi>},
+    {<ffi>}}
+   {{f-},
+    {i},
+    {<ff>-}}{c}{e}
+\stoptyping
+
+The two discretionaries have different subtypes from a discretionary appearing on
+its own: the first has subtype 4, and the second has subtype 5. The need for
+these special subtypes stems from the fact that not all of the fields appear in
+their \quote {normal} location. The second discretionary especially looks odd,
+with things like the \type {<ff>-} appearing in \type {disc2.replace}. The fact
+that some of the fields have different meanings (and different processing code
+internally) is what makes it necessary to have different subtypes: this enables
+\LUATEX\ to distinguish this sequence of two joined discretionary nodes from the
+case of two standalone discretionaries appearing in a row.
+
+Of course there is still that relationship with fonts: ligatures can be implemented by
+mapping a sequence of glyphs onto one glyph, but also by selective replacement and
+kerning. This means that the above examples are just representing the traditional
+approach.
+
+\stopsection
+
+\startsection[title={Breaking paragraphs into lines}]
+
+\topicindex {linebreaks}
+\topicindex {paragraphs}
+\topicindex {discretionaries}
+
+This code is almost unchanged, but because of the above|-|mentioned changes
+with respect to discretionaries and ligatures, line breaking will potentially be
+different from traditional \TEX. The actual line breaking code is still based on
+the \TEX82 algorithms, and it does not expect there to be discretionaries inside
+of discretionaries. But, as patterns evolve and font handling can influence
+discretionaries, you need to be aware of the fact that long term consistency is not
+an engine matter only.
+
+But that situation is now fairly common in \LUATEX, due to the changes to the
+ligaturing mechanism. And also, the \LUATEX\ discretionary nodes are implemented
+slightly different from the \TEX82 nodes: the \type {no_break} text is now
+embedded inside the disc node, where previously these nodes kept their place in
+the horizontal list. In traditional \TEX\ the discretionary node contains a
+counter indicating how many nodes to skip, but in \LUATEX\ we store the pre, post
+and replace text in the discretionary node.
+
+The combined effect of these two differences is that \LUATEX\ does not always use
+all of the potential breakpoints in a paragraph, especially when fonts with many
+ligatures are used. Of course kerning also complicates matters here.
+
+\stopsection
+
+\startsection[title={The \type {lang} library}][library=lang]
+
+\subsection {\type {new} and \type {id}}
+
+\topicindex {languages+library}
+
+\libindex {new}
+\libindex {id}
+
+This library provides the interface to \LUATEX's structure representing a
+language, and the associated functions.
+
+\startfunctioncall
+<language> l = lang.new()
+<language> l = lang.new(<number> id)
+\stopfunctioncall
+
+This function creates a new userdata object. An object of type \type {<language>}
+is the first argument to most of the other functions in the \type {lang} library.
+These functions can also be used as if they were object methods, using the colon
+syntax. Without an argument, the next available internal id number will be
+assigned to this object. With argument, an object will be created that links to
+the internal language with that id number.
+
+\startfunctioncall
+<number> n = lang.id(<language> l)
+\stopfunctioncall
+
+The number returned is the internal \prm {language} id number this object refers to.
+
+\subsection {\type {hyphenation}}
+
+\libindex {hyphenation}
+
+You can hyphenate a string directly with:
+
+\startfunctioncall
+<string> n = lang.hyphenation(<language> l)
+lang.hyphenation(<language> l, <string> n)
+\stopfunctioncall
+
+\subsection {\type {clear_hyphenation} and \type {clean}}
+
+\libindex {clear_hyphenation}
+\libindex {clean}
+
+This either returns the current hyphenation exceptions for this language, or adds
+new ones. The syntax of the string is explained in~\in {section}
+[patternsexceptions].
+
+\startfunctioncall
+lang.clear_hyphenation(<language> l)
+\stopfunctioncall
+
+This call clears the exception dictionary (string) for this language.
+
+\startfunctioncall
+<string> n = lang.clean(<language> l, <string> o)
+<string> n = lang.clean(<string> o)
+\stopfunctioncall
+
+This function creates a hyphenation key from the supplied hyphenation value. The
+syntax of the argument string is explained in \in {section} [patternsexceptions].
+This function is useful if you want to do something else based on the words in a
+dictionary file, like spell|-|checking.
+
+\subsection {\type {patterns} and \type {clear_patterns}}
+
+\libindex {patterns}
+\libindex {clear_patterns}
+
+\startfunctioncall
+<string> n = lang.patterns(<language> l)
+lang.patterns(<language> l, <string> n)
+\stopfunctioncall
+
+This adds additional patterns for this language object, or returns the current
+set. The syntax of this string is explained in \in {section}
+[patternsexceptions].
+
+\startfunctioncall
+lang.clear_patterns(<language> l)
+\stopfunctioncall
+
+This can be used to clear the pattern dictionary for a language.
+
+\subsection {\type {hyphenationmin}}
+
+\libindex {hyphenationmin}
+
+This function sets (or gets) the value of the \TEX\ parameter
+\type {\hyphenationmin}.
+
+\startfunctioncall
+n = lang.hyphenationmin(<language> l)
+lang.hyphenationmin(<language> l, <number> n)
+\stopfunctioncall
+
+\subsection {\type {[pre|post][ex|]hyphenchar}}
+
+\libindex {prehyphenchar}
+\libindex {posthyphenchar}
+\libindex {preexhyphenchar}
+\libindex {postexhyphenchar}
+
+\startfunctioncall
+<number> n = lang.prehyphenchar(<language> l)
+lang.prehyphenchar(<language> l, <number> n)
+
+<number> n = lang.posthyphenchar(<language> l)
+lang.posthyphenchar(<language> l, <number> n)
+\stopfunctioncall
+
+These two are used to get or set the \quote {pre|-|break} and \quote
+{post|-|break} hyphen characters for implicit hyphenation in this language. The
+intial values are decimal 45 (hyphen) and decimal~0 (indicating emptiness).
+
+\startfunctioncall
+<number> n = lang.preexhyphenchar(<language> l)
+lang.preexhyphenchar(<language> l, <number> n)
+
+<number> n = lang.postexhyphenchar(<language> l)
+lang.postexhyphenchar(<language> l, <number> n)
+\stopfunctioncall
+
+These gets or set the \quote {pre|-|break} and \quote {post|-|break} hyphen
+characters for explicit hyphenation in this language. Both are initially
+decimal~0 (indicating emptiness).
+
+\subsection {\type {hyphenate}}
+
+\libindex {hyphenate}
+
+The next call inserts hyphenation points (discretionary nodes) in a node list. If
+\type {tail} is given as argument, processing stops on that node. Currently,
+\type {success} is always true if \type {head} (and \type {tail}, if specified)
+are proper nodes, regardless of possible other errors.
+
+\startfunctioncall
+<boolean> success = lang.hyphenate(<node> head)
+<boolean> success = lang.hyphenate(<node> head, <node> tail)
+\stopfunctioncall
+
+Hyphenation works only on \quote {characters}, a special subtype of all the glyph
+nodes with the node subtype having the value \type {1}. Glyph modes with
+different subtypes are not processed. See \in {section} [charsandglyphs] for
+more details.
+
+\subsection {\type {[set|get]hjcode}}
+
+\libindex {sethjcode}
+\libindex {gethjcode}
+
+The following two commands can be used to set or query hj codes:
+
+\startfunctioncall
+lang.sethjcode(<language> l, <number> char, <number> usedchar)
+<number> usedchar = lang.gethjcode(<language> l, <number> char)
+\stopfunctioncall
+
+When you set a hjcode the current sets get initialized unless the set was already
+initialized due to \prm {savinghyphcodes} being larger than zero.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
+
+% \parindent0pt \hsize=1.1cm
+% 12-34-56 \par
+% 12-34-\hbox{56} \par
+% 12-34-\vrule width 1em height 1.5ex \par
+% 12-\hbox{34}-56 \par
+% 12-\vrule width 1em height 1.5ex-56 \par
+% \hjcode`\1=`\1 \hjcode`\2=`\2 \hjcode`\3=`\3 \hjcode`\4=`\4 \vskip.5cm
+% 12-34-56 \par
+% 12-34-\hbox{56} \par
+% 12-34-\vrule width 1em height 1.5ex \par
+% 12-\hbox{34}-56 \par
+% 12-\vrule width 1em height 1.5ex-56 \par
+
diff --git a/systems/doc/luatex/luatex-logos.tex b/systems/doc/luatex/luatex-logos.tex
index d67ce5c0b1..3172336ec3 100644
--- a/systems/doc/luatex/luatex-logos.tex
+++ b/systems/doc/luatex/luatex-logos.tex
@@ -1,21 +1,21 @@
-\startenvironment luatex-logos

-

-\usemodule[abr-02]

-

-\logo[DFONT]     {dfont}

-\logo[CFF]       {cff}

-\logo[CMAP]      {CMap}

-\logo[PATGEN]    {patgen}

-\logo[MP]        {MetaPost}

-\logo[METAPOST]  {MetaPost}

-\logo[MPLIB]     {MPlib}

-\logo[COCO]      {coco}

-\logo[SUNOS]     {SunOS}

-\logo[BSD]       {bsd}

-\logo[SYSV]      {sysv}

-\logo[DPI]       {dpi}

-\logo[DLL]       {dll}

-\logo[OPENOFFICE]{OpenOffice}

-\logo[OCP]       {OCP}

-

-\stopenvironment

+\startenvironment luatex-logos
+
+\usemodule[abr-02]
+
+\logo[DFONT]     {dfont}
+\logo[CFF]       {cff}
+\logo[CMAP]      {CMap}
+\logo[PATGEN]    {patgen}
+\logo[MP]        {MetaPost}
+\logo[METAPOST]  {MetaPost}
+\logo[MPLIB]     {MPlib}
+\logo[COCO]      {coco}
+\logo[SUNOS]     {SunOS}
+\logo[BSD]       {bsd}
+\logo[SYSV]      {sysv}
+\logo[DPI]       {dpi}
+\logo[DLL]       {dll}
+\logo[OPENOFFICE]{OpenOffice}
+\logo[OCP]       {OCP}
+
+\stopenvironment
diff --git a/systems/doc/luatex/luatex-lua.tex b/systems/doc/luatex/luatex-lua.tex
index 3d6d20c35d..f9107fa1f9 100644
--- a/systems/doc/luatex/luatex-lua.tex
+++ b/systems/doc/luatex/luatex-lua.tex
@@ -1,760 +1,760 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-lua

-

-\startchapter[reference=lua,title={Using \LUATEX}]

-

-\startsection[title={Initialization},reference=init]

-

-\startsubsection[title={\LUATEX\ as a \LUA\ interpreter}]

-

-\topicindex {initialization}

-\topicindex {\LUA+interpreter}

-

-There are some situations that make \LUATEX\ behave like a standalone \LUA\

-interpreter:

-

-\startitemize[packed]

-\startitem

-    if a \type {--luaonly} option is given on the commandline, or

-\stopitem

-\startitem

-    if the executable is named \type {texlua} or \type {luatexlua}, or

-\stopitem

-\startitem

-    if the only non|-|option argument (file) on the commandline has the extension

-    \type {lua} or \type {luc}.

-\stopitem

-\stopitemize

-

-In this mode, it will set \LUA's \type {arg[0]} to the found script name, pushing

-preceding options in negative values and the rest of the command line in the

-positive values, just like the \LUA\ interpreter.

-

-\LUATEX\ will exit immediately after executing the specified \LUA\ script and is,

-in effect, a somewhat bulky stand alone \LUA\ interpreter with a bunch of extra

-preloaded libraries.

-

-\stopsubsection

-

-\startsubsection[title={\LUATEX\ as a \LUA\ byte compiler}]

-

-\topicindex {\LUA+byte code}

-

-There are two situations that make \LUATEX\ behave like the \LUA\ byte compiler:

-

-\startitemize[packed]

-\startitem if a \type {--luaconly} option is given on the command line, or \stopitem

-\startitem if the executable is named \type {texluac} \stopitem

-\stopitemize

-

-In this mode, \LUATEX\ is exactly like \type {luac} from the stand alone \LUA\

-distribution, except that it does not have the \type {-l} switch, and that it

-accepts (but ignores) the \type {--luaconly} switch. The current version of \LUA\

-can dump bytecode using \type {string.dump} so we might decide to drop this

-version of \LUATEX.

-

-\stopsubsection

-

-\startsubsection[title={Other commandline processing}]

-

-\topicindex {command line}

-

-When the \LUATEX\ executable starts, it looks for the \type {--lua} command line

-option. If there is no \type {--lua} option, the command line is interpreted in a

-similar fashion as the other \TEX\ engines. Some options are accepted but have no

-consequence. The following command|-|line options are understood:

-

-\starttabulate[|l|p|]

-\DB commandline argument                \BC explanation \NC \NR

-\TB

-\NC \type{--credits}                    \NC display credits and exit \NC \NR

-\NC \type{--debug-format}               \NC enable format debugging \NC \NR

-\NC \type{--draftmode}                  \NC switch on draft mode i.e.\ generate no output in \PDF\ mode \NC \NR

-\NC \type{--[no-]file-line-error}       \NC disable/enable \type {file:line:error} style messages \NC \NR

-\NC \type{--[no-]file-line-error-style} \NC aliases of \type {--[no-]file-line-error} \NC \NR

-\NC \type{--fmt=FORMAT}                 \NC load the format file \type {FORMAT} \NC\NR

-\NC \type{--halt-on-error}              \NC stop processing at the first error\NC \NR

-\NC \type{--help}                       \NC display help and exit \NC\NR

-\NC \type{--ini}                        \NC be \type {iniluatex}, for dumping formats \NC\NR

-\NC \type{--interaction=STRING}         \NC set interaction mode: \type {batchmode}, \type {nonstopmode},

-                                            \type {scrollmode} or \type {errorstopmode} \NC \NR

-\NC \type{--jobname=STRING}             \NC set the job name to \type {STRING} \NC \NR

-\NC \type{--kpathsea-debug=NUMBER}      \NC set path searching debugging flags according to the bits of

-                                           \type {NUMBER} \NC \NR

-\NC \type{--lua=FILE}                   \NC load and execute a \LUA\ initialization script \NC\NR

-\NC \type{--[no-]mktex=FMT}             \NC disable/enable \type {mktexFMT} generation with \type {FMT} is

-                                            \type {tex} or \type {tfm} \NC \NR

-\NC \type{--nosocket}                   \NC disable the \LUA\ socket library \NC\NR

-\NC \type{--output-comment=STRING}      \NC use \type {STRING} for \DVI\ file comment instead of date (no

-                                            effect for \PDF) \NC \NR

-\NC \type{--output-directory=DIR}       \NC use \type {DIR} as the directory to write files to \NC \NR

-\NC \type{--output-format=FORMAT}       \NC use \type {FORMAT} for job output; \type {FORMAT} is \type {dvi}

-                                            or \type {pdf} \NC \NR

-\NC \type{--progname=STRING}            \NC set the program name to \type {STRING} \NC \NR

-\NC \type{--recorder}                   \NC enable filename recorder \NC \NR

-\NC \type{--safer}                      \NC disable easily exploitable \LUA\ commands \NC\NR

-\NC \type{--[no-]shell-escape}          \NC disable/enable system calls \NC \NR

-\NC \type{--shell-restricted}           \NC restrict system calls to a list of commands given in \type

-                                            {texmf.cnf} \NC \NR

-\NC \type{--synctex=NUMBER}             \NC enable \type {synctex} \NC \NR

-\NC \type{--utc}                        \NC use utc times when applicable \NC \NR

-\NC \type{--version}                    \NC display version and exit \NC \NR

-\LL

-\stoptabulate

-

-We don't support \prm {write} 18 because \type {os.execute} can do the same. It

-simplifies the code and makes more write targets possible.

-

-The value to use for \prm {jobname} is decided as follows:

-

-\startitemize

-\startitem

-    If \type {--jobname} is given on the command line, its argument will be the

-    value for \prm {jobname}, without any changes. The argument will not be

-    used for actual input so it need not exist. The \type {--jobname} switch only

-    controls the \prm {jobname} setting.

-\stopitem

-\startitem

-    Otherwise, \prm {jobname} will be the name of the first file that is read

-    from the file system, with any path components and the last extension (the

-    part following the last \type {.}) stripped off.

-\stopitem

-\startitem

-    There is an exception to the previous point: if the command line goes into

-    interactive mode (by starting with a command) and there are no files input

-    via \prm {everyjob} either, then the \prm {jobname} is set to \type

-    {texput} as a last resort.

-\stopitem

-\stopitemize

-

-The file names for output files that are generated automatically are created by

-attaching the proper extension (\type {log}, \type {pdf}, etc.) to the found

-\prm {jobname}. These files are created in the directory pointed to by \type

-{--output-directory}, or in the current directory, if that switch is not present.

-

-Without the \type {--lua} option, command line processing works like it does in

-any other \WEBC|-|based typesetting engine, except that \LUATEX\ has a few extra

-switches and lacks some others. Also, if the \type {--lua} option is present,

-\LUATEX\ will enter an alternative mode of command line processing in comparison

-to the standard \WEBC\ programs. In this mode, a small series of actions is taken

-in the following order:

-

-\startitemize[n]

-

-\startitem

-    First, it will parse the command line as usual, but it will only interpret a

-    small subset of the options immediately: \type {--safer}, \type {--nosocket},

-    \type {--[no-]shell-escape}, \type {--enable-write18}, \type

-    {--disable-write18}, \type {--shell-restricted}, \type {--help}, \type

-    {--version}, and \type {--credits}.

-\stopitem

-

-\startitem

-    Next \LUATEX\ searches for the requested \LUA\ initialization script. If it

-    cannot be found using the actual name given on the command line, a second

-    attempt is made by prepending the value of the environment variable \type

-    {LUATEXDIR}, if that variable is defined in the environment.

-\stopitem

-

-\startitem

-    Then it checks the various safety switches. You can use those to disable some

-    \LUA\ commands that can easily be abused by a malicious document. At the

-    moment, \type {--safer} \type {nil}s the following functions:

-

-    \blank

-

-    \starttabulate[|c|l|]

-        \DB library     \BC functions \NC \NR

-        \TB

-        \NC \type {os}  \NC \type {execute} \type {exec} \type {spawn} \type {setenv}

-                            \type {rename} \type {remove} \type {tmpdir} \NC \NR

-        \NC \type {io}  \NC \type {popen} \type {output} \type {tmpfile} \NC \NR

-        \NC \type {lfs} \NC \type {rmdir} \type {mkdir} \type {chdir} \type {lock}

-                            \type {touch} \NC \NR

-        \LL

-    \stoptabulate

-

-    \blank

-

-    Furthermore, it disables loading of compiled \LUA\ libraries and it makes

-    \type {io.open()} fail on files that are opened for anything besides reading.

-\stopitem

-

-\startitem

-    When \LUATEX\ starts it sets the \type {locale} to a neutral value. If for

-    some reason you use \type {os.locale}, you need to make sure you \type {nil}

-    it afterwards because otherwise it can interfere with code that for instance

-    generates dates. You can ignore the \type {locale} with:

-

-    \starttyping

-    os.setlocale(nil,nil)

-    \stoptyping

-

-    The \type {--nosocket} option makes the socket library unavailable, so that \LUA\

-    cannot use networking.

-

-    The switches \type {--[no-]shell-escape}, \type {--[enable|disable]-write18}, and

-    \type {--shell-restricted} have the same effects as in \PDFTEX, and additionally

-    make \type {io.popen()}, \type {os.execute}, \type {os.exec} and \type {os.spawn}

-    adhere to the requested option.

-\stopitem

-

-\startitem

-    Next the initialization script is loaded and executed. From within the

-    script, the entire command line is available in the \LUA\ table \type {arg},

-    beginning with \type {arg[0]}, containing the name of the executable. As

-    consequence warnings about unrecognized options are suppressed.

-\stopitem

-

-\stopitemize

-

-Command line processing happens very early on. So early, in fact, that none of

-\TEX's initializations have taken place yet. For that reason, the tables that

-deal with typesetting, like \type {tex}, \type {token}, \type {node} and

-\type {pdf}, are off|-|limits during the execution of the startup file (they

-are \type {nil}'d). Special care is taken that \type {texio.write} and \type

-{texio.write_nl} function properly, so that you can at least report your actions

-to the log file when (and if) it eventually becomes opened (note that \TEX\ does

-not even know its \prm {jobname} yet at this point).

-

-Everything you do in the \LUA\ initialization script will remain visible during

-the rest of the run, with the exception of the \TEX\ specific libraries like

-\type {tex}, \type {token}, \type {node} and \type {pdf} tables. These will be

-initialized to their documented state after the execution of the script. You

-should not store anything in variables or within tables with these four global

-names, as they will be overwritten completely.

-

-We recommend you use the startup file only for your own \TEX|-|independent

-initializations (if you need any), to parse the command line, set values in the

-\type {texconfig} table, and register the callbacks you need.

-

-\LUATEX\ allows some of the command line options to be overridden by reading

-values from the \type {texconfig} table at the end of script execution (see the

-description of the \type {texconfig} table later on in this document for more

-details on which ones exactly).

-

-Unless the \type {texconfig} table tells \LUATEX\ not to initialize \KPATHSEA\

-at all (set \type {texconfig.kpse_init} to \type {false} for that), \LUATEX\

-acts on some more command line options after the initialization script is

-finished: in order to initialize the built|-|in \KPATHSEA\ library properly,

-\LUATEX\ needs to know the correct program name to use, and for that it needs to

-check \type {--progname}, or \type {--ini} and \type {--fmt}, if \type

-{--progname} is missing.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={\LUA\ behaviour}]

-

-\startsubsection[title={The \LUA\ version}]

-

-\topicindex {\LUA+libraries}

-\topicindex {\LUA+extensions}

-

-We currently use \LUA\ 5.3 and will follow developments of the language but

-normally with some delay. Therefore the user needs to keep an eye on (subtle)

-differences in successive versions of the language. Also, \LUAJITTEX\ lags behind

-in the sense that \LUAJIT\ is not in sync with regular \LUA\ development. Here is

-an example of one aspect.

-

-\LUA s \type {tostring} function (and \type {string.format} may return values in

-scientific notation, thereby confusing the \TEX\ end of things when it is used as

-the right|-|hand side of an assignment to a \prm {dimen} or \prm {count}. The

-output of these serializers also depend on the \LUA\ version, so in \LUA\ 5.3 you

-can get different output than from 5.2.

-

-\stopsubsection

-

-\startsubsection[title={Integration in the \TDS\ ecosystem}]

-

-The main \TEX\ distributions follow the \TEX\ directory structure (\TDS).

-\LUATEX\ is able to use the kpathsea library to find \type {require()}d modules.

-For this purpose, \type {package.searchers[2]} is replaced by a different loader

-function, that decides at runtime whether to use kpathsea or the built|-|in core

-\LUA\ function. It uses \KPATHSEA\ when that is already initialized at that point

-in time, otherwise it reverts to using the normal \type {package.path} loader.

-

-Initialization of \KPATHSEA\ can happen either implicitly (when \LUATEX\ starts

-up and the startup script has not set \type {texconfig.kpse_init} to false), or

-explicitly by calling the \LUA\ function \type {kpse.set_program_name()}.

-

-\stopsubsection

-

-\startsubsection[title={Loading libraries}]

-

-\LUATEX\ is able to use dynamically loadable \LUA\ libraries, unless

-\type {--safer} was given as an option on the command line. For this purpose,

-\type {package.searchers[3]} is replaced by a different loader function, that

-decides at runtime whether to use \KPATHSEA\ or the built|-|in core \LUA\

-function. It uses \KPATHSEA\ when that is already initialized at that point in

-time, otherwise it reverts to using the normal \type {package.cpath} loader.

-

-This functionality required an extension to kpathsea. There is a new kpathsea

-file format: \type {kpse_clua_format} that searches for files with extension

-\type {.dll} and \type {.so}. The \type {texmf.cnf} setting for this variable is

-\type {CLUAINPUTS}, and by default it has this value:

-

-\starttyping

-CLUAINPUTS=.:$SELFAUTOLOC/lib/{$progname,$engine,}/lua//

-\stoptyping

-

-This path is imperfect (it requires a \TDS\ subtree below the binaries

-directory), but the architecture has to be in the path somewhere, and the

-currently simplest way to do that is to search below the binaries directory only.

-Of course it no big deal to write an alternative loader and use that in a macro

-package. One level up (a \type {lib} directory parallel to \type {bin}) would

-have been nicer, but that is not doable because \TEXLIVE\ uses a \type

-{bin/<arch>} structure.

-

-Loading dynamic \LUA\ libraries will fail if there are two \LUA\ libraries loaded

-at the same time (which will typically happen on \type {win32}, because there is

-one \LUA\ 5.3 inside \LUATEX, and another will likely be linked to the \DLL\ file

-of the module itself).

-

-\stopsubsection

-

-\startsubsection[title={Executing programs}]

-

-In keeping with the other \TEX|-|like programs in \TEXLIVE, the two \LUA\ functions

-\type {os.execute} and \type {io.popen}, as well as the two new functions \type

-{os.exec} and \type {os.spawn} that are explained below, take the value of \type

-{shell_escape} and|/|or \type {shell_escape_commands} in account. Whenever

-\LUATEX\ is run with the assumed intention to typeset a document (and by that we

-mean that it is called as \type {luatex}, as opposed to \type {texlua}, and that

-the command line option \type {--luaonly} was not given), it will only run the

-four functions above if the matching \type {texmf.cnf} variable(s) or their \type

-{texconfig} (see \in {section} [texconfig]) counterparts allow execution of the

-requested system command. In \quote {script interpreter} runs of \LUATEX, these

-settings have no effect, and all four functions have their original meaning.

-

-Some libraries have a few more functions, either coded in \CCODE\ or in \LUA. For

-instance, when we started with \LUATEX\ we added some helpers to the \type

-{luafilesystem} namespace \type {lfs}. The two boolean functions \type

-{lfs.isdir} and \type {lfs.isfile} were speedy and better variants of what could

-be done with \type {lfs.attributes}. The additional function \type

-{lfs.shortname} takes a file name and returns its short name on \type {win32}

-platforms. Finally, for non|-|\type {win32} platforms only, we provided \type

-{lfs.readlink} that takes an existing symbolic link as argument and returns its

-name. However, the \type library evolved so we have dropped these in favour of

-pure \LUA\ variants. The \type {shortname} helper is obsolete and now just

-returns the name.

-

-\stopsubsection

-

-\startsubsection[title={Multibyte \type {string} functions}]

-

-The \type {string} library has a few extra functions, for example \libidx

-{string} {explode}. This function takes upto two arguments: \type

-{string.explode(s[,m])} and returns an array containing the string argument \type

-{s} split into sub-strings based on the value of the string argument \type {m}.

-The second argument is a string that is either empty (this splits the string into

-characters), a single character (this splits on each occurrence of that

-character, possibly introducing empty strings), or a single character followed by

-the plus sign \type {+} (this special version does not create empty sub-strings).

-The default value for \type {m} is \quote {\type { +}} (multiple spaces). Note:

-\type {m} is not hidden by surrounding braces as it would be if this function was

-written in \TEX\ macros.

-

-The \type {string} library also has six extra iterators that return strings

-piecemeal: \libidx {string} {utfvalues}, \libidx {string} {utfcharacters},

-\libidx {string} {characters}, \libidx {string} {characterpairs}, \libidx

-{string} {bytes} and \libidx {string} {bytepairs}.

-

-\startitemize

-\startitem

-    \type {string.utfvalues(s)}: an integer value in the \UNICODE\ range

-\stopitem

-\startitem

-    \type {string.utfcharacters(s)}: a string with a single \UTF-8 token in it

-\stopitem

-\startitem

-    \type {string.cWharacters(s)}: a string containing one byte

-\stopitem

-\startitem

-    \type {string.characterpairs(s)}: two strings each containing one byte or an

-    empty second string if the string length was odd

-\stopitem

-\startitem

-    \type {string.bytes(s)}: a single byte value

-\stopitem

-\startitem

-    \type {string.bytepairs(s)}: two byte values or nil instead of a number as

-    its second return value if the string length was odd

-\stopitem

-\stopitemize

-

-The \type {string.characterpairs()} and \type {string.bytepairs()} iterators

-are useful especially in the conversion of \UTF16 encoded data into \UTF8.

-

-There is also a two|-|argument form of \type {string.dump()}. The second argument

-is a boolean which, if true, strips the symbols from the dumped data. This

-matches an extension made in \type {luajit}. This is typically a function that

-gets adapted as \LUA\ itself progresses.

-

-The \type {string} library functions \type {len}, \type {lower}, \type {sub}

-etc.\ are not \UNICODE|-|aware. For strings in the \UTF8 encoding, i.e., strings

-containing characters above code point 127, the corresponding functions from the

-\type {slnunicode} library can be used, e.g., \type {unicode.utf8.len}, \type

-{unicode.utf8.lower} etc.\ The exceptions are \type {unicode.utf8.find}, that

-always returns byte positions in a string, and \type {unicode.utf8.match} and

-\type {unicode.utf8.gmatch}. While the latter two functions in general {\it

-are} \UNICODE|-|aware, they fall|-|back to non|-|\UNICODE|-|aware behavior when

-using the empty capture \type {()} but other captures work as expected. For the

-interpretation of character classes in \type {unicode.utf8} functions refer to

-the library sources at \hyphenatedurl {http://luaforge.net/projects/sln}.

-

-Version 5.3 of \LUA\ provides some native \UTF8 support but we have added a few

-similar helpers too: \libidx {string} {utfvalue}, \libidx {string} {utfcharacter}

-and \libidx {string} {utflength}.

-

-\startitemize

-\startitem

-    \type {string.utfvalue(s)}: returns the codepoints of the characters in the

-    given string

-\stopitem

-\startitem

-    \type {string.utfcharacter(c,...)}: returns a string with the characters of

-    the given code points

-\stopitem

-\startitem

-    \type {string.utflength(s)}: returns the length oif the given string

-\stopitem

-\stopitemize

-

-These three functions are relative fast and don't do much checking. They can be

-used as building blocks for other helpers.

-

-\stopsubsection

-

-\startsubsection[title={Extra \type {os} library functions}]

-

-The \type {os} library has a few extra functions and variables: \libidx {os}

-{selfdir}, \libidx {os} {exec}, \libidx {os} {spawn}, \libidx {os} {setenv},

-\libidx {os} {env}, \libidx {os} {gettimeofday}, \libidx {os} {times}, \libidx

-{os} {tmpdir}, \libidx {os} {type}, \libidx {os} {name} and \libidx {os} {uname},

-that we will discuss here.

-

-\startitemize

-

-\startitem

-    \type {os.selfdir} is a variable that holds the directory path of the

-    actual executable. For example: \type {\directlua {tex.sprint(os.selfdir)}}.

-\stopitem

-

-\startitem

-    \type {os.exec(commandline)} is a variation on \type {os.execute}. Here

-    \type {commandline} can be either a single string or a single table.

-

-    \startitemize

-

-    \startitem

-        If the argument is a table \LUATEX\ first checks if there is a value at

-        integer index zero. If there is, this is the command to be executed.

-        Otherwise, it will use the value at integer index one. If neither are

-        present, nothing at all happens.

-    \stopitem

-

-    \startitem

-        The set of consecutive values starting at integer~1 in the table are the

-        arguments that are passed on to the command (the value at index~1 becomes

-        \type {arg[0]}). The command is searched for in the execution path, so

-        there is normally no need to pass on a fully qualified path name.

-    \stopitem

-

-    \startitem

-        If the argument is a string, then it is automatically converted into a

-        table by splitting on whitespace. In this case, it is impossible for the

-        command and first argument to differ from each other.

-    \stopitem

-

-    \startitem

-        In the string argument format, whitespace can be protected by putting

-        (part of) an argument inside single or double quotes. One layer of quotes

-        is interpreted by \LUATEX, and all occurrences of \type {\"}, \type {\'}

-        or \type {\\} within the quoted text are unescaped. In the table format,

-        there is no string handling taking place.

-    \stopitem

-

-    \stopitemize

-

-    This function normally does not return control back to the \LUA\ script: the

-    command will replace the current process. However, it will return the two

-    values \type {nil} and \type {error} if there was a problem while

-    attempting to execute the command.

-

-    On \MSWINDOWS, the current process is actually kept in memory until after the

-    execution of the command has finished. This prevents crashes in situations

-    where \TEXLUA\ scripts are run inside integrated \TEX\ environments.

-

-    The original reason for this command is that it cleans out the current

-    process before starting the new one, making it especially useful for use in

-    \TEXLUA.

-\stopitem

-

-\startitem

-    \type {os.spawn(commandline)} is a returning version of \type {os.exec},

-    with otherwise identical calling conventions.

-

-    If the command ran ok, then the return value is the exit status of the

-    command. Otherwise, it will return the two values \type {nil} and \type

-    {error}.

-\stopitem

-

-\startitem

-    \type {os.setenv(key,value)} sets a variable in the environment. Passing

-    \type {nil} instead of a value string will remove the variable.

-\stopitem

-

-\startitem

-    \type {os.env} is a hash table containing a dump of the variables and

-    values in the process environment at the start of the run. It is writeable,

-    but the actual environment is \notabene {not} updated automatically.

-\stopitem

-

-\startitem

-    \type {os.gettimeofday()} returns the current \quote {\UNIX\ time}, but as a

-    float. This function is not available on the \SUNOS\ platforms, so do not use

-    this function for portable documents.

-\stopitem

-

-\startitem

-    \type {os.times()}returns the current process times according to \ the

-    \UNIX\ C library function \quote {times}. This function is not available on

-    the \MSWINDOWS\ and \SUNOS\ platforms, so do not use this function for

-    portable documents.

-\stopitem

-

-\startitem

-    \type {os.tmpdir()} creates a directory in the \quote {current directory}

-    with the name \type {luatex.XXXXXX} where the \type {X}-es are replaced by a

-    unique string. The function also returns this string, so you can \type

-    {lfs.chdir()} into it, or \type {nil} if it failed to create the directory.

-    The user is responsible for cleaning up at the end of the run, it does not

-    happen automatically.

-\stopitem

-

-\startitem

-    \type {os.type} is a string that gives a global indication of the class of

-    operating system. The possible values are currently \type {windows}, \type

-    {unix}, and \type {msdos} (you are unlikely to find this value \quote {in the

-    wild}).

-\stopitem

-

-\startitem

-    \type {os.name} is a string that gives a more precise indication of the

-    operating system. These possible values are not yet fixed, and for \type

-    {os.type} values \type {windows} and \type {msdos}, the \type {os.name}

-    values are simply \type {windows} and \type {msdos}

-

-    The list for the type \type {unix} is more precise: \type {linux}, \type

-    {freebsd}, \type {kfreebsd}, \type {cygwin}, \type {openbsd}, \type

-    {solaris}, \type {sunos} (pre-solaris), \type {hpux}, \type {irix}, \type

-    {macosx}, \type {gnu} (hurd), \type {bsd} (unknown, but \BSD|-|like), \type

-    {sysv} (unknown, but \SYSV|-|like), \type {generic} (unknown).

-\stopitem

-

-\startitem

-    \type {os.uname} returns a table with specific operating system

-    information acquired at runtime. The keys in the returned table are all

-    string values, and their names are: \type {sysname}, \type {machine}, \type

-    {release}, \type {version}, and \type {nodename}.

-\stopitem

-

-\stopitemize

-

-\stopsubsection

-

-\startsubsection[title={Binary input from files with \type {fio}}]

-

-There is a whole set of helpers for reading numbers and strings from a file:

-\libidx {fio} {readcardinal1}, \libidx {fio} {readcardinal2}, \libidx {fio}

-{readcardinal3}, \libidx {fio} {readcardinal4}, \libidx {fio}

-{readcardinaltable}, \libidx {fio} {readinteger1}, \libidx {fio} {readinteger2},

-\libidx {fio} {readinteger3}, \libidx {fio} {readinteger4}, \libidx {fio}

-{readintegertable}, \libidx {fio} {readfixed2}, \libidx {fio} {readfixed4},

-\libidx {fio} {read2dot14}, \libidx {fio} {setposition}, \libidx {fio}

-{getposition}, \libidx {fio} {skipposition}, \libidx {fio} {readbytes}, \libidx

-{fio} {readbytetable}. They work on normal \LUA\ file handles.

-

-%libidx{fio}{readline}

-%libidx{fio}{recordfilename}

-%libidx{fio}{checkpermission}

-

-This library provides a set of functions for reading numbers from a file and

-in addition to the regular \type {io} library functions.

-

-\starttabulate

-\NC \type{readcardinal1(f)}         \NC a 1 byte unsigned integer \NC \NR

-\NC \type{readcardinal2(f)}         \NC a 2 byte unsigned integer \NC \NR

-\NC \type{readcardinal3(f)}         \NC a 3 byte unsigned integer \NC \NR

-\NC \type{readcardinal4(f)}         \NC a 4 byte unsigned integer \NC \NR

-\NC \type{readcardinaltable(f,n,b)} \NC \type {n} cardinals of \type {b} bytes \NC \NR

-\NC \type{readinteger1(f)}          \NC a 1 byte signed integer \NC \NR

-\NC \type{readinteger2(f)}          \NC a 2 byte signed integer \NC \NR

-\NC \type{readinteger3(f)}          \NC a 3 byte signed integer \NC \NR

-\NC \type{readinteger4(f)}          \NC a 4 byte signed integer \NC \NR

-\NC \type{readintegertable(f,n,b)}  \NC \type {n} integers of \type {b} bytes \NC \NR

-\NC \type{readfixed2(f)}            \NC a 2 byte float (used in font files) \NC \NR

-\NC \type{readfixed4(f)}            \NC a 4 byte float (used in font files) \NC \NR

-\NC \type{read2dot14(f)}            \NC a 2 byte float (used in font files) \NC \NR

-\NC \type{setposition(f,p)}         \NC goto position \type {p} \NC \NR

-\NC \type{getposition(f)}           \NC get the current position \NC \NR

-\NC \type{skipposition(f,n)}        \NC skip \type {n} positions \NC \NR

-\NC \type{readbytes(f,n)}           \NC \type {n} bytes \NC \NR

-\NC \type{readbytetable(f,n)}       \NC \type {n} bytes\NC \NR

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={Binary input from strings with \type {sio}}]

-

-A similar set of function as in the \type {fio} library is available in the \type

-{sio} library: \libidx {sio} {readcardinal1}, \libidx {sio} {readcardinal2},

-\libidx {sio} {readcardinal3}, \libidx {sio} {readcardinal4}, \libidx {sio}

-{readcardinaltable}, \libidx {sio} {readinteger1}, \libidx {sio} {readinteger2},

-\libidx {sio} {readinteger3}, \libidx {sio} {readinteger4}, \libidx {sio}

-{readintegertable}, \libidx {sio} {readfixed2}, \libidx {sio} {readfixed4},

-\libidx {sio} {read2dot14}, \libidx {sio} {setposition}, \libidx {sio}

-{getposition}, \libidx {sio} {skipposition}, \libidx {sio} {readbytes} and

-\libidx {sio} {readbytetable}. Here the first argument is a string instead of a

-file handle. More details can be found in the previous section.

-

-\stopsubsection

-

-\startsubsection[title={Hashes conform \type {sha2}}]

-

-This library is a side effect of the \type {pdfe} library that needs such

-helpers. The \libidx{sha2}{digest256}, \libidx{sha2}{digest384} and

-\libidx{sha2}{digest512} functions accept a string and return a string with the

-hash.

-

-\stopsubsection

-

-\startsubsection[title={Locales}]

-

-\index {locales}

-

-In stock \LUA, many things depend on the current locale. In \LUATEX, we can't do

-that, because it makes documents unportable.  While \LUATEX\ is running if

-forces the following locale settings:

-

-\starttyping

-LC_CTYPE=C

-LC_COLLATE=C

-LC_NUMERIC=C

-\stoptyping

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={\LUA\ modules}]

-

-\topicindex {\LUA+libraries}

-\topicindex {\LUA+modules}

-

-Some modules that are normally external to \LUA\ are statically linked in with

-\LUATEX, because they offer useful functionality:

-

-\startitemize

-

-\startitem

-    \type {lpeg}, by Roberto Ierusalimschy, \hyphenatedurl

-    {http://www.inf.puc-rio.br/~roberto/lpeg/lpeg.html}. This library is not

-    \UNICODE|-|aware, but interprets strings on a byte|-|per|-|byte basis. This

-    mainly means that \type {lpeg.S} cannot be used with \UTF8 characters encoded

-    in more than two bytes, and thus \type {lpeg.S} will look for one of those

-    two bytes when matching, not the combination of the two. The same is true for

-    \type {lpeg.R}, although the latter will display an error message if used

-    with multibyte characters. Therefore \type {lpeg.R('aä')} results in the

-    message \type {bad argument #1 to 'R' (range must have two characters)},

-    since to \type {lpeg}, \type {ä} is two 'characters' (bytes), so \type {aä}

-    totals three. In practice this is no real issue and with some care you can

-    deal with \UNICODE\ just fine.

-\stopitem

-

-\startitem

-    \type {slnunicode}, from the \type {selene} libraries, \hyphenatedurl

-    {http://luaforge.net/projects/sln}. This library has been slightly extended

-    so that the \type {unicode.utf8.*} functions also accept the first 256 values

-    of plane~18. This is the range \LUATEX\ uses for raw binary output, as

-    explained above. We have no plans to provide more like this because you can

-    basically do all that you want in \LUA.

-\stopitem

-

-\startitem

-    \type {luazip}, from the kepler project, \hyphenatedurl

-    {http://www.keplerproject.org/luazip/}.

-\stopitem

-

-\startitem

-    \type {luafilesystem}, also from the kepler project, \hyphenatedurl

-    {http://www.keplerproject.org/luafilesystem/}.

-\stopitem

-

-\startitem

-    \type {lzlib}, by Tiago Dionizio, \hyphenatedurl

-    {http://luaforge.net/projects/lzlib/}.

-\stopitem

-

-\startitem

-    \type {md5}, by Roberto Ierusalimschy \hyphenatedurl

-    {http://www.inf.puc-rio.br/~roberto/md5/md5-5/md5.html}.

-\stopitem

-

-\startitem

-    \type {luasocket}, by Diego Nehab \hyphenatedurl

-    {http://w3.impa.br/~diego/software/luasocket/}. The \type {.lua} support

-    modules from \type {luasocket} are also preloaded inside the executable,

-    there are no external file dependencies.

-\stopitem

-

-\stopitemize

-

-\stopsection

-

-\startsection[title={Testing}]

-

-\topicindex {testing}

-\topicindex {\PDF+date}

-

-For development reasons you can influence the used startup date and time. This can

-be done in two ways.

-

-\startitemize[n]

-

-\startitem

-    By setting the environmment variable \type {SOURCE_DATE_EPOCH}. This will

-    influence the \TEX\ parameters \type {time} and \type {date}, the random seed,

-    the \PDF\ timestamp and the \PDF\ id that is derived from the time as well. This

-    variable is consulted when the \KPSE\ library is enabled. Resolving is

-    delegated to this library.

-\stopitem

-

-\startitem

-    By setting the \type {start_time} variable in the \type {texconfig} table; as

-    with other variables we use the internal name there. For compatibility

-    reasons we also honour a \type {SOURCE_DATE_EPOCH} entry. It should be noted

-    that there are no such variables in other engines and this method is only

-    relevant in case the while setup happens in \LUA.

-\stopitem

-

-\stopitemize

-

-When Universal Time is needed, you can pass the flag \type {utc} to the engine. This

-property also works when the date and time are set by \LUATEX\ itself. It has a

-complementary entry \type {use_utc_time} in the \type {texconfig} table.

-

-There is some control possible, for instance prevent filename to be written to

-the \PDF\ file. This is discussed elsewhere. In \CONTEXT\ we provide the command

-line argument \type {--nodates} that does a bit more disabling of dates.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-lua
+
+\startchapter[reference=lua,title={Using \LUATEX}]
+
+\startsection[title={Initialization},reference=init]
+
+\startsubsection[title={\LUATEX\ as a \LUA\ interpreter}]
+
+\topicindex {initialization}
+\topicindex {\LUA+interpreter}
+
+There are some situations that make \LUATEX\ behave like a standalone \LUA\
+interpreter:
+
+\startitemize[packed]
+\startitem
+    if a \type {--luaonly} option is given on the commandline, or
+\stopitem
+\startitem
+    if the executable is named \type {texlua} or \type {luatexlua}, or
+\stopitem
+\startitem
+    if the only non|-|option argument (file) on the commandline has the extension
+    \type {lua} or \type {luc}.
+\stopitem
+\stopitemize
+
+In this mode, it will set \LUA's \type {arg[0]} to the found script name, pushing
+preceding options in negative values and the rest of the command line in the
+positive values, just like the \LUA\ interpreter.
+
+\LUATEX\ will exit immediately after executing the specified \LUA\ script and is,
+in effect, a somewhat bulky stand alone \LUA\ interpreter with a bunch of extra
+preloaded libraries.
+
+\stopsubsection
+
+\startsubsection[title={\LUATEX\ as a \LUA\ byte compiler}]
+
+\topicindex {\LUA+byte code}
+
+There are two situations that make \LUATEX\ behave like the \LUA\ byte compiler:
+
+\startitemize[packed]
+\startitem if a \type {--luaconly} option is given on the command line, or \stopitem
+\startitem if the executable is named \type {texluac} \stopitem
+\stopitemize
+
+In this mode, \LUATEX\ is exactly like \type {luac} from the stand alone \LUA\
+distribution, except that it does not have the \type {-l} switch, and that it
+accepts (but ignores) the \type {--luaconly} switch. The current version of \LUA\
+can dump bytecode using \type {string.dump} so we might decide to drop this
+version of \LUATEX.
+
+\stopsubsection
+
+\startsubsection[title={Other commandline processing}]
+
+\topicindex {command line}
+
+When the \LUATEX\ executable starts, it looks for the \type {--lua} command line
+option. If there is no \type {--lua} option, the command line is interpreted in a
+similar fashion as the other \TEX\ engines. Some options are accepted but have no
+consequence. The following command|-|line options are understood:
+
+\starttabulate[|l|p|]
+\DB commandline argument                \BC explanation \NC \NR
+\TB
+\NC \type{--credits}                    \NC display credits and exit \NC \NR
+\NC \type{--debug-format}               \NC enable format debugging \NC \NR
+\NC \type{--draftmode}                  \NC switch on draft mode i.e.\ generate no output in \PDF\ mode \NC \NR
+\NC \type{--[no-]file-line-error}       \NC disable/enable \type {file:line:error} style messages \NC \NR
+\NC \type{--[no-]file-line-error-style} \NC aliases of \type {--[no-]file-line-error} \NC \NR
+\NC \type{--fmt=FORMAT}                 \NC load the format file \type {FORMAT} \NC\NR
+\NC \type{--halt-on-error}              \NC stop processing at the first error\NC \NR
+\NC \type{--help}                       \NC display help and exit \NC\NR
+\NC \type{--ini}                        \NC be \type {iniluatex}, for dumping formats \NC\NR
+\NC \type{--interaction=STRING}         \NC set interaction mode: \type {batchmode}, \type {nonstopmode},
+                                            \type {scrollmode} or \type {errorstopmode} \NC \NR
+\NC \type{--jobname=STRING}             \NC set the job name to \type {STRING} \NC \NR
+\NC \type{--kpathsea-debug=NUMBER}      \NC set path searching debugging flags according to the bits of
+                                           \type {NUMBER} \NC \NR
+\NC \type{--lua=FILE}                   \NC load and execute a \LUA\ initialization script \NC\NR
+\NC \type{--[no-]mktex=FMT}             \NC disable/enable \type {mktexFMT} generation with \type {FMT} is
+                                            \type {tex} or \type {tfm} \NC \NR
+\NC \type{--nosocket}                   \NC disable the \LUA\ socket library \NC\NR
+\NC \type{--output-comment=STRING}      \NC use \type {STRING} for \DVI\ file comment instead of date (no
+                                            effect for \PDF) \NC \NR
+\NC \type{--output-directory=DIR}       \NC use \type {DIR} as the directory to write files to \NC \NR
+\NC \type{--output-format=FORMAT}       \NC use \type {FORMAT} for job output; \type {FORMAT} is \type {dvi}
+                                            or \type {pdf} \NC \NR
+\NC \type{--progname=STRING}            \NC set the program name to \type {STRING} \NC \NR
+\NC \type{--recorder}                   \NC enable filename recorder \NC \NR
+\NC \type{--safer}                      \NC disable easily exploitable \LUA\ commands \NC\NR
+\NC \type{--[no-]shell-escape}          \NC disable/enable system calls \NC \NR
+\NC \type{--shell-restricted}           \NC restrict system calls to a list of commands given in \type
+                                            {texmf.cnf} \NC \NR
+\NC \type{--synctex=NUMBER}             \NC enable \type {synctex} \NC \NR
+\NC \type{--utc}                        \NC use utc times when applicable \NC \NR
+\NC \type{--version}                    \NC display version and exit \NC \NR
+\LL
+\stoptabulate
+
+We don't support \prm {write} 18 because \type {os.execute} can do the same. It
+simplifies the code and makes more write targets possible.
+
+The value to use for \prm {jobname} is decided as follows:
+
+\startitemize
+\startitem
+    If \type {--jobname} is given on the command line, its argument will be the
+    value for \prm {jobname}, without any changes. The argument will not be
+    used for actual input so it need not exist. The \type {--jobname} switch only
+    controls the \prm {jobname} setting.
+\stopitem
+\startitem
+    Otherwise, \prm {jobname} will be the name of the first file that is read
+    from the file system, with any path components and the last extension (the
+    part following the last \type {.}) stripped off.
+\stopitem
+\startitem
+    There is an exception to the previous point: if the command line goes into
+    interactive mode (by starting with a command) and there are no files input
+    via \prm {everyjob} either, then the \prm {jobname} is set to \type
+    {texput} as a last resort.
+\stopitem
+\stopitemize
+
+The file names for output files that are generated automatically are created by
+attaching the proper extension (\type {log}, \type {pdf}, etc.) to the found
+\prm {jobname}. These files are created in the directory pointed to by \type
+{--output-directory}, or in the current directory, if that switch is not present.
+
+Without the \type {--lua} option, command line processing works like it does in
+any other \WEBC|-|based typesetting engine, except that \LUATEX\ has a few extra
+switches and lacks some others. Also, if the \type {--lua} option is present,
+\LUATEX\ will enter an alternative mode of command line processing in comparison
+to the standard \WEBC\ programs. In this mode, a small series of actions is taken
+in the following order:
+
+\startitemize[n]
+
+\startitem
+    First, it will parse the command line as usual, but it will only interpret a
+    small subset of the options immediately: \type {--safer}, \type {--nosocket},
+    \type {--[no-]shell-escape}, \type {--enable-write18}, \type
+    {--disable-write18}, \type {--shell-restricted}, \type {--help}, \type
+    {--version}, and \type {--credits}.
+\stopitem
+
+\startitem
+    Next \LUATEX\ searches for the requested \LUA\ initialization script. If it
+    cannot be found using the actual name given on the command line, a second
+    attempt is made by prepending the value of the environment variable \type
+    {LUATEXDIR}, if that variable is defined in the environment.
+\stopitem
+
+\startitem
+    Then it checks the various safety switches. You can use those to disable some
+    \LUA\ commands that can easily be abused by a malicious document. At the
+    moment, \type {--safer} \type {nil}s the following functions:
+
+    \blank
+
+    \starttabulate[|c|l|]
+        \DB library     \BC functions \NC \NR
+        \TB
+        \NC \type {os}  \NC \type {execute} \type {exec} \type {spawn} \type {setenv}
+                            \type {rename} \type {remove} \type {tmpdir} \NC \NR
+        \NC \type {io}  \NC \type {popen} \type {output} \type {tmpfile} \NC \NR
+        \NC \type {lfs} \NC \type {rmdir} \type {mkdir} \type {chdir} \type {lock}
+                            \type {touch} \NC \NR
+        \LL
+    \stoptabulate
+
+    \blank
+
+    Furthermore, it disables loading of compiled \LUA\ libraries and it makes
+    \type {io.open()} fail on files that are opened for anything besides reading.
+\stopitem
+
+\startitem
+    When \LUATEX\ starts it sets the \type {locale} to a neutral value. If for
+    some reason you use \type {os.locale}, you need to make sure you \type {nil}
+    it afterwards because otherwise it can interfere with code that for instance
+    generates dates. You can ignore the \type {locale} with:
+
+    \starttyping
+    os.setlocale(nil,nil)
+    \stoptyping
+
+    The \type {--nosocket} option makes the socket library unavailable, so that \LUA\
+    cannot use networking.
+
+    The switches \type {--[no-]shell-escape}, \type {--[enable|disable]-write18}, and
+    \type {--shell-restricted} have the same effects as in \PDFTEX, and additionally
+    make \type {io.popen()}, \type {os.execute}, \type {os.exec} and \type {os.spawn}
+    adhere to the requested option.
+\stopitem
+
+\startitem
+    Next the initialization script is loaded and executed. From within the
+    script, the entire command line is available in the \LUA\ table \type {arg},
+    beginning with \type {arg[0]}, containing the name of the executable. As
+    consequence warnings about unrecognized options are suppressed.
+\stopitem
+
+\stopitemize
+
+Command line processing happens very early on. So early, in fact, that none of
+\TEX's initializations have taken place yet. For that reason, the tables that
+deal with typesetting, like \type {tex}, \type {token}, \type {node} and
+\type {pdf}, are off|-|limits during the execution of the startup file (they
+are \type {nil}'d). Special care is taken that \type {texio.write} and \type
+{texio.write_nl} function properly, so that you can at least report your actions
+to the log file when (and if) it eventually becomes opened (note that \TEX\ does
+not even know its \prm {jobname} yet at this point).
+
+Everything you do in the \LUA\ initialization script will remain visible during
+the rest of the run, with the exception of the \TEX\ specific libraries like
+\type {tex}, \type {token}, \type {node} and \type {pdf} tables. These will be
+initialized to their documented state after the execution of the script. You
+should not store anything in variables or within tables with these four global
+names, as they will be overwritten completely.
+
+We recommend you use the startup file only for your own \TEX|-|independent
+initializations (if you need any), to parse the command line, set values in the
+\type {texconfig} table, and register the callbacks you need.
+
+\LUATEX\ allows some of the command line options to be overridden by reading
+values from the \type {texconfig} table at the end of script execution (see the
+description of the \type {texconfig} table later on in this document for more
+details on which ones exactly).
+
+Unless the \type {texconfig} table tells \LUATEX\ not to initialize \KPATHSEA\
+at all (set \type {texconfig.kpse_init} to \type {false} for that), \LUATEX\
+acts on some more command line options after the initialization script is
+finished: in order to initialize the built|-|in \KPATHSEA\ library properly,
+\LUATEX\ needs to know the correct program name to use, and for that it needs to
+check \type {--progname}, or \type {--ini} and \type {--fmt}, if \type
+{--progname} is missing.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={\LUA\ behaviour}]
+
+\startsubsection[title={The \LUA\ version}]
+
+\topicindex {\LUA+libraries}
+\topicindex {\LUA+extensions}
+
+We currently use \LUA\ 5.3 and will follow developments of the language but
+normally with some delay. Therefore the user needs to keep an eye on (subtle)
+differences in successive versions of the language. Also, \LUAJITTEX\ lags behind
+in the sense that \LUAJIT\ is not in sync with regular \LUA\ development. Here is
+an example of one aspect.
+
+\LUA s \type {tostring} function (and \type {string.format} may return values in
+scientific notation, thereby confusing the \TEX\ end of things when it is used as
+the right|-|hand side of an assignment to a \prm {dimen} or \prm {count}. The
+output of these serializers also depend on the \LUA\ version, so in \LUA\ 5.3 you
+can get different output than from 5.2.
+
+\stopsubsection
+
+\startsubsection[title={Integration in the \TDS\ ecosystem}]
+
+The main \TEX\ distributions follow the \TEX\ directory structure (\TDS).
+\LUATEX\ is able to use the kpathsea library to find \type {require()}d modules.
+For this purpose, \type {package.searchers[2]} is replaced by a different loader
+function, that decides at runtime whether to use kpathsea or the built|-|in core
+\LUA\ function. It uses \KPATHSEA\ when that is already initialized at that point
+in time, otherwise it reverts to using the normal \type {package.path} loader.
+
+Initialization of \KPATHSEA\ can happen either implicitly (when \LUATEX\ starts
+up and the startup script has not set \type {texconfig.kpse_init} to false), or
+explicitly by calling the \LUA\ function \type {kpse.set_program_name()}.
+
+\stopsubsection
+
+\startsubsection[title={Loading libraries}]
+
+\LUATEX\ is able to use dynamically loadable \LUA\ libraries, unless
+\type {--safer} was given as an option on the command line. For this purpose,
+\type {package.searchers[3]} is replaced by a different loader function, that
+decides at runtime whether to use \KPATHSEA\ or the built|-|in core \LUA\
+function. It uses \KPATHSEA\ when that is already initialized at that point in
+time, otherwise it reverts to using the normal \type {package.cpath} loader.
+
+This functionality required an extension to kpathsea. There is a new kpathsea
+file format: \type {kpse_clua_format} that searches for files with extension
+\type {.dll} and \type {.so}. The \type {texmf.cnf} setting for this variable is
+\type {CLUAINPUTS}, and by default it has this value:
+
+\starttyping
+CLUAINPUTS=.:$SELFAUTOLOC/lib/{$progname,$engine,}/lua//
+\stoptyping
+
+This path is imperfect (it requires a \TDS\ subtree below the binaries
+directory), but the architecture has to be in the path somewhere, and the
+currently simplest way to do that is to search below the binaries directory only.
+Of course it no big deal to write an alternative loader and use that in a macro
+package. One level up (a \type {lib} directory parallel to \type {bin}) would
+have been nicer, but that is not doable because \TEXLIVE\ uses a \type
+{bin/<arch>} structure.
+
+Loading dynamic \LUA\ libraries will fail if there are two \LUA\ libraries loaded
+at the same time (which will typically happen on \type {win32}, because there is
+one \LUA\ 5.3 inside \LUATEX, and another will likely be linked to the \DLL\ file
+of the module itself).
+
+\stopsubsection
+
+\startsubsection[title={Executing programs}]
+
+In keeping with the other \TEX|-|like programs in \TEXLIVE, the two \LUA\ functions
+\type {os.execute} and \type {io.popen}, as well as the two new functions \type
+{os.exec} and \type {os.spawn} that are explained below, take the value of \type
+{shell_escape} and|/|or \type {shell_escape_commands} in account. Whenever
+\LUATEX\ is run with the assumed intention to typeset a document (and by that we
+mean that it is called as \type {luatex}, as opposed to \type {texlua}, and that
+the command line option \type {--luaonly} was not given), it will only run the
+four functions above if the matching \type {texmf.cnf} variable(s) or their \type
+{texconfig} (see \in {section} [texconfig]) counterparts allow execution of the
+requested system command. In \quote {script interpreter} runs of \LUATEX, these
+settings have no effect, and all four functions have their original meaning.
+
+Some libraries have a few more functions, either coded in \CCODE\ or in \LUA. For
+instance, when we started with \LUATEX\ we added some helpers to the \type
+{luafilesystem} namespace \type {lfs}. The two boolean functions \type
+{lfs.isdir} and \type {lfs.isfile} were speedy and better variants of what could
+be done with \type {lfs.attributes}. The additional function \type
+{lfs.shortname} takes a file name and returns its short name on \type {win32}
+platforms. Finally, for non|-|\type {win32} platforms only, we provided \type
+{lfs.readlink} that takes an existing symbolic link as argument and returns its
+name. However, the \type library evolved so we have dropped these in favour of
+pure \LUA\ variants. The \type {shortname} helper is obsolete and now just
+returns the name.
+
+\stopsubsection
+
+\startsubsection[title={Multibyte \type {string} functions}]
+
+The \type {string} library has a few extra functions, for example \libidx
+{string} {explode}. This function takes upto two arguments: \type
+{string.explode(s[,m])} and returns an array containing the string argument \type
+{s} split into sub-strings based on the value of the string argument \type {m}.
+The second argument is a string that is either empty (this splits the string into
+characters), a single character (this splits on each occurrence of that
+character, possibly introducing empty strings), or a single character followed by
+the plus sign \type {+} (this special version does not create empty sub-strings).
+The default value for \type {m} is \quote {\type { +}} (multiple spaces). Note:
+\type {m} is not hidden by surrounding braces as it would be if this function was
+written in \TEX\ macros.
+
+The \type {string} library also has six extra iterators that return strings
+piecemeal: \libidx {string} {utfvalues}, \libidx {string} {utfcharacters},
+\libidx {string} {characters}, \libidx {string} {characterpairs}, \libidx
+{string} {bytes} and \libidx {string} {bytepairs}.
+
+\startitemize
+\startitem
+    \type {string.utfvalues(s)}: an integer value in the \UNICODE\ range
+\stopitem
+\startitem
+    \type {string.utfcharacters(s)}: a string with a single \UTF-8 token in it
+\stopitem
+\startitem
+    \type {string.cWharacters(s)}: a string containing one byte
+\stopitem
+\startitem
+    \type {string.characterpairs(s)}: two strings each containing one byte or an
+    empty second string if the string length was odd
+\stopitem
+\startitem
+    \type {string.bytes(s)}: a single byte value
+\stopitem
+\startitem
+    \type {string.bytepairs(s)}: two byte values or nil instead of a number as
+    its second return value if the string length was odd
+\stopitem
+\stopitemize
+
+The \type {string.characterpairs()} and \type {string.bytepairs()} iterators
+are useful especially in the conversion of \UTF16 encoded data into \UTF8.
+
+There is also a two|-|argument form of \type {string.dump()}. The second argument
+is a boolean which, if true, strips the symbols from the dumped data. This
+matches an extension made in \type {luajit}. This is typically a function that
+gets adapted as \LUA\ itself progresses.
+
+The \type {string} library functions \type {len}, \type {lower}, \type {sub}
+etc.\ are not \UNICODE|-|aware. For strings in the \UTF8 encoding, i.e., strings
+containing characters above code point 127, the corresponding functions from the
+\type {slnunicode} library can be used, e.g., \type {unicode.utf8.len}, \type
+{unicode.utf8.lower} etc.\ The exceptions are \type {unicode.utf8.find}, that
+always returns byte positions in a string, and \type {unicode.utf8.match} and
+\type {unicode.utf8.gmatch}. While the latter two functions in general {\it
+are} \UNICODE|-|aware, they fall|-|back to non|-|\UNICODE|-|aware behavior when
+using the empty capture \type {()} but other captures work as expected. For the
+interpretation of character classes in \type {unicode.utf8} functions refer to
+the library sources at \hyphenatedurl {http://luaforge.net/projects/sln}.
+
+Version 5.3 of \LUA\ provides some native \UTF8 support but we have added a few
+similar helpers too: \libidx {string} {utfvalue}, \libidx {string} {utfcharacter}
+and \libidx {string} {utflength}.
+
+\startitemize
+\startitem
+    \type {string.utfvalue(s)}: returns the codepoints of the characters in the
+    given string
+\stopitem
+\startitem
+    \type {string.utfcharacter(c,...)}: returns a string with the characters of
+    the given code points
+\stopitem
+\startitem
+    \type {string.utflength(s)}: returns the length oif the given string
+\stopitem
+\stopitemize
+
+These three functions are relative fast and don't do much checking. They can be
+used as building blocks for other helpers.
+
+\stopsubsection
+
+\startsubsection[title={Extra \type {os} library functions}]
+
+The \type {os} library has a few extra functions and variables: \libidx {os}
+{selfdir}, \libidx {os} {exec}, \libidx {os} {spawn}, \libidx {os} {setenv},
+\libidx {os} {env}, \libidx {os} {gettimeofday}, \libidx {os} {times}, \libidx
+{os} {tmpdir}, \libidx {os} {type}, \libidx {os} {name} and \libidx {os} {uname},
+that we will discuss here.
+
+\startitemize
+
+\startitem
+    \type {os.selfdir} is a variable that holds the directory path of the
+    actual executable. For example: \type {\directlua {tex.sprint(os.selfdir)}}.
+\stopitem
+
+\startitem
+    \type {os.exec(commandline)} is a variation on \type {os.execute}. Here
+    \type {commandline} can be either a single string or a single table.
+
+    \startitemize
+
+    \startitem
+        If the argument is a table \LUATEX\ first checks if there is a value at
+        integer index zero. If there is, this is the command to be executed.
+        Otherwise, it will use the value at integer index one. If neither are
+        present, nothing at all happens.
+    \stopitem
+
+    \startitem
+        The set of consecutive values starting at integer~1 in the table are the
+        arguments that are passed on to the command (the value at index~1 becomes
+        \type {arg[0]}). The command is searched for in the execution path, so
+        there is normally no need to pass on a fully qualified path name.
+    \stopitem
+
+    \startitem
+        If the argument is a string, then it is automatically converted into a
+        table by splitting on whitespace. In this case, it is impossible for the
+        command and first argument to differ from each other.
+    \stopitem
+
+    \startitem
+        In the string argument format, whitespace can be protected by putting
+        (part of) an argument inside single or double quotes. One layer of quotes
+        is interpreted by \LUATEX, and all occurrences of \type {\"}, \type {\'}
+        or \type {\\} within the quoted text are unescaped. In the table format,
+        there is no string handling taking place.
+    \stopitem
+
+    \stopitemize
+
+    This function normally does not return control back to the \LUA\ script: the
+    command will replace the current process. However, it will return the two
+    values \type {nil} and \type {error} if there was a problem while
+    attempting to execute the command.
+
+    On \MSWINDOWS, the current process is actually kept in memory until after the
+    execution of the command has finished. This prevents crashes in situations
+    where \TEXLUA\ scripts are run inside integrated \TEX\ environments.
+
+    The original reason for this command is that it cleans out the current
+    process before starting the new one, making it especially useful for use in
+    \TEXLUA.
+\stopitem
+
+\startitem
+    \type {os.spawn(commandline)} is a returning version of \type {os.exec},
+    with otherwise identical calling conventions.
+
+    If the command ran ok, then the return value is the exit status of the
+    command. Otherwise, it will return the two values \type {nil} and \type
+    {error}.
+\stopitem
+
+\startitem
+    \type {os.setenv(key,value)} sets a variable in the environment. Passing
+    \type {nil} instead of a value string will remove the variable.
+\stopitem
+
+\startitem
+    \type {os.env} is a hash table containing a dump of the variables and
+    values in the process environment at the start of the run. It is writeable,
+    but the actual environment is \notabene {not} updated automatically.
+\stopitem
+
+\startitem
+    \type {os.gettimeofday()} returns the current \quote {\UNIX\ time}, but as a
+    float. This function is not available on the \SUNOS\ platforms, so do not use
+    this function for portable documents.
+\stopitem
+
+\startitem
+    \type {os.times()}returns the current process times according to \ the
+    \UNIX\ C library function \quote {times}. This function is not available on
+    the \MSWINDOWS\ and \SUNOS\ platforms, so do not use this function for
+    portable documents.
+\stopitem
+
+\startitem
+    \type {os.tmpdir()} creates a directory in the \quote {current directory}
+    with the name \type {luatex.XXXXXX} where the \type {X}-es are replaced by a
+    unique string. The function also returns this string, so you can \type
+    {lfs.chdir()} into it, or \type {nil} if it failed to create the directory.
+    The user is responsible for cleaning up at the end of the run, it does not
+    happen automatically.
+\stopitem
+
+\startitem
+    \type {os.type} is a string that gives a global indication of the class of
+    operating system. The possible values are currently \type {windows}, \type
+    {unix}, and \type {msdos} (you are unlikely to find this value \quote {in the
+    wild}).
+\stopitem
+
+\startitem
+    \type {os.name} is a string that gives a more precise indication of the
+    operating system. These possible values are not yet fixed, and for \type
+    {os.type} values \type {windows} and \type {msdos}, the \type {os.name}
+    values are simply \type {windows} and \type {msdos}
+
+    The list for the type \type {unix} is more precise: \type {linux}, \type
+    {freebsd}, \type {kfreebsd}, \type {cygwin}, \type {openbsd}, \type
+    {solaris}, \type {sunos} (pre-solaris), \type {hpux}, \type {irix}, \type
+    {macosx}, \type {gnu} (hurd), \type {bsd} (unknown, but \BSD|-|like), \type
+    {sysv} (unknown, but \SYSV|-|like), \type {generic} (unknown).
+\stopitem
+
+\startitem
+    \type {os.uname} returns a table with specific operating system
+    information acquired at runtime. The keys in the returned table are all
+    string values, and their names are: \type {sysname}, \type {machine}, \type
+    {release}, \type {version}, and \type {nodename}.
+\stopitem
+
+\stopitemize
+
+\stopsubsection
+
+\startsubsection[title={Binary input from files with \type {fio}}]
+
+There is a whole set of helpers for reading numbers and strings from a file:
+\libidx {fio} {readcardinal1}, \libidx {fio} {readcardinal2}, \libidx {fio}
+{readcardinal3}, \libidx {fio} {readcardinal4}, \libidx {fio}
+{readcardinaltable}, \libidx {fio} {readinteger1}, \libidx {fio} {readinteger2},
+\libidx {fio} {readinteger3}, \libidx {fio} {readinteger4}, \libidx {fio}
+{readintegertable}, \libidx {fio} {readfixed2}, \libidx {fio} {readfixed4},
+\libidx {fio} {read2dot14}, \libidx {fio} {setposition}, \libidx {fio}
+{getposition}, \libidx {fio} {skipposition}, \libidx {fio} {readbytes}, \libidx
+{fio} {readbytetable}. They work on normal \LUA\ file handles.
+
+%libidx{fio}{readline}
+%libidx{fio}{recordfilename}
+%libidx{fio}{checkpermission}
+
+This library provides a set of functions for reading numbers from a file and
+in addition to the regular \type {io} library functions.
+
+\starttabulate
+\NC \type{readcardinal1(f)}         \NC a 1 byte unsigned integer \NC \NR
+\NC \type{readcardinal2(f)}         \NC a 2 byte unsigned integer \NC \NR
+\NC \type{readcardinal3(f)}         \NC a 3 byte unsigned integer \NC \NR
+\NC \type{readcardinal4(f)}         \NC a 4 byte unsigned integer \NC \NR
+\NC \type{readcardinaltable(f,n,b)} \NC \type {n} cardinals of \type {b} bytes \NC \NR
+\NC \type{readinteger1(f)}          \NC a 1 byte signed integer \NC \NR
+\NC \type{readinteger2(f)}          \NC a 2 byte signed integer \NC \NR
+\NC \type{readinteger3(f)}          \NC a 3 byte signed integer \NC \NR
+\NC \type{readinteger4(f)}          \NC a 4 byte signed integer \NC \NR
+\NC \type{readintegertable(f,n,b)}  \NC \type {n} integers of \type {b} bytes \NC \NR
+\NC \type{readfixed2(f)}            \NC a 2 byte float (used in font files) \NC \NR
+\NC \type{readfixed4(f)}            \NC a 4 byte float (used in font files) \NC \NR
+\NC \type{read2dot14(f)}            \NC a 2 byte float (used in font files) \NC \NR
+\NC \type{setposition(f,p)}         \NC goto position \type {p} \NC \NR
+\NC \type{getposition(f)}           \NC get the current position \NC \NR
+\NC \type{skipposition(f,n)}        \NC skip \type {n} positions \NC \NR
+\NC \type{readbytes(f,n)}           \NC \type {n} bytes \NC \NR
+\NC \type{readbytetable(f,n)}       \NC \type {n} bytes\NC \NR
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={Binary input from strings with \type {sio}}]
+
+A similar set of function as in the \type {fio} library is available in the \type
+{sio} library: \libidx {sio} {readcardinal1}, \libidx {sio} {readcardinal2},
+\libidx {sio} {readcardinal3}, \libidx {sio} {readcardinal4}, \libidx {sio}
+{readcardinaltable}, \libidx {sio} {readinteger1}, \libidx {sio} {readinteger2},
+\libidx {sio} {readinteger3}, \libidx {sio} {readinteger4}, \libidx {sio}
+{readintegertable}, \libidx {sio} {readfixed2}, \libidx {sio} {readfixed4},
+\libidx {sio} {read2dot14}, \libidx {sio} {setposition}, \libidx {sio}
+{getposition}, \libidx {sio} {skipposition}, \libidx {sio} {readbytes} and
+\libidx {sio} {readbytetable}. Here the first argument is a string instead of a
+file handle. More details can be found in the previous section.
+
+\stopsubsection
+
+\startsubsection[title={Hashes conform \type {sha2}}]
+
+This library is a side effect of the \type {pdfe} library that needs such
+helpers. The \libidx{sha2}{digest256}, \libidx{sha2}{digest384} and
+\libidx{sha2}{digest512} functions accept a string and return a string with the
+hash.
+
+\stopsubsection
+
+\startsubsection[title={Locales}]
+
+\index {locales}
+
+In stock \LUA, many things depend on the current locale. In \LUATEX, we can't do
+that, because it makes documents unportable.  While \LUATEX\ is running if
+forces the following locale settings:
+
+\starttyping
+LC_CTYPE=C
+LC_COLLATE=C
+LC_NUMERIC=C
+\stoptyping
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={\LUA\ modules}]
+
+\topicindex {\LUA+libraries}
+\topicindex {\LUA+modules}
+
+Some modules that are normally external to \LUA\ are statically linked in with
+\LUATEX, because they offer useful functionality:
+
+\startitemize
+
+\startitem
+    \type {lpeg}, by Roberto Ierusalimschy, \hyphenatedurl
+    {http://www.inf.puc-rio.br/~roberto/lpeg/lpeg.html}. This library is not
+    \UNICODE|-|aware, but interprets strings on a byte|-|per|-|byte basis. This
+    mainly means that \type {lpeg.S} cannot be used with \UTF8 characters encoded
+    in more than two bytes, and thus \type {lpeg.S} will look for one of those
+    two bytes when matching, not the combination of the two. The same is true for
+    \type {lpeg.R}, although the latter will display an error message if used
+    with multibyte characters. Therefore \type {lpeg.R('aä')} results in the
+    message \type {bad argument #1 to 'R' (range must have two characters)},
+    since to \type {lpeg}, \type {ä} is two 'characters' (bytes), so \type {aä}
+    totals three. In practice this is no real issue and with some care you can
+    deal with \UNICODE\ just fine.
+\stopitem
+
+\startitem
+    \type {slnunicode}, from the \type {selene} libraries, \hyphenatedurl
+    {http://luaforge.net/projects/sln}. This library has been slightly extended
+    so that the \type {unicode.utf8.*} functions also accept the first 256 values
+    of plane~18. This is the range \LUATEX\ uses for raw binary output, as
+    explained above. We have no plans to provide more like this because you can
+    basically do all that you want in \LUA.
+\stopitem
+
+\startitem
+    \type {luazip}, from the kepler project, \hyphenatedurl
+    {http://www.keplerproject.org/luazip/}.
+\stopitem
+
+\startitem
+    \type {luafilesystem}, also from the kepler project, \hyphenatedurl
+    {http://www.keplerproject.org/luafilesystem/}.
+\stopitem
+
+\startitem
+    \type {lzlib}, by Tiago Dionizio, \hyphenatedurl
+    {http://luaforge.net/projects/lzlib/}.
+\stopitem
+
+\startitem
+    \type {md5}, by Roberto Ierusalimschy \hyphenatedurl
+    {http://www.inf.puc-rio.br/~roberto/md5/md5-5/md5.html}.
+\stopitem
+
+\startitem
+    \type {luasocket}, by Diego Nehab \hyphenatedurl
+    {http://w3.impa.br/~diego/software/luasocket/}. The \type {.lua} support
+    modules from \type {luasocket} are also preloaded inside the executable,
+    there are no external file dependencies.
+\stopitem
+
+\stopitemize
+
+\stopsection
+
+\startsection[title={Testing}]
+
+\topicindex {testing}
+\topicindex {\PDF+date}
+
+For development reasons you can influence the used startup date and time. This can
+be done in two ways.
+
+\startitemize[n]
+
+\startitem
+    By setting the environmment variable \type {SOURCE_DATE_EPOCH}. This will
+    influence the \TEX\ parameters \type {time} and \type {date}, the random seed,
+    the \PDF\ timestamp and the \PDF\ id that is derived from the time as well. This
+    variable is consulted when the \KPSE\ library is enabled. Resolving is
+    delegated to this library.
+\stopitem
+
+\startitem
+    By setting the \type {start_time} variable in the \type {texconfig} table; as
+    with other variables we use the internal name there. For compatibility
+    reasons we also honour a \type {SOURCE_DATE_EPOCH} entry. It should be noted
+    that there are no such variables in other engines and this method is only
+    relevant in case the while setup happens in \LUA.
+\stopitem
+
+\stopitemize
+
+When Universal Time is needed, you can pass the flag \type {utc} to the engine. This
+property also works when the date and time are set by \LUATEX\ itself. It has a
+complementary entry \type {use_utc_time} in the \type {texconfig} table.
+
+There is some control possible, for instance prevent filename to be written to
+the \PDF\ file. This is discussed elsewhere. In \CONTEXT\ we provide the command
+line argument \type {--nodates} that does a bit more disabling of dates.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-math.tex b/systems/doc/luatex/luatex-math.tex
index fd038150f5..4623ce706d 100644
--- a/systems/doc/luatex/luatex-math.tex
+++ b/systems/doc/luatex/luatex-math.tex
@@ -1,1647 +1,1647 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-math

-

-\startchapter[reference=math,title={Math}]

-

-\startsection[title={Traditional alongside \OPENTYPE}]

-

-\topicindex {math}

-

-The handling of mathematics in \LUATEX\ differs quite a bit from how \TEX82 (and

-therefore \PDFTEX) handles math. First, \LUATEX\ adds primitives and extends some

-others so that \UNICODE\ input can be used easily. Second, all of \TEX82's

-internal special values (for example for operator spacing) have been made

-accessible and changeable via control sequences. Third, there are extensions that

-make it easier to use \OPENTYPE\ math fonts. And finally, there are some

-extensions that have been proposed or considered in the past that are now added

-to the engine.

-

-\stopsection

-

-\startsection[title={Unicode math characters}]

-

-\topicindex {math+\UNICODE}

-\topicindex {\UNICODE+math}

-

-Character handling is now extended up to the full \UNICODE\ range (the \type {\U}

-prefix), which is compatible with \XETEX.

-

-The math primitives from \TEX\ are kept as they are, except for the ones that

-convert from input to math commands: \type {mathcode}, and \type {delcode}. These

-two now allow for a 21-bit character argument on the left hand side of the equals

-sign.

-

-Some of the new \LUATEX\ primitives read more than one separate value. This is

-shown in the tables below by a plus sign.

-

-The input for such primitives would look like this:

-

-\starttyping

-\def\overbrace{\Umathaccent 0 1 "23DE }

-\stoptyping

-

-The altered \TEX82 primitives are:

-

-\starttabulate[|l|l|r|c|l|r|]

-\DB primitive       \BC min \BC max    \BC \kern 2em \BC min \BC max    \NC \NR

-\TB

-\NC \prm {mathcode} \NC 0   \NC 10FFFF \NC =         \NC 0   \NC 8000   \NC \NR

-\NC \prm {delcode}  \NC 0   \NC 10FFFF \NC =         \NC 0   \NC FFFFFF \NC \NR

-\LL

-\stoptabulate

-

-The unaltered ones are:

-

-\starttabulate[|l|l|r|]

-\DB primitive          \BC min \BC max     \NC \NR

-\TB

-\NC \prm {mathchardef} \NC 0   \NC    8000 \NC \NR

-\NC \prm {mathchar}    \NC 0   \NC    7FFF \NC \NR

-\NC \prm {mathaccent}  \NC 0   \NC    7FFF \NC \NR

-\NC \prm {delimiter}   \NC 0   \NC 7FFFFFF \NC \NR

-\NC \prm {radical}     \NC 0   \NC 7FFFFFF \NC \NR

-\LL

-\stoptabulate

-

-For practical reasons \prm {mathchardef} will silently accept values larger

-that \type {0x8000} and interpret it as \lpr {Umathcharnumdef}. This is needed

-to satisfy older macro packages.

-

-The following new primitives are compatible with \XETEX:

-

-% somewhat fuzzy:

-

-\starttabulate[|l|l|r|c|l|r|]

-\DB primitive                             \BC min       \BC max         \BC \kern 2em \BC min       \BC max         \NC \NR

-\TB

-\NC \lpr {Umathchardef}                   \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Umathcharnumdef}\rlap{\high{5}} \NC -80000000 \NC    7FFFFFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Umathcode}                      \NC 0         \NC      10FFFF \NC =         \NC 0+0+0     \NC 7+FF+10FFFF \NC \NR

-\NC \lpr {Udelcode}                       \NC 0         \NC      10FFFF \NC =         \NC 0+0       \NC   FF+10FFFF \NC \NR

-\NC \lpr {Umathchar}                      \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Umathaccent}                    \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Udelimiter}                     \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Uradical}                       \NC 0+0       \NC   FF+10FFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Umathcharnum}                   \NC -80000000 \NC    7FFFFFFF \NC           \NC           \NC             \NC \NR

-\NC \lpr {Umathcodenum}                   \NC 0         \NC      10FFFF \NC =         \NC -80000000 \NC    7FFFFFFF \NC \NR

-\NC \lpr {Udelcodenum}                    \NC 0         \NC      10FFFF \NC =         \NC -80000000 \NC    7FFFFFFF \NC \NR

-\LL

-\stoptabulate

-

-Specifications typically look like:

-

-\starttyping

-\Umathchardef\xx="1"0"456

-\Umathcode   123="1"0"789

-\stoptyping

-

-The new primitives that deal with delimiter|-|style objects do not set up a

-\quote {large family}. Selecting a suitable size for display purposes is expected

-to be dealt with by the font via the \lpr {Umathoperatorsize} parameter.

-

-For some of these primitives, all information is packed into a single signed

-integer. For the first two (\lpr {Umathcharnum} and \lpr {Umathcodenum}), the

-lowest 21 bits are the character code, the 3 bits above that represent the math

-class, and the family data is kept in the topmost bits. This means that the values

-for math families 128--255 are actually negative. For \lpr {Udelcodenum} there

-is no math class. The math family information is stored in the bits directly on

-top of the character code. Using these three commands is not as natural as using

-the two- and three|-|value commands, so unless you know exactly what you are

-doing and absolutely require the speedup resulting from the faster input

-scanning, it is better to use the verbose commands instead.

-

-The \lpr {Umathaccent} command accepts optional keywords to control various

-details regarding math accents. See \in {section} [mathacc] below for details.

-

-There are more new primitives and all of these will be explained in following

-sections:

-

-\starttabulate[|l|l|]

-\DB primitive                \BC value range (in hex) \NC \NR

-\TB

-\NC \lpr {Uroot}           \NC 0 + 0--FF + 10FFFF   \NC \NR

-\NC \lpr {Uoverdelimiter}  \NC 0 + 0--FF + 10FFFF   \NC \NR

-\NC \lpr {Uunderdelimiter} \NC 0 + 0--FF + 10FFFF   \NC \NR

-\NC \lpr {Udelimiterover}  \NC 0 + 0--FF + 10FFFF   \NC \NR

-\NC \lpr {Udelimiterunder} \NC 0 + 0--FF + 10FFFF   \NC \NR

-\LL

-\stoptabulate

-

-\stopsection

-

-\startsection[title={Math styles}]

-

-\subsection{\lpr {mathstyle}}

-

-\topicindex {math+styles}

-

-It is possible to discover the math style that will be used for a formula in an

-expandable fashion (while the math list is still being read). To make this

-possible, \LUATEX\ adds the new primitive: \lpr {mathstyle}. This is a \quote

-{convert command} like e.g. \prm {romannumeral}: its value can only be read,

-not set.

-

-The returned value is between 0 and 7 (in math mode), or $-1$ (all other modes).

-For easy testing, the eight math style commands have been altered so that they can

-be used as numeric values, so you can write code like this:

-

-\starttyping

-\ifnum\mathstyle=\textstyle

-    \message{normal text style}

-\else \ifnum\mathstyle=\crampedtextstyle

-    \message{cramped text style}

-\fi \fi

-\stoptyping

-

-Sometimes you won't get what you expect so a bit of explanation might help to

-understand what happens. When math is parsed and expanded it gets turned into a

-linked list. In a second pass the formula will be build. This has to do with the

-fact that in order to determine the automatically chosen sizes (in for instance

-fractions) following content can influence preceding sizes. A side effect of this

-is for instance that one cannot change the definition of a font family (and

-thereby reusing numbers) because the number that got used is stored and used in

-the second pass (so changing \type {\fam 12} mid|-|formula spoils over to

-preceding use of that family).

-

-The style switching primitives like \prm {textstyle} are turned into nodes so the

-styles set there are frozen. The \prm {mathchoice} primitive results in four

-lists being constructed of which one is used in the second pass. The fact that

-some automatic styles are not yet known also means that the \lpr {mathstyle}

-primitive expands to the current style which can of course be different from the

-one really used. It's a snapshot of the first pass state. As a consequence in the

-following example you get a style number (first pass) typeset that can actually

-differ from the used style (second pass). In the case of a math choice used

-ungrouped, the chosen style is used after the choice too, unless you group.

-

-\startbuffer[1]

-    [a:\mathstyle]\quad

-    \bgroup

-    \mathchoice

-        {\bf \scriptstyle       (x:d :\mathstyle)}

-        {\bf \scriptscriptstyle (x:t :\mathstyle)}

-        {\bf \scriptscriptstyle (x:s :\mathstyle)}

-        {\bf \scriptscriptstyle (x:ss:\mathstyle)}

-    \egroup

-    \quad[b:\mathstyle]\quad

-    \mathchoice

-        {\bf \scriptstyle       (y:d :\mathstyle)}

-        {\bf \scriptscriptstyle (y:t :\mathstyle)}

-        {\bf \scriptscriptstyle (y:s :\mathstyle)}

-        {\bf \scriptscriptstyle (y:ss:\mathstyle)}

-    \quad[c:\mathstyle]\quad

-    \bgroup

-    \mathchoice

-        {\bf \scriptstyle       (z:d :\mathstyle)}

-        {\bf \scriptscriptstyle (z:t :\mathstyle)}

-        {\bf \scriptscriptstyle (z:s :\mathstyle)}

-        {\bf \scriptscriptstyle (z:ss:\mathstyle)}

-    \egroup

-    \quad[d:\mathstyle]

-\stopbuffer

-

-\startbuffer[2]

-    [a:\mathstyle]\quad

-    \begingroup

-    \mathchoice

-        {\bf \scriptstyle       (x:d :\mathstyle)}

-        {\bf \scriptscriptstyle (x:t :\mathstyle)}

-        {\bf \scriptscriptstyle (x:s :\mathstyle)}

-        {\bf \scriptscriptstyle (x:ss:\mathstyle)}

-    \endgroup

-    \quad[b:\mathstyle]\quad

-    \mathchoice

-        {\bf \scriptstyle       (y:d :\mathstyle)}

-        {\bf \scriptscriptstyle (y:t :\mathstyle)}

-        {\bf \scriptscriptstyle (y:s :\mathstyle)}

-        {\bf \scriptscriptstyle (y:ss:\mathstyle)}

-    \quad[c:\mathstyle]\quad

-    \begingroup

-    \mathchoice

-        {\bf \scriptstyle       (z:d :\mathstyle)}

-        {\bf \scriptscriptstyle (z:t :\mathstyle)}

-        {\bf \scriptscriptstyle (z:s :\mathstyle)}

-        {\bf \scriptscriptstyle (z:ss:\mathstyle)}

-    \endgroup

-    \quad[d:\mathstyle]

-\stopbuffer

-

-\typebuffer[1]

-

-% \typebuffer[2]

-

-This gives:

-

-\blank $\displaystyle \getbuffer[1]$ \blank

-\blank $\textstyle    \getbuffer[1]$ \blank

-

-Using \prm {begingroup} \unknown\ \prm {endgroup} instead gives:

-

-\blank $\displaystyle \getbuffer[2]$ \blank

-\blank $\textstyle    \getbuffer[2]$ \blank

-

-This might look wrong but it's just a side effect of \lpr {mathstyle} expanding

-to the current (first pass) style and the number being injected in the list that

-gets converted in the second pass. It all makes sense and it illustrates the

-importance of grouping. In fact, the math choice style being effective afterwards

-has advantages. It would be hard to get it otherwise.

-

-\subsection{\lpr {Ustack}}

-

-\topicindex {math+stacks}

-

-There are a few math commands in \TEX\ where the style that will be used is not

-known straight from the start. These commands (\prm {over}, \prm {atop},

-\prm {overwithdelims}, \prm {atopwithdelims}) would therefore normally return

-wrong values for \lpr {mathstyle}. To fix this, \LUATEX\ introduces a special

-prefix command: \lpr {Ustack}:

-

-\starttyping

-$\Ustack {a \over b}$

-\stoptyping

-

-The \lpr {Ustack} command will scan the next brace and start a new math group

-with the correct (numerator) math style.

-

-\subsection{Cramped math styles}

-

-\topicindex {math+styles}

-\topicindex {math+spacing}

-\topicindex {math+cramped}

-

-\LUATEX\ has four new primitives to set the cramped math styles directly:

-

-\starttyping

-\crampeddisplaystyle

-\crampedtextstyle

-\crampedscriptstyle

-\crampedscriptscriptstyle

-\stoptyping

-

-These additional commands are not all that valuable on their own, but they come

-in handy as arguments to the math parameter settings that will be added shortly.

-

-In Eijkhouts \quotation {\TEX\ by Topic} the rules for handling styles in scripts

-are described as follows:

-

-\startitemize

-\startitem

-    In any style superscripts and subscripts are taken from the next smaller style.

-    Exception: in display style they are in script style.

-\stopitem

-\startitem

-    Subscripts are always in the cramped variant of the style; superscripts are only

-    cramped if the original style was cramped.

-\stopitem

-\startitem

-    In an \type {..\over..} formula in any style the numerator and denominator are

-    taken from the next smaller style.

-\stopitem

-\startitem

-    The denominator is always in cramped style; the numerator is only in cramped

-    style if the original style was cramped.

-\stopitem

-\startitem

-    Formulas under a \type {\sqrt} or \prm {overline} are in cramped style.

-\stopitem

-\stopitemize

-

-In \LUATEX\ one can set the styles in more detail which means that you sometimes

-have to set both normal and cramped styles to get the effect you want. (Even) if

-we force styles in the script using \prm {scriptstyle} and \lpr

-{crampedscriptstyle} we get this:

-

-\startbuffer[demo]

-\starttabulate

-\DB style         \BC example \NC \NR

-\TB

-\NC default       \NC $b_{x=xx}^{x=xx}$ \NC \NR

-\NC script        \NC $b_{\scriptstyle x=xx}^{\scriptstyle x=xx}$ \NC \NR

-\NC crampedscript \NC $b_{\crampedscriptstyle x=xx}^{\crampedscriptstyle x=xx}$ \NC \NR

-\LL

-\stoptabulate

-\stopbuffer

-

-\getbuffer[demo]

-

-Now we set the following parameters

-

-\startbuffer[setup]

-\Umathordrelspacing\scriptstyle=30mu

-\Umathordordspacing\scriptstyle=30mu

-\stopbuffer

-

-\typebuffer[setup]

-

-This gives a different result:

-

-\start\getbuffer[setup,demo]\stop

-

-But, as this is not what is expected (visually) we should say:

-

-\startbuffer[setup]

-\Umathordrelspacing\scriptstyle=30mu

-\Umathordordspacing\scriptstyle=30mu

-\Umathordrelspacing\crampedscriptstyle=30mu

-\Umathordordspacing\crampedscriptstyle=30mu

-\stopbuffer

-

-\typebuffer[setup]

-

-Now we get:

-

-\start\getbuffer[setup,demo]\stop

-

-\stopsection

-

-\startsection[title={Math parameter settings}]

-

-\subsection {Many new \lpr {Umath*} primitives}

-

-\topicindex {math+parameters}

-

-In \LUATEX, the font dimension parameters that \TEX\ used in math typesetting are

-now accessible via primitive commands. In fact, refactoring of the math engine

-has resulted in many more parameters than were not accessible before.

-

-\starttabulate

-\DB primitive name                   \BC description \NC \NR

-\TB

-\NC \lpr {Umathquad}               \NC the width of 18 mu's \NC \NR

-\NC \lpr {Umathaxis}               \NC height of the vertical center axis of

-                                         the math formula above the baseline \NC \NR

-\NC \lpr {Umathoperatorsize}       \NC minimum size of large operators in display mode \NC \NR

-\NC \lpr {Umathoverbarkern}        \NC vertical clearance above the rule \NC \NR

-\NC \lpr {Umathoverbarrule}        \NC the width of the rule \NC \NR

-\NC \lpr {Umathoverbarvgap}        \NC vertical clearance below the rule \NC \NR

-\NC \lpr {Umathunderbarkern}       \NC vertical clearance below the rule \NC \NR

-\NC \lpr {Umathunderbarrule}       \NC the width of the rule \NC \NR

-\NC \lpr {Umathunderbarvgap}       \NC vertical clearance above the rule \NC \NR

-\NC \lpr {Umathradicalkern}        \NC vertical clearance above the rule \NC \NR

-\NC \lpr {Umathradicalrule}        \NC the width of the rule \NC \NR

-\NC \lpr {Umathradicalvgap}        \NC vertical clearance below the rule \NC \NR

-\NC \lpr {Umathradicaldegreebefore}\NC the forward kern that takes place before placement of

-                                       the radical degree \NC \NR

-\NC \lpr {Umathradicaldegreeafter} \NC the backward kern that takes place after placement of

-                                       the radical degree \NC \NR

-\NC \lpr {Umathradicaldegreeraise} \NC this is the percentage of the total height and depth of

-                                       the radical sign that the degree is raised by; it is

-                                       expressed in \type {percents}, so 60\% is expressed as the

-                                       integer $60$ \NC \NR

-\NC \lpr {Umathstackvgap}          \NC vertical clearance between the two

-                                       elements in a \prm {atop} stack \NC \NR

-\NC \lpr {Umathstacknumup}         \NC numerator shift upward in \prm {atop} stack \NC \NR

-\NC \lpr {Umathstackdenomdown}     \NC denominator shift downward in \prm {atop} stack \NC \NR

-\NC \lpr {Umathfractionrule}       \NC the width of the rule in a \prm {over} \NC \NR

-\NC \lpr {Umathfractionnumvgap}    \NC vertical clearance between the numerator and the rule \NC \NR

-\NC \lpr {Umathfractionnumup}      \NC numerator shift upward in \prm {over} \NC \NR

-\NC \lpr {Umathfractiondenomvgap}  \NC vertical clearance between the denominator and the rule \NC \NR

-\NC \lpr {Umathfractiondenomdown}  \NC denominator shift downward in \prm {over} \NC \NR

-\NC \lpr {Umathfractiondelsize}    \NC minimum delimiter size for \type {\...withdelims} \NC \NR

-\NC \lpr {Umathlimitabovevgap}     \NC vertical clearance for limits above operators \NC \NR

-\NC \lpr {Umathlimitabovebgap}     \NC vertical baseline clearance for limits above operators \NC \NR

-\NC \lpr {Umathlimitabovekern}     \NC space reserved at the top of the limit \NC \NR

-\NC \lpr {Umathlimitbelowvgap}     \NC vertical clearance for limits below operators \NC \NR

-\NC \lpr {Umathlimitbelowbgap}     \NC vertical baseline clearance for limits below operators \NC \NR

-\NC \lpr {Umathlimitbelowkern}     \NC space reserved at the bottom of the limit \NC \NR

-\NC \lpr {Umathoverdelimitervgap}  \NC vertical clearance for limits above delimiters \NC \NR

-\NC \lpr {Umathoverdelimiterbgap}  \NC vertical baseline clearance for limits above delimiters \NC \NR

-\NC \lpr {Umathunderdelimitervgap} \NC vertical clearance for limits below delimiters \NC \NR

-\NC \lpr {Umathunderdelimiterbgap} \NC vertical baseline clearance for limits below delimiters \NC \NR

-\NC \lpr {Umathsubshiftdrop}       \NC subscript drop for boxes and subformulas \NC \NR

-\NC \lpr {Umathsubshiftdown}       \NC subscript drop for characters \NC \NR

-\NC \lpr {Umathsupshiftdrop}       \NC superscript drop (raise, actually) for boxes and subformulas \NC \NR

-\NC \lpr {Umathsupshiftup}         \NC superscript raise for characters \NC \NR

-\NC \lpr {Umathsubsupshiftdown}    \NC subscript drop in the presence of a superscript \NC \NR

-\NC \lpr {Umathsubtopmax}          \NC the top of standalone subscripts cannot be higher than this

-                                       above the baseline \NC \NR

-\NC \lpr {Umathsupbottommin}       \NC the bottom of standalone superscripts cannot be less than

-                                       this above the baseline \NC \NR

-\NC \lpr {Umathsupsubbottommax}    \NC the bottom of the superscript of a combined super- and subscript

-                                       be at least as high as this above the baseline \NC \NR

-\NC \lpr {Umathsubsupvgap}         \NC vertical clearance between super- and subscript \NC \NR

-\NC \lpr {Umathspaceafterscript}   \NC additional space added after a super- or subscript \NC \NR

-\NC \lpr {Umathconnectoroverlapmin}\NC minimum overlap between parts in an extensible recipe \NC \NR

-\LL

-\stoptabulate

-

-Each of the parameters in this section can be set by a command like this:

-

-\starttyping

-\Umathquad\displaystyle=1em

-\stoptyping

-

-they obey grouping, and you can use \type {\the\Umathquad\displaystyle} if

-needed.

-

-\subsection{Font|-|based math parameters}

-

-\topicindex {math+parameters}

-

-While it is nice to have these math parameters available for tweaking, it would

-be tedious to have to set each of them by hand. For this reason, \LUATEX\

-initializes a bunch of these parameters whenever you assign a font identifier to

-a math family based on either the traditional math font dimensions in the font

-(for assignments to math family~2 and~3 using \TFM|-|based fonts like \type

-{cmsy} and \type {cmex}), or based on the named values in a potential \type

-{MathConstants} table when the font is loaded via Lua. If there is a \type

-{MathConstants} table, this takes precedence over font dimensions, and in that

-case no attention is paid to which family is being assigned to: the \type

-{MathConstants} tables in the last assigned family sets all parameters.

-

-In the table below, the one|-|letter style abbreviations and symbolic tfm font

-dimension names match those used in the \TeX book. Assignments to \prm

-{textfont} set the values for the cramped and uncramped display and text styles,

-\prm {scriptfont} sets the script styles, and \prm {scriptscriptfont} sets the

-scriptscript styles, so we have eight parameters for three font sizes. In the

-\TFM\ case, assignments only happen in family~2 and family~3 (and of course only

-for the parameters for which there are font dimensions).

-

-Besides the parameters below, \LUATEX\ also looks at the \quote {space} font

-dimension parameter. For math fonts, this should be set to zero.

-

-\def\MathLine#1#2#3#4#5%

-  {\TB

-   \NC \llap{\high{\tx #2\enspace}}\ttbf \string #1 \NC \tt #5 \NC \NR

-   \NC \tx #3 \NC \tt #4 \NC \NR}

-

-\starttabulate[|l|l|]

-\DB variable / style \BC tfm / opentype \NC \NR

-\MathLine{\Umathaxis}               {}   {}                     {AxisHeight}                              {axis_height}

-\MathLine{\Umathoperatorsize}       {6}  {D, D'}                {DisplayOperatorMinHeight}                {\emdash}

-\MathLine{\Umathfractiondelsize}    {9}  {D, D'}                {FractionDelimiterDisplayStyleSize}       {delim1}

-\MathLine{\Umathfractiondelsize}    {9}  {T, T', S, S', SS, SS'}{FractionDelimiterSize}                   {delim2}

-\MathLine{\Umathfractiondenomdown}  {}   {D, D'}                {FractionDenominatorDisplayStyleShiftDown}{denom1}

-\MathLine{\Umathfractiondenomdown}  {}   {T, T', S, S', SS, SS'}{FractionDenominatorShiftDown}            {denom2}

-\MathLine{\Umathfractiondenomvgap}  {}   {D, D'}                {FractionDenominatorDisplayStyleGapMin}   {3*default_rule_thickness}

-\MathLine{\Umathfractiondenomvgap}  {}   {T, T', S, S', SS, SS'}{FractionDenominatorGapMin}               {default_rule_thickness}

-\MathLine{\Umathfractionnumup}      {}   {D, D'}                {FractionNumeratorDisplayStyleShiftUp}    {num1}

-\MathLine{\Umathfractionnumup}      {}   {T, T', S, S', SS, SS'}{FractionNumeratorShiftUp}                {num2}

-\MathLine{\Umathfractionnumvgap}    {}   {D, D'}                {FractionNumeratorDisplayStyleGapMin}     {3*default_rule_thickness}

-\MathLine{\Umathfractionnumvgap}    {}   {T, T', S, S', SS, SS'}{FractionNumeratorGapMin}                 {default_rule_thickness}

-\MathLine{\Umathfractionrule}       {}   {}                     {FractionRuleThickness}                   {default_rule_thickness}

-\MathLine{\Umathskewedfractionhgap} {}   {}                     {SkewedFractionHorizontalGap}             {math_quad/2}

-\MathLine{\Umathskewedfractionvgap} {}   {}                     {SkewedFractionVerticalGap}               {math_x_height}

-\MathLine{\Umathlimitabovebgap}     {}   {}                     {UpperLimitBaselineRiseMin}               {big_op_spacing3}

-\MathLine{\Umathlimitabovekern}     {1}  {}                     {0}                                       {big_op_spacing5}

-\MathLine{\Umathlimitabovevgap}     {}   {}                     {UpperLimitGapMin}                        {big_op_spacing1}

-\MathLine{\Umathlimitbelowbgap}     {}   {}                     {LowerLimitBaselineDropMin}               {big_op_spacing4}

-\MathLine{\Umathlimitbelowkern}     {1}  {}                     {0}                                       {big_op_spacing5}

-\MathLine{\Umathlimitbelowvgap}     {}   {}                     {LowerLimitGapMin}                        {big_op_spacing2}

-\MathLine{\Umathoverdelimitervgap}  {}   {}                     {StretchStackGapBelowMin}                 {big_op_spacing1}

-\MathLine{\Umathoverdelimiterbgap}  {}   {}                     {StretchStackTopShiftUp}                  {big_op_spacing3}

-\MathLine{\Umathunderdelimitervgap} {}   {}                     {StretchStackGapAboveMin}                 {big_op_spacing2}

-\MathLine{\Umathunderdelimiterbgap} {}   {}                     {StretchStackBottomShiftDown}             {big_op_spacing4}

-\MathLine{\Umathoverbarkern}        {}   {}                     {OverbarExtraAscender}                    {default_rule_thickness}

-\MathLine{\Umathoverbarrule}        {}   {}                     {OverbarRuleThickness}                    {default_rule_thickness}

-\MathLine{\Umathoverbarvgap}        {}   {}                     {OverbarVerticalGap}                      {3*default_rule_thickness}

-\MathLine{\Umathquad}               {1}  {}                     {<font_size(f)>}                          {math_quad}

-\MathLine{\Umathradicalkern}        {}   {}                     {RadicalExtraAscender}                    {default_rule_thickness}

-\MathLine{\Umathradicalrule}        {2}  {}                     {RadicalRuleThickness}                    {<not set>}

-\MathLine{\Umathradicalvgap}        {3}  {D, D'}                {RadicalDisplayStyleVerticalGap}          {default_rule_thickness+abs(math_x_height)/4}

-\MathLine{\Umathradicalvgap}        {3}  {T, T', S, S', SS, SS'}{RadicalVerticalGap}                      {default_rule_thickness+abs(default_rule_thickness)/4}

-\MathLine{\Umathradicaldegreebefore}{2}  {}                     {RadicalKernBeforeDegree}                 {<not set>}

-\MathLine{\Umathradicaldegreeafter} {2}  {}                     {RadicalKernAfterDegree}                  {<not set>}

-\MathLine{\Umathradicaldegreeraise} {2,7}{}                     {RadicalDegreeBottomRaisePercent}         {<not set>}

-\MathLine{\Umathspaceafterscript}   {4}  {}                     {SpaceAfterScript}                        {script_space}

-\MathLine{\Umathstackdenomdown}     {}   {D, D'}                {StackBottomDisplayStyleShiftDown}        {denom1}

-\MathLine{\Umathstackdenomdown}     {}   {T, T', S, S', SS, SS'}{StackBottomShiftDown}                    {denom2}

-\MathLine{\Umathstacknumup}         {}   {D, D'}                {StackTopDisplayStyleShiftUp}             {num1}

-\MathLine{\Umathstacknumup}         {}   {T, T', S, S', SS, SS'}{StackTopShiftUp}                         {num3}

-\MathLine{\Umathstackvgap}          {}   {D, D'}                {StackDisplayStyleGapMin}                 {7*default_rule_thickness}

-\MathLine{\Umathstackvgap}          {}   {T, T', S, S', SS, SS'}{StackGapMin}                             {3*default_rule_thickness}

-\MathLine{\Umathsubshiftdown}       {}   {}                     {SubscriptShiftDown}                      {sub1}

-\MathLine{\Umathsubshiftdrop}       {}   {}                     {SubscriptBaselineDropMin}                {sub_drop}

-\MathLine{\Umathsubsupshiftdown}    {8}  {}                     {SubscriptShiftDownWithSuperscript}       {\emdash}

-\MathLine{\Umathsubtopmax}          {}   {}                     {SubscriptTopMax}                         {abs(math_x_height*4)/5}

-\MathLine{\Umathsubsupvgap}         {}   {}                     {SubSuperscriptGapMin}                    {4*default_rule_thickness}

-\MathLine{\Umathsupbottommin}       {}   {}                     {SuperscriptBottomMin}                    {abs(math_x_height/4)}

-\MathLine{\Umathsupshiftdrop}       {}   {}                     {SuperscriptBaselineDropMax}              {sup_drop}

-\MathLine{\Umathsupshiftup}         {}   {D}                    {SuperscriptShiftUp}                      {sup1}

-\MathLine{\Umathsupshiftup}         {}   {T, S, SS,}            {SuperscriptShiftUp}                      {sup2}

-\MathLine{\Umathsupshiftup}         {}   {D', T', S', SS'}      {SuperscriptShiftUpCramped}               {sup3}

-\MathLine{\Umathsupsubbottommax}    {}   {}                     {SuperscriptBottomMaxWithSubscript}       {abs(math_x_height*4)/5}

-\MathLine{\Umathunderbarkern}       {}   {}                     {UnderbarExtraDescender}                  {default_rule_thickness}

-\MathLine{\Umathunderbarrule}       {}   {}                     {UnderbarRuleThickness}                   {default_rule_thickness}

-\MathLine{\Umathunderbarvgap}       {}   {}                     {UnderbarVerticalGap}                     {3*default_rule_thickness}

-\MathLine{\Umathconnectoroverlapmin}{5}  {}                     {MinConnectorOverlap}                     {0}

-\LL

-\stoptabulate

-

-Note 1: \OPENTYPE\ fonts set \lpr {Umathlimitabovekern} and \lpr

-{Umathlimitbelowkern} to zero and set \lpr {Umathquad} to the font size of the

-used font, because these are not supported in the \type {MATH} table,

-

-Note 2: Traditional \TFM\ fonts do not set \lpr {Umathradicalrule} because

-\TEX82\ uses the height of the radical instead. When this parameter is indeed not

-set when \LUATEX\ has to typeset a radical, a backward compatibility mode will

-kick in that assumes that an oldstyle \TEX\ font is used. Also, they do not set

-\lpr {Umathradicaldegreebefore}, \lpr {Umathradicaldegreeafter}, and \lpr

-{Umathradicaldegreeraise}. These are then automatically initialized to

-$5/18$quad, $-10/18$quad, and 60.

-

-Note 3: If \TFM\ fonts are used, then the \lpr {Umathradicalvgap} is not set

-until the first time \LUATEX\ has to typeset a formula because this needs

-parameters from both family~2 and family~3. This provides a partial backward

-compatibility with \TEX82, but that compatibility is only partial: once the \lpr

-{Umathradicalvgap} is set, it will not be recalculated any more.

-

-Note 4: When \TFM\ fonts are used a similar situation arises with respect to \lpr

-{Umathspaceafterscript}: it is not set until the first time \LUATEX\ has to

-typeset a formula. This provides some backward compatibility with \TEX82. But

-once the \lpr {Umathspaceafterscript} is set, \prm {scriptspace} will never be

-looked at again.

-

-Note 5: Traditional \TFM\ fonts set \lpr {Umathconnectoroverlapmin} to zero

-because \TEX82\ always stacks extensibles without any overlap.

-

-Note 6: The \lpr {Umathoperatorsize} is only used in \prm {displaystyle}, and is

-only set in \OPENTYPE\ fonts. In \TFM\ font mode, it is artificially set to one

-scaled point more than the initial attempt's size, so that always the \quote

-{first next} will be tried, just like in \TEX82.

-

-Note 7: The \lpr {Umathradicaldegreeraise} is a special case because it is the

-only parameter that is expressed in a percentage instead of a number of scaled

-points.

-

-Note 8: \type {SubscriptShiftDownWithSuperscript} does not actually exist in the

-\quote {standard} \OPENTYPE\ math font Cambria, but it is useful enough to be

-added.

-

-Note 9: \type {FractionDelimiterDisplayStyleSize} and \type

-{FractionDelimiterSize} do not actually exist in the \quote {standard} \OPENTYPE\

-math font Cambria, but were useful enough to be added.

-

-\stopsection

-

-\startsection[title={Math spacing}]

-

-\subsection{Inline surrounding space}

-

-\topicindex {math+spacing}

-

-Inline math is surrounded by (optional) \prm {mathsurround} spacing but that is a fixed

-dimension. There is now an additional parameter \lpr {mathsurroundskip}. When set to a

-non|-|zero value (or zero with some stretch or shrink) this parameter will replace

-\prm {mathsurround}. By using an additional parameter instead of changing the nature

-of \prm {mathsurround}, we can remain compatible. In the meantime a bit more

-control has been added via \lpr {mathsurroundmode}. This directive can take 6 values

-with zero being the default behaviour.

-

-\start

-

-\def\OneLiner#1#2%

-  {\NC \type{#1}

-   \NC \dontleavehmode\inframed[align=normal,offset=0pt,frame=off]{\mathsurroundmode#1\relax\hsize 100pt   x$x$x}

-   \NC \dontleavehmode\inframed[align=normal,offset=0pt,frame=off]{\mathsurroundmode#1\relax\hsize 100pt x $x$ x}

-   \NC #2

-   \NC \NR}

-

-\startbuffer

-\mathsurround    10pt

-\mathsurroundskip20pt

-\stopbuffer

-

-\typebuffer \getbuffer

-

-\starttabulate[|c|c|c|pl|]

-\DB mode \BC x\$x\$x \BC x \$x\$ x \BC effect \NC \NR

-\TB

-\OneLiner{0}{obey \prm {mathsurround} when \lpr {mathsurroundskip} is 0pt}

-\OneLiner{1}{only add skip to the left}

-\OneLiner{2}{only add skip to the right}

-\OneLiner{3}{add skip to the left and right}

-\OneLiner{4}{ignore the skip setting, obey \prm {mathsurround}}

-\OneLiner{5}{disable all spacing around math}

-\OneLiner{6}{only apply \lpr {mathsurroundskip} when also spacing}

-\OneLiner{7}{only apply \lpr {mathsurroundskip} when no spacing}

-\LL

-\stoptabulate

-

-\stop

-

-Method six omits the surround glue when there is (x)spacing glue present while

-method seven does the opposite, the glue is only applied when there is (x)space

-glue present too. Anything more fancy, like checking the begining or end of a

-paragraph (or edges of a box) would not be robust anyway. If you want that you

-can write a callback that runs over a list and analyzes a paragraph. Actually, in

-that case you could also inject glue (or set the properties of a math node)

-explicitly. So, these modes are in practice mostly useful for special purposes

-and experiments (they originate in a tracker item). Keep in mind that this glue

-is part of the math node and not always treated as normal glue: it travels with

-the begin and end math nodes. Also, method 6 and 7 will zero the skip related

-fields in a node when applicable in the first occasion that checks them

-(linebreaking or packaging).

-

-\subsection{Pairwise spacing}

-

-\topicindex {math+spacing}

-

-Besides the parameters mentioned in the previous sections, there are also 64 new

-primitives to control the math spacing table (as explained in Chapter~18 of the

-\TEX book). The primitive names are a simple matter of combining two math atom

-types, but for completeness' sake, here is the whole list:

-

-\starttwocolumns

-\startlines

-\lpr {Umathordordspacing}

-\lpr {Umathordopspacing}

-\lpr {Umathordbinspacing}

-\lpr {Umathordrelspacing}

-\lpr {Umathordopenspacing}

-\lpr {Umathordclosespacing}

-\lpr {Umathordpunctspacing}

-\lpr {Umathordinnerspacing}

-\lpr {Umathopordspacing}

-\lpr {Umathopopspacing}

-\lpr {Umathopbinspacing}

-\lpr {Umathoprelspacing}

-\lpr {Umathopopenspacing}

-\lpr {Umathopclosespacing}

-\lpr {Umathoppunctspacing}

-\lpr {Umathopinnerspacing}

-\lpr {Umathbinordspacing}

-\lpr {Umathbinopspacing}

-\lpr {Umathbinbinspacing}

-\lpr {Umathbinrelspacing}

-\lpr {Umathbinopenspacing}

-\lpr {Umathbinclosespacing}

-\lpr {Umathbinpunctspacing}

-\lpr {Umathbininnerspacing}

-\lpr {Umathrelordspacing}

-\lpr {Umathrelopspacing}

-\lpr {Umathrelbinspacing}

-\lpr {Umathrelrelspacing}

-\lpr {Umathrelopenspacing}

-\lpr {Umathrelclosespacing}

-\lpr {Umathrelpunctspacing}

-\lpr {Umathrelinnerspacing}

-\lpr {Umathopenordspacing}

-\lpr {Umathopenopspacing}

-\lpr {Umathopenbinspacing}

-\lpr {Umathopenrelspacing}

-\lpr {Umathopenopenspacing}

-\lpr {Umathopenclosespacing}

-\lpr {Umathopenpunctspacing}

-\lpr {Umathopeninnerspacing}

-\lpr {Umathcloseordspacing}

-\lpr {Umathcloseopspacing}

-\lpr {Umathclosebinspacing}

-\lpr {Umathcloserelspacing}

-\lpr {Umathcloseopenspacing}

-\lpr {Umathcloseclosespacing}

-\lpr {Umathclosepunctspacing}

-\lpr {Umathcloseinnerspacing}

-\lpr {Umathpunctordspacing}

-\lpr {Umathpunctopspacing}

-\lpr {Umathpunctbinspacing}

-\lpr {Umathpunctrelspacing}

-\lpr {Umathpunctopenspacing}

-\lpr {Umathpunctclosespacing}

-\lpr {Umathpunctpunctspacing}

-\lpr {Umathpunctinnerspacing}

-\lpr {Umathinnerordspacing}

-\lpr {Umathinneropspacing}

-\lpr {Umathinnerbinspacing}

-\lpr {Umathinnerrelspacing}

-\lpr {Umathinneropenspacing}

-\lpr {Umathinnerclosespacing}

-\lpr {Umathinnerpunctspacing}

-\lpr {Umathinnerinnerspacing}

-\stoplines

-\stoptwocolumns

-

-These parameters are of type \prm {muskip}, so setting a parameter can be done

-like this:

-

-\starttyping

-\Umathopordspacing\displaystyle=4mu plus 2mu

-\stoptyping

-

-They are all initialized by \type {initex} to the values mentioned in the table

-in Chapter~18 of the \TEX book.

-

-Note 1: for ease of use as well as for backward compatibility, \prm {thinmuskip},

-\prm {medmuskip} and \prm {thickmuskip} are treated specially. In their case a

-pointer to the corresponding internal parameter is saved, not the actual \prm

-{muskip} value. This means that any later changes to one of these three

-parameters will be taken into account.

-

-Note 2: Careful readers will realise that there are also primitives for the items

-marked \type {*} in the \TEX book. These will not actually be used as those

-combinations of atoms cannot actually happen, but it seemed better not to break

-orthogonality. They are initialized to zero.

-

-\subsection{Skips around display math}

-

-\topicindex {math+spacing}

-

-The injection of \prm {abovedisplayskip} and \prm {belowdisplayskip} is not

-symmetrical. An above one is always inserted, also when zero, but the below is

-only inserted when larger than zero. Especially the latter makes it sometimes hard

-to fully control spacing. Therefore \LUATEX\ comes with a new directive: \lpr

-{mathdisplayskipmode}. The following values apply:

-

-\starttabulate[|c|l|]

-\DB value  \BC meaning \NC \NR

-\TB

-\NC 0 \NC normal \TEX\ behaviour \NC \NR

-\NC 1 \NC always (same as 0) \NC \NR

-\NC 2 \NC only when not zero \NC \NR

-\NC 3 \NC never, not even when not zero \NC \NR

-\LL

-\stoptabulate

-

-\subsection {Nolimit correction}

-

-\topicindex {math+limits}

-

-There are two extra math parameters \lpr {Umathnolimitsupfactor} and \lpr

-{Umathnolimitsubfactor} that were added to provide some control over how limits

-are spaced (for example the position of super and subscripts after integral

-operators). They relate to an extra parameter \lpr {mathnolimitsmode}. The half

-corrections are what happens when scripts are placed above and below. The

-problem with italic corrections is that officially that correction italic is used

-for above|/|below placement while advanced kerns are used for placement at the

-right end. The question is: how often is this implemented, and if so, do the

-kerns assume correction too. Anyway, with this parameter one can control it.

-

-\starttabulate[|l|ck1|ck1|ck1|ck1|ck1|ck1|]

-    \NC

-        \NC \mathnolimitsmode0    $\displaystyle\int\nolimits^0_1$

-        \NC \mathnolimitsmode1    $\displaystyle\int\nolimits^0_1$

-        \NC \mathnolimitsmode2    $\displaystyle\int\nolimits^0_1$

-        \NC \mathnolimitsmode3    $\displaystyle\int\nolimits^0_1$

-        \NC \mathnolimitsmode4    $\displaystyle\int\nolimits^0_1$

-        \NC \mathnolimitsmode8000 $\displaystyle\int\nolimits^0_1$

-    \NC \NR

-    \TB

-    \BC mode

-        \NC \tttf 0

-        \NC \tttf 1

-        \NC \tttf 2

-        \NC \tttf 3

-        \NC \tttf 4

-        \NC \tttf 8000

-    \NC \NR

-    \BC superscript

-        \NC 0

-        \NC font

-        \NC 0

-        \NC 0

-        \NC +ic/2

-        \NC 0

-    \NC \NR

-    \BC subscript

-        \NC -ic

-        \NC font

-        \NC 0

-        \NC -ic/2

-        \NC -ic/2

-        \NC 8000ic/1000

-    \NC \NR

-\stoptabulate

-

-When the mode is set to one, the math parameters are used. This way a macro

-package writer can decide what looks best. Given the current state of fonts in

-\CONTEXT\ we currently use mode 1 with factor 0 for the superscript and 750 for

-the subscripts. Positive values are used for both parameters but the subscript

-shifts to the left. A \lpr {mathnolimitsmode} larger that 15 is considered to

-be a factor for the subscript correction. This feature can be handy when

-experimenting.

-

-\subsection {Math italic mess}

-

-\topicindex {math+italics}

-

-The \lpr {mathitalicsmode} parameter can be set to~1 to force italic correction

-before noads that represent some more complex structure (read: everything

-that is not an ord, bin, rel, open, close, punct or inner). We show a Cambria

-example.

-

-\starttexdefinition Whatever #1

-    \NC \type{\mathitalicsmode = #1}

-    \NC \mathitalicsmode#1\ruledhbox{$\left|T^1\right|$}

-    \NC \mathitalicsmode#1\ruledhbox{$\left|T\right|$}

-    \NC \mathitalicsmode#1\ruledhbox{$T+1$}

-    \NC \mathitalicsmode#1\ruledhbox{$T{1\over2}$}

-    \NC \mathitalicsmode#1\ruledhbox{$T\sqrt{1}$}

-    \NC \NR

-\stoptexdefinition

-

-\start

-    \switchtobodyfont[cambria]

-    \starttabulate[|c|c|c|c|c|c|]

-        \Whatever{0}%

-        \Whatever{1}%

-    \stoptabulate

-\stop

-

-This kind of parameters relate to the fact that italic correction in \OPENTYPE\

-math is bound to fuzzy rules. So, control is the solution.

-

-\subsection {Script and kerning}

-

-\topicindex {math+kerning}

-\topicindex {math+scripts}

-

-If you want to typeset text in math macro packages often provide something \type

-{\text} which obeys the script sizes. As the definition can be anything there is

-a good chance that the kerning doesn't come out well when used in a script. Given

-that the first glyph ends up in a \prm {hbox} we have some control over this.

-And, as a bonus we also added control over the normal sublist kerning. The \lpr

-{mathscriptboxmode} parameter defaults to~1.

-

-\starttabulate[|c|l|]

-\DB value     \BC meaning \NC \NR

-\TB

-\NC \type {0} \NC forget about kerning \NC \NR

-\NC \type {1} \NC kern math sub lists with a valid glyph \NC \NR

-\NC \type {2} \NC also kern math sub boxes that have a valid glyph \NC \NR

-\NC \type {2} \NC only kern math sub boxes with a boundary node present\NC \NR

-\LL

-\stoptabulate

-

-Here we show some examples. Of course this doesn't solve all our problems, if

-only because some fonts have characters with bounding boxes that compensate for

-italics, while other fonts can lack kerns.

-

-\startbuffer[1]

-    $T_{\tf fluff}$

-\stopbuffer

-

-\startbuffer[2]

-    $T_{\text{fluff}}$

-\stopbuffer

-

-\startbuffer[3]

-    $T_{\text{\boundary1 fluff}}$

-\stopbuffer

-

-\unexpanded\def\Show#1#2#3%

-  {\doifelsenothing{#3}

-     {\small\tx\typeinlinebuffer[#1]}

-     {\doifelse{#3}{-}

-        {\small\bf\tt mode #2}

-        {\switchtobodyfont[#3]\showfontkerns\showglyphs\mathscriptboxmode#2\relax\inlinebuffer[#1]}}}

-

-\starttabulate[|lBT|c|c|c|c|c|]

-    \NC          \NC \Show{1}{0}{}         \NC\Show{1}{1}{}         \NC \Show{2}{1}{}         \NC \Show{2}{2}{}         \NC \Show{3}{3}{}         \NC \NR

-    \NC          \NC \Show{1}{0}{-}        \NC\Show{1}{1}{-}        \NC \Show{2}{1}{-}        \NC \Show{2}{2}{-}        \NC \Show{3}{3}{-}        \NC \NR

-    \NC modern   \NC \Show{1}{0}{modern}   \NC\Show{1}{1}{modern}   \NC \Show{2}{1}{modern}   \NC \Show{2}{2}{modern}   \NC \Show{3}{3}{modern}   \NC \NR

-    \NC lucidaot \NC \Show{1}{0}{lucidaot} \NC\Show{1}{1}{lucidaot} \NC \Show{2}{1}{lucidaot} \NC \Show{2}{2}{lucidaot} \NC \Show{3}{3}{lucidaot} \NC \NR

-    \NC pagella  \NC \Show{1}{0}{pagella}  \NC\Show{1}{1}{pagella}  \NC \Show{2}{1}{pagella}  \NC \Show{2}{2}{pagella}  \NC \Show{3}{3}{pagella}  \NC \NR

-    \NC cambria  \NC \Show{1}{0}{cambria}  \NC\Show{1}{1}{cambria}  \NC \Show{2}{1}{cambria}  \NC \Show{2}{2}{cambria}  \NC \Show{3}{3}{cambria}  \NC \NR

-    \NC dejavu   \NC \Show{1}{0}{dejavu}   \NC\Show{1}{1}{dejavu}   \NC \Show{2}{1}{dejavu}   \NC \Show{2}{2}{dejavu}   \NC \Show{3}{3}{dejavu}   \NC \NR

-\stoptabulate

-

-Kerning between a character subscript is controlled by \lpr {mathscriptcharmode}

-which also defaults to~1.

-

-Here is another example. Internally we tag kerns as italic kerns or font kerns

-where font kerns result from the staircase kern tables. In 2018 fonts like Latin

-Modern and Pagella rely on cheats with the boundingbox, Cambria uses staircase

-kerns and Lucida a mixture. Depending on how fonts evolve we might add some more

-control over what one can turn on and off.

-

-\def\MathSample#1#2#3%

-  {\NC

-   #1 \NC

-   #2 \NC

-   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3T_{f}$         \NC

-   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3\gamma_{e}$    \NC

-   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3\gamma_{ee}$   \NC

-   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3T_{\tf fluff}$ \NC

-   \NR}

-

-\starttabulate[|Tl|Tl|l|l|l|l|]

-    \FL

-    \MathSample{normal}{modern}  {\mr}

-    \MathSample{}      {pagella} {\mr}

-    \MathSample{}      {cambria} {\mr}

-    \MathSample{}      {lucidaot}{\mr}

-    \ML

-    \MathSample{bold}  {modern}  {\mb}

-    \MathSample{}      {pagella} {\mb}

-    \MathSample{}      {cambria} {\mb}

-    \MathSample{}      {lucidaot}{\mb}

-    \LL

-\stoptabulate

-

-\subsection{Fixed scripts}

-

-We have three parameters that are used for this fixed anchoring:

-

-\starttabulate[|c|l|]

-\DB parameter \BC register \NC \NR

-\NC $d$ \NC \lpr {Umathsubshiftdown}    \NC \NR

-\NC $u$ \NC \lpr {Umathsupshiftup}      \NC \NR

-\NC $s$ \NC \lpr {Umathsubsupshiftdown} \NC \NR

-\LL

-\stoptabulate

-

-When we set \lpr {mathscriptsmode} to a value other than zero these are used

-for calculating fixed positions. This is something that is needed for instance

-for chemistry. You can manipulate the mentioned variables to achieve different

-effects.

-

-\def\SampleMath#1%

-  {$\mathscriptsmode#1\mathupright CH_2 + CH^+_2 + CH^2_2$}

-

-\starttabulate[|c|c|c|p|]

-\DB mode \BC down          \BC up            \BC example        \NC \NR

-\TB

-\NC 0    \NC dynamic       \NC dynamic       \NC \SampleMath{0} \NC \NR

-\NC 1    \NC $d$           \NC $u$           \NC \SampleMath{1} \NC \NR

-\NC 2    \NC $s$           \NC $u$           \NC \SampleMath{2} \NC \NR

-\NC 3    \NC $s$           \NC $u + s - d$   \NC \SampleMath{3} \NC \NR

-\NC 4    \NC $d + (s-d)/2$ \NC $u + (s-d)/2$ \NC \SampleMath{4} \NC \NR

-\NC 5    \NC $d$           \NC $u + s - d$   \NC \SampleMath{5} \NC \NR

-\LL

-\stoptabulate

-

-The value of this parameter obeys grouping but applies to the whole current

-formula.

-

-% if needed we can put the value in stylenodes but maybe more should go there

-

-\subsection{Penalties: \lpr {mathpenaltiesmode}}

-

-\topicindex {math+penalties}

-

-Only in inline math penalties will be added in a math list. You can force

-penalties (also in display math) by setting:

-

-\starttyping

-\mathpenaltiesmode = 1

-\stoptyping

-

-This primnitive is not really needed in \LUATEX\ because you can use the callback

-\cbk {mlist_to_hlist} to force penalties by just calling the regular routine

-with forced penalties. However, as part of opening up and control this primitive

-makes sense. As a bonus we also provide two extra penalties:

-

-\starttyping

-\prebinoppenalty = -100 % example value

-\prerelpenalty   =  900 % example value

-\stoptyping

-

-They default to inifinite which signals that they don't need to be inserted. When

-set they are injected before a binop or rel noad. This is an experimental feature.

-

-\subsection{Equation spacing: \lpr {matheqnogapstep}}

-

-By default \TEX\ will add one quad between the equation and the number. This is

-hard coded. A new primitive can control this:

-

-\startsyntax

-\matheqnogapstep = 1000

-\stopsyntax

-

-Because a math quad from the math text font is used instead of a dimension, we

-use a step to control the size. A value of zero will suppress the gap. The step

-is divided by 1000 which is the usual way to mimmick floating point factors in

-\TEX.

-

-\stopsection

-

-\startsection[title={Math constructs}]

-

-\subsection {Unscaled fences}

-

-\topicindex {math+fences}

-

-The \lpr {mathdelimitersmode} primitive is experimental and deals with the

-following (potential) problems. Three bits can be set. The first bit prevents an

-unwanted shift when the fence symbol is not scaled (a cambria side effect). The

-second bit forces italic correction between a preceding character ordinal and the

-fenced subformula, while the third bit turns that subformula into an ordinary so

-that the same spacing applies as with unfenced variants. Here we show Cambria

-(with \lpr {mathitalicsmode} enabled).

-

-\starttexdefinition Whatever #1

-    \NC \type{\mathdelimitersmode = #1}

-    \NC \mathitalicsmode1\mathdelimitersmode#1\ruledhbox{\showglyphs\showfontkerns\showfontitalics$f(x)$}

-    \NC \mathitalicsmode1\mathdelimitersmode#1\ruledhbox{\showglyphs\showfontkerns\showfontitalics$f\left(x\right)$}

-    \NC \NR

-\stoptexdefinition

-

-\start

-    \switchtobodyfont[cambria]

-    \starttabulate[|l|l|l|]

-        \Whatever{0}\Whatever{1}\Whatever{2}\Whatever{3}%

-        \Whatever{4}\Whatever{5}\Whatever{6}\Whatever{7}%

-    \stoptabulate

-\stop

-

-So, when set to 7 fenced subformulas with unscaled delimiters come out the same

-as unfenced ones. This can be handy for cases where one is forced to use \prm

-{left} and \prm {right} always because of unpredictable content. As said, it's an

-experimental feature (which somehow fits in the exceptional way fences are dealt

-with in the engine). The full list of flags is given in the next table:

-

-\starttabulate[|c|l|]

-\DB value  \BC meaning \NC \NR

-\TB

-\NC \type{"01} \NC don't apply the usual shift \NC \NR

-\NC \type{"02} \NC apply italic correction when possible \NC \NR

-\NC \type{"04} \NC force an ordinary subformula \NC \NR

-\NC \type{"08} \NC no shift when a base character \NC \NR

-\NC \type{"10} \NC only shift when an extensible \NC \NR

-\LL

-\stoptabulate

-

-The effect can depend on the font (and for Cambria one can use for instance \type {"16}).

-

-\subsection[mathacc]{Accent handling}

-

-\topicindex {math+accents}

-

-\LUATEX\ supports both top accents and bottom accents in math mode, and math

-accents stretch automatically (if this is supported by the font the accent comes

-from, of course). Bottom and combined accents as well as fixed-width math accents

-are controlled by optional keywords following \lpr {Umathaccent}.

-

-The keyword \type {bottom} after \lpr {Umathaccent} signals that a bottom accent

-is needed, and the keyword \type {both} signals that both a top and a bottom

-accent are needed (in this case two accents need to be specified, of course).

-

-Then the set of three integers defining the accent is read. This set of integers

-can be prefixed by the \type {fixed} keyword to indicate that a non-stretching

-variant is requested (in case of both accents, this step is repeated).

-

-A simple example:

-

-\starttyping

-\Umathaccent both fixed 0 0 "20D7 fixed 0 0 "20D7 {example}

-\stoptyping

-

-If a math top accent has to be placed and the accentee is a character and has a

-non-zero \type {top_accent} value, then this value will be used to place the

-accent instead of the \prm {skewchar} kern used by \TEX82.

-

-The \type {top_accent} value represents a vertical line somewhere in the

-accentee. The accent will be shifted horizontally such that its own \type

-{top_accent} line coincides with the one from the accentee. If the \type

-{top_accent} value of the accent is zero, then half the width of the accent

-followed by its italic correction is used instead.

-

-The vertical placement of a top accent depends on the \type {x_height} of the

-font of the accentee (as explained in the \TEX book), but if a value turns out

-to be zero and the font had a \type {MathConstants} table, then \type

-{AccentBaseHeight} is used instead.

-

-The vertical placement of a bottom accent is straight below the accentee, no

-correction takes place.

-

-Possible locations are \type {top}, \type {bottom}, \type {both} and \type

-{center}. When no location is given \type {top} is assumed. An additional

-parameter \nod {fraction} can be specified followed by a number; a value of for

-instance 1200 means that the criterium is 1.2 times the width of the nucleus. The

-fraction only applies to the stepwise selected shapes and is mostly meant for the

-\type {overlay} location. It also works for the other locations but then it

-concerns the width.

-

-\subsection{Radical extensions}

-

-\topicindex {math+radicals}

-

-The new primitive \lpr {Uroot} allows the construction of a radical noad

-including a degree field. Its syntax is an extension of \lpr {Uradical}:

-

-\starttyping

-\Uradical <fam integer> <char integer> <radicand>

-\Uroot    <fam integer> <char integer> <degree> <radicand>

-\stoptyping

-

-The placement of the degree is controlled by the math parameters \lpr

-{Umathradicaldegreebefore}, \lpr {Umathradicaldegreeafter}, and \lpr

-{Umathradicaldegreeraise}. The degree will be typeset in \prm

-{scriptscriptstyle}.

-

-\subsection{Super- and subscripts}

-

-The character fields in a \LUA|-|loaded \OPENTYPE\ math font can have a \quote

-{mathkern} table. The format of this table is the same as the \quote {mathkern}

-table that is returned by the \type {fontloader} library, except that all height

-and kern values have to be specified in actual scaled points.

-

-When a super- or subscript has to be placed next to a math item, \LUATEX\ checks

-whether the super- or subscript and the nucleus are both simple character items.

-If they are, and if the fonts of both character items are \OPENTYPE\ fonts (as

-opposed to legacy \TEX\ fonts), then \LUATEX\ will use the \OPENTYPE\ math

-algorithm for deciding on the horizontal placement of the super- or subscript.

-

-This works as follows:

-

-\startitemize

-    \startitem

-        The vertical position of the script is calculated.

-    \stopitem

-    \startitem

-        The default horizontal position is flat next to the base character.

-    \stopitem

-    \startitem

-        For superscripts, the italic correction of the base character is added.

-    \stopitem

-    \startitem

-        For a superscript, two vertical values are calculated: the bottom of the

-        script (after shifting up), and the top of the base. For a subscript, the two

-        values are the top of the (shifted down) script, and the bottom of the base.

-    \stopitem

-    \startitem

-        For each of these two locations:

-        \startitemize

-            \startitem

-                find the math kern value at this height for the base (for a subscript

-                placement, this is the bottom_right corner, for a superscript

-                placement the top_right corner)

-            \stopitem

-            \startitem

-                find the math kern value at this height for the script (for a

-                subscript placement, this is the top_left corner, for a superscript

-                placement the bottom_left corner)

-            \stopitem

-            \startitem

-                add the found values together to get a preliminary result.

-            \stopitem

-        \stopitemize

-    \stopitem

-    \startitem

-        The horizontal kern to be applied is the smallest of the two results from

-        previous step.

-    \stopitem

-\stopitemize

-

-The math kern value at a specific height is the kern value that is specified by the

-next higher height and kern pair, or the highest one in the character (if there is no

-value high enough in the character), or simply zero (if the character has no math kern

-pairs at all).

-

-\subsection{Scripts on extensibles}

-

-\topicindex {math+scripts}

-\topicindex {math+delimiters}

-\topicindex {math+extensibles}

-

-The primitives \lpr {Uunderdelimiter} and \lpr {Uoverdelimiter} allow the

-placement of a subscript or superscript on an automatically extensible item and

-\lpr {Udelimiterunder} and \lpr {Udelimiterover} allow the placement of an

-automatically extensible item as a subscript or superscript on a nucleus. The

-input:

-

-% these produce radical noads .. in fact the code base has the numbers wrong for

-% quite a while, so no one seems to use this

-

-\startbuffer

-$\Uoverdelimiter  0 "2194 {\hbox{\strut  overdelimiter}}$

-$\Uunderdelimiter 0 "2194 {\hbox{\strut underdelimiter}}$

-$\Udelimiterover  0 "2194 {\hbox{\strut  delimiterover}}$

-$\Udelimiterunder 0 "2194 {\hbox{\strut delimiterunder}}$

-\stopbuffer

-

-\typebuffer will render this:

-

-\blank \startnarrower \getbuffer \stopnarrower \blank

-

-The vertical placements are controlled by \lpr {Umathunderdelimiterbgap}, \lpr

-{Umathunderdelimitervgap}, \lpr {Umathoverdelimiterbgap}, and \lpr

-{Umathoverdelimitervgap} in a similar way as limit placements on large operators.

-The superscript in \lpr {Uoverdelimiter} is typeset in a suitable scripted style,

-the subscript in \lpr {Uunderdelimiter} is cramped as well.

-

-These primitives accepts an option \type {width} specification. When used the

-also optional keywords \type {left}, \type {middle} and \type {right} will

-determine what happens when a requested size can't be met (which can happen when

-we step to successive larger variants).

-

-An extra primitive \lpr {Uhextensible} is available that can be used like this:

-

-\startbuffer

-$\Uhextensible width 10cm 0 "2194$

-\stopbuffer

-

-\typebuffer This will render this:

-

-\blank \startnarrower \getbuffer \stopnarrower \blank

-

-Here you can also pass options, like:

-

-\startbuffer

-$\Uhextensible width 1pt middle 0 "2194$

-\stopbuffer

-

-\typebuffer This gives:

-

-\blank \startnarrower \getbuffer \stopnarrower \blank

-

-\LUATEX\ internally uses a structure that supports \OPENTYPE\ \quote

-{MathVariants} as well as \TFM\ \quote {extensible recipes}. In most cases where

-font metrics are involved we have a different code path for traditional fonts end

-\OPENTYPE\ fonts.

-

-\subsection{Fractions}

-

-\topicindex {math+fractions}

-

-The \prm {abovewithdelims} command accepts a keyword \type {exact}. When issued

-the extra space relative to the rule thickness is not added. One can of course

-use the \type {\Umathfraction..gap} commands to influence the spacing. Also the

-rule is still positioned around the math axis.

-

-\starttyping

-$$ { {a} \abovewithdelims() exact 4pt {b} }$$

-\stoptyping

-

-The math parameter table contains some parameters that specify a horizontal and

-vertical gap for skewed fractions. Of course some guessing is needed in order to

-implement something that uses them. And so we now provide a primitive similar to the

-other fraction related ones but with a few options so that one can influence the

-rendering. Of course a user can also mess around a bit with the parameters

-\lpr {Umathskewedfractionhgap} and \lpr {Umathskewedfractionvgap}.

-

-The syntax used here is:

-

-\starttyping

-{ {1} \Uskewed / <options> {2} }

-{ {1} \Uskewedwithdelims / () <options> {2} }

-\stoptyping

-

-where the options can be \type {noaxis} and \type {exact}. By default we add half

-the axis to the shifts and by default we zero the width of the middle character.

-For Latin Modern the result looks as follows:

-

-\def\ShowA#1#2#3{$x + { {#1} \Uskewed           /    #3 {#2} } + x$}

-\def\ShowB#1#2#3{$x + { {#1} \Uskewedwithdelims / () #3 {#2} } + x$}

-

-\start

-    \switchtobodyfont[modern]

-    \starttabulate[||||||]

-        \NC \NC

-            \ShowA{a}{b}{} \NC

-            \ShowA{1}{2}{} \NC

-            \ShowB{a}{b}{} \NC

-            \ShowB{1}{2}{} \NC

-        \NR

-        \NC \type{exact} \NC

-            \ShowA{a}{b}{exact} \NC

-            \ShowA{1}{2}{exact} \NC

-            \ShowB{a}{b}{exact} \NC

-            \ShowB{1}{2}{exact} \NC

-        \NR

-        \NC \type{noaxis} \NC

-            \ShowA{a}{b}{noaxis} \NC

-            \ShowA{1}{2}{noaxis} \NC

-            \ShowB{a}{b}{noaxis} \NC

-            \ShowB{1}{2}{noaxis} \NC

-        \NR

-        \NC \type{exact noaxis} \NC

-            \ShowA{a}{b}{exact noaxis} \NC

-            \ShowA{1}{2}{exact noaxis} \NC

-            \ShowB{a}{b}{exact noaxis} \NC

-            \ShowB{1}{2}{exact noaxis} \NC

-        \NR

-    \stoptabulate

-\stop

-

-\subsection {Delimiters: \type{\Uleft}, \prm {Umiddle} and \prm {Uright}}

-

-\topicindex {math+delimiters}

-

-Normally you will force delimiters to certain sizes by putting an empty box or

-rule next to it. The resulting delimiter will either be a character from the

-stepwise size range or an extensible. The latter can be quite differently

-positioned than the characters as it depends on the fit as well as the fact if

-the used characters in the font have depth or height. Commands like (plain \TEX

-s) \type {\big} need use this feature. In \LUATEX\ we provide a bit more control

-by three variants that support optional parameters \type {height}, \type {depth}

-and \type {axis}. The following example uses this:

-

-\startbuffer

-\Uleft   height 30pt depth 10pt      \Udelimiter "0 "0 "000028

-\quad x\quad

-\Umiddle height 40pt depth 15pt      \Udelimiter "0 "0 "002016

-\quad x\quad

-\Uright  height 30pt depth 10pt      \Udelimiter "0 "0 "000029

-\quad \quad \quad

-\Uleft   height 30pt depth 10pt axis \Udelimiter "0 "0 "000028

-\quad x\quad

-\Umiddle height 40pt depth 15pt axis \Udelimiter "0 "0 "002016

-\quad x\quad

-\Uright  height 30pt depth 10pt axis \Udelimiter "0 "0 "000029

-\stopbuffer

-

-\typebuffer

-

-\startlinecorrection

-\ruledhbox{\mathematics{\getbuffer}}

-\stoplinecorrection

-

-The keyword \type {exact} can be used as directive that the real dimensions

-should be applied when the criteria can't be met which can happen when we're

-still stepping through the successively larger variants. When no dimensions are

-given the \type {noaxis} command can be used to prevent shifting over the axis.

-

-You can influence the final class with the keyword \type {class} which will

-influence the spacing. The numbers are the same as for character classes.

-

-\stopsection

-

-\startsection[title={Extracting values}]

-

-\subsection{Codes}

-

-\topicindex {math+codes}

-

-You can extract the components of a math character. Say that we have defined:

-

-\starttyping

-\Umathcode 1 2 3 4

-\stoptyping

-

-then

-

-\starttyping

-[\Umathcharclass1] [\Umathcharfam1] [\Umathcharslot1]

-\stoptyping

-

-will return:

-

-\starttyping

-[2] [3] [4]

-\stoptyping

-

-These commands are provides as convenience. Before they come available you could

-do the following:

-

-\starttyping

-\def\Umathcharclass{\directlua{tex.print(tex.getmathcode(token.scan_int())[1])}}

-\def\Umathcharfam  {\directlua{tex.print(tex.getmathcode(token.scan_int())[2])}}

-\def\Umathcharslot {\directlua{tex.print(tex.getmathcode(token.scan_int())[3])}}

-\stoptyping

-

-\subsection {Last lines}

-

-\topicindex {math+last line}

-

-There is a new primitive to control the overshoot in the calculation of the

-previous line in mid|-|paragraph display math. The default value is 2 times

-the em width of the current font:

-

-\starttyping

-\predisplaygapfactor=2000

-\stoptyping

-

-If you want to have the length of the last line independent of math i.e.\ you don't

-want to revert to a hack where you insert a fake display math formula in order to

-get the length of the last line, the following will often work too:

-

-\starttyping

-\def\lastlinelength{\dimexpr

-    \directlua {tex.sprint (

-        (nodes.dimensions(node.tail(tex.lists.page_head).list))

-    )}sp

-\relax}

-\stoptyping

-

-\stopsection

-

-\startsection[title={Math mode}]

-

-\subsection {Verbose versions of single|-|character math commands}

-

-\topicindex {math+styles}

-

-\LUATEX\ defines six new primitives that have the same function as

-\type {^}, \type {_}, \type {$}, and \type {$$}:

-

-\starttabulate[|l|l|]

-\DB primitive                  \BC explanation \NC \NR

-\TB

-\NC \lpr {Usuperscript}      \NC duplicates the functionality of \type {^} \NC \NR

-\NC \lpr {Usubscript}        \NC duplicates the functionality of \type {_} \NC \NR

-\NC \lpr {Ustartmath}        \NC duplicates the functionality of \type {$}, % $

-                                   when used in non-math mode. \NC \NR

-\NC \lpr {Ustopmath}         \NC duplicates the functionality of \type {$}, % $

-                                   when used in inline math mode. \NC \NR

-\NC \lpr {Ustartdisplaymath} \NC duplicates the functionality of \type {$$}, % $$

-                                   when used in non-math mode. \NC \NR

-\NC \lpr {Ustopdisplaymath}  \NC duplicates the functionality of \type {$$}, % $$

-                                   when used in display math mode. \NC \NR

-\LL

-\stoptabulate

-

-The \lpr {Ustopmath} and \lpr {Ustopdisplaymath} primitives check if the current

-math mode is the correct one (inline vs.\ displayed), but you can freely intermix

-the four mathon|/|mathoff commands with explicit dollar sign(s).

-

-\subsection{Script commands \lpr {Unosuperscript} and \lpr {Unosubscript}}

-

-\topicindex {math+styles}

-\topicindex {math+scripts}

-

-These two commands result in super- and subscripts but with the current style (at the

-time of rendering). So,

-

-\startbuffer[script]

-$

-    x\Usuperscript  {1}\Usubscript  {2} =

-    x\Unosuperscript{1}\Unosubscript{2} =

-    x\Usuperscript  {1}\Unosubscript{2} =

-    x\Unosuperscript{1}\Usubscript  {2}

-$

-\stopbuffer

-

-\typebuffer

-

-results in \inlinebuffer[script].

-

-\subsection{Allowed math commands in non|-|math modes}

-

-\topicindex {math+text}

-\topicindex {text+math}

-

-The commands \prm {mathchar}, and \lpr {Umathchar} and control sequences that are

-the result of \prm {mathchardef} or \lpr {Umathchardef} are also acceptable in

-the horizontal and vertical modes. In those cases, the \prm {textfont} from the

-requested math family is used.

-

-% \startsection[title={Math todo}]

-%

-% The following items are still todo.

-%

-% \startitemize

-% \startitem

-%     Pre-scripts.

-% \stopitem

-% \startitem

-%     Multi-story stacks.

-% \stopitem

-% \startitem

-%     Flattened accents for high characters (maybe).

-% \stopitem

-% \startitem

-%     Better control over the spacing around displays and handling of equation numbers.

-% \stopitem

-% \startitem

-%     Support for multi|-|line displays using \MATHML\ style alignment points.

-% \stopitem

-% \stopitemize

-%

-% \stopsection

-

-\stopsection

-

-\startsection[title={Goodies}]

-

-\subsection {Flattening: \lpr {mathflattenmode}}

-

-\topicindex {math+flattening}

-

-The \TEX\ math engine collapses \type {ord} noads without sub- and superscripts

-and a character as nucleus. and which has the side effect that in \OPENTYPE\ mode

-italic corrections are applied (given that they are enabled).

-

-\startbuffer[sample]

-\switchtobodyfont[modern]

-$V \mathbin{\mathbin{v}} V$\par

-$V \mathord{\mathord{v}} V$\par

-\stopbuffer

-

-\typebuffer[sample]

-

-This renders as:

-

-\blank \start \mathflattenmode\plusone \getbuffer[sample] \stop \blank

-

-When we set \lpr {mathflattenmode} to 31 we get:

-

-\blank \start \mathflattenmode\numexpr1+2+4+8+16\relax \getbuffer[sample] \stop \blank

-

-When you see no difference, then the font probably has the proper character

-dimensions and no italic correction is needed. For Latin Modern (at least till

-2018) there was a visual difference. In that respect this parameter is not always

-needed unless of course you want efficient math lists anyway.

-

-You can influence flattening by adding the appropriate number to the value of the

-mode parameter. The default value is~1.

-

-\starttabulate[|Tc|c|]

-\DB mode \BC class \NC \NR

-\TB

-\NC  1   \NC ord   \NC \NR

-\NC  2   \NC bin   \NC \NR

-\NC  4   \NC rel   \NC \NR

-\NC  8   \NC punct \NC \NR

-\NC 16   \NC inner \NC \NR

-\LL

-\stoptabulate

-

-\subsection {Less Tracing}

-

-\topicindex {math+tracing}

-

-Because there are quite some math related parameters and values, it is possible

-to limit tracing. Only when \type {tracingassigns} and|/|or \type

-{tracingrestores} are set to~2 or more they will be traced.

-

-\subsection {Math options with \lpr {mathoption}}

-

-The logic in the math engine is rather complex and there are often no universal

-solutions (read: what works out well for one font, fails for another). Therefore

-some variations in the implementation are driven by parameters (modes). In

-addition there is a new primitive \lpr {mathoption} which will be used for

-testing. Don't rely on any option to be there in a production version as they are

-meant for development.

-

-This option was introduced for testing purposes when the math engine got split

-code paths and it forces the engine to treat new fonts as old ones with respect

-to italic correction etc. There are no guarantees given with respect to the final

-result and unexpected side effects are not seen as bugs as they relate to font

-properties. Ther eis currently only one option:

-

-\startbuffer

-\mathoption old 1

-\stopbuffer

-

-The \type {oldmath} boolean flag in the \LUA\ font table is the official way to

-force old treatment as it's bound to fonts. Like with all options we may

-temporarily introduce with this command this feature is not meant for production.

-

-% % obsolete:

-%

-% \subsubsection {\type {\mathoption noitaliccompensation}}

-%

-% This option compensates placement for characters with a built|-|in italic

-% correction.

-%

-% \startbuffer

-% {\showboxes\int}\quad

-% {\showboxes\int_{|}^{|}}\quad

-% {\showboxes\int\limits_{|}^{|}}

-% \stopbuffer

-%

-% \typebuffer

-%

-% Gives (with computer modern that has such italics):

-%

-% \startlinecorrection[blank]

-%     \switchtobodyfont[modern]

-%     \startcombination[nx=2,ny=2,distance=5em]

-%         {\mathoption noitaliccompensation 0\relax \mathematics{\getbuffer}}

-%             {\nohyphens\type{0:inline}}

-%         {\mathoption noitaliccompensation 0\relax \mathematics{\displaymath\getbuffer}}

-%             {\nohyphens\type{0:display}}

-%         {\mathoption noitaliccompensation 1\relax \mathematics{\getbuffer}}

-%             {\nohyphens\type{1:inline}}

-%         {\mathoption noitaliccompensation 1\relax \mathematics{\displaymath\getbuffer}}

-%             {\nohyphens\type{1:display}}

-%     \stopcombination

-% \stoplinecorrection

-

-% % obsolete:

-%

-% \subsubsection {\type {\mathoption nocharitalic}}

-%

-% When two characters follow each other italic correction can interfere. The

-% following example shows what this option does:

-%

-% \startbuffer

-% \catcode"1D443=11

-% \catcode"1D444=11

-% \catcode"1D445=11

-% P( PP PQR

-% \stopbuffer

-%

-% \typebuffer

-%

-% Gives (with computer modern that has such italics):

-%

-% \startlinecorrection[blank]

-%     \switchtobodyfont[modern]

-%     \startcombination[nx=2,ny=2,distance=5em]

-%         {\mathoption nocharitalic 0\relax \mathematics{\getbuffer}}

-%             {\nohyphens\type{0:inline}}

-%         {\mathoption nocharitalic 0\relax \mathematics{\displaymath\getbuffer}}

-%             {\nohyphens\type{0:display}}

-%         {\mathoption nocharitalic 1\relax \mathematics{\getbuffer}}

-%             {\nohyphens\type{1:inline}}

-%         {\mathoption nocharitalic 1\relax \mathematics{\displaymath\getbuffer}}

-%             {\nohyphens\type{1:display}}

-%     \stopcombination

-% \stoplinecorrection

-

-% % obsolete:

-%

-% \subsubsection {\type {\mathoption useoldfractionscaling}}

-%

-% This option has been introduced as solution for tracker item 604 for fuzzy cases

-% around either or not present fraction related settings for new fonts.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-math
+
+\startchapter[reference=math,title={Math}]
+
+\startsection[title={Traditional alongside \OPENTYPE}]
+
+\topicindex {math}
+
+The handling of mathematics in \LUATEX\ differs quite a bit from how \TEX82 (and
+therefore \PDFTEX) handles math. First, \LUATEX\ adds primitives and extends some
+others so that \UNICODE\ input can be used easily. Second, all of \TEX82's
+internal special values (for example for operator spacing) have been made
+accessible and changeable via control sequences. Third, there are extensions that
+make it easier to use \OPENTYPE\ math fonts. And finally, there are some
+extensions that have been proposed or considered in the past that are now added
+to the engine.
+
+\stopsection
+
+\startsection[title={Unicode math characters}]
+
+\topicindex {math+\UNICODE}
+\topicindex {\UNICODE+math}
+
+Character handling is now extended up to the full \UNICODE\ range (the \type {\U}
+prefix), which is compatible with \XETEX.
+
+The math primitives from \TEX\ are kept as they are, except for the ones that
+convert from input to math commands: \type {mathcode}, and \type {delcode}. These
+two now allow for a 21-bit character argument on the left hand side of the equals
+sign.
+
+Some of the new \LUATEX\ primitives read more than one separate value. This is
+shown in the tables below by a plus sign.
+
+The input for such primitives would look like this:
+
+\starttyping
+\def\overbrace{\Umathaccent 0 1 "23DE }
+\stoptyping
+
+The altered \TEX82 primitives are:
+
+\starttabulate[|l|l|r|c|l|r|]
+\DB primitive       \BC min \BC max    \BC \kern 2em \BC min \BC max    \NC \NR
+\TB
+\NC \prm {mathcode} \NC 0   \NC 10FFFF \NC =         \NC 0   \NC 8000   \NC \NR
+\NC \prm {delcode}  \NC 0   \NC 10FFFF \NC =         \NC 0   \NC FFFFFF \NC \NR
+\LL
+\stoptabulate
+
+The unaltered ones are:
+
+\starttabulate[|l|l|r|]
+\DB primitive          \BC min \BC max     \NC \NR
+\TB
+\NC \prm {mathchardef} \NC 0   \NC    8000 \NC \NR
+\NC \prm {mathchar}    \NC 0   \NC    7FFF \NC \NR
+\NC \prm {mathaccent}  \NC 0   \NC    7FFF \NC \NR
+\NC \prm {delimiter}   \NC 0   \NC 7FFFFFF \NC \NR
+\NC \prm {radical}     \NC 0   \NC 7FFFFFF \NC \NR
+\LL
+\stoptabulate
+
+For practical reasons \prm {mathchardef} will silently accept values larger
+that \type {0x8000} and interpret it as \lpr {Umathcharnumdef}. This is needed
+to satisfy older macro packages.
+
+The following new primitives are compatible with \XETEX:
+
+% somewhat fuzzy:
+
+\starttabulate[|l|l|r|c|l|r|]
+\DB primitive                             \BC min       \BC max         \BC \kern 2em \BC min       \BC max         \NC \NR
+\TB
+\NC \lpr {Umathchardef}                   \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Umathcharnumdef}\rlap{\high{5}} \NC -80000000 \NC    7FFFFFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Umathcode}                      \NC 0         \NC      10FFFF \NC =         \NC 0+0+0     \NC 7+FF+10FFFF \NC \NR
+\NC \lpr {Udelcode}                       \NC 0         \NC      10FFFF \NC =         \NC 0+0       \NC   FF+10FFFF \NC \NR
+\NC \lpr {Umathchar}                      \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Umathaccent}                    \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Udelimiter}                     \NC 0+0+0     \NC 7+FF+10FFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Uradical}                       \NC 0+0       \NC   FF+10FFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Umathcharnum}                   \NC -80000000 \NC    7FFFFFFF \NC           \NC           \NC             \NC \NR
+\NC \lpr {Umathcodenum}                   \NC 0         \NC      10FFFF \NC =         \NC -80000000 \NC    7FFFFFFF \NC \NR
+\NC \lpr {Udelcodenum}                    \NC 0         \NC      10FFFF \NC =         \NC -80000000 \NC    7FFFFFFF \NC \NR
+\LL
+\stoptabulate
+
+Specifications typically look like:
+
+\starttyping
+\Umathchardef\xx="1"0"456
+\Umathcode   123="1"0"789
+\stoptyping
+
+The new primitives that deal with delimiter|-|style objects do not set up a
+\quote {large family}. Selecting a suitable size for display purposes is expected
+to be dealt with by the font via the \lpr {Umathoperatorsize} parameter.
+
+For some of these primitives, all information is packed into a single signed
+integer. For the first two (\lpr {Umathcharnum} and \lpr {Umathcodenum}), the
+lowest 21 bits are the character code, the 3 bits above that represent the math
+class, and the family data is kept in the topmost bits. This means that the values
+for math families 128--255 are actually negative. For \lpr {Udelcodenum} there
+is no math class. The math family information is stored in the bits directly on
+top of the character code. Using these three commands is not as natural as using
+the two- and three|-|value commands, so unless you know exactly what you are
+doing and absolutely require the speedup resulting from the faster input
+scanning, it is better to use the verbose commands instead.
+
+The \lpr {Umathaccent} command accepts optional keywords to control various
+details regarding math accents. See \in {section} [mathacc] below for details.
+
+There are more new primitives and all of these will be explained in following
+sections:
+
+\starttabulate[|l|l|]
+\DB primitive                \BC value range (in hex) \NC \NR
+\TB
+\NC \lpr {Uroot}           \NC 0 + 0--FF + 10FFFF   \NC \NR
+\NC \lpr {Uoverdelimiter}  \NC 0 + 0--FF + 10FFFF   \NC \NR
+\NC \lpr {Uunderdelimiter} \NC 0 + 0--FF + 10FFFF   \NC \NR
+\NC \lpr {Udelimiterover}  \NC 0 + 0--FF + 10FFFF   \NC \NR
+\NC \lpr {Udelimiterunder} \NC 0 + 0--FF + 10FFFF   \NC \NR
+\LL
+\stoptabulate
+
+\stopsection
+
+\startsection[title={Math styles}]
+
+\subsection{\lpr {mathstyle}}
+
+\topicindex {math+styles}
+
+It is possible to discover the math style that will be used for a formula in an
+expandable fashion (while the math list is still being read). To make this
+possible, \LUATEX\ adds the new primitive: \lpr {mathstyle}. This is a \quote
+{convert command} like e.g. \prm {romannumeral}: its value can only be read,
+not set.
+
+The returned value is between 0 and 7 (in math mode), or $-1$ (all other modes).
+For easy testing, the eight math style commands have been altered so that they can
+be used as numeric values, so you can write code like this:
+
+\starttyping
+\ifnum\mathstyle=\textstyle
+    \message{normal text style}
+\else \ifnum\mathstyle=\crampedtextstyle
+    \message{cramped text style}
+\fi \fi
+\stoptyping
+
+Sometimes you won't get what you expect so a bit of explanation might help to
+understand what happens. When math is parsed and expanded it gets turned into a
+linked list. In a second pass the formula will be build. This has to do with the
+fact that in order to determine the automatically chosen sizes (in for instance
+fractions) following content can influence preceding sizes. A side effect of this
+is for instance that one cannot change the definition of a font family (and
+thereby reusing numbers) because the number that got used is stored and used in
+the second pass (so changing \type {\fam 12} mid|-|formula spoils over to
+preceding use of that family).
+
+The style switching primitives like \prm {textstyle} are turned into nodes so the
+styles set there are frozen. The \prm {mathchoice} primitive results in four
+lists being constructed of which one is used in the second pass. The fact that
+some automatic styles are not yet known also means that the \lpr {mathstyle}
+primitive expands to the current style which can of course be different from the
+one really used. It's a snapshot of the first pass state. As a consequence in the
+following example you get a style number (first pass) typeset that can actually
+differ from the used style (second pass). In the case of a math choice used
+ungrouped, the chosen style is used after the choice too, unless you group.
+
+\startbuffer[1]
+    [a:\mathstyle]\quad
+    \bgroup
+    \mathchoice
+        {\bf \scriptstyle       (x:d :\mathstyle)}
+        {\bf \scriptscriptstyle (x:t :\mathstyle)}
+        {\bf \scriptscriptstyle (x:s :\mathstyle)}
+        {\bf \scriptscriptstyle (x:ss:\mathstyle)}
+    \egroup
+    \quad[b:\mathstyle]\quad
+    \mathchoice
+        {\bf \scriptstyle       (y:d :\mathstyle)}
+        {\bf \scriptscriptstyle (y:t :\mathstyle)}
+        {\bf \scriptscriptstyle (y:s :\mathstyle)}
+        {\bf \scriptscriptstyle (y:ss:\mathstyle)}
+    \quad[c:\mathstyle]\quad
+    \bgroup
+    \mathchoice
+        {\bf \scriptstyle       (z:d :\mathstyle)}
+        {\bf \scriptscriptstyle (z:t :\mathstyle)}
+        {\bf \scriptscriptstyle (z:s :\mathstyle)}
+        {\bf \scriptscriptstyle (z:ss:\mathstyle)}
+    \egroup
+    \quad[d:\mathstyle]
+\stopbuffer
+
+\startbuffer[2]
+    [a:\mathstyle]\quad
+    \begingroup
+    \mathchoice
+        {\bf \scriptstyle       (x:d :\mathstyle)}
+        {\bf \scriptscriptstyle (x:t :\mathstyle)}
+        {\bf \scriptscriptstyle (x:s :\mathstyle)}
+        {\bf \scriptscriptstyle (x:ss:\mathstyle)}
+    \endgroup
+    \quad[b:\mathstyle]\quad
+    \mathchoice
+        {\bf \scriptstyle       (y:d :\mathstyle)}
+        {\bf \scriptscriptstyle (y:t :\mathstyle)}
+        {\bf \scriptscriptstyle (y:s :\mathstyle)}
+        {\bf \scriptscriptstyle (y:ss:\mathstyle)}
+    \quad[c:\mathstyle]\quad
+    \begingroup
+    \mathchoice
+        {\bf \scriptstyle       (z:d :\mathstyle)}
+        {\bf \scriptscriptstyle (z:t :\mathstyle)}
+        {\bf \scriptscriptstyle (z:s :\mathstyle)}
+        {\bf \scriptscriptstyle (z:ss:\mathstyle)}
+    \endgroup
+    \quad[d:\mathstyle]
+\stopbuffer
+
+\typebuffer[1]
+
+% \typebuffer[2]
+
+This gives:
+
+\blank $\displaystyle \getbuffer[1]$ \blank
+\blank $\textstyle    \getbuffer[1]$ \blank
+
+Using \prm {begingroup} \unknown\ \prm {endgroup} instead gives:
+
+\blank $\displaystyle \getbuffer[2]$ \blank
+\blank $\textstyle    \getbuffer[2]$ \blank
+
+This might look wrong but it's just a side effect of \lpr {mathstyle} expanding
+to the current (first pass) style and the number being injected in the list that
+gets converted in the second pass. It all makes sense and it illustrates the
+importance of grouping. In fact, the math choice style being effective afterwards
+has advantages. It would be hard to get it otherwise.
+
+\subsection{\lpr {Ustack}}
+
+\topicindex {math+stacks}
+
+There are a few math commands in \TEX\ where the style that will be used is not
+known straight from the start. These commands (\prm {over}, \prm {atop},
+\prm {overwithdelims}, \prm {atopwithdelims}) would therefore normally return
+wrong values for \lpr {mathstyle}. To fix this, \LUATEX\ introduces a special
+prefix command: \lpr {Ustack}:
+
+\starttyping
+$\Ustack {a \over b}$
+\stoptyping
+
+The \lpr {Ustack} command will scan the next brace and start a new math group
+with the correct (numerator) math style.
+
+\subsection{Cramped math styles}
+
+\topicindex {math+styles}
+\topicindex {math+spacing}
+\topicindex {math+cramped}
+
+\LUATEX\ has four new primitives to set the cramped math styles directly:
+
+\starttyping
+\crampeddisplaystyle
+\crampedtextstyle
+\crampedscriptstyle
+\crampedscriptscriptstyle
+\stoptyping
+
+These additional commands are not all that valuable on their own, but they come
+in handy as arguments to the math parameter settings that will be added shortly.
+
+In Eijkhouts \quotation {\TEX\ by Topic} the rules for handling styles in scripts
+are described as follows:
+
+\startitemize
+\startitem
+    In any style superscripts and subscripts are taken from the next smaller style.
+    Exception: in display style they are in script style.
+\stopitem
+\startitem
+    Subscripts are always in the cramped variant of the style; superscripts are only
+    cramped if the original style was cramped.
+\stopitem
+\startitem
+    In an \type {..\over..} formula in any style the numerator and denominator are
+    taken from the next smaller style.
+\stopitem
+\startitem
+    The denominator is always in cramped style; the numerator is only in cramped
+    style if the original style was cramped.
+\stopitem
+\startitem
+    Formulas under a \type {\sqrt} or \prm {overline} are in cramped style.
+\stopitem
+\stopitemize
+
+In \LUATEX\ one can set the styles in more detail which means that you sometimes
+have to set both normal and cramped styles to get the effect you want. (Even) if
+we force styles in the script using \prm {scriptstyle} and \lpr
+{crampedscriptstyle} we get this:
+
+\startbuffer[demo]
+\starttabulate
+\DB style         \BC example \NC \NR
+\TB
+\NC default       \NC $b_{x=xx}^{x=xx}$ \NC \NR
+\NC script        \NC $b_{\scriptstyle x=xx}^{\scriptstyle x=xx}$ \NC \NR
+\NC crampedscript \NC $b_{\crampedscriptstyle x=xx}^{\crampedscriptstyle x=xx}$ \NC \NR
+\LL
+\stoptabulate
+\stopbuffer
+
+\getbuffer[demo]
+
+Now we set the following parameters
+
+\startbuffer[setup]
+\Umathordrelspacing\scriptstyle=30mu
+\Umathordordspacing\scriptstyle=30mu
+\stopbuffer
+
+\typebuffer[setup]
+
+This gives a different result:
+
+\start\getbuffer[setup,demo]\stop
+
+But, as this is not what is expected (visually) we should say:
+
+\startbuffer[setup]
+\Umathordrelspacing\scriptstyle=30mu
+\Umathordordspacing\scriptstyle=30mu
+\Umathordrelspacing\crampedscriptstyle=30mu
+\Umathordordspacing\crampedscriptstyle=30mu
+\stopbuffer
+
+\typebuffer[setup]
+
+Now we get:
+
+\start\getbuffer[setup,demo]\stop
+
+\stopsection
+
+\startsection[title={Math parameter settings}]
+
+\subsection {Many new \lpr {Umath*} primitives}
+
+\topicindex {math+parameters}
+
+In \LUATEX, the font dimension parameters that \TEX\ used in math typesetting are
+now accessible via primitive commands. In fact, refactoring of the math engine
+has resulted in many more parameters than were not accessible before.
+
+\starttabulate
+\DB primitive name                   \BC description \NC \NR
+\TB
+\NC \lpr {Umathquad}               \NC the width of 18 mu's \NC \NR
+\NC \lpr {Umathaxis}               \NC height of the vertical center axis of
+                                         the math formula above the baseline \NC \NR
+\NC \lpr {Umathoperatorsize}       \NC minimum size of large operators in display mode \NC \NR
+\NC \lpr {Umathoverbarkern}        \NC vertical clearance above the rule \NC \NR
+\NC \lpr {Umathoverbarrule}        \NC the width of the rule \NC \NR
+\NC \lpr {Umathoverbarvgap}        \NC vertical clearance below the rule \NC \NR
+\NC \lpr {Umathunderbarkern}       \NC vertical clearance below the rule \NC \NR
+\NC \lpr {Umathunderbarrule}       \NC the width of the rule \NC \NR
+\NC \lpr {Umathunderbarvgap}       \NC vertical clearance above the rule \NC \NR
+\NC \lpr {Umathradicalkern}        \NC vertical clearance above the rule \NC \NR
+\NC \lpr {Umathradicalrule}        \NC the width of the rule \NC \NR
+\NC \lpr {Umathradicalvgap}        \NC vertical clearance below the rule \NC \NR
+\NC \lpr {Umathradicaldegreebefore}\NC the forward kern that takes place before placement of
+                                       the radical degree \NC \NR
+\NC \lpr {Umathradicaldegreeafter} \NC the backward kern that takes place after placement of
+                                       the radical degree \NC \NR
+\NC \lpr {Umathradicaldegreeraise} \NC this is the percentage of the total height and depth of
+                                       the radical sign that the degree is raised by; it is
+                                       expressed in \type {percents}, so 60\% is expressed as the
+                                       integer $60$ \NC \NR
+\NC \lpr {Umathstackvgap}          \NC vertical clearance between the two
+                                       elements in a \prm {atop} stack \NC \NR
+\NC \lpr {Umathstacknumup}         \NC numerator shift upward in \prm {atop} stack \NC \NR
+\NC \lpr {Umathstackdenomdown}     \NC denominator shift downward in \prm {atop} stack \NC \NR
+\NC \lpr {Umathfractionrule}       \NC the width of the rule in a \prm {over} \NC \NR
+\NC \lpr {Umathfractionnumvgap}    \NC vertical clearance between the numerator and the rule \NC \NR
+\NC \lpr {Umathfractionnumup}      \NC numerator shift upward in \prm {over} \NC \NR
+\NC \lpr {Umathfractiondenomvgap}  \NC vertical clearance between the denominator and the rule \NC \NR
+\NC \lpr {Umathfractiondenomdown}  \NC denominator shift downward in \prm {over} \NC \NR
+\NC \lpr {Umathfractiondelsize}    \NC minimum delimiter size for \type {\...withdelims} \NC \NR
+\NC \lpr {Umathlimitabovevgap}     \NC vertical clearance for limits above operators \NC \NR
+\NC \lpr {Umathlimitabovebgap}     \NC vertical baseline clearance for limits above operators \NC \NR
+\NC \lpr {Umathlimitabovekern}     \NC space reserved at the top of the limit \NC \NR
+\NC \lpr {Umathlimitbelowvgap}     \NC vertical clearance for limits below operators \NC \NR
+\NC \lpr {Umathlimitbelowbgap}     \NC vertical baseline clearance for limits below operators \NC \NR
+\NC \lpr {Umathlimitbelowkern}     \NC space reserved at the bottom of the limit \NC \NR
+\NC \lpr {Umathoverdelimitervgap}  \NC vertical clearance for limits above delimiters \NC \NR
+\NC \lpr {Umathoverdelimiterbgap}  \NC vertical baseline clearance for limits above delimiters \NC \NR
+\NC \lpr {Umathunderdelimitervgap} \NC vertical clearance for limits below delimiters \NC \NR
+\NC \lpr {Umathunderdelimiterbgap} \NC vertical baseline clearance for limits below delimiters \NC \NR
+\NC \lpr {Umathsubshiftdrop}       \NC subscript drop for boxes and subformulas \NC \NR
+\NC \lpr {Umathsubshiftdown}       \NC subscript drop for characters \NC \NR
+\NC \lpr {Umathsupshiftdrop}       \NC superscript drop (raise, actually) for boxes and subformulas \NC \NR
+\NC \lpr {Umathsupshiftup}         \NC superscript raise for characters \NC \NR
+\NC \lpr {Umathsubsupshiftdown}    \NC subscript drop in the presence of a superscript \NC \NR
+\NC \lpr {Umathsubtopmax}          \NC the top of standalone subscripts cannot be higher than this
+                                       above the baseline \NC \NR
+\NC \lpr {Umathsupbottommin}       \NC the bottom of standalone superscripts cannot be less than
+                                       this above the baseline \NC \NR
+\NC \lpr {Umathsupsubbottommax}    \NC the bottom of the superscript of a combined super- and subscript
+                                       be at least as high as this above the baseline \NC \NR
+\NC \lpr {Umathsubsupvgap}         \NC vertical clearance between super- and subscript \NC \NR
+\NC \lpr {Umathspaceafterscript}   \NC additional space added after a super- or subscript \NC \NR
+\NC \lpr {Umathconnectoroverlapmin}\NC minimum overlap between parts in an extensible recipe \NC \NR
+\LL
+\stoptabulate
+
+Each of the parameters in this section can be set by a command like this:
+
+\starttyping
+\Umathquad\displaystyle=1em
+\stoptyping
+
+they obey grouping, and you can use \type {\the\Umathquad\displaystyle} if
+needed.
+
+\subsection{Font|-|based math parameters}
+
+\topicindex {math+parameters}
+
+While it is nice to have these math parameters available for tweaking, it would
+be tedious to have to set each of them by hand. For this reason, \LUATEX\
+initializes a bunch of these parameters whenever you assign a font identifier to
+a math family based on either the traditional math font dimensions in the font
+(for assignments to math family~2 and~3 using \TFM|-|based fonts like \type
+{cmsy} and \type {cmex}), or based on the named values in a potential \type
+{MathConstants} table when the font is loaded via Lua. If there is a \type
+{MathConstants} table, this takes precedence over font dimensions, and in that
+case no attention is paid to which family is being assigned to: the \type
+{MathConstants} tables in the last assigned family sets all parameters.
+
+In the table below, the one|-|letter style abbreviations and symbolic tfm font
+dimension names match those used in the \TeX book. Assignments to \prm
+{textfont} set the values for the cramped and uncramped display and text styles,
+\prm {scriptfont} sets the script styles, and \prm {scriptscriptfont} sets the
+scriptscript styles, so we have eight parameters for three font sizes. In the
+\TFM\ case, assignments only happen in family~2 and family~3 (and of course only
+for the parameters for which there are font dimensions).
+
+Besides the parameters below, \LUATEX\ also looks at the \quote {space} font
+dimension parameter. For math fonts, this should be set to zero.
+
+\def\MathLine#1#2#3#4#5%
+  {\TB
+   \NC \llap{\high{\tx #2\enspace}}\ttbf \string #1 \NC \tt #5 \NC \NR
+   \NC \tx #3 \NC \tt #4 \NC \NR}
+
+\starttabulate[|l|l|]
+\DB variable / style \BC tfm / opentype \NC \NR
+\MathLine{\Umathaxis}               {}   {}                     {AxisHeight}                              {axis_height}
+\MathLine{\Umathoperatorsize}       {6}  {D, D'}                {DisplayOperatorMinHeight}                {\emdash}
+\MathLine{\Umathfractiondelsize}    {9}  {D, D'}                {FractionDelimiterDisplayStyleSize}       {delim1}
+\MathLine{\Umathfractiondelsize}    {9}  {T, T', S, S', SS, SS'}{FractionDelimiterSize}                   {delim2}
+\MathLine{\Umathfractiondenomdown}  {}   {D, D'}                {FractionDenominatorDisplayStyleShiftDown}{denom1}
+\MathLine{\Umathfractiondenomdown}  {}   {T, T', S, S', SS, SS'}{FractionDenominatorShiftDown}            {denom2}
+\MathLine{\Umathfractiondenomvgap}  {}   {D, D'}                {FractionDenominatorDisplayStyleGapMin}   {3*default_rule_thickness}
+\MathLine{\Umathfractiondenomvgap}  {}   {T, T', S, S', SS, SS'}{FractionDenominatorGapMin}               {default_rule_thickness}
+\MathLine{\Umathfractionnumup}      {}   {D, D'}                {FractionNumeratorDisplayStyleShiftUp}    {num1}
+\MathLine{\Umathfractionnumup}      {}   {T, T', S, S', SS, SS'}{FractionNumeratorShiftUp}                {num2}
+\MathLine{\Umathfractionnumvgap}    {}   {D, D'}                {FractionNumeratorDisplayStyleGapMin}     {3*default_rule_thickness}
+\MathLine{\Umathfractionnumvgap}    {}   {T, T', S, S', SS, SS'}{FractionNumeratorGapMin}                 {default_rule_thickness}
+\MathLine{\Umathfractionrule}       {}   {}                     {FractionRuleThickness}                   {default_rule_thickness}
+\MathLine{\Umathskewedfractionhgap} {}   {}                     {SkewedFractionHorizontalGap}             {math_quad/2}
+\MathLine{\Umathskewedfractionvgap} {}   {}                     {SkewedFractionVerticalGap}               {math_x_height}
+\MathLine{\Umathlimitabovebgap}     {}   {}                     {UpperLimitBaselineRiseMin}               {big_op_spacing3}
+\MathLine{\Umathlimitabovekern}     {1}  {}                     {0}                                       {big_op_spacing5}
+\MathLine{\Umathlimitabovevgap}     {}   {}                     {UpperLimitGapMin}                        {big_op_spacing1}
+\MathLine{\Umathlimitbelowbgap}     {}   {}                     {LowerLimitBaselineDropMin}               {big_op_spacing4}
+\MathLine{\Umathlimitbelowkern}     {1}  {}                     {0}                                       {big_op_spacing5}
+\MathLine{\Umathlimitbelowvgap}     {}   {}                     {LowerLimitGapMin}                        {big_op_spacing2}
+\MathLine{\Umathoverdelimitervgap}  {}   {}                     {StretchStackGapBelowMin}                 {big_op_spacing1}
+\MathLine{\Umathoverdelimiterbgap}  {}   {}                     {StretchStackTopShiftUp}                  {big_op_spacing3}
+\MathLine{\Umathunderdelimitervgap} {}   {}                     {StretchStackGapAboveMin}                 {big_op_spacing2}
+\MathLine{\Umathunderdelimiterbgap} {}   {}                     {StretchStackBottomShiftDown}             {big_op_spacing4}
+\MathLine{\Umathoverbarkern}        {}   {}                     {OverbarExtraAscender}                    {default_rule_thickness}
+\MathLine{\Umathoverbarrule}        {}   {}                     {OverbarRuleThickness}                    {default_rule_thickness}
+\MathLine{\Umathoverbarvgap}        {}   {}                     {OverbarVerticalGap}                      {3*default_rule_thickness}
+\MathLine{\Umathquad}               {1}  {}                     {<font_size(f)>}                          {math_quad}
+\MathLine{\Umathradicalkern}        {}   {}                     {RadicalExtraAscender}                    {default_rule_thickness}
+\MathLine{\Umathradicalrule}        {2}  {}                     {RadicalRuleThickness}                    {<not set>}
+\MathLine{\Umathradicalvgap}        {3}  {D, D'}                {RadicalDisplayStyleVerticalGap}          {default_rule_thickness+abs(math_x_height)/4}
+\MathLine{\Umathradicalvgap}        {3}  {T, T', S, S', SS, SS'}{RadicalVerticalGap}                      {default_rule_thickness+abs(default_rule_thickness)/4}
+\MathLine{\Umathradicaldegreebefore}{2}  {}                     {RadicalKernBeforeDegree}                 {<not set>}
+\MathLine{\Umathradicaldegreeafter} {2}  {}                     {RadicalKernAfterDegree}                  {<not set>}
+\MathLine{\Umathradicaldegreeraise} {2,7}{}                     {RadicalDegreeBottomRaisePercent}         {<not set>}
+\MathLine{\Umathspaceafterscript}   {4}  {}                     {SpaceAfterScript}                        {script_space}
+\MathLine{\Umathstackdenomdown}     {}   {D, D'}                {StackBottomDisplayStyleShiftDown}        {denom1}
+\MathLine{\Umathstackdenomdown}     {}   {T, T', S, S', SS, SS'}{StackBottomShiftDown}                    {denom2}
+\MathLine{\Umathstacknumup}         {}   {D, D'}                {StackTopDisplayStyleShiftUp}             {num1}
+\MathLine{\Umathstacknumup}         {}   {T, T', S, S', SS, SS'}{StackTopShiftUp}                         {num3}
+\MathLine{\Umathstackvgap}          {}   {D, D'}                {StackDisplayStyleGapMin}                 {7*default_rule_thickness}
+\MathLine{\Umathstackvgap}          {}   {T, T', S, S', SS, SS'}{StackGapMin}                             {3*default_rule_thickness}
+\MathLine{\Umathsubshiftdown}       {}   {}                     {SubscriptShiftDown}                      {sub1}
+\MathLine{\Umathsubshiftdrop}       {}   {}                     {SubscriptBaselineDropMin}                {sub_drop}
+\MathLine{\Umathsubsupshiftdown}    {8}  {}                     {SubscriptShiftDownWithSuperscript}       {\emdash}
+\MathLine{\Umathsubtopmax}          {}   {}                     {SubscriptTopMax}                         {abs(math_x_height*4)/5}
+\MathLine{\Umathsubsupvgap}         {}   {}                     {SubSuperscriptGapMin}                    {4*default_rule_thickness}
+\MathLine{\Umathsupbottommin}       {}   {}                     {SuperscriptBottomMin}                    {abs(math_x_height/4)}
+\MathLine{\Umathsupshiftdrop}       {}   {}                     {SuperscriptBaselineDropMax}              {sup_drop}
+\MathLine{\Umathsupshiftup}         {}   {D}                    {SuperscriptShiftUp}                      {sup1}
+\MathLine{\Umathsupshiftup}         {}   {T, S, SS,}            {SuperscriptShiftUp}                      {sup2}
+\MathLine{\Umathsupshiftup}         {}   {D', T', S', SS'}      {SuperscriptShiftUpCramped}               {sup3}
+\MathLine{\Umathsupsubbottommax}    {}   {}                     {SuperscriptBottomMaxWithSubscript}       {abs(math_x_height*4)/5}
+\MathLine{\Umathunderbarkern}       {}   {}                     {UnderbarExtraDescender}                  {default_rule_thickness}
+\MathLine{\Umathunderbarrule}       {}   {}                     {UnderbarRuleThickness}                   {default_rule_thickness}
+\MathLine{\Umathunderbarvgap}       {}   {}                     {UnderbarVerticalGap}                     {3*default_rule_thickness}
+\MathLine{\Umathconnectoroverlapmin}{5}  {}                     {MinConnectorOverlap}                     {0}
+\LL
+\stoptabulate
+
+Note 1: \OPENTYPE\ fonts set \lpr {Umathlimitabovekern} and \lpr
+{Umathlimitbelowkern} to zero and set \lpr {Umathquad} to the font size of the
+used font, because these are not supported in the \type {MATH} table,
+
+Note 2: Traditional \TFM\ fonts do not set \lpr {Umathradicalrule} because
+\TEX82\ uses the height of the radical instead. When this parameter is indeed not
+set when \LUATEX\ has to typeset a radical, a backward compatibility mode will
+kick in that assumes that an oldstyle \TEX\ font is used. Also, they do not set
+\lpr {Umathradicaldegreebefore}, \lpr {Umathradicaldegreeafter}, and \lpr
+{Umathradicaldegreeraise}. These are then automatically initialized to
+$5/18$quad, $-10/18$quad, and 60.
+
+Note 3: If \TFM\ fonts are used, then the \lpr {Umathradicalvgap} is not set
+until the first time \LUATEX\ has to typeset a formula because this needs
+parameters from both family~2 and family~3. This provides a partial backward
+compatibility with \TEX82, but that compatibility is only partial: once the \lpr
+{Umathradicalvgap} is set, it will not be recalculated any more.
+
+Note 4: When \TFM\ fonts are used a similar situation arises with respect to \lpr
+{Umathspaceafterscript}: it is not set until the first time \LUATEX\ has to
+typeset a formula. This provides some backward compatibility with \TEX82. But
+once the \lpr {Umathspaceafterscript} is set, \prm {scriptspace} will never be
+looked at again.
+
+Note 5: Traditional \TFM\ fonts set \lpr {Umathconnectoroverlapmin} to zero
+because \TEX82\ always stacks extensibles without any overlap.
+
+Note 6: The \lpr {Umathoperatorsize} is only used in \prm {displaystyle}, and is
+only set in \OPENTYPE\ fonts. In \TFM\ font mode, it is artificially set to one
+scaled point more than the initial attempt's size, so that always the \quote
+{first next} will be tried, just like in \TEX82.
+
+Note 7: The \lpr {Umathradicaldegreeraise} is a special case because it is the
+only parameter that is expressed in a percentage instead of a number of scaled
+points.
+
+Note 8: \type {SubscriptShiftDownWithSuperscript} does not actually exist in the
+\quote {standard} \OPENTYPE\ math font Cambria, but it is useful enough to be
+added.
+
+Note 9: \type {FractionDelimiterDisplayStyleSize} and \type
+{FractionDelimiterSize} do not actually exist in the \quote {standard} \OPENTYPE\
+math font Cambria, but were useful enough to be added.
+
+\stopsection
+
+\startsection[title={Math spacing}]
+
+\subsection{Inline surrounding space}
+
+\topicindex {math+spacing}
+
+Inline math is surrounded by (optional) \prm {mathsurround} spacing but that is a fixed
+dimension. There is now an additional parameter \lpr {mathsurroundskip}. When set to a
+non|-|zero value (or zero with some stretch or shrink) this parameter will replace
+\prm {mathsurround}. By using an additional parameter instead of changing the nature
+of \prm {mathsurround}, we can remain compatible. In the meantime a bit more
+control has been added via \lpr {mathsurroundmode}. This directive can take 6 values
+with zero being the default behaviour.
+
+\start
+
+\def\OneLiner#1#2%
+  {\NC \type{#1}
+   \NC \dontleavehmode\inframed[align=normal,offset=0pt,frame=off]{\mathsurroundmode#1\relax\hsize 100pt   x$x$x}
+   \NC \dontleavehmode\inframed[align=normal,offset=0pt,frame=off]{\mathsurroundmode#1\relax\hsize 100pt x $x$ x}
+   \NC #2
+   \NC \NR}
+
+\startbuffer
+\mathsurround    10pt
+\mathsurroundskip20pt
+\stopbuffer
+
+\typebuffer \getbuffer
+
+\starttabulate[|c|c|c|pl|]
+\DB mode \BC x\$x\$x \BC x \$x\$ x \BC effect \NC \NR
+\TB
+\OneLiner{0}{obey \prm {mathsurround} when \lpr {mathsurroundskip} is 0pt}
+\OneLiner{1}{only add skip to the left}
+\OneLiner{2}{only add skip to the right}
+\OneLiner{3}{add skip to the left and right}
+\OneLiner{4}{ignore the skip setting, obey \prm {mathsurround}}
+\OneLiner{5}{disable all spacing around math}
+\OneLiner{6}{only apply \lpr {mathsurroundskip} when also spacing}
+\OneLiner{7}{only apply \lpr {mathsurroundskip} when no spacing}
+\LL
+\stoptabulate
+
+\stop
+
+Method six omits the surround glue when there is (x)spacing glue present while
+method seven does the opposite, the glue is only applied when there is (x)space
+glue present too. Anything more fancy, like checking the begining or end of a
+paragraph (or edges of a box) would not be robust anyway. If you want that you
+can write a callback that runs over a list and analyzes a paragraph. Actually, in
+that case you could also inject glue (or set the properties of a math node)
+explicitly. So, these modes are in practice mostly useful for special purposes
+and experiments (they originate in a tracker item). Keep in mind that this glue
+is part of the math node and not always treated as normal glue: it travels with
+the begin and end math nodes. Also, method 6 and 7 will zero the skip related
+fields in a node when applicable in the first occasion that checks them
+(linebreaking or packaging).
+
+\subsection{Pairwise spacing}
+
+\topicindex {math+spacing}
+
+Besides the parameters mentioned in the previous sections, there are also 64 new
+primitives to control the math spacing table (as explained in Chapter~18 of the
+\TEX book). The primitive names are a simple matter of combining two math atom
+types, but for completeness' sake, here is the whole list:
+
+\starttwocolumns
+\startlines
+\lpr {Umathordordspacing}
+\lpr {Umathordopspacing}
+\lpr {Umathordbinspacing}
+\lpr {Umathordrelspacing}
+\lpr {Umathordopenspacing}
+\lpr {Umathordclosespacing}
+\lpr {Umathordpunctspacing}
+\lpr {Umathordinnerspacing}
+\lpr {Umathopordspacing}
+\lpr {Umathopopspacing}
+\lpr {Umathopbinspacing}
+\lpr {Umathoprelspacing}
+\lpr {Umathopopenspacing}
+\lpr {Umathopclosespacing}
+\lpr {Umathoppunctspacing}
+\lpr {Umathopinnerspacing}
+\lpr {Umathbinordspacing}
+\lpr {Umathbinopspacing}
+\lpr {Umathbinbinspacing}
+\lpr {Umathbinrelspacing}
+\lpr {Umathbinopenspacing}
+\lpr {Umathbinclosespacing}
+\lpr {Umathbinpunctspacing}
+\lpr {Umathbininnerspacing}
+\lpr {Umathrelordspacing}
+\lpr {Umathrelopspacing}
+\lpr {Umathrelbinspacing}
+\lpr {Umathrelrelspacing}
+\lpr {Umathrelopenspacing}
+\lpr {Umathrelclosespacing}
+\lpr {Umathrelpunctspacing}
+\lpr {Umathrelinnerspacing}
+\lpr {Umathopenordspacing}
+\lpr {Umathopenopspacing}
+\lpr {Umathopenbinspacing}
+\lpr {Umathopenrelspacing}
+\lpr {Umathopenopenspacing}
+\lpr {Umathopenclosespacing}
+\lpr {Umathopenpunctspacing}
+\lpr {Umathopeninnerspacing}
+\lpr {Umathcloseordspacing}
+\lpr {Umathcloseopspacing}
+\lpr {Umathclosebinspacing}
+\lpr {Umathcloserelspacing}
+\lpr {Umathcloseopenspacing}
+\lpr {Umathcloseclosespacing}
+\lpr {Umathclosepunctspacing}
+\lpr {Umathcloseinnerspacing}
+\lpr {Umathpunctordspacing}
+\lpr {Umathpunctopspacing}
+\lpr {Umathpunctbinspacing}
+\lpr {Umathpunctrelspacing}
+\lpr {Umathpunctopenspacing}
+\lpr {Umathpunctclosespacing}
+\lpr {Umathpunctpunctspacing}
+\lpr {Umathpunctinnerspacing}
+\lpr {Umathinnerordspacing}
+\lpr {Umathinneropspacing}
+\lpr {Umathinnerbinspacing}
+\lpr {Umathinnerrelspacing}
+\lpr {Umathinneropenspacing}
+\lpr {Umathinnerclosespacing}
+\lpr {Umathinnerpunctspacing}
+\lpr {Umathinnerinnerspacing}
+\stoplines
+\stoptwocolumns
+
+These parameters are of type \prm {muskip}, so setting a parameter can be done
+like this:
+
+\starttyping
+\Umathopordspacing\displaystyle=4mu plus 2mu
+\stoptyping
+
+They are all initialized by \type {initex} to the values mentioned in the table
+in Chapter~18 of the \TEX book.
+
+Note 1: for ease of use as well as for backward compatibility, \prm {thinmuskip},
+\prm {medmuskip} and \prm {thickmuskip} are treated specially. In their case a
+pointer to the corresponding internal parameter is saved, not the actual \prm
+{muskip} value. This means that any later changes to one of these three
+parameters will be taken into account.
+
+Note 2: Careful readers will realise that there are also primitives for the items
+marked \type {*} in the \TEX book. These will not actually be used as those
+combinations of atoms cannot actually happen, but it seemed better not to break
+orthogonality. They are initialized to zero.
+
+\subsection{Skips around display math}
+
+\topicindex {math+spacing}
+
+The injection of \prm {abovedisplayskip} and \prm {belowdisplayskip} is not
+symmetrical. An above one is always inserted, also when zero, but the below is
+only inserted when larger than zero. Especially the latter makes it sometimes hard
+to fully control spacing. Therefore \LUATEX\ comes with a new directive: \lpr
+{mathdisplayskipmode}. The following values apply:
+
+\starttabulate[|c|l|]
+\DB value  \BC meaning \NC \NR
+\TB
+\NC 0 \NC normal \TEX\ behaviour \NC \NR
+\NC 1 \NC always (same as 0) \NC \NR
+\NC 2 \NC only when not zero \NC \NR
+\NC 3 \NC never, not even when not zero \NC \NR
+\LL
+\stoptabulate
+
+\subsection {Nolimit correction}
+
+\topicindex {math+limits}
+
+There are two extra math parameters \lpr {Umathnolimitsupfactor} and \lpr
+{Umathnolimitsubfactor} that were added to provide some control over how limits
+are spaced (for example the position of super and subscripts after integral
+operators). They relate to an extra parameter \lpr {mathnolimitsmode}. The half
+corrections are what happens when scripts are placed above and below. The
+problem with italic corrections is that officially that correction italic is used
+for above|/|below placement while advanced kerns are used for placement at the
+right end. The question is: how often is this implemented, and if so, do the
+kerns assume correction too. Anyway, with this parameter one can control it.
+
+\starttabulate[|l|ck1|ck1|ck1|ck1|ck1|ck1|]
+    \NC
+        \NC \mathnolimitsmode0    $\displaystyle\int\nolimits^0_1$
+        \NC \mathnolimitsmode1    $\displaystyle\int\nolimits^0_1$
+        \NC \mathnolimitsmode2    $\displaystyle\int\nolimits^0_1$
+        \NC \mathnolimitsmode3    $\displaystyle\int\nolimits^0_1$
+        \NC \mathnolimitsmode4    $\displaystyle\int\nolimits^0_1$
+        \NC \mathnolimitsmode8000 $\displaystyle\int\nolimits^0_1$
+    \NC \NR
+    \TB
+    \BC mode
+        \NC \tttf 0
+        \NC \tttf 1
+        \NC \tttf 2
+        \NC \tttf 3
+        \NC \tttf 4
+        \NC \tttf 8000
+    \NC \NR
+    \BC superscript
+        \NC 0
+        \NC font
+        \NC 0
+        \NC 0
+        \NC +ic/2
+        \NC 0
+    \NC \NR
+    \BC subscript
+        \NC -ic
+        \NC font
+        \NC 0
+        \NC -ic/2
+        \NC -ic/2
+        \NC 8000ic/1000
+    \NC \NR
+\stoptabulate
+
+When the mode is set to one, the math parameters are used. This way a macro
+package writer can decide what looks best. Given the current state of fonts in
+\CONTEXT\ we currently use mode 1 with factor 0 for the superscript and 750 for
+the subscripts. Positive values are used for both parameters but the subscript
+shifts to the left. A \lpr {mathnolimitsmode} larger that 15 is considered to
+be a factor for the subscript correction. This feature can be handy when
+experimenting.
+
+\subsection {Math italic mess}
+
+\topicindex {math+italics}
+
+The \lpr {mathitalicsmode} parameter can be set to~1 to force italic correction
+before noads that represent some more complex structure (read: everything
+that is not an ord, bin, rel, open, close, punct or inner). We show a Cambria
+example.
+
+\starttexdefinition Whatever #1
+    \NC \type{\mathitalicsmode = #1}
+    \NC \mathitalicsmode#1\ruledhbox{$\left|T^1\right|$}
+    \NC \mathitalicsmode#1\ruledhbox{$\left|T\right|$}
+    \NC \mathitalicsmode#1\ruledhbox{$T+1$}
+    \NC \mathitalicsmode#1\ruledhbox{$T{1\over2}$}
+    \NC \mathitalicsmode#1\ruledhbox{$T\sqrt{1}$}
+    \NC \NR
+\stoptexdefinition
+
+\start
+    \switchtobodyfont[cambria]
+    \starttabulate[|c|c|c|c|c|c|]
+        \Whatever{0}%
+        \Whatever{1}%
+    \stoptabulate
+\stop
+
+This kind of parameters relate to the fact that italic correction in \OPENTYPE\
+math is bound to fuzzy rules. So, control is the solution.
+
+\subsection {Script and kerning}
+
+\topicindex {math+kerning}
+\topicindex {math+scripts}
+
+If you want to typeset text in math macro packages often provide something \type
+{\text} which obeys the script sizes. As the definition can be anything there is
+a good chance that the kerning doesn't come out well when used in a script. Given
+that the first glyph ends up in a \prm {hbox} we have some control over this.
+And, as a bonus we also added control over the normal sublist kerning. The \lpr
+{mathscriptboxmode} parameter defaults to~1.
+
+\starttabulate[|c|l|]
+\DB value     \BC meaning \NC \NR
+\TB
+\NC \type {0} \NC forget about kerning \NC \NR
+\NC \type {1} \NC kern math sub lists with a valid glyph \NC \NR
+\NC \type {2} \NC also kern math sub boxes that have a valid glyph \NC \NR
+\NC \type {2} \NC only kern math sub boxes with a boundary node present\NC \NR
+\LL
+\stoptabulate
+
+Here we show some examples. Of course this doesn't solve all our problems, if
+only because some fonts have characters with bounding boxes that compensate for
+italics, while other fonts can lack kerns.
+
+\startbuffer[1]
+    $T_{\tf fluff}$
+\stopbuffer
+
+\startbuffer[2]
+    $T_{\text{fluff}}$
+\stopbuffer
+
+\startbuffer[3]
+    $T_{\text{\boundary1 fluff}}$
+\stopbuffer
+
+\unexpanded\def\Show#1#2#3%
+  {\doifelsenothing{#3}
+     {\small\tx\typeinlinebuffer[#1]}
+     {\doifelse{#3}{-}
+        {\small\bf\tt mode #2}
+        {\switchtobodyfont[#3]\showfontkerns\showglyphs\mathscriptboxmode#2\relax\inlinebuffer[#1]}}}
+
+\starttabulate[|lBT|c|c|c|c|c|]
+    \NC          \NC \Show{1}{0}{}         \NC\Show{1}{1}{}         \NC \Show{2}{1}{}         \NC \Show{2}{2}{}         \NC \Show{3}{3}{}         \NC \NR
+    \NC          \NC \Show{1}{0}{-}        \NC\Show{1}{1}{-}        \NC \Show{2}{1}{-}        \NC \Show{2}{2}{-}        \NC \Show{3}{3}{-}        \NC \NR
+    \NC modern   \NC \Show{1}{0}{modern}   \NC\Show{1}{1}{modern}   \NC \Show{2}{1}{modern}   \NC \Show{2}{2}{modern}   \NC \Show{3}{3}{modern}   \NC \NR
+    \NC lucidaot \NC \Show{1}{0}{lucidaot} \NC\Show{1}{1}{lucidaot} \NC \Show{2}{1}{lucidaot} \NC \Show{2}{2}{lucidaot} \NC \Show{3}{3}{lucidaot} \NC \NR
+    \NC pagella  \NC \Show{1}{0}{pagella}  \NC\Show{1}{1}{pagella}  \NC \Show{2}{1}{pagella}  \NC \Show{2}{2}{pagella}  \NC \Show{3}{3}{pagella}  \NC \NR
+    \NC cambria  \NC \Show{1}{0}{cambria}  \NC\Show{1}{1}{cambria}  \NC \Show{2}{1}{cambria}  \NC \Show{2}{2}{cambria}  \NC \Show{3}{3}{cambria}  \NC \NR
+    \NC dejavu   \NC \Show{1}{0}{dejavu}   \NC\Show{1}{1}{dejavu}   \NC \Show{2}{1}{dejavu}   \NC \Show{2}{2}{dejavu}   \NC \Show{3}{3}{dejavu}   \NC \NR
+\stoptabulate
+
+Kerning between a character subscript is controlled by \lpr {mathscriptcharmode}
+which also defaults to~1.
+
+Here is another example. Internally we tag kerns as italic kerns or font kerns
+where font kerns result from the staircase kern tables. In 2018 fonts like Latin
+Modern and Pagella rely on cheats with the boundingbox, Cambria uses staircase
+kerns and Lucida a mixture. Depending on how fonts evolve we might add some more
+control over what one can turn on and off.
+
+\def\MathSample#1#2#3%
+  {\NC
+   #1 \NC
+   #2 \NC
+   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3T_{f}$         \NC
+   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3\gamma_{e}$    \NC
+   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3\gamma_{ee}$   \NC
+   \showglyphdata \switchtobodyfont[#2,17.3pt]$#3T_{\tf fluff}$ \NC
+   \NR}
+
+\starttabulate[|Tl|Tl|l|l|l|l|]
+    \FL
+    \MathSample{normal}{modern}  {\mr}
+    \MathSample{}      {pagella} {\mr}
+    \MathSample{}      {cambria} {\mr}
+    \MathSample{}      {lucidaot}{\mr}
+    \ML
+    \MathSample{bold}  {modern}  {\mb}
+    \MathSample{}      {pagella} {\mb}
+    \MathSample{}      {cambria} {\mb}
+    \MathSample{}      {lucidaot}{\mb}
+    \LL
+\stoptabulate
+
+\subsection{Fixed scripts}
+
+We have three parameters that are used for this fixed anchoring:
+
+\starttabulate[|c|l|]
+\DB parameter \BC register \NC \NR
+\NC $d$ \NC \lpr {Umathsubshiftdown}    \NC \NR
+\NC $u$ \NC \lpr {Umathsupshiftup}      \NC \NR
+\NC $s$ \NC \lpr {Umathsubsupshiftdown} \NC \NR
+\LL
+\stoptabulate
+
+When we set \lpr {mathscriptsmode} to a value other than zero these are used
+for calculating fixed positions. This is something that is needed for instance
+for chemistry. You can manipulate the mentioned variables to achieve different
+effects.
+
+\def\SampleMath#1%
+  {$\mathscriptsmode#1\mathupright CH_2 + CH^+_2 + CH^2_2$}
+
+\starttabulate[|c|c|c|p|]
+\DB mode \BC down          \BC up            \BC example        \NC \NR
+\TB
+\NC 0    \NC dynamic       \NC dynamic       \NC \SampleMath{0} \NC \NR
+\NC 1    \NC $d$           \NC $u$           \NC \SampleMath{1} \NC \NR
+\NC 2    \NC $s$           \NC $u$           \NC \SampleMath{2} \NC \NR
+\NC 3    \NC $s$           \NC $u + s - d$   \NC \SampleMath{3} \NC \NR
+\NC 4    \NC $d + (s-d)/2$ \NC $u + (s-d)/2$ \NC \SampleMath{4} \NC \NR
+\NC 5    \NC $d$           \NC $u + s - d$   \NC \SampleMath{5} \NC \NR
+\LL
+\stoptabulate
+
+The value of this parameter obeys grouping but applies to the whole current
+formula.
+
+% if needed we can put the value in stylenodes but maybe more should go there
+
+\subsection{Penalties: \lpr {mathpenaltiesmode}}
+
+\topicindex {math+penalties}
+
+Only in inline math penalties will be added in a math list. You can force
+penalties (also in display math) by setting:
+
+\starttyping
+\mathpenaltiesmode = 1
+\stoptyping
+
+This primnitive is not really needed in \LUATEX\ because you can use the callback
+\cbk {mlist_to_hlist} to force penalties by just calling the regular routine
+with forced penalties. However, as part of opening up and control this primitive
+makes sense. As a bonus we also provide two extra penalties:
+
+\starttyping
+\prebinoppenalty = -100 % example value
+\prerelpenalty   =  900 % example value
+\stoptyping
+
+They default to inifinite which signals that they don't need to be inserted. When
+set they are injected before a binop or rel noad. This is an experimental feature.
+
+\subsection{Equation spacing: \lpr {matheqnogapstep}}
+
+By default \TEX\ will add one quad between the equation and the number. This is
+hard coded. A new primitive can control this:
+
+\startsyntax
+\matheqnogapstep = 1000
+\stopsyntax
+
+Because a math quad from the math text font is used instead of a dimension, we
+use a step to control the size. A value of zero will suppress the gap. The step
+is divided by 1000 which is the usual way to mimmick floating point factors in
+\TEX.
+
+\stopsection
+
+\startsection[title={Math constructs}]
+
+\subsection {Unscaled fences}
+
+\topicindex {math+fences}
+
+The \lpr {mathdelimitersmode} primitive is experimental and deals with the
+following (potential) problems. Three bits can be set. The first bit prevents an
+unwanted shift when the fence symbol is not scaled (a cambria side effect). The
+second bit forces italic correction between a preceding character ordinal and the
+fenced subformula, while the third bit turns that subformula into an ordinary so
+that the same spacing applies as with unfenced variants. Here we show Cambria
+(with \lpr {mathitalicsmode} enabled).
+
+\starttexdefinition Whatever #1
+    \NC \type{\mathdelimitersmode = #1}
+    \NC \mathitalicsmode1\mathdelimitersmode#1\ruledhbox{\showglyphs\showfontkerns\showfontitalics$f(x)$}
+    \NC \mathitalicsmode1\mathdelimitersmode#1\ruledhbox{\showglyphs\showfontkerns\showfontitalics$f\left(x\right)$}
+    \NC \NR
+\stoptexdefinition
+
+\start
+    \switchtobodyfont[cambria]
+    \starttabulate[|l|l|l|]
+        \Whatever{0}\Whatever{1}\Whatever{2}\Whatever{3}%
+        \Whatever{4}\Whatever{5}\Whatever{6}\Whatever{7}%
+    \stoptabulate
+\stop
+
+So, when set to 7 fenced subformulas with unscaled delimiters come out the same
+as unfenced ones. This can be handy for cases where one is forced to use \prm
+{left} and \prm {right} always because of unpredictable content. As said, it's an
+experimental feature (which somehow fits in the exceptional way fences are dealt
+with in the engine). The full list of flags is given in the next table:
+
+\starttabulate[|c|l|]
+\DB value  \BC meaning \NC \NR
+\TB
+\NC \type{"01} \NC don't apply the usual shift \NC \NR
+\NC \type{"02} \NC apply italic correction when possible \NC \NR
+\NC \type{"04} \NC force an ordinary subformula \NC \NR
+\NC \type{"08} \NC no shift when a base character \NC \NR
+\NC \type{"10} \NC only shift when an extensible \NC \NR
+\LL
+\stoptabulate
+
+The effect can depend on the font (and for Cambria one can use for instance \type {"16}).
+
+\subsection[mathacc]{Accent handling}
+
+\topicindex {math+accents}
+
+\LUATEX\ supports both top accents and bottom accents in math mode, and math
+accents stretch automatically (if this is supported by the font the accent comes
+from, of course). Bottom and combined accents as well as fixed-width math accents
+are controlled by optional keywords following \lpr {Umathaccent}.
+
+The keyword \type {bottom} after \lpr {Umathaccent} signals that a bottom accent
+is needed, and the keyword \type {both} signals that both a top and a bottom
+accent are needed (in this case two accents need to be specified, of course).
+
+Then the set of three integers defining the accent is read. This set of integers
+can be prefixed by the \type {fixed} keyword to indicate that a non-stretching
+variant is requested (in case of both accents, this step is repeated).
+
+A simple example:
+
+\starttyping
+\Umathaccent both fixed 0 0 "20D7 fixed 0 0 "20D7 {example}
+\stoptyping
+
+If a math top accent has to be placed and the accentee is a character and has a
+non-zero \type {top_accent} value, then this value will be used to place the
+accent instead of the \prm {skewchar} kern used by \TEX82.
+
+The \type {top_accent} value represents a vertical line somewhere in the
+accentee. The accent will be shifted horizontally such that its own \type
+{top_accent} line coincides with the one from the accentee. If the \type
+{top_accent} value of the accent is zero, then half the width of the accent
+followed by its italic correction is used instead.
+
+The vertical placement of a top accent depends on the \type {x_height} of the
+font of the accentee (as explained in the \TEX book), but if a value turns out
+to be zero and the font had a \type {MathConstants} table, then \type
+{AccentBaseHeight} is used instead.
+
+The vertical placement of a bottom accent is straight below the accentee, no
+correction takes place.
+
+Possible locations are \type {top}, \type {bottom}, \type {both} and \type
+{center}. When no location is given \type {top} is assumed. An additional
+parameter \nod {fraction} can be specified followed by a number; a value of for
+instance 1200 means that the criterium is 1.2 times the width of the nucleus. The
+fraction only applies to the stepwise selected shapes and is mostly meant for the
+\type {overlay} location. It also works for the other locations but then it
+concerns the width.
+
+\subsection{Radical extensions}
+
+\topicindex {math+radicals}
+
+The new primitive \lpr {Uroot} allows the construction of a radical noad
+including a degree field. Its syntax is an extension of \lpr {Uradical}:
+
+\starttyping
+\Uradical <fam integer> <char integer> <radicand>
+\Uroot    <fam integer> <char integer> <degree> <radicand>
+\stoptyping
+
+The placement of the degree is controlled by the math parameters \lpr
+{Umathradicaldegreebefore}, \lpr {Umathradicaldegreeafter}, and \lpr
+{Umathradicaldegreeraise}. The degree will be typeset in \prm
+{scriptscriptstyle}.
+
+\subsection{Super- and subscripts}
+
+The character fields in a \LUA|-|loaded \OPENTYPE\ math font can have a \quote
+{mathkern} table. The format of this table is the same as the \quote {mathkern}
+table that is returned by the \type {fontloader} library, except that all height
+and kern values have to be specified in actual scaled points.
+
+When a super- or subscript has to be placed next to a math item, \LUATEX\ checks
+whether the super- or subscript and the nucleus are both simple character items.
+If they are, and if the fonts of both character items are \OPENTYPE\ fonts (as
+opposed to legacy \TEX\ fonts), then \LUATEX\ will use the \OPENTYPE\ math
+algorithm for deciding on the horizontal placement of the super- or subscript.
+
+This works as follows:
+
+\startitemize
+    \startitem
+        The vertical position of the script is calculated.
+    \stopitem
+    \startitem
+        The default horizontal position is flat next to the base character.
+    \stopitem
+    \startitem
+        For superscripts, the italic correction of the base character is added.
+    \stopitem
+    \startitem
+        For a superscript, two vertical values are calculated: the bottom of the
+        script (after shifting up), and the top of the base. For a subscript, the two
+        values are the top of the (shifted down) script, and the bottom of the base.
+    \stopitem
+    \startitem
+        For each of these two locations:
+        \startitemize
+            \startitem
+                find the math kern value at this height for the base (for a subscript
+                placement, this is the bottom_right corner, for a superscript
+                placement the top_right corner)
+            \stopitem
+            \startitem
+                find the math kern value at this height for the script (for a
+                subscript placement, this is the top_left corner, for a superscript
+                placement the bottom_left corner)
+            \stopitem
+            \startitem
+                add the found values together to get a preliminary result.
+            \stopitem
+        \stopitemize
+    \stopitem
+    \startitem
+        The horizontal kern to be applied is the smallest of the two results from
+        previous step.
+    \stopitem
+\stopitemize
+
+The math kern value at a specific height is the kern value that is specified by the
+next higher height and kern pair, or the highest one in the character (if there is no
+value high enough in the character), or simply zero (if the character has no math kern
+pairs at all).
+
+\subsection{Scripts on extensibles}
+
+\topicindex {math+scripts}
+\topicindex {math+delimiters}
+\topicindex {math+extensibles}
+
+The primitives \lpr {Uunderdelimiter} and \lpr {Uoverdelimiter} allow the
+placement of a subscript or superscript on an automatically extensible item and
+\lpr {Udelimiterunder} and \lpr {Udelimiterover} allow the placement of an
+automatically extensible item as a subscript or superscript on a nucleus. The
+input:
+
+% these produce radical noads .. in fact the code base has the numbers wrong for
+% quite a while, so no one seems to use this
+
+\startbuffer
+$\Uoverdelimiter  0 "2194 {\hbox{\strut  overdelimiter}}$
+$\Uunderdelimiter 0 "2194 {\hbox{\strut underdelimiter}}$
+$\Udelimiterover  0 "2194 {\hbox{\strut  delimiterover}}$
+$\Udelimiterunder 0 "2194 {\hbox{\strut delimiterunder}}$
+\stopbuffer
+
+\typebuffer will render this:
+
+\blank \startnarrower \getbuffer \stopnarrower \blank
+
+The vertical placements are controlled by \lpr {Umathunderdelimiterbgap}, \lpr
+{Umathunderdelimitervgap}, \lpr {Umathoverdelimiterbgap}, and \lpr
+{Umathoverdelimitervgap} in a similar way as limit placements on large operators.
+The superscript in \lpr {Uoverdelimiter} is typeset in a suitable scripted style,
+the subscript in \lpr {Uunderdelimiter} is cramped as well.
+
+These primitives accepts an option \type {width} specification. When used the
+also optional keywords \type {left}, \type {middle} and \type {right} will
+determine what happens when a requested size can't be met (which can happen when
+we step to successive larger variants).
+
+An extra primitive \lpr {Uhextensible} is available that can be used like this:
+
+\startbuffer
+$\Uhextensible width 10cm 0 "2194$
+\stopbuffer
+
+\typebuffer This will render this:
+
+\blank \startnarrower \getbuffer \stopnarrower \blank
+
+Here you can also pass options, like:
+
+\startbuffer
+$\Uhextensible width 1pt middle 0 "2194$
+\stopbuffer
+
+\typebuffer This gives:
+
+\blank \startnarrower \getbuffer \stopnarrower \blank
+
+\LUATEX\ internally uses a structure that supports \OPENTYPE\ \quote
+{MathVariants} as well as \TFM\ \quote {extensible recipes}. In most cases where
+font metrics are involved we have a different code path for traditional fonts end
+\OPENTYPE\ fonts.
+
+\subsection{Fractions}
+
+\topicindex {math+fractions}
+
+The \prm {abovewithdelims} command accepts a keyword \type {exact}. When issued
+the extra space relative to the rule thickness is not added. One can of course
+use the \type {\Umathfraction..gap} commands to influence the spacing. Also the
+rule is still positioned around the math axis.
+
+\starttyping
+$$ { {a} \abovewithdelims() exact 4pt {b} }$$
+\stoptyping
+
+The math parameter table contains some parameters that specify a horizontal and
+vertical gap for skewed fractions. Of course some guessing is needed in order to
+implement something that uses them. And so we now provide a primitive similar to the
+other fraction related ones but with a few options so that one can influence the
+rendering. Of course a user can also mess around a bit with the parameters
+\lpr {Umathskewedfractionhgap} and \lpr {Umathskewedfractionvgap}.
+
+The syntax used here is:
+
+\starttyping
+{ {1} \Uskewed / <options> {2} }
+{ {1} \Uskewedwithdelims / () <options> {2} }
+\stoptyping
+
+where the options can be \type {noaxis} and \type {exact}. By default we add half
+the axis to the shifts and by default we zero the width of the middle character.
+For Latin Modern the result looks as follows:
+
+\def\ShowA#1#2#3{$x + { {#1} \Uskewed           /    #3 {#2} } + x$}
+\def\ShowB#1#2#3{$x + { {#1} \Uskewedwithdelims / () #3 {#2} } + x$}
+
+\start
+    \switchtobodyfont[modern]
+    \starttabulate[||||||]
+        \NC \NC
+            \ShowA{a}{b}{} \NC
+            \ShowA{1}{2}{} \NC
+            \ShowB{a}{b}{} \NC
+            \ShowB{1}{2}{} \NC
+        \NR
+        \NC \type{exact} \NC
+            \ShowA{a}{b}{exact} \NC
+            \ShowA{1}{2}{exact} \NC
+            \ShowB{a}{b}{exact} \NC
+            \ShowB{1}{2}{exact} \NC
+        \NR
+        \NC \type{noaxis} \NC
+            \ShowA{a}{b}{noaxis} \NC
+            \ShowA{1}{2}{noaxis} \NC
+            \ShowB{a}{b}{noaxis} \NC
+            \ShowB{1}{2}{noaxis} \NC
+        \NR
+        \NC \type{exact noaxis} \NC
+            \ShowA{a}{b}{exact noaxis} \NC
+            \ShowA{1}{2}{exact noaxis} \NC
+            \ShowB{a}{b}{exact noaxis} \NC
+            \ShowB{1}{2}{exact noaxis} \NC
+        \NR
+    \stoptabulate
+\stop
+
+\subsection {Delimiters: \type{\Uleft}, \prm {Umiddle} and \prm {Uright}}
+
+\topicindex {math+delimiters}
+
+Normally you will force delimiters to certain sizes by putting an empty box or
+rule next to it. The resulting delimiter will either be a character from the
+stepwise size range or an extensible. The latter can be quite differently
+positioned than the characters as it depends on the fit as well as the fact if
+the used characters in the font have depth or height. Commands like (plain \TEX
+s) \type {\big} need use this feature. In \LUATEX\ we provide a bit more control
+by three variants that support optional parameters \type {height}, \type {depth}
+and \type {axis}. The following example uses this:
+
+\startbuffer
+\Uleft   height 30pt depth 10pt      \Udelimiter "0 "0 "000028
+\quad x\quad
+\Umiddle height 40pt depth 15pt      \Udelimiter "0 "0 "002016
+\quad x\quad
+\Uright  height 30pt depth 10pt      \Udelimiter "0 "0 "000029
+\quad \quad \quad
+\Uleft   height 30pt depth 10pt axis \Udelimiter "0 "0 "000028
+\quad x\quad
+\Umiddle height 40pt depth 15pt axis \Udelimiter "0 "0 "002016
+\quad x\quad
+\Uright  height 30pt depth 10pt axis \Udelimiter "0 "0 "000029
+\stopbuffer
+
+\typebuffer
+
+\startlinecorrection
+\ruledhbox{\mathematics{\getbuffer}}
+\stoplinecorrection
+
+The keyword \type {exact} can be used as directive that the real dimensions
+should be applied when the criteria can't be met which can happen when we're
+still stepping through the successively larger variants. When no dimensions are
+given the \type {noaxis} command can be used to prevent shifting over the axis.
+
+You can influence the final class with the keyword \type {class} which will
+influence the spacing. The numbers are the same as for character classes.
+
+\stopsection
+
+\startsection[title={Extracting values}]
+
+\subsection{Codes}
+
+\topicindex {math+codes}
+
+You can extract the components of a math character. Say that we have defined:
+
+\starttyping
+\Umathcode 1 2 3 4
+\stoptyping
+
+then
+
+\starttyping
+[\Umathcharclass1] [\Umathcharfam1] [\Umathcharslot1]
+\stoptyping
+
+will return:
+
+\starttyping
+[2] [3] [4]
+\stoptyping
+
+These commands are provides as convenience. Before they come available you could
+do the following:
+
+\starttyping
+\def\Umathcharclass{\directlua{tex.print(tex.getmathcode(token.scan_int())[1])}}
+\def\Umathcharfam  {\directlua{tex.print(tex.getmathcode(token.scan_int())[2])}}
+\def\Umathcharslot {\directlua{tex.print(tex.getmathcode(token.scan_int())[3])}}
+\stoptyping
+
+\subsection {Last lines}
+
+\topicindex {math+last line}
+
+There is a new primitive to control the overshoot in the calculation of the
+previous line in mid|-|paragraph display math. The default value is 2 times
+the em width of the current font:
+
+\starttyping
+\predisplaygapfactor=2000
+\stoptyping
+
+If you want to have the length of the last line independent of math i.e.\ you don't
+want to revert to a hack where you insert a fake display math formula in order to
+get the length of the last line, the following will often work too:
+
+\starttyping
+\def\lastlinelength{\dimexpr
+    \directlua {tex.sprint (
+        (nodes.dimensions(node.tail(tex.lists.page_head).list))
+    )}sp
+\relax}
+\stoptyping
+
+\stopsection
+
+\startsection[title={Math mode}]
+
+\subsection {Verbose versions of single|-|character math commands}
+
+\topicindex {math+styles}
+
+\LUATEX\ defines six new primitives that have the same function as
+\type {^}, \type {_}, \type {$}, and \type {$$}:
+
+\starttabulate[|l|l|]
+\DB primitive                  \BC explanation \NC \NR
+\TB
+\NC \lpr {Usuperscript}      \NC duplicates the functionality of \type {^} \NC \NR
+\NC \lpr {Usubscript}        \NC duplicates the functionality of \type {_} \NC \NR
+\NC \lpr {Ustartmath}        \NC duplicates the functionality of \type {$}, % $
+                                   when used in non-math mode. \NC \NR
+\NC \lpr {Ustopmath}         \NC duplicates the functionality of \type {$}, % $
+                                   when used in inline math mode. \NC \NR
+\NC \lpr {Ustartdisplaymath} \NC duplicates the functionality of \type {$$}, % $$
+                                   when used in non-math mode. \NC \NR
+\NC \lpr {Ustopdisplaymath}  \NC duplicates the functionality of \type {$$}, % $$
+                                   when used in display math mode. \NC \NR
+\LL
+\stoptabulate
+
+The \lpr {Ustopmath} and \lpr {Ustopdisplaymath} primitives check if the current
+math mode is the correct one (inline vs.\ displayed), but you can freely intermix
+the four mathon|/|mathoff commands with explicit dollar sign(s).
+
+\subsection{Script commands \lpr {Unosuperscript} and \lpr {Unosubscript}}
+
+\topicindex {math+styles}
+\topicindex {math+scripts}
+
+These two commands result in super- and subscripts but with the current style (at the
+time of rendering). So,
+
+\startbuffer[script]
+$
+    x\Usuperscript  {1}\Usubscript  {2} =
+    x\Unosuperscript{1}\Unosubscript{2} =
+    x\Usuperscript  {1}\Unosubscript{2} =
+    x\Unosuperscript{1}\Usubscript  {2}
+$
+\stopbuffer
+
+\typebuffer
+
+results in \inlinebuffer[script].
+
+\subsection{Allowed math commands in non|-|math modes}
+
+\topicindex {math+text}
+\topicindex {text+math}
+
+The commands \prm {mathchar}, and \lpr {Umathchar} and control sequences that are
+the result of \prm {mathchardef} or \lpr {Umathchardef} are also acceptable in
+the horizontal and vertical modes. In those cases, the \prm {textfont} from the
+requested math family is used.
+
+% \startsection[title={Math todo}]
+%
+% The following items are still todo.
+%
+% \startitemize
+% \startitem
+%     Pre-scripts.
+% \stopitem
+% \startitem
+%     Multi-story stacks.
+% \stopitem
+% \startitem
+%     Flattened accents for high characters (maybe).
+% \stopitem
+% \startitem
+%     Better control over the spacing around displays and handling of equation numbers.
+% \stopitem
+% \startitem
+%     Support for multi|-|line displays using \MATHML\ style alignment points.
+% \stopitem
+% \stopitemize
+%
+% \stopsection
+
+\stopsection
+
+\startsection[title={Goodies}]
+
+\subsection {Flattening: \lpr {mathflattenmode}}
+
+\topicindex {math+flattening}
+
+The \TEX\ math engine collapses \type {ord} noads without sub- and superscripts
+and a character as nucleus. and which has the side effect that in \OPENTYPE\ mode
+italic corrections are applied (given that they are enabled).
+
+\startbuffer[sample]
+\switchtobodyfont[modern]
+$V \mathbin{\mathbin{v}} V$\par
+$V \mathord{\mathord{v}} V$\par
+\stopbuffer
+
+\typebuffer[sample]
+
+This renders as:
+
+\blank \start \mathflattenmode\plusone \getbuffer[sample] \stop \blank
+
+When we set \lpr {mathflattenmode} to 31 we get:
+
+\blank \start \mathflattenmode\numexpr1+2+4+8+16\relax \getbuffer[sample] \stop \blank
+
+When you see no difference, then the font probably has the proper character
+dimensions and no italic correction is needed. For Latin Modern (at least till
+2018) there was a visual difference. In that respect this parameter is not always
+needed unless of course you want efficient math lists anyway.
+
+You can influence flattening by adding the appropriate number to the value of the
+mode parameter. The default value is~1.
+
+\starttabulate[|Tc|c|]
+\DB mode \BC class \NC \NR
+\TB
+\NC  1   \NC ord   \NC \NR
+\NC  2   \NC bin   \NC \NR
+\NC  4   \NC rel   \NC \NR
+\NC  8   \NC punct \NC \NR
+\NC 16   \NC inner \NC \NR
+\LL
+\stoptabulate
+
+\subsection {Less Tracing}
+
+\topicindex {math+tracing}
+
+Because there are quite some math related parameters and values, it is possible
+to limit tracing. Only when \type {tracingassigns} and|/|or \type
+{tracingrestores} are set to~2 or more they will be traced.
+
+\subsection {Math options with \lpr {mathoption}}
+
+The logic in the math engine is rather complex and there are often no universal
+solutions (read: what works out well for one font, fails for another). Therefore
+some variations in the implementation are driven by parameters (modes). In
+addition there is a new primitive \lpr {mathoption} which will be used for
+testing. Don't rely on any option to be there in a production version as they are
+meant for development.
+
+This option was introduced for testing purposes when the math engine got split
+code paths and it forces the engine to treat new fonts as old ones with respect
+to italic correction etc. There are no guarantees given with respect to the final
+result and unexpected side effects are not seen as bugs as they relate to font
+properties. Ther eis currently only one option:
+
+\startbuffer
+\mathoption old 1
+\stopbuffer
+
+The \type {oldmath} boolean flag in the \LUA\ font table is the official way to
+force old treatment as it's bound to fonts. Like with all options we may
+temporarily introduce with this command this feature is not meant for production.
+
+% % obsolete:
+%
+% \subsubsection {\type {\mathoption noitaliccompensation}}
+%
+% This option compensates placement for characters with a built|-|in italic
+% correction.
+%
+% \startbuffer
+% {\showboxes\int}\quad
+% {\showboxes\int_{|}^{|}}\quad
+% {\showboxes\int\limits_{|}^{|}}
+% \stopbuffer
+%
+% \typebuffer
+%
+% Gives (with computer modern that has such italics):
+%
+% \startlinecorrection[blank]
+%     \switchtobodyfont[modern]
+%     \startcombination[nx=2,ny=2,distance=5em]
+%         {\mathoption noitaliccompensation 0\relax \mathematics{\getbuffer}}
+%             {\nohyphens\type{0:inline}}
+%         {\mathoption noitaliccompensation 0\relax \mathematics{\displaymath\getbuffer}}
+%             {\nohyphens\type{0:display}}
+%         {\mathoption noitaliccompensation 1\relax \mathematics{\getbuffer}}
+%             {\nohyphens\type{1:inline}}
+%         {\mathoption noitaliccompensation 1\relax \mathematics{\displaymath\getbuffer}}
+%             {\nohyphens\type{1:display}}
+%     \stopcombination
+% \stoplinecorrection
+
+% % obsolete:
+%
+% \subsubsection {\type {\mathoption nocharitalic}}
+%
+% When two characters follow each other italic correction can interfere. The
+% following example shows what this option does:
+%
+% \startbuffer
+% \catcode"1D443=11
+% \catcode"1D444=11
+% \catcode"1D445=11
+% P( PP PQR
+% \stopbuffer
+%
+% \typebuffer
+%
+% Gives (with computer modern that has such italics):
+%
+% \startlinecorrection[blank]
+%     \switchtobodyfont[modern]
+%     \startcombination[nx=2,ny=2,distance=5em]
+%         {\mathoption nocharitalic 0\relax \mathematics{\getbuffer}}
+%             {\nohyphens\type{0:inline}}
+%         {\mathoption nocharitalic 0\relax \mathematics{\displaymath\getbuffer}}
+%             {\nohyphens\type{0:display}}
+%         {\mathoption nocharitalic 1\relax \mathematics{\getbuffer}}
+%             {\nohyphens\type{1:inline}}
+%         {\mathoption nocharitalic 1\relax \mathematics{\displaymath\getbuffer}}
+%             {\nohyphens\type{1:display}}
+%     \stopcombination
+% \stoplinecorrection
+
+% % obsolete:
+%
+% \subsubsection {\type {\mathoption useoldfractionscaling}}
+%
+% This option has been introduced as solution for tracker item 604 for fuzzy cases
+% around either or not present fraction related settings for new fonts.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-modifications.tex b/systems/doc/luatex/luatex-modifications.tex
index 294f3fc3f8..b7ce6ca2bd 100644
--- a/systems/doc/luatex/luatex-modifications.tex
+++ b/systems/doc/luatex/luatex-modifications.tex
@@ -1,1380 +1,1389 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-modifications

-

-\startchapter[reference=modifications,title={Modifications}]

-

-\startsection[title=The merged engines]

-

-\startsubsection[title=The need for change]

-

-\topicindex {engines}

-\topicindex {history}

-

-The first version of \LUATEX\ only had a few extra primitives and it was largely

-the same as \PDFTEX. Then we merged substantial parts of \ALEPH\ into the code

-and got more primitives. When we got more stable the decision was made to clean

-up the rather hybrid nature of the program. This means that some primitives have

-been promoted to core primitives, often with a different name, and that others

-were removed. This made it possible to start cleaning up the code base. In \in

-{chapter} [enhancements] we discussed some new primitives, here we will cover

-most of the adapted ones.

-

-Besides the expected changes caused by new functionality, there are a number of

-not|-|so|-|expected changes. These are sometimes a side|-|effect of a new

-(conflicting) feature, or, more often than not, a change necessary to clean up

-the internal interfaces. These will also be mentioned.

-

-\stopsubsection

-

-\startsubsection[title=Changes from \TEX\ 3.1415926]

-

-\topicindex {\TEX}

-

-Of course it all starts with traditional \TEX. Even if we started with \PDFTEX,

-most still comes from the original. But we divert a bit.

-

-\startitemize

-

-\startitem

-    The current code base is written in \CCODE, not \PASCAL. We use \CWEB\ when

-    possible. As a consequence instead of one large file plus change files, we

-    now have multiple files organized in categories like \type {tex}, \type

-    {pdf}, \type {lang}, \type {font}, \type {lua}, etc. There are some artifacts

-    of the conversion to \CCODE, but in due time we will clean up the source code

-    and make sure that the documentation is done right. Many files are in the

-    \CWEB\ format, but others, like those interfacing to \LUA, are \CCODE\ files.

-    Of course we want to stay as close as possible to the original so that the

-    documentation of the fundamentals behind \TEX\ by Don Knuth still applies.

-\stopitem

-

-\startitem

-    See \in {chapter} [languages] for many small changes related to paragraph

-    building, language handling and hyphenation. The most important change is

-    that adding a brace group in the middle of a word (like in \type {of{}fice})

-    does not prevent ligature creation.

-\stopitem

-

-\startitem

-    There is no pool file, all strings are embedded during compilation.

-\stopitem

-

-\startitem

-    The specifier \type {plus 1 fillll} does not generate an error. The extra

-    \quote{l} is simply typeset.

-\stopitem

-

-\startitem

-    The upper limit to \prm {endlinechar} and \prm {newlinechar} is 127.

-\stopitem

-

-\startitem

-    Magnification (\prm {mag}) is only supported in \DVI\ output mode. You can

-    set this parameter and it even works with \type {true} units till you switch

-    to \PDF\ output mode. When you use \PDF\ output you can best not touch the

-    \prm {mag} variable. This fuzzy behaviour is not much different from using

-    \PDF\ backend related functionality while eventually \DVI\ output is

-    required.

-

-    After the output mode has been frozen (normally that happens when the first

-    page is shipped out) or when \PDF\ output is enabled, the \type {true}

-    specification is ignored. When you preload a plain format adapted to

-    \LUATEX\ it can be that the \prm {mag} parameter already has been set.

-\stopitem

-

-\stopitemize

-

-\stopsubsection

-

-\startsubsection[title=Changes from \ETEX\ 2.2]

-

-\topicindex {\ETEX}

-

-Being the de factor standard extension of course we provide the \ETEX\

-functionality, but with a few small adaptations.

-

-\startitemize

-

-\startitem

-    The \ETEX\ functionality is always present and enabled so the prepended

-    asterisk or \type {-etex} switch for \INITEX\ is not needed.

-\stopitem

-

-\startitem

-    The \TEXXET\ extension is not present, so the primitives \type

-    {\TeXXeTstate}, \type {\beginR}, \type {\beginL}, \type {\endR} and \type

-    {\endL} are missing. Instead we used the \OMEGA/\ALEPH\ approach to

-    directionality as starting point.

-\stopitem

-

-\startitem

-    Some of the tracing information that is output by \ETEX's \prm

-    {tracingassigns} and \prm {tracingrestores} is not there.

-\stopitem

-

-\startitem

-    Register management in \LUATEX\ uses the \OMEGA/\ALEPH\ model, so the maximum

-    value is 65535 and the implementation uses a flat array instead of the mixed

-    flat & sparse model from \ETEX.

-\stopitem

-

-\startitem

-    When kpathsea is used to find files, \LUATEX\ uses the \type {ofm} file

-    format to search for font metrics. In turn, this means that \LUATEX\ looks at

-    the \type {OFMFONTS} configuration variable (like \OMEGA\ and \ALEPH) instead

-    of \type {TFMFONTS} (like \TEX\ and \PDFTEX). Likewise for virtual fonts

-    (\LUATEX\ uses the variable \type {OVFFONTS} instead of \type {VFFONTS}).

-\stopitem

-

-\stopitemize

-

-\stopsubsection

-

-\startsubsection[title=Changes from \PDFTEX\ 1.40]

-

-\topicindex {\PDFTEX}

-

-Because we want to produce \PDF\ the most natural starting point was the popular

-\PDFTEX\ program. We inherit the stable features, dropped most of the

-experimental code and promoted some functionality to core \LUATEX\ functionality

-which in turn triggered renaming primitives.

-

-For compatibility reasons we still refer to \type {\pdf...} commands but \LUATEX\

-has a different backend interface. Instead of these primitives there are three

-interfacing primitives: \lpr {pdfextension}, \lpr {pdfvariable} and \lpr

-{pdffeedback} that take keywords and optional further arguments (below we will

-still use the \tex {pdf} prefix names as reference). This way we can extend the

-features when needed but don't need to adapt the core engine. The front- and

-backend are decoupled as much as possible.

-

-\startitemize

-

-\startitem

-    The (experimental) support for snap nodes has been removed, because it is

-    much more natural to build this functionality on top of node processing and

-    attributes. The associated primitives that are gone are: \orm

-    {pdfsnaprefpoint}, \orm {pdfsnapy}, and \orm {pdfsnapycomp}.

-\stopitem

-

-\startitem

-    The (experimental) support for specialized spacing around nodes has also been

-    removed. The associated primitives that are gone are: \orm

-    {pdfadjustinterwordglue}, \orm {pdfprependkern}, and \orm {pdfappendkern}, as

-    well as the five supporting primitives \orm {knbscode}, \orm {stbscode}, \orm

-    {shbscode}, \orm {knbccode}, and \orm {knaccode}.

-\stopitem

-

-\startitem

-    A number of \quote {\PDFTEX\ primitives} have been removed as they can be

-    implemented using \LUA: \orm {pdfelapsedtime}, \orm {pdfescapehex}, \orm

-    {pdfescapename}, \orm {pdfescapestring}, \orm {pdffiledump}, \orm

-    {pdffilemoddate}, \orm {pdffilesize}, \orm {pdfforcepagebox}, \orm

-    {pdflastmatch}, \orm {pdfmatch}, \orm {pdfmdfivesum}, \orm {pdfmovechars},

-    \orm {pdfoptionalwaysusepdfpagebox}, \orm {pdfoptionpdfinclusionerrorlevel},

-    \orm {pdfresettimer}, \orm {pdfshellescape}, \orm {pdfstrcmp} and \orm

-    {pdfunescapehex}.

-\stopitem

-

-\startitem

-    The version related primitives \orm {pdftexbanner}, \orm {pdftexversion}

-    and \orm {pdftexrevision} are no longer present as there is no longer a

-    relationship with \PDFTEX\ development.

-\stopitem

-

-\startitem

-    The experimental snapper mechanism has been removed and therefore also the

-    primitives \orm {pdfignoreddimen}, \orm {pdffirstlineheight}, \orm

-    {pdfeachlineheight}, \orm {pdfeachlinedepth} and \orm {pdflastlinedepth}.

-\stopitem

-

-\startitem

-    The experimental primitives \lpr {primitive}, \lpr {ifprimitive}, \lpr

-    {ifabsnum} and \lpr {ifabsdim} are promoted to core primitives. The \type

-    {\pdf*} prefixed originals are not available.

-\stopitem

-

-\startitem

-    Because \LUATEX\ has a different subsystem for managing images, more

-    diversion from its ancestor happened in the meantime. We don't adapt to

-    changes in \PDFTEX.

-\stopitem

-

-\startitem

-    Two extra token lists are provided, \orm {pdfxformresources} and \orm

-    {pdfxformattr}, as an alternative to \orm {pdfxform} keywords.

-\stopitem

-

-\startitem

-    Image specifications also support \type {visiblefilename}, \type

-    {userpassword} and \type {ownerpassword}. The password options are only

-    relevant for encrypted \PDF\ files.

-\stopitem

-

-\startitem

-    The current version of \LUATEX\ no longer replaces and|/|or merges fonts in

-    embedded \PDF\ files with fonts of the enveloping \PDF\ document. This

-    regression may be temporary, depending on how the rewritten font backend will

-    look like.

-\stopitem

-

-\startitem

-    The primitives \orm {pdfpagewidth} and \orm {pdfpageheight} have been removed

-    because \lpr {pagewidth} and \lpr {pageheight} have that purpose.

-\stopitem

-

-\startitem

-    The primitives \orm {pdfnormaldeviate}, \orm {pdfuniformdeviate}, \orm

-    {pdfsetrandomseed} and \orm {pdfrandomseed} have been promoted to core

-    primitives without \type {pdf} prefix so the original commands are no longer

-    recognized.

-\stopitem

-

-\startitem

-    The primitives \lpr {ifincsname}, \lpr {expanded} and \lpr {quitvmode}

-    are now core primitives.

-\stopitem

-

-\startitem

-    As the hz and protrusion mechanism are part of the core the related

-    primitives \lpr {lpcode}, \lpr {rpcode}, \lpr {efcode}, \lpr

-    {leftmarginkern}, \lpr {rightmarginkern} are promoted to core primitives. The

-    two commands \lpr {protrudechars} and \lpr {adjustspacing} replace their

-    prefixed with \type {\pdf} originals.

-\stopitem

-

-\startitem

-    The hz optimization code has been partially redone so that we no longer need

-    to create extra font instances. The front- and backend have been decoupled

-    and more efficient (\PDF) code is generated.

-\stopitem

-

-\startitem

-    When \lpr {adjustspacing} has value~2, hz optimization will be applied to

-    glyphs and kerns. When the value is~3, only glyphs will be treated. A value

-    smaller than~2 disables this feature.

-\stopitem

-

-\startitem

-    The \lpr {tagcode} primitive is promoted to core primitive.

-\stopitem

-

-\startitem

-    The \lpr {letterspacefont} feature is now part of the core but will not be

-    changed (improved). We just provide it for legacy use.

-\stopitem

-

-\startitem

-    The \orm {pdfnoligatures} primitive is now \lpr {ignoreligaturesinfont}.

-\stopitem

-

-\startitem

-    The \orm {pdfcopyfont} primitive is now \lpr {copyfont}.

-\stopitem

-

-\startitem

-    The \orm {pdffontexpand} primitive is now \lpr {expandglyphsinfont}.

-\stopitem

-

-\startitem

-    Because position tracking is also available in \DVI\ mode the \lpr {savepos},

-    \lpr {lastxpos} and \lpr {lastypos} commands now replace their \type {pdf}

-    prefixed originals.

-\stopitem

-

-\startitem

-    The introspective primitives \type {\pdflastximagecolordepth} and \type

-    {\pdfximagebbox} have been removed. One can use external applications to

-    determine these properties or use the built|-|in \type {img} library.

-\stopitem

-

-\startitem

-    The initializers \orm {pdfoutput} has been replaced by \lpr {outputmode} and

-    \orm {pdfdraftmode} is now \lpr {draftmode}.

-\stopitem

-

-\startitem

-    The pixel multiplier dimension \orm {pdfpxdimen} lost its prefix and is now

-    called \lpr {pxdimen}.

-\stopitem

-

-\startitem

-    An extra \orm {pdfimageaddfilename} option has been added that can be used to

-    block writing the filename to the \PDF\ file.

-\stopitem

-

-\startitem

-    The primitive \orm {pdftracingfonts} is now \lpr {tracingfonts} as it

-    doesn't relate to the backend.

-\stopitem

-

-\startitem

-    The experimental primitive \orm {pdfinsertht} is kept as \lpr {insertht}.

-\stopitem

-

-\startitem

-    There is some more control over what metadata goes into the \PDF\ file.

-\stopitem

-

-\startitem

-    The promotion of primitives to core primitives as well as the separation of

-    font- and backend means that the initialization namespace \type {pdftex} is

-    gone.

-\stopitem

-

-\stopitemize

-

-One change involves the so called xforms and ximages. In \PDFTEX\ these are

-implemented as so called whatsits. But contrary to other whatsits they have

-dimensions that need to be taken into account when for instance calculating

-optimal line breaks. In \LUATEX\ these are now promoted to a special type of rule

-nodes, which simplifies code that needs those dimensions.

-

-Another reason for promotion is that these are useful concepts. Backends can

-provide the ability to use content that has been rendered in several places, and

-images are also common. As already mentioned in \in {section}

-[sec:imagedandforms], we now have:

-

-\starttabulate[|l|l|]

-\DB \LUATEX \BC \PDFTEX \NC \NR

-\TB

-\NC \lpr {saveboxresource}             \NC \orm {pdfxform}           \NC \NR

-\NC \lpr {saveimageresource}           \NC \orm {pdfximage}          \NC \NR

-\NC \lpr {useboxresource}              \NC \orm {pdfrefxform}        \NC \NR

-\NC \lpr {useimageresource}            \NC \orm {pdfrefximage}       \NC \NR

-\NC \lpr {lastsavedboxresourceindex}   \NC \orm {pdflastxform}       \NC \NR

-\NC \lpr {lastsavedimageresourceindex} \NC \orm {pdflastximage}      \NC \NR

-\NC \lpr {lastsavedimageresourcepages} \NC \orm {pdflastximagepages} \NC \NR

-\LL

-\stoptabulate

-

-There are a few \lpr {pdffeedback} features that relate to this but these are

-typical backend specific ones. The index that gets returned is to be considered

-as \quote {just a number} and although it still has the same meaning (object

-related) as before, you should not depend on that.

-

-The protrusion detection mechanism is enhanced a bit to enable a bit more complex

-situations. When protrusion characters are identified some nodes are skipped:

-

-\startitemize[packed,columns,two]

-\startitem zero glue \stopitem

-\startitem penalties \stopitem

-\startitem empty discretionaries \stopitem

-\startitem normal zero kerns \stopitem

-\startitem rules with zero dimensions \stopitem

-\startitem math nodes with a surround of zero \stopitem

-\startitem dir nodes \stopitem

-\startitem empty horizontal lists \stopitem

-\startitem local par nodes \stopitem

-\startitem inserts, marks and adjusts \stopitem

-\startitem boundaries \stopitem

-\startitem whatsits \stopitem

-\stopitemize

-

-Because this can not be enough, you can also use a protrusion boundary node to

-make the next node being ignored. When the value is~1 or~3, the next node will be

-ignored in the test when locating a left boundary condition. When the value is~2

-or~3, the previous node will be ignored when locating a right boundary condition

-(the search goes from right to left). This permits protrusion combined with for

-instance content moved into the margin:

-

-\starttyping

-\protrusionboundary1\llap{!\quad}«Who needs protrusion?»

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title=Changes from \ALEPH\ RC4]

-

-\topicindex {\ALEPH}

-

-Because we wanted proper directional typesetting the \ALEPH\ mechanisms looked

-most attractive. These are rather close to the ones provided by \OMEGA, so what

-we say next applies to both these programs.

-

-\startitemize

-

-\startitem

-    The extended 16-bit math primitives (\orm {omathcode} etc.) have been

-    removed.

-\stopitem

-

-\startitem

-    The \OCP\ processing has been removed completely and as a consequence, the

-    following primitives have been removed: \orm {ocp}, \orm {externalocp}, \orm

-    {ocplist}, \orm {pushocplist}, \orm {popocplist}, \orm {clearocplists}, \orm

-    {addbeforeocplist}, \orm {addafterocplist}, \orm {removebeforeocplist}, \orm

-    {removeafterocplist} and \orm {ocptracelevel}.

-\stopitem

-

-\startitem

-    \LUATEX\ only understands 4~of the 16~direction specifiers of \ALEPH: \type

-    {TLT} (latin), \type {TRT} (arabic), \type {RTT} (cjk), \type {LTL} (mongolian).

-    All other direction specifiers generate an error. In addition to a keyword

-    driven model we also provide an integer driven one.

-\stopitem

-

-\startitem

-    The input translations from \ALEPH\ are not implemented, the related

-    primitives are not available: \orm {DefaultInputMode}, \orm

-    {noDefaultInputMode}, \orm {noInputMode}, \orm {InputMode}, \orm

-    {DefaultOutputMode}, \orm {noDefaultOutputMode}, \orm {noOutputMode}, \orm

-    {OutputMode}, \orm {DefaultInputTranslation}, \orm

-    {noDefaultInputTranslation}, \orm {noInputTranslation}, \orm

-    {InputTranslation}, \orm {DefaultOutputTranslation}, \orm

-    {noDefaultOutputTranslation}, \orm {noOutputTranslation} and \orm

-    {OutputTranslation}.

-\stopitem

-

-\startitem

-    Several bugs have been fixed and confusing implementation details have been

-    sorted out.

-\stopitem

-

-\startitem

-    The scanner for direction specifications now allows an optional space after

-    the direction is completely parsed.

-\stopitem

-

-\startitem

-    The \type {^^} notation has been extended: after \type {^^^^} four

-    hexadecimal characters are expected and after \type {^^^^^^} six hexadecimal

-    characters have to be given. The original \TEX\ interpretation is still valid

-    for the \type {^^} case but the four and six variants do no backtracking,

-    i.e.\ when they are not followed by the right number of hexadecimal digits

-    they issue an error message. Because \type{^^^} is a normal \TEX\ case, we

-    don't support the odd number of \type {^^^^^} either.

-\stopitem

-

-\startitem

-    Glues {\it immediately after} direction change commands are not legal

-    breakpoints.

-\stopitem

-

-\startitem

-    Several mechanisms that need to be right|-|to|-|left aware have been

-    improved. For instance placement of formula numbers.

-\stopitem

-

-\startitem

-    The page dimension related primitives \lpr {pagewidth} and \lpr {pageheight}

-    have been promoted to core primitives. The \prm {hoffset} and \prm {voffset}

-    primitives have been fixed.

-\stopitem

-

-\startitem

-    The primitives \type {\charwd}, \type {\charht}, \type {\chardp} and \type

-    {\charit} have been removed as we have the \ETEX\ variants \type

-    {\fontchar*}.

-\stopitem

-

-\startitem

-    The two dimension registers \lpr {pagerightoffset} and \lpr

-    {pagebottomoffset} are now core primitives.

-\stopitem

-

-\startitem

-    The direction related primitives \lpr {pagedir}, \lpr {bodydir}, \lpr

-    {pardir}, \lpr {textdir}, \lpr {mathdir} and \lpr {boxdir} are now core

-    primitives.

-\stopitem

-

-\startitem

-    The promotion of primitives to core primitives as well as removing of all

-    others means that the initialization namespace \type {aleph} that early

-    versions of \LUATEX\ provided is gone.

-\stopitem

-

-\stopitemize

-

-The above let's itself summarize as: we took the 32 bit aspects and much of the

-directional mechanisms and merged it into the \PDFTEX\ code base as starting

-point for further development. Then we simplified directionality, fixed it and

-opened it up.

-

-\stopsubsection

-

-\startsubsection[title=Changes from standard \WEBC]

-

-\topicindex {\WEBC}

-

-The compilation framework is \WEBC\ and we keep using that but without the

-\PASCAL\ to \CCODE\ step. This framework also provides some common features that

-deal with reading bytes from files and locating files in \TDS. This is what we do

-different:

-

-\startitemize

-

-\startitem

-    There is no mltex support.

-\stopitem

-

-\startitem

-    There is no enctex support.

-\stopitem

-

-\startitem

-    The following encoding related command line switches are silently ignored,

-    even in non|-|\LUA\ mode: \type {-8bit}, \type {-translate-file}, \type

-    {-mltex}, \type {-enc} and \type {-etex}.

-\stopitem

-

-\startitem

-    The \prm {openout} whatsits are not written to the log file.

-\stopitem

-

-\startitem

-    Some of the so|-|called \WEBC\ extensions are hard to set up in non|-|\KPSE\

-    mode because \type {texmf.cnf} is not read: \type {shell-escape} is off (but

-    that is not a problem because of \LUA's \type {os.execute}), and the paranoia

-    checks on \type {openin} and \type {openout} do not happen. However, it is

-    easy for a \LUA\ script to do this itself by overloading \type {io.open} and

-    alike.

-\stopitem

-

-\startitem

-    The \quote{E} option does not do anything useful.

-\stopitem

-

-\stopitemize

-

-\stopsubsection

-

-\stopsection

-

-\startsection[reference=backendprimitives,title=The backend primitives]

-

-\startsubsection[title={Less primitives}]

-

-\topicindex {backend}

-\topicindex {\PDF+backend}

-

-In a previous section we mentioned that some \PDFTEX\ primitives were removed and

-others promoted to core \LUATEX\ primitives. That is only part of the story. In

-order to separate the backend specific primitives in de code these commands are

-now replaced by only a few. In traditional \TEX\ we only had the \DVI\ backend

-but now we have two: \DVI\ and \PDF. Additional functionality is implemented as

-\quote {extensions} in \TEX\ speak. By separating more strickly we are able to

-keep the core (frontend) clean and stable and isolate these extensions. If for

-some reason an extra backend option is needed, it can be implemented without

-touching the core. The three \PDF\ backend related primitives are:

-

-\starttyping

-\pdfextension command [specification]

-\pdfvariable  name

-\pdffeedback  name

-\stoptyping

-

-An extension triggers further parsing, depending on the command given. A variable is

-a (kind of) register and can be read and written, while a feedback is reporting

-something (as it comes from the backend it's normally a sequence of tokens).

-

-\stopsubsection

-

-\startsubsection[title={\lpr{pdfextension}, \lpr {pdfvariable} and \lpr {pdffeedback}},reference=sec:pdfextensions]

-

-In order for \LUATEX\ to be more than just \TEX\ you need to enable primitives. That

-has already been the case right from the start. If you want the traditional \PDFTEX\

-primitives (for as far their functionality is still around) you now can do this:

-

-\starttyping

-\protected\def\pdfliteral             {\pdfextension literal}

-\protected\def\pdfcolorstack          {\pdfextension colorstack}

-\protected\def\pdfsetmatrix           {\pdfextension setmatrix}

-\protected\def\pdfsave                {\pdfextension save\relax}

-\protected\def\pdfrestore             {\pdfextension restore\relax}

-\protected\def\pdfobj                 {\pdfextension obj }

-\protected\def\pdfrefobj              {\pdfextension refobj }

-\protected\def\pdfannot               {\pdfextension annot }

-\protected\def\pdfstartlink           {\pdfextension startlink }

-\protected\def\pdfendlink             {\pdfextension endlink\relax}

-\protected\def\pdfoutline             {\pdfextension outline }

-\protected\def\pdfdest                {\pdfextension dest }

-\protected\def\pdfthread              {\pdfextension thread }

-\protected\def\pdfstartthread         {\pdfextension startthread }

-\protected\def\pdfendthread           {\pdfextension endthread\relax}

-\protected\def\pdfinfo                {\pdfextension info }

-\protected\def\pdfcatalog             {\pdfextension catalog }

-\protected\def\pdfnames               {\pdfextension names }

-\protected\def\pdfincludechars        {\pdfextension includechars }

-\protected\def\pdffontattr            {\pdfextension fontattr }

-\protected\def\pdfmapfile             {\pdfextension mapfile }

-\protected\def\pdfmapline             {\pdfextension mapline }

-\protected\def\pdftrailer             {\pdfextension trailer }

-\protected\def\pdfglyphtounicode      {\pdfextension glyphtounicode }

-\stoptyping

-

-The introspective primitives can be defined as:

-

-\starttyping

-\def\pdftexversion    {\numexpr\pdffeedback version\relax}

-\def\pdftexrevision           {\pdffeedback revision}

-\def\pdflastlink      {\numexpr\pdffeedback lastlink\relax}

-\def\pdfretval        {\numexpr\pdffeedback retval\relax}

-\def\pdflastobj       {\numexpr\pdffeedback lastobj\relax}

-\def\pdflastannot     {\numexpr\pdffeedback lastannot\relax}

-\def\pdfxformname     {\numexpr\pdffeedback xformname\relax}

-\def\pdfcreationdate          {\pdffeedback creationdate}

-\def\pdffontname      {\numexpr\pdffeedback fontname\relax}

-\def\pdffontobjnum    {\numexpr\pdffeedback fontobjnum\relax}

-\def\pdffontsize      {\dimexpr\pdffeedback fontsize\relax}

-\def\pdfpageref       {\numexpr\pdffeedback pageref\relax}

-\def\pdfcolorstackinit        {\pdffeedback colorstackinit}

-\stoptyping

-

-The configuration related registers have become:

-

-\starttyping

-\edef\pdfcompresslevel            {\pdfvariable compresslevel}

-\edef\pdfobjcompresslevel         {\pdfvariable objcompresslevel}

-\edef\pdfrecompress               {\pdfvariable recompress}

-\edef\pdfdecimaldigits            {\pdfvariable decimaldigits}

-\edef\pdfgamma                    {\pdfvariable gamma}

-\edef\pdfimageresolution          {\pdfvariable imageresolution}

-\edef\pdfimageapplygamma          {\pdfvariable imageapplygamma}

-\edef\pdfimagegamma               {\pdfvariable imagegamma}

-\edef\pdfimagehicolor             {\pdfvariable imagehicolor}

-\edef\pdfimageaddfilename         {\pdfvariable imageaddfilename}

-\edef\pdfpkresolution             {\pdfvariable pkresolution}

-\edef\pdfpkfixeddpi               {\pdfvariable pkfixeddpi}

-\edef\pdfinclusioncopyfonts       {\pdfvariable inclusioncopyfonts}

-\edef\pdfinclusionerrorlevel      {\pdfvariable inclusionerrorlevel}

-\edef\pdfignoreunknownimages      {\pdfvariable ignoreunknownimages}

-\edef\pdfgentounicode             {\pdfvariable gentounicode}

-\edef\pdfomitcidset               {\pdfvariable omitcidset}

-\edef\pdfomitcharset              {\pdfvariable omitcharset}

-\edef\pdfpagebox                  {\pdfvariable pagebox}

-\edef\pdfminorversion             {\pdfvariable minorversion}

-\edef\pdfuniqueresname            {\pdfvariable uniqueresname}

-

-\edef\pdfhorigin                  {\pdfvariable horigin}

-\edef\pdfvorigin                  {\pdfvariable vorigin}

-\edef\pdflinkmargin               {\pdfvariable linkmargin}

-\edef\pdfdestmargin               {\pdfvariable destmargin}

-\edef\pdfthreadmargin             {\pdfvariable threadmargin}

-\edef\pdfxformmargin              {\pdfvariable xformmargin}

-

-\edef\pdfpagesattr                {\pdfvariable pagesattr}

-\edef\pdfpageattr                 {\pdfvariable pageattr}

-\edef\pdfpageresources            {\pdfvariable pageresources}

-\edef\pdfxformattr                {\pdfvariable xformattr}

-\edef\pdfxformresources           {\pdfvariable xformresources}

-\edef\pdfpkmode                   {\pdfvariable pkmode}

-

-\edef\pdfsuppressoptionalinfo     {\pdfvariable suppressoptionalinfo }

-\edef\pdftrailerid                {\pdfvariable trailerid }

-\stoptyping

-

-The variables are internal ones, so they are anonymous. When you ask for the

-meaning of a few previously defined ones:

-

-\starttyping

-\meaning\pdfhorigin

-\meaning\pdfcompresslevel

-\meaning\pdfpageattr

-\stoptyping

-

-you will get:

-

-\starttyping

-macro:->[internal backend dimension]

-macro:->[internal backend integer]

-macro:->[internal backend tokenlist]

-\stoptyping

-

-The \prm {edef} can also be a \prm {def} but it's a bit more efficient to expand

-the lookup related register beforehand.

-

-The backend is derived from \PDFTEX\ so the same syntax applies. However, the

-\type {outline} command accepts a \type {objnum} followed by a number. No

-checking takes place so when this is used it had better be a valid (flushed)

-object.

-

-In order to be (more or less) compatible with \PDFTEX\ we also support the option

-to suppress some info but we do so via a bitset:

-

-\starttyping

-\pdfvariable suppressoptionalinfo \numexpr

-        0

-    +   1   % PTEX.FullBanner

-    +   2   % PTEX.FileName

-    +   4   % PTEX.PageNumber

-    +   8   % PTEX.InfoDict

-    +  16   % Creator

-    +  32   % CreationDate

-    +  64   % ModDate

-    + 128   % Producer

-    + 256   % Trapped

-    + 512   % ID

-\relax

-\stoptyping

-

-In addition you can overload the trailer id, but we don't do any checking on

-validity, so you have to pass a valid array. The following is like the ones

-normally generated by the engine. You even need to include the brackets here!

-

-\starttyping

-\pdfvariable trailerid {[

-    <FA052949448907805BA83C1E78896398>

-    <FA052949448907805BA83C1E78896398>

-]}

-\stoptyping

-

-Although we started from a merge of \PDFTEX\ and \ALEPH, by now the code base as

-well as functionality has diverted from those parents. Here we show the options

-that can be passed to the extensions.

-

-\starttexsyntax

-\pdfextension literal

-    [ direct | page | raw ] { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension dest

-    num integer | name { tokens }!crlf

-    [ fitbh | fitbv | fitb | fith| fitv | fit |

-      fitr <rule spec> | xyz [ zoom <integer> ]

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension annot

-    reserveobjnum | useobjnum <integer>

-    { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension save

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension restore

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension setmatrix

-    { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-[ \immediate ] \pdfextension obj

-    reserveobjnum

-\stoptexsyntax

-

-\starttexsyntax

-[ \immediate ] \pdfextension obj

-    [ useobjnum <integer> ]

-    [ uncompressed ]

-    [ stream  [ attr { tokens } ] ]

-    [ file ]

-    { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension refobj

-    <integer>

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension colorstack

-    <integer>

-    set { tokens } | push { tokens } | pop | current

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension startlink

-    [ attr { tokens } ]

-    user { tokens } | goto | thread

-    [ file { tokens } ]

-    [ page <integer> { tokens } | name { tokens } | num  integer ]

-    [ newwindow  | nonewwindow ]

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension endlink

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension startthread

-    num <integer> | name { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension endthread

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension thread

-    num <integer> | name { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension outline

-    [ attr { tokens } ]

-    [ useobjnum <integer> ]

-    [ count <integer> ]

-    { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension glyphtounicode

-    { tokens }

-    { tokens }

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension catalog

-    { tokens }

-    [ openaction

-      user { tokens } | goto | thread

-      [ file { tokens } ]

-      [ page <integer> { tokens } | name { tokens } | num <integer> ]

-      [ newwindow  | nonewwindow ] ]

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension fontattr

-    <integer>

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension mapfile

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension mapline

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension includechars

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension info

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension names

-    {tokens}

-\stoptexsyntax

-

-\starttexsyntax

-\pdfextension trailer

-    {tokens}

-\stoptexsyntax

-

-\stopsubsection

-

-\startsubsection[title={Defaults}]

-

-The engine sets the following defaults.

-

-\starttyping

-\pdfcompresslevel         9

-\pdfobjcompresslevel      1 % used: (0,9)

-\pdfrecompress            0 % mostly for debugging

-\pdfdecimaldigits         4 % used: (3,6)

-\pdfgamma              1000

-\pdfimageresolution      71

-\pdfimageapplygamma       0

-\pdfimagegamma         2200

-\pdfimagehicolor          1

-\pdfimageaddfilename      1

-\pdfpkresolution         72

-\pdfpkfixeddpi            0

-\pdfinclusioncopyfonts    0

-\pdfinclusionerrorlevel   0

-\pdfignoreunknownimages   0

-\pdfgentounicode          0

-\pdfomitcidset            0

-\pdfomitcharset           0

-\pdfpagebox               0

-\pdfminorversion          4

-\pdfuniqueresname         0

-

-\pdfhorigin             1in

-\pdfvorigin             1in

-\pdflinkmargin          0pt

-\pdfdestmargin          0pt

-\pdfthreadmargin        0pt

-\pdfxformmargin         0pt

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={Backward compatibility}]

-

-If you also want some backward compatibility, you can add:

-

-\starttyping

-\let\pdfpagewidth      \pagewidth

-\let\pdfpageheight     \pageheight

-

-\let\pdfadjustspacing  \adjustspacing

-\let\pdfprotrudechars  \protrudechars

-\let\pdfnoligatures    \ignoreligaturesinfont

-\let\pdffontexpand     \expandglyphsinfont

-\let\pdfcopyfont       \copyfont

-

-\let\pdfxform          \saveboxresource

-\let\pdflastxform      \lastsavedboxresourceindex

-\let\pdfrefxform       \useboxresource

-

-\let\pdfximage         \saveimageresource

-\let\pdflastximage     \lastsavedimageresourceindex

-\let\pdflastximagepages\lastsavedimageresourcepages

-\let\pdfrefximage      \useimageresource

-

-\let\pdfsavepos        \savepos

-\let\pdflastxpos       \lastxpos

-\let\pdflastypos       \lastypos

-

-\let\pdfoutput         \outputmode

-\let\pdfdraftmode      \draftmode

-

-\let\pdfpxdimen        \pxdimen

-

-\let\pdfinsertht       \insertht

-

-\let\pdfnormaldeviate  \normaldeviate

-\let\pdfuniformdeviate \uniformdeviate

-\let\pdfsetrandomseed  \setrandomseed

-\let\pdfrandomseed     \randomseed

-

-\let\pdfprimitive      \primitive

-\let\ifpdfprimitive    \ifprimitive

-

-\let\ifpdfabsnum       \ifabsnum

-\let\ifpdfabsdim       \ifabsdim

-\stoptyping

-

-And even:

-

-\starttyping

-\newdimen\pdfeachlineheight

-\newdimen\pdfeachlinedepth

-\newdimen\pdflastlinedepth

-\newdimen\pdffirstlineheight

-\newdimen\pdfignoreddimen

-\stoptyping

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title=Directions]

-

-\topicindex {\OMEGA}

-\topicindex {\ALEPH}

-\topicindex {directions}

-

-\startsubsection[title={Four directions}]

-

-The directional model in \LUATEX\ is inherited from \OMEGA|/|\ALEPH\ but we tried

-to improve it a bit. At some point we played with recovery of modes but that was

-disabled later on when we found that it interfered with nested directions. That

-itself had as side effect that the node list was no longer balanced with respect

-to directional nodes which in turn can give side effects when a series of dir

-changes happens without grouping.

-

-When extending the \PDF\ backend to support directions some inconsistencies were

-found and as a result we decided to support only the four models that make sense

-\type {TLT} (latin), \type {TRT} (arabic), \type {RTT} (cjk) and \type {LTL}

-(mongolian).

-

-\stopsubsection

-

-\startsubsection[title={How it works}]

-

-The approach is that we again make the list balanced but try to avoid some side

-effects. What happens is quite intuitive if we forget about spaces (turned into

-glue) but even there what happens makes sense if you look at it in detail.

-However that logic makes in|-|group switching kind of useless when no proper

-nested grouping is used: switching from right to left several times nested,

-results in spacing ending up after each other due to nested mirroring. Of course

-a sane macro package will manage this for the user but here we are discussing the

-low level dir injection.

-

-This is what happens:

-

-\starttyping

-\textdir TRT nur {\textdir TLT run \textdir TRT NUR} nur

-\stoptyping

-

-This becomes stepwise:

-

-\startnarrower

-\starttyping

-injected: [+TRT]nur {[+TLT]run [+TRT]NUR} nur

-balanced: [+TRT]nur {[+TLT]run [-TLT][+TRT]NUR[-TRT]} nur[-TRT]

-result  : run {RUNrun } run

-\stoptyping

-\stopnarrower

-

-And this:

-

-\starttyping

-\textdir TRT nur {nur \textdir TLT run \textdir TRT NUR} nur

-\stoptyping

-

-becomes:

-

-\startnarrower

-\starttyping

-injected: [+TRT]nur {nur [+TLT]run [+TRT]NUR} nur

-balanced: [+TRT]nur {nur [+TLT]run [-TLT][+TRT]NUR[-TRT]} nur[-TRT]

-result  : run {run RUNrun } run

-\stoptyping

-\stopnarrower

-

-Now, in the following examples watch where we put the braces:

-

-\startbuffer

-\textdir TRT nur {{\textdir TLT run} {\textdir TRT NUR}} nur

-\stopbuffer

-

-\typebuffer

-

-This becomes:

-

-\startnarrower

-\getbuffer

-\stopnarrower

-

-Compare this to:

-

-\startbuffer

-\textdir TRT nur {{\textdir TLT run }{\textdir TRT NUR}} nur

-\stopbuffer

-

-\typebuffer

-

-Which renders as:

-

-\startnarrower

-\getbuffer

-\stopnarrower

-

-So how do we deal with the next?

-

-\startbuffer

-\def\ltr{\textdir TLT\relax}

-\def\rtl{\textdir TRT\relax}

-

-run {\rtl nur {\ltr run \rtl NUR \ltr run \rtl NUR} nur}

-run {\ltr run {\rtl nur \ltr RUN \rtl nur \ltr RUN} run}

-\stopbuffer

-

-\typebuffer

-

-It gets typeset as:

-

-\startnarrower

-\startlines

-\getbuffer

-\stoplines

-\stopnarrower

-

-We could define the two helpers to look back, pick up a skip, remove it and

-inject it after the dir node. But that way we loose the subtype information that

-for some applications can be handy to be kept as|-|is. This is why we now have a

-variant of \lpr {textdir} which injects the balanced node before the skip.

-Instead of the previous definition we can use:

-

-\startbuffer[def]

-\def\ltr{\linedir TLT\relax}

-\def\rtl{\linedir TRT\relax}

-\stopbuffer

-

-\typebuffer[def]

-

-and this time:

-

-\startbuffer[txt]

-run {\rtl nur {\ltr run \rtl NUR \ltr run \rtl NUR} nur}

-run {\ltr run {\rtl nur \ltr RUN \rtl nur \ltr RUN} run}

-\stopbuffer

-

-\typebuffer[txt]

-

-comes out as a properly spaced:

-

-\startnarrower

-\startlines

-\getbuffer[def,txt]

-\stoplines

-\stopnarrower

-

-Anything more complex that this, like combination of skips and penalties, or

-kerns, should be handled in the input or macro package because there is no way we

-can predict the expected behaviour. In fact, the \lpr {linedir} is just a

-convenience extra which could also have been implemented using node list parsing.

-

-\stopsubsection

-

-\startsubsection[title={Controlling glue with \lpr {breakafterdirmode}}]

-

-Glue after a dir node is ignored in the linebreak decision but you can bypass that

-by setting \lpr {breakafterdirmode} to~\type {1}. The following table shows the

-difference. Watch your spaces.

-

-\def\ShowSome#1{%

-    \BC \type{#1}

-    \NC \breakafterdirmode\zerocount\hsize\zeropoint#1

-    \NC

-    \NC \breakafterdirmode\plusone\hsize\zeropoint#1

-    \NC

-    \NC \NR

-}

-

-\starttabulate[|l|Tp(1pt)|w(5em)|Tp(1pt)|w(5em)|]

-    \DB

-    \BC \type{0}

-    \NC

-    \BC \type{1}

-    \NC

-    \NC \NR

-    \TB

-    \ShowSome{pre {\textdir TLT xxx} post}

-    \ShowSome{pre {\textdir TLT xxx }post}

-    \ShowSome{pre{ \textdir TLT xxx} post}

-    \ShowSome{pre{ \textdir TLT xxx }post}

-    \ShowSome{pre { \textdir TLT xxx } post}

-    \ShowSome{pre {\textdir TLT\relax\space xxx} post}

-    \LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={Controling parshapes with \lpr {shapemode}}]

-

-Another adaptation to the \ALEPH\ directional model is control over shapes driven

-by \prm {hangindent} and \prm {parshape}. This is controlled by a new parameter

-\lpr {shapemode}:

-

-\starttabulate[|c|l|l|]

-\DB value    \BC \prm {hangindent} \BC \prm {parshape} \NC \NR

-\TB

-\BC \type{0} \NC  normal             \NC normal            \NC \NR

-\BC \type{1} \NC  mirrored           \NC normal            \NC \NR

-\BC \type{2} \NC  normal             \NC mirrored          \NC \NR

-\BC \type{3} \NC  mirrored           \NC mirrored          \NC \NR

-\LL

-\stoptabulate

-

-The value is reset to zero (like \prm {hangindent} and \prm {parshape})

-after the paragraph is done with. You can use negative values to prevent

-this. In \in {figure} [fig:shapemode] a few examples are given.

-

-\startplacefigure[reference=fig:shapemode,title={The effect of \type {shapemode}.}]

-    \startcombination[2*3]

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-                \pardir TLT \textdir TLT

-                \hangindent 40pt \hangafter -3

-                \leftskip10pt \input tufte \par

-         \egroup} {TLT: hangindent}

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-            \pardir TLT \textdir TLT

-            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize

-            \input tufte \par

-         \egroup} {TLT: parshape}

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-            \pardir TRT \textdir TRT

-            \hangindent 40pt \hangafter -3

-            \leftskip10pt \input tufte \par

-         \egroup} {TRT: hangindent mode 0}

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-            \pardir TRT \textdir TRT

-            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize

-            \input tufte \par

-         \egroup} {TRT: parshape mode 0}

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-            \shapemode=3

-            \pardir TRT \textdir TRT

-            \hangindent 40pt \hangafter -3

-            \leftskip10pt \input tufte \par

-         \egroup} {TRT: hangindent mode 1 & 3}

-        {\ruledvbox \bgroup \setuptolerance[verytolerant]

-            \hsize .45\textwidth \switchtobodyfont[6pt]

-            \shapemode=3

-            \pardir TRT \textdir TRT

-            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize

-            \input tufte \par

-         \egroup} {TRT: parshape mode 2 & 3}

-    \stopcombination

-\stopplacefigure

-

-\stopsubsection

-

-\startsubsection[title={Symbols or numbers}]

-

-Internally the implementation is different from \ALEPH. First of all we use no

-whatsits but dedicated nodes, but also we have only 4 directions that are mapped

-onto 4 numbers. A text direction node can mark the start or end of a sequence of

-nodes, and therefore has two states. At the \TEX\ end we don't see these states

-because \TEX\ itself will add proper end state nodes if needed.

-

-The symbolic names \type {TLT}, \type {TRT}, etc.\ originate in \OMEGA. In

-\LUATEX\ we also have a number based model which sometimes makes more sense.

-

-\starttabulate[|c|l|l|]

-\DB value     \BC equivalent \NC \NR

-\TB

-\BC \type {0} \NC TLT \NC \NR

-\BC \type {1} \NC TRT \NC \NR

-\BC \type {2} \NC LTL \NC \NR

-\BC \type {3} \NC RTT \NC \NR

-\LL

-\stoptabulate

-

-We support the \OMEGA\ primitives \orm {textdir}, \orm {pardir}, \orm {pagedir},

-\orm {pardir} and \orm {mathdir}. These accept three character keywords. The

-primitives that set the direction by number are: \lpr {textdirection}, \lpr

-{pardirection}, \lpr {pagedirection} and \lpr {bodydirection} and \lpr

-{mathdirection}. When specifying a direction for a box you can use \type {bdir}

-instead of \type {dir}.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title=Implementation notes]

-

-\startsubsection[title=Memory allocation]

-

-\topicindex {memory}

-

-The single internal memory heap that traditional \TEX\ used for tokens and nodes

-is split into two separate arrays. Each of these will grow dynamically when

-needed.

-

-The \type {texmf.cnf} settings related to main memory are no longer used (these

-are: \type {main_memory}, \type {mem_bot}, \type {extra_mem_top} and \type

-{extra_mem_bot}). \quote {Out of main memory} errors can still occur, but the

-limiting factor is now the amount of RAM in your system, not a predefined limit.

-

-Also, the memory (de)allocation routines for nodes are completely rewritten. The

-relevant code now lives in the C file \type {texnode.c}, and basically uses a

-dozen or so \quote {avail} lists instead of a doubly|-|linked model. An extra

-function layer is added so that the code can ask for nodes by type instead of

-directly requisitioning a certain amount of memory words.

-

-Because of the split into two arrays and the resulting differences in the data

-structures, some of the macros have been duplicated. For instance, there are now

-\type {vlink} and \type {vinfo} as well as \type {token_link} and \type

-{token_info}. All access to the variable memory array is now hidden behind a

-macro called \type {vmem}. We mention this because using the \TEX book as

-reference is still quite valid but not for memory related details. Another

-significant detail is that we have double linked node lists and that most nodes

-carry more data.

-

-The input line buffer and pool size are now also reallocated when needed, and the

-\type {texmf.cnf} settings \type {buf_size} and \type {pool_size} are silently

-ignored.

-

-\stopsubsection

-

-\startsubsection[title=Sparse arrays]

-

-The \prm {mathcode}, \prm {delcode}, \prm {catcode}, \prm {sfcode}, \prm {lccode}

-and \prm {uccode} (and the new \lpr {hjcode}) tables are now sparse arrays that

-are implemented in~\CCODE. They are no longer part of the \TEX\ \quote

-{equivalence table} and because each had 1.1 million entries with a few memory

-words each, this makes a major difference in memory usage. Performance is not

-really hurt by this.

-

-The \prm {catcode}, \prm {sfcode}, \prm {lccode}, \prm {uccode} and \lpr {hjcode}

-assignments don't show up when using the \ETEX\ tracing routines \prm

-{tracingassigns} and \prm {tracingrestores} but we don't see that as a real

-limitation.

-

-A side|-|effect of the current implementation is that \prm {global} is now more

-expensive in terms of processing than non|-|global assignments but not many users

-will notice that.

-

-The glyph ids within a font are also managed by means of a sparse array as glyph

-ids can go up to index $2^{21}-1$ but these are never accessed directly so again

-users will not notice this.

-

-\stopsubsection

-

-\startsubsection[title=Simple single|-|character csnames]

-

-\topicindex {csnames}

-

-Single|-|character commands are no longer treated specially in the internals,

-they are stored in the hash just like the multiletter csnames.

-

-The code that displays control sequences explicitly checks if the length is one

-when it has to decide whether or not to add a trailing space.

-

-Active characters are internally implemented as a special type of multi|-|letter

-control sequences that uses a prefix that is otherwise impossible to obtain.

-

-\stopsubsection

-

-\startsubsection[title=The compressed format file]

-

-\topicindex {format}

-

-The format is passed through \type {zlib}, allowing it to shrink to roughly half

-of the size it would have had in uncompressed form. This takes a bit more \CPU\

-cycles but much less disk \IO, so it should still be faster. We use a level~3

-compression which we found to be the optimal trade|-|off between filesize and

-decompression speed.

-

-\stopsubsection

-

-\startsubsection[title=Binary file reading]

-

-\topicindex {files+binary}

-

-All of the internal code is changed in such a way that if one of the \type

-{read_xxx_file} callbacks is not set, then the file is read by a \CCODE\ function

-using basically the same convention as the callback: a single read into a buffer

-big enough to hold the entire file contents. While this uses more memory than the

-previous code (that mostly used \type {getc} calls), it can be quite a bit faster

-(depending on your \IO\ subsystem).

-

-\stopsubsection

-

-\startsubsection[title=Tabs and spaces]

-

-\topicindex {space}

-\topicindex {newline}

-

-We conform to the way other \TEX\ engines handle trailing tabs and spaces. For

-decades trailing tabs and spaces (before a newline) were removed from the input

-but this behaviour was changed in September 2017 to only handle spaces. We are

-aware that this can introduce compatibility issues in existing workflows but

-because we don't want too many differences with upstream \TEXLIVE\ we just follow

-up on that patch (which is a functional one and not really a fix). It is up to

-macro packages maintainers to deal with possible compatibility issues and in

-\LUATEX\ they can do so via the callbacks that deal with reading from files.

-

-The previous behaviour was a known side effect and (as that kind of input

-normally comes from generated sources) it was normally dealt with by adding a

-comment token to the line in case the spaces and|/|or tabs were intentional and

-to be kept. We are aware of the fact that this contradicts some of our other

-choices but consistency with other engines and the fact that in \KPSE\ mode a

-common file \IO\ layer is used can have a side effect of breaking compatibility.

-We still stick to our view that at the log level we can (and might be) more

-incompatible. We already expose some more details.

-

-\stopsubsection

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-modifications
+
+\startchapter[reference=modifications,title={Modifications}]
+
+\startsection[title=The merged engines]
+
+\startsubsection[title=The need for change]
+
+\topicindex {engines}
+\topicindex {history}
+
+The first version of \LUATEX\ only had a few extra primitives and it was largely
+the same as \PDFTEX. Then we merged substantial parts of \ALEPH\ into the code
+and got more primitives. When we got more stable the decision was made to clean
+up the rather hybrid nature of the program. This means that some primitives have
+been promoted to core primitives, often with a different name, and that others
+were removed. This made it possible to start cleaning up the code base. In \in
+{chapter} [enhancements] we discussed some new primitives, here we will cover
+most of the adapted ones.
+
+Besides the expected changes caused by new functionality, there are a number of
+not|-|so|-|expected changes. These are sometimes a side|-|effect of a new
+(conflicting) feature, or, more often than not, a change necessary to clean up
+the internal interfaces. These will also be mentioned.
+
+\stopsubsection
+
+\startsubsection[title=Changes from \TEX\ 3.1415926]
+
+\topicindex {\TEX}
+
+Of course it all starts with traditional \TEX. Even if we started with \PDFTEX,
+most still comes from the original. But we divert a bit.
+
+\startitemize
+
+\startitem
+    The current code base is written in \CCODE, not \PASCAL. We use \CWEB\ when
+    possible. As a consequence instead of one large file plus change files, we
+    now have multiple files organized in categories like \type {tex}, \type
+    {pdf}, \type {lang}, \type {font}, \type {lua}, etc. There are some artifacts
+    of the conversion to \CCODE, but in due time we will clean up the source code
+    and make sure that the documentation is done right. Many files are in the
+    \CWEB\ format, but others, like those interfacing to \LUA, are \CCODE\ files.
+    Of course we want to stay as close as possible to the original so that the
+    documentation of the fundamentals behind \TEX\ by Don Knuth still applies.
+\stopitem
+
+\startitem
+    See \in {chapter} [languages] for many small changes related to paragraph
+    building, language handling and hyphenation. The most important change is
+    that adding a brace group in the middle of a word (like in \type {of{}fice})
+    does not prevent ligature creation.
+\stopitem
+
+\startitem
+    There is no pool file, all strings are embedded during compilation.
+\stopitem
+
+\startitem
+    The specifier \type {plus 1 fillll} does not generate an error. The extra
+    \quote{l} is simply typeset.
+\stopitem
+
+\startitem
+    The upper limit to \prm {endlinechar} and \prm {newlinechar} is 127.
+\stopitem
+
+\startitem
+    Magnification (\prm {mag}) is only supported in \DVI\ output mode. You can
+    set this parameter and it even works with \type {true} units till you switch
+    to \PDF\ output mode. When you use \PDF\ output you can best not touch the
+    \prm {mag} variable. This fuzzy behaviour is not much different from using
+    \PDF\ backend related functionality while eventually \DVI\ output is
+    required.
+
+    After the output mode has been frozen (normally that happens when the first
+    page is shipped out) or when \PDF\ output is enabled, the \type {true}
+    specification is ignored. When you preload a plain format adapted to
+    \LUATEX\ it can be that the \prm {mag} parameter already has been set.
+\stopitem
+
+\stopitemize
+
+\stopsubsection
+
+\startsubsection[title=Changes from \ETEX\ 2.2]
+
+\topicindex {\ETEX}
+
+Being the de factor standard extension of course we provide the \ETEX\
+functionality, but with a few small adaptations.
+
+\startitemize
+
+\startitem
+    The \ETEX\ functionality is always present and enabled so the prepended
+    asterisk or \type {-etex} switch for \INITEX\ is not needed.
+\stopitem
+
+\startitem
+    The \TEXXET\ extension is not present, so the primitives \type
+    {\TeXXeTstate}, \type {\beginR}, \type {\beginL}, \type {\endR} and \type
+    {\endL} are missing. Instead we used the \OMEGA/\ALEPH\ approach to
+    directionality as starting point.
+\stopitem
+
+\startitem
+    Some of the tracing information that is output by \ETEX's \prm
+    {tracingassigns} and \prm {tracingrestores} is not there.
+\stopitem
+
+\startitem
+    Register management in \LUATEX\ uses the \OMEGA/\ALEPH\ model, so the maximum
+    value is 65535 and the implementation uses a flat array instead of the mixed
+    flat & sparse model from \ETEX.
+\stopitem
+
+\startitem
+    When kpathsea is used to find files, \LUATEX\ uses the \type {ofm} file
+    format to search for font metrics. In turn, this means that \LUATEX\ looks at
+    the \type {OFMFONTS} configuration variable (like \OMEGA\ and \ALEPH) instead
+    of \type {TFMFONTS} (like \TEX\ and \PDFTEX). Likewise for virtual fonts
+    (\LUATEX\ uses the variable \type {OVFFONTS} instead of \type {VFFONTS}).
+\stopitem
+
+\startitem
+    The primitives that report a stretch or shrink order report a value in a
+    convenient range zero upto four. Because some macro packages can break on
+    that we also provide \type {\eTeXgluestretchorder} and \type
+    {\eTeXglueshrinkorder} which report values compatible with \ETEX. The (new)
+    \type {fi} value is reported as \type {-1} (so when used in an \type
+    {\ifcase} test that value makes one end up in the \type {\else}).
+\stopitem
+
+\stopitemize
+
+\stopsubsection
+
+\startsubsection[title=Changes from \PDFTEX\ 1.40]
+
+\topicindex {\PDFTEX}
+
+Because we want to produce \PDF\ the most natural starting point was the popular
+\PDFTEX\ program. We inherit the stable features, dropped most of the
+experimental code and promoted some functionality to core \LUATEX\ functionality
+which in turn triggered renaming primitives.
+
+For compatibility reasons we still refer to \type {\pdf...} commands but \LUATEX\
+has a different backend interface. Instead of these primitives there are three
+interfacing primitives: \lpr {pdfextension}, \lpr {pdfvariable} and \lpr
+{pdffeedback} that take keywords and optional further arguments (below we will
+still use the \tex {pdf} prefix names as reference). This way we can extend the
+features when needed but don't need to adapt the core engine. The front- and
+backend are decoupled as much as possible.
+
+\startitemize
+
+\startitem
+    The (experimental) support for snap nodes has been removed, because it is
+    much more natural to build this functionality on top of node processing and
+    attributes. The associated primitives that are gone are: \orm
+    {pdfsnaprefpoint}, \orm {pdfsnapy}, and \orm {pdfsnapycomp}.
+\stopitem
+
+\startitem
+    The (experimental) support for specialized spacing around nodes has also been
+    removed. The associated primitives that are gone are: \orm
+    {pdfadjustinterwordglue}, \orm {pdfprependkern}, and \orm {pdfappendkern}, as
+    well as the five supporting primitives \orm {knbscode}, \orm {stbscode}, \orm
+    {shbscode}, \orm {knbccode}, and \orm {knaccode}.
+\stopitem
+
+\startitem
+    A number of \quote {\PDFTEX\ primitives} have been removed as they can be
+    implemented using \LUA: \orm {pdfelapsedtime}, \orm {pdfescapehex}, \orm
+    {pdfescapename}, \orm {pdfescapestring}, \orm {pdffiledump}, \orm
+    {pdffilemoddate}, \orm {pdffilesize}, \orm {pdfforcepagebox}, \orm
+    {pdflastmatch}, \orm {pdfmatch}, \orm {pdfmdfivesum}, \orm {pdfmovechars},
+    \orm {pdfoptionalwaysusepdfpagebox}, \orm {pdfoptionpdfinclusionerrorlevel},
+    \orm {pdfresettimer}, \orm {pdfshellescape}, \orm {pdfstrcmp} and \orm
+    {pdfunescapehex}.
+\stopitem
+
+\startitem
+    The version related primitives \orm {pdftexbanner}, \orm {pdftexversion}
+    and \orm {pdftexrevision} are no longer present as there is no longer a
+    relationship with \PDFTEX\ development.
+\stopitem
+
+\startitem
+    The experimental snapper mechanism has been removed and therefore also the
+    primitives \orm {pdfignoreddimen}, \orm {pdffirstlineheight}, \orm
+    {pdfeachlineheight}, \orm {pdfeachlinedepth} and \orm {pdflastlinedepth}.
+\stopitem
+
+\startitem
+    The experimental primitives \lpr {primitive}, \lpr {ifprimitive}, \lpr
+    {ifabsnum} and \lpr {ifabsdim} are promoted to core primitives. The \type
+    {\pdf*} prefixed originals are not available.
+\stopitem
+
+\startitem
+    Because \LUATEX\ has a different subsystem for managing images, more
+    diversion from its ancestor happened in the meantime. We don't adapt to
+    changes in \PDFTEX.
+\stopitem
+
+\startitem
+    Two extra token lists are provided, \orm {pdfxformresources} and \orm
+    {pdfxformattr}, as an alternative to \orm {pdfxform} keywords.
+\stopitem
+
+\startitem
+    Image specifications also support \type {visiblefilename}, \type
+    {userpassword} and \type {ownerpassword}. The password options are only
+    relevant for encrypted \PDF\ files.
+\stopitem
+
+\startitem
+    The current version of \LUATEX\ no longer replaces and|/|or merges fonts in
+    embedded \PDF\ files with fonts of the enveloping \PDF\ document. This
+    regression may be temporary, depending on how the rewritten font backend will
+    look like.
+\stopitem
+
+\startitem
+    The primitives \orm {pdfpagewidth} and \orm {pdfpageheight} have been removed
+    because \lpr {pagewidth} and \lpr {pageheight} have that purpose.
+\stopitem
+
+\startitem
+    The primitives \orm {pdfnormaldeviate}, \orm {pdfuniformdeviate}, \orm
+    {pdfsetrandomseed} and \orm {pdfrandomseed} have been promoted to core
+    primitives without \type {pdf} prefix so the original commands are no longer
+    recognized.
+\stopitem
+
+\startitem
+    The primitives \lpr {ifincsname}, \lpr {expanded} and \lpr {quitvmode}
+    are now core primitives.
+\stopitem
+
+\startitem
+    As the hz and protrusion mechanism are part of the core the related
+    primitives \lpr {lpcode}, \lpr {rpcode}, \lpr {efcode}, \lpr
+    {leftmarginkern}, \lpr {rightmarginkern} are promoted to core primitives. The
+    two commands \lpr {protrudechars} and \lpr {adjustspacing} replace their
+    prefixed with \type {\pdf} originals.
+\stopitem
+
+\startitem
+    The hz optimization code has been partially redone so that we no longer need
+    to create extra font instances. The front- and backend have been decoupled
+    and more efficient (\PDF) code is generated.
+\stopitem
+
+\startitem
+    When \lpr {adjustspacing} has value~2, hz optimization will be applied to
+    glyphs and kerns. When the value is~3, only glyphs will be treated. A value
+    smaller than~2 disables this feature.
+\stopitem
+
+\startitem
+    The \lpr {tagcode} primitive is promoted to core primitive.
+\stopitem
+
+\startitem
+    The \lpr {letterspacefont} feature is now part of the core but will not be
+    changed (improved). We just provide it for legacy use.
+\stopitem
+
+\startitem
+    The \orm {pdfnoligatures} primitive is now \lpr {ignoreligaturesinfont}.
+\stopitem
+
+\startitem
+    The \orm {pdfcopyfont} primitive is now \lpr {copyfont}.
+\stopitem
+
+\startitem
+    The \orm {pdffontexpand} primitive is now \lpr {expandglyphsinfont}.
+\stopitem
+
+\startitem
+    Because position tracking is also available in \DVI\ mode the \lpr {savepos},
+    \lpr {lastxpos} and \lpr {lastypos} commands now replace their \type {pdf}
+    prefixed originals.
+\stopitem
+
+\startitem
+    The introspective primitives \type {\pdflastximagecolordepth} and \type
+    {\pdfximagebbox} have been removed. One can use external applications to
+    determine these properties or use the built|-|in \type {img} library.
+\stopitem
+
+\startitem
+    The initializers \orm {pdfoutput} has been replaced by \lpr {outputmode} and
+    \orm {pdfdraftmode} is now \lpr {draftmode}.
+\stopitem
+
+\startitem
+    The pixel multiplier dimension \orm {pdfpxdimen} lost its prefix and is now
+    called \lpr {pxdimen}.
+\stopitem
+
+\startitem
+    An extra \orm {pdfimageaddfilename} option has been added that can be used to
+    block writing the filename to the \PDF\ file.
+\stopitem
+
+\startitem
+    The primitive \orm {pdftracingfonts} is now \lpr {tracingfonts} as it
+    doesn't relate to the backend.
+\stopitem
+
+\startitem
+    The experimental primitive \orm {pdfinsertht} is kept as \lpr {insertht}.
+\stopitem
+
+\startitem
+    There is some more control over what metadata goes into the \PDF\ file.
+\stopitem
+
+\startitem
+    The promotion of primitives to core primitives as well as the separation of
+    font- and backend means that the initialization namespace \type {pdftex} is
+    gone.
+\stopitem
+
+\stopitemize
+
+One change involves the so called xforms and ximages. In \PDFTEX\ these are
+implemented as so called whatsits. But contrary to other whatsits they have
+dimensions that need to be taken into account when for instance calculating
+optimal line breaks. In \LUATEX\ these are now promoted to a special type of rule
+nodes, which simplifies code that needs those dimensions.
+
+Another reason for promotion is that these are useful concepts. Backends can
+provide the ability to use content that has been rendered in several places, and
+images are also common. As already mentioned in \in {section}
+[sec:imagedandforms], we now have:
+
+\starttabulate[|l|l|]
+\DB \LUATEX \BC \PDFTEX \NC \NR
+\TB
+\NC \lpr {saveboxresource}             \NC \orm {pdfxform}           \NC \NR
+\NC \lpr {saveimageresource}           \NC \orm {pdfximage}          \NC \NR
+\NC \lpr {useboxresource}              \NC \orm {pdfrefxform}        \NC \NR
+\NC \lpr {useimageresource}            \NC \orm {pdfrefximage}       \NC \NR
+\NC \lpr {lastsavedboxresourceindex}   \NC \orm {pdflastxform}       \NC \NR
+\NC \lpr {lastsavedimageresourceindex} \NC \orm {pdflastximage}      \NC \NR
+\NC \lpr {lastsavedimageresourcepages} \NC \orm {pdflastximagepages} \NC \NR
+\LL
+\stoptabulate
+
+There are a few \lpr {pdffeedback} features that relate to this but these are
+typical backend specific ones. The index that gets returned is to be considered
+as \quote {just a number} and although it still has the same meaning (object
+related) as before, you should not depend on that.
+
+The protrusion detection mechanism is enhanced a bit to enable a bit more complex
+situations. When protrusion characters are identified some nodes are skipped:
+
+\startitemize[packed,columns,two]
+\startitem zero glue \stopitem
+\startitem penalties \stopitem
+\startitem empty discretionaries \stopitem
+\startitem normal zero kerns \stopitem
+\startitem rules with zero dimensions \stopitem
+\startitem math nodes with a surround of zero \stopitem
+\startitem dir nodes \stopitem
+\startitem empty horizontal lists \stopitem
+\startitem local par nodes \stopitem
+\startitem inserts, marks and adjusts \stopitem
+\startitem boundaries \stopitem
+\startitem whatsits \stopitem
+\stopitemize
+
+Because this can not be enough, you can also use a protrusion boundary node to
+make the next node being ignored. When the value is~1 or~3, the next node will be
+ignored in the test when locating a left boundary condition. When the value is~2
+or~3, the previous node will be ignored when locating a right boundary condition
+(the search goes from right to left). This permits protrusion combined with for
+instance content moved into the margin:
+
+\starttyping
+\protrusionboundary1\llap{!\quad}«Who needs protrusion?»
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title=Changes from \ALEPH\ RC4]
+
+\topicindex {\ALEPH}
+
+Because we wanted proper directional typesetting the \ALEPH\ mechanisms looked
+most attractive. These are rather close to the ones provided by \OMEGA, so what
+we say next applies to both these programs.
+
+\startitemize
+
+\startitem
+    The extended 16-bit math primitives (\orm {omathcode} etc.) have been
+    removed.
+\stopitem
+
+\startitem
+    The \OCP\ processing has been removed completely and as a consequence, the
+    following primitives have been removed: \orm {ocp}, \orm {externalocp}, \orm
+    {ocplist}, \orm {pushocplist}, \orm {popocplist}, \orm {clearocplists}, \orm
+    {addbeforeocplist}, \orm {addafterocplist}, \orm {removebeforeocplist}, \orm
+    {removeafterocplist} and \orm {ocptracelevel}.
+\stopitem
+
+\startitem
+    \LUATEX\ only understands 4~of the 16~direction specifiers of \ALEPH: \type
+    {TLT} (latin), \type {TRT} (arabic), \type {RTT} (cjk), \type {LTL} (mongolian).
+    All other direction specifiers generate an error. In addition to a keyword
+    driven model we also provide an integer driven one.
+\stopitem
+
+\startitem
+    The input translations from \ALEPH\ are not implemented, the related
+    primitives are not available: \orm {DefaultInputMode}, \orm
+    {noDefaultInputMode}, \orm {noInputMode}, \orm {InputMode}, \orm
+    {DefaultOutputMode}, \orm {noDefaultOutputMode}, \orm {noOutputMode}, \orm
+    {OutputMode}, \orm {DefaultInputTranslation}, \orm
+    {noDefaultInputTranslation}, \orm {noInputTranslation}, \orm
+    {InputTranslation}, \orm {DefaultOutputTranslation}, \orm
+    {noDefaultOutputTranslation}, \orm {noOutputTranslation} and \orm
+    {OutputTranslation}.
+\stopitem
+
+\startitem
+    Several bugs have been fixed and confusing implementation details have been
+    sorted out.
+\stopitem
+
+\startitem
+    The scanner for direction specifications now allows an optional space after
+    the direction is completely parsed.
+\stopitem
+
+\startitem
+    The \type {^^} notation has been extended: after \type {^^^^} four
+    hexadecimal characters are expected and after \type {^^^^^^} six hexadecimal
+    characters have to be given. The original \TEX\ interpretation is still valid
+    for the \type {^^} case but the four and six variants do no backtracking,
+    i.e.\ when they are not followed by the right number of hexadecimal digits
+    they issue an error message. Because \type{^^^} is a normal \TEX\ case, we
+    don't support the odd number of \type {^^^^^} either.
+\stopitem
+
+\startitem
+    Glues {\it immediately after} direction change commands are not legal
+    breakpoints.
+\stopitem
+
+\startitem
+    Several mechanisms that need to be right|-|to|-|left aware have been
+    improved. For instance placement of formula numbers.
+\stopitem
+
+\startitem
+    The page dimension related primitives \lpr {pagewidth} and \lpr {pageheight}
+    have been promoted to core primitives. The \prm {hoffset} and \prm {voffset}
+    primitives have been fixed.
+\stopitem
+
+\startitem
+    The primitives \type {\charwd}, \type {\charht}, \type {\chardp} and \type
+    {\charit} have been removed as we have the \ETEX\ variants \type
+    {\fontchar*}.
+\stopitem
+
+\startitem
+    The two dimension registers \lpr {pagerightoffset} and \lpr
+    {pagebottomoffset} are now core primitives.
+\stopitem
+
+\startitem
+    The direction related primitives \lpr {pagedir}, \lpr {bodydir}, \lpr
+    {pardir}, \lpr {textdir}, \lpr {mathdir} and \lpr {boxdir} are now core
+    primitives.
+\stopitem
+
+\startitem
+    The promotion of primitives to core primitives as well as removing of all
+    others means that the initialization namespace \type {aleph} that early
+    versions of \LUATEX\ provided is gone.
+\stopitem
+
+\stopitemize
+
+The above let's itself summarize as: we took the 32 bit aspects and much of the
+directional mechanisms and merged it into the \PDFTEX\ code base as starting
+point for further development. Then we simplified directionality, fixed it and
+opened it up.
+
+\stopsubsection
+
+\startsubsection[title=Changes from standard \WEBC]
+
+\topicindex {\WEBC}
+
+The compilation framework is \WEBC\ and we keep using that but without the
+\PASCAL\ to \CCODE\ step. This framework also provides some common features that
+deal with reading bytes from files and locating files in \TDS. This is what we do
+different:
+
+\startitemize
+
+\startitem
+    There is no mltex support.
+\stopitem
+
+\startitem
+    There is no enctex support.
+\stopitem
+
+\startitem
+    The following encoding related command line switches are silently ignored,
+    even in non|-|\LUA\ mode: \type {-8bit}, \type {-translate-file}, \type
+    {-mltex}, \type {-enc} and \type {-etex}.
+\stopitem
+
+\startitem
+    The \prm {openout} whatsits are not written to the log file.
+\stopitem
+
+\startitem
+    Some of the so|-|called \WEBC\ extensions are hard to set up in non|-|\KPSE\
+    mode because \type {texmf.cnf} is not read: \type {shell-escape} is off (but
+    that is not a problem because of \LUA's \type {os.execute}), and the paranoia
+    checks on \type {openin} and \type {openout} do not happen. However, it is
+    easy for a \LUA\ script to do this itself by overloading \type {io.open} and
+    alike.
+\stopitem
+
+\startitem
+    The \quote{E} option does not do anything useful.
+\stopitem
+
+\stopitemize
+
+\stopsubsection
+
+\stopsection
+
+\startsection[reference=backendprimitives,title=The backend primitives]
+
+\startsubsection[title={Less primitives}]
+
+\topicindex {backend}
+\topicindex {\PDF+backend}
+
+In a previous section we mentioned that some \PDFTEX\ primitives were removed and
+others promoted to core \LUATEX\ primitives. That is only part of the story. In
+order to separate the backend specific primitives in de code these commands are
+now replaced by only a few. In traditional \TEX\ we only had the \DVI\ backend
+but now we have two: \DVI\ and \PDF. Additional functionality is implemented as
+\quote {extensions} in \TEX\ speak. By separating more strickly we are able to
+keep the core (frontend) clean and stable and isolate these extensions. If for
+some reason an extra backend option is needed, it can be implemented without
+touching the core. The three \PDF\ backend related primitives are:
+
+\starttyping
+\pdfextension command [specification]
+\pdfvariable  name
+\pdffeedback  name
+\stoptyping
+
+An extension triggers further parsing, depending on the command given. A variable is
+a (kind of) register and can be read and written, while a feedback is reporting
+something (as it comes from the backend it's normally a sequence of tokens).
+
+\stopsubsection
+
+\startsubsection[title={\lpr{pdfextension}, \lpr {pdfvariable} and \lpr {pdffeedback}},reference=sec:pdfextensions]
+
+In order for \LUATEX\ to be more than just \TEX\ you need to enable primitives. That
+has already been the case right from the start. If you want the traditional \PDFTEX\
+primitives (for as far their functionality is still around) you now can do this:
+
+\starttyping
+\protected\def\pdfliteral             {\pdfextension literal}
+\protected\def\pdfcolorstack          {\pdfextension colorstack}
+\protected\def\pdfsetmatrix           {\pdfextension setmatrix}
+\protected\def\pdfsave                {\pdfextension save\relax}
+\protected\def\pdfrestore             {\pdfextension restore\relax}
+\protected\def\pdfobj                 {\pdfextension obj }
+\protected\def\pdfrefobj              {\pdfextension refobj }
+\protected\def\pdfannot               {\pdfextension annot }
+\protected\def\pdfstartlink           {\pdfextension startlink }
+\protected\def\pdfendlink             {\pdfextension endlink\relax}
+\protected\def\pdfoutline             {\pdfextension outline }
+\protected\def\pdfdest                {\pdfextension dest }
+\protected\def\pdfthread              {\pdfextension thread }
+\protected\def\pdfstartthread         {\pdfextension startthread }
+\protected\def\pdfendthread           {\pdfextension endthread\relax}
+\protected\def\pdfinfo                {\pdfextension info }
+\protected\def\pdfcatalog             {\pdfextension catalog }
+\protected\def\pdfnames               {\pdfextension names }
+\protected\def\pdfincludechars        {\pdfextension includechars }
+\protected\def\pdffontattr            {\pdfextension fontattr }
+\protected\def\pdfmapfile             {\pdfextension mapfile }
+\protected\def\pdfmapline             {\pdfextension mapline }
+\protected\def\pdftrailer             {\pdfextension trailer }
+\protected\def\pdfglyphtounicode      {\pdfextension glyphtounicode }
+\stoptyping
+
+The introspective primitives can be defined as:
+
+\starttyping
+\def\pdftexversion    {\numexpr\pdffeedback version\relax}
+\def\pdftexrevision           {\pdffeedback revision}
+\def\pdflastlink      {\numexpr\pdffeedback lastlink\relax}
+\def\pdfretval        {\numexpr\pdffeedback retval\relax}
+\def\pdflastobj       {\numexpr\pdffeedback lastobj\relax}
+\def\pdflastannot     {\numexpr\pdffeedback lastannot\relax}
+\def\pdfxformname     {\numexpr\pdffeedback xformname\relax}
+\def\pdfcreationdate          {\pdffeedback creationdate}
+\def\pdffontname      {\numexpr\pdffeedback fontname\relax}
+\def\pdffontobjnum    {\numexpr\pdffeedback fontobjnum\relax}
+\def\pdffontsize      {\dimexpr\pdffeedback fontsize\relax}
+\def\pdfpageref       {\numexpr\pdffeedback pageref\relax}
+\def\pdfcolorstackinit        {\pdffeedback colorstackinit}
+\stoptyping
+
+The configuration related registers have become:
+
+\starttyping
+\edef\pdfcompresslevel            {\pdfvariable compresslevel}
+\edef\pdfobjcompresslevel         {\pdfvariable objcompresslevel}
+\edef\pdfrecompress               {\pdfvariable recompress}
+\edef\pdfdecimaldigits            {\pdfvariable decimaldigits}
+\edef\pdfgamma                    {\pdfvariable gamma}
+\edef\pdfimageresolution          {\pdfvariable imageresolution}
+\edef\pdfimageapplygamma          {\pdfvariable imageapplygamma}
+\edef\pdfimagegamma               {\pdfvariable imagegamma}
+\edef\pdfimagehicolor             {\pdfvariable imagehicolor}
+\edef\pdfimageaddfilename         {\pdfvariable imageaddfilename}
+\edef\pdfpkresolution             {\pdfvariable pkresolution}
+\edef\pdfpkfixeddpi               {\pdfvariable pkfixeddpi}
+\edef\pdfinclusioncopyfonts       {\pdfvariable inclusioncopyfonts}
+\edef\pdfinclusionerrorlevel      {\pdfvariable inclusionerrorlevel}
+\edef\pdfignoreunknownimages      {\pdfvariable ignoreunknownimages}
+\edef\pdfgentounicode             {\pdfvariable gentounicode}
+\edef\pdfomitcidset               {\pdfvariable omitcidset}
+\edef\pdfomitcharset              {\pdfvariable omitcharset}
+\edef\pdfpagebox                  {\pdfvariable pagebox}
+\edef\pdfminorversion             {\pdfvariable minorversion}
+\edef\pdfuniqueresname            {\pdfvariable uniqueresname}
+
+\edef\pdfhorigin                  {\pdfvariable horigin}
+\edef\pdfvorigin                  {\pdfvariable vorigin}
+\edef\pdflinkmargin               {\pdfvariable linkmargin}
+\edef\pdfdestmargin               {\pdfvariable destmargin}
+\edef\pdfthreadmargin             {\pdfvariable threadmargin}
+\edef\pdfxformmargin              {\pdfvariable xformmargin}
+
+\edef\pdfpagesattr                {\pdfvariable pagesattr}
+\edef\pdfpageattr                 {\pdfvariable pageattr}
+\edef\pdfpageresources            {\pdfvariable pageresources}
+\edef\pdfxformattr                {\pdfvariable xformattr}
+\edef\pdfxformresources           {\pdfvariable xformresources}
+\edef\pdfpkmode                   {\pdfvariable pkmode}
+
+\edef\pdfsuppressoptionalinfo     {\pdfvariable suppressoptionalinfo }
+\edef\pdftrailerid                {\pdfvariable trailerid }
+\stoptyping
+
+The variables are internal ones, so they are anonymous. When you ask for the
+meaning of a few previously defined ones:
+
+\starttyping
+\meaning\pdfhorigin
+\meaning\pdfcompresslevel
+\meaning\pdfpageattr
+\stoptyping
+
+you will get:
+
+\starttyping
+macro:->[internal backend dimension]
+macro:->[internal backend integer]
+macro:->[internal backend tokenlist]
+\stoptyping
+
+The \prm {edef} can also be a \prm {def} but it's a bit more efficient to expand
+the lookup related register beforehand.
+
+The backend is derived from \PDFTEX\ so the same syntax applies. However, the
+\type {outline} command accepts a \type {objnum} followed by a number. No
+checking takes place so when this is used it had better be a valid (flushed)
+object.
+
+In order to be (more or less) compatible with \PDFTEX\ we also support the option
+to suppress some info but we do so via a bitset:
+
+\starttyping
+\pdfvariable suppressoptionalinfo \numexpr
+        0
+    +   1   % PTEX.FullBanner
+    +   2   % PTEX.FileName
+    +   4   % PTEX.PageNumber
+    +   8   % PTEX.InfoDict
+    +  16   % Creator
+    +  32   % CreationDate
+    +  64   % ModDate
+    + 128   % Producer
+    + 256   % Trapped
+    + 512   % ID
+\relax
+\stoptyping
+
+In addition you can overload the trailer id, but we don't do any checking on
+validity, so you have to pass a valid array. The following is like the ones
+normally generated by the engine. You even need to include the brackets here!
+
+\starttyping
+\pdfvariable trailerid {[
+    <FA052949448907805BA83C1E78896398>
+    <FA052949448907805BA83C1E78896398>
+]}
+\stoptyping
+
+Although we started from a merge of \PDFTEX\ and \ALEPH, by now the code base as
+well as functionality has diverted from those parents. Here we show the options
+that can be passed to the extensions.
+
+\starttexsyntax
+\pdfextension literal
+    [ direct | page | raw ] { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension dest
+    num integer | name { tokens }!crlf
+    [ fitbh | fitbv | fitb | fith| fitv | fit |
+      fitr <rule spec> | xyz [ zoom <integer> ]
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension annot
+    reserveobjnum | useobjnum <integer>
+    { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension save
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension restore
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension setmatrix
+    { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+[ \immediate ] \pdfextension obj
+    reserveobjnum
+\stoptexsyntax
+
+\starttexsyntax
+[ \immediate ] \pdfextension obj
+    [ useobjnum <integer> ]
+    [ uncompressed ]
+    [ stream  [ attr { tokens } ] ]
+    [ file ]
+    { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension refobj
+    <integer>
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension colorstack
+    <integer>
+    set { tokens } | push { tokens } | pop | current
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension startlink
+    [ attr { tokens } ]
+    user { tokens } | goto | thread
+    [ file { tokens } ]
+    [ page <integer> { tokens } | name { tokens } | num  integer ]
+    [ newwindow  | nonewwindow ]
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension endlink
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension startthread
+    num <integer> | name { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension endthread
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension thread
+    num <integer> | name { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension outline
+    [ attr { tokens } ]
+    [ useobjnum <integer> ]
+    [ count <integer> ]
+    { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension glyphtounicode
+    { tokens }
+    { tokens }
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension catalog
+    { tokens }
+    [ openaction
+      user { tokens } | goto | thread
+      [ file { tokens } ]
+      [ page <integer> { tokens } | name { tokens } | num <integer> ]
+      [ newwindow  | nonewwindow ] ]
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension fontattr
+    <integer>
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension mapfile
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension mapline
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension includechars
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension info
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension names
+    {tokens}
+\stoptexsyntax
+
+\starttexsyntax
+\pdfextension trailer
+    {tokens}
+\stoptexsyntax
+
+\stopsubsection
+
+\startsubsection[title={Defaults}]
+
+The engine sets the following defaults.
+
+\starttyping
+\pdfcompresslevel         9
+\pdfobjcompresslevel      1 % used: (0,9)
+\pdfrecompress            0 % mostly for debugging
+\pdfdecimaldigits         4 % used: (3,6)
+\pdfgamma              1000
+\pdfimageresolution      71
+\pdfimageapplygamma       0
+\pdfimagegamma         2200
+\pdfimagehicolor          1
+\pdfimageaddfilename      1
+\pdfpkresolution         72
+\pdfpkfixeddpi            0
+\pdfinclusioncopyfonts    0
+\pdfinclusionerrorlevel   0
+\pdfignoreunknownimages   0
+\pdfgentounicode          0
+\pdfomitcidset            0
+\pdfomitcharset           0
+\pdfpagebox               0
+\pdfminorversion          4
+\pdfuniqueresname         0
+
+\pdfhorigin             1in
+\pdfvorigin             1in
+\pdflinkmargin          0pt
+\pdfdestmargin          0pt
+\pdfthreadmargin        0pt
+\pdfxformmargin         0pt
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={Backward compatibility}]
+
+If you also want some backward compatibility, you can add:
+
+\starttyping
+\let\pdfpagewidth      \pagewidth
+\let\pdfpageheight     \pageheight
+
+\let\pdfadjustspacing  \adjustspacing
+\let\pdfprotrudechars  \protrudechars
+\let\pdfnoligatures    \ignoreligaturesinfont
+\let\pdffontexpand     \expandglyphsinfont
+\let\pdfcopyfont       \copyfont
+
+\let\pdfxform          \saveboxresource
+\let\pdflastxform      \lastsavedboxresourceindex
+\let\pdfrefxform       \useboxresource
+
+\let\pdfximage         \saveimageresource
+\let\pdflastximage     \lastsavedimageresourceindex
+\let\pdflastximagepages\lastsavedimageresourcepages
+\let\pdfrefximage      \useimageresource
+
+\let\pdfsavepos        \savepos
+\let\pdflastxpos       \lastxpos
+\let\pdflastypos       \lastypos
+
+\let\pdfoutput         \outputmode
+\let\pdfdraftmode      \draftmode
+
+\let\pdfpxdimen        \pxdimen
+
+\let\pdfinsertht       \insertht
+
+\let\pdfnormaldeviate  \normaldeviate
+\let\pdfuniformdeviate \uniformdeviate
+\let\pdfsetrandomseed  \setrandomseed
+\let\pdfrandomseed     \randomseed
+
+\let\pdfprimitive      \primitive
+\let\ifpdfprimitive    \ifprimitive
+
+\let\ifpdfabsnum       \ifabsnum
+\let\ifpdfabsdim       \ifabsdim
+\stoptyping
+
+And even:
+
+\starttyping
+\newdimen\pdfeachlineheight
+\newdimen\pdfeachlinedepth
+\newdimen\pdflastlinedepth
+\newdimen\pdffirstlineheight
+\newdimen\pdfignoreddimen
+\stoptyping
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title=Directions]
+
+\topicindex {\OMEGA}
+\topicindex {\ALEPH}
+\topicindex {directions}
+
+\startsubsection[title={Four directions}]
+
+The directional model in \LUATEX\ is inherited from \OMEGA|/|\ALEPH\ but we tried
+to improve it a bit. At some point we played with recovery of modes but that was
+disabled later on when we found that it interfered with nested directions. That
+itself had as side effect that the node list was no longer balanced with respect
+to directional nodes which in turn can give side effects when a series of dir
+changes happens without grouping.
+
+When extending the \PDF\ backend to support directions some inconsistencies were
+found and as a result we decided to support only the four models that make sense
+\type {TLT} (latin), \type {TRT} (arabic), \type {RTT} (cjk) and \type {LTL}
+(mongolian).
+
+\stopsubsection
+
+\startsubsection[title={How it works}]
+
+The approach is that we again make the list balanced but try to avoid some side
+effects. What happens is quite intuitive if we forget about spaces (turned into
+glue) but even there what happens makes sense if you look at it in detail.
+However that logic makes in|-|group switching kind of useless when no proper
+nested grouping is used: switching from right to left several times nested,
+results in spacing ending up after each other due to nested mirroring. Of course
+a sane macro package will manage this for the user but here we are discussing the
+low level dir injection.
+
+This is what happens:
+
+\starttyping
+\textdir TRT nur {\textdir TLT run \textdir TRT NUR} nur
+\stoptyping
+
+This becomes stepwise:
+
+\startnarrower
+\starttyping
+injected: [+TRT]nur {[+TLT]run [+TRT]NUR} nur
+balanced: [+TRT]nur {[+TLT]run [-TLT][+TRT]NUR[-TRT]} nur[-TRT]
+result  : run {RUNrun } run
+\stoptyping
+\stopnarrower
+
+And this:
+
+\starttyping
+\textdir TRT nur {nur \textdir TLT run \textdir TRT NUR} nur
+\stoptyping
+
+becomes:
+
+\startnarrower
+\starttyping
+injected: [+TRT]nur {nur [+TLT]run [+TRT]NUR} nur
+balanced: [+TRT]nur {nur [+TLT]run [-TLT][+TRT]NUR[-TRT]} nur[-TRT]
+result  : run {run RUNrun } run
+\stoptyping
+\stopnarrower
+
+Now, in the following examples watch where we put the braces:
+
+\startbuffer
+\textdir TRT nur {{\textdir TLT run} {\textdir TRT NUR}} nur
+\stopbuffer
+
+\typebuffer
+
+This becomes:
+
+\startnarrower
+\getbuffer
+\stopnarrower
+
+Compare this to:
+
+\startbuffer
+\textdir TRT nur {{\textdir TLT run }{\textdir TRT NUR}} nur
+\stopbuffer
+
+\typebuffer
+
+Which renders as:
+
+\startnarrower
+\getbuffer
+\stopnarrower
+
+So how do we deal with the next?
+
+\startbuffer
+\def\ltr{\textdir TLT\relax}
+\def\rtl{\textdir TRT\relax}
+
+run {\rtl nur {\ltr run \rtl NUR \ltr run \rtl NUR} nur}
+run {\ltr run {\rtl nur \ltr RUN \rtl nur \ltr RUN} run}
+\stopbuffer
+
+\typebuffer
+
+It gets typeset as:
+
+\startnarrower
+\startlines
+\getbuffer
+\stoplines
+\stopnarrower
+
+We could define the two helpers to look back, pick up a skip, remove it and
+inject it after the dir node. But that way we loose the subtype information that
+for some applications can be handy to be kept as|-|is. This is why we now have a
+variant of \lpr {textdir} which injects the balanced node before the skip.
+Instead of the previous definition we can use:
+
+\startbuffer[def]
+\def\ltr{\linedir TLT\relax}
+\def\rtl{\linedir TRT\relax}
+\stopbuffer
+
+\typebuffer[def]
+
+and this time:
+
+\startbuffer[txt]
+run {\rtl nur {\ltr run \rtl NUR \ltr run \rtl NUR} nur}
+run {\ltr run {\rtl nur \ltr RUN \rtl nur \ltr RUN} run}
+\stopbuffer
+
+\typebuffer[txt]
+
+comes out as a properly spaced:
+
+\startnarrower
+\startlines
+\getbuffer[def,txt]
+\stoplines
+\stopnarrower
+
+Anything more complex that this, like combination of skips and penalties, or
+kerns, should be handled in the input or macro package because there is no way we
+can predict the expected behaviour. In fact, the \lpr {linedir} is just a
+convenience extra which could also have been implemented using node list parsing.
+
+\stopsubsection
+
+\startsubsection[title={Controlling glue with \lpr {breakafterdirmode}}]
+
+Glue after a dir node is ignored in the linebreak decision but you can bypass that
+by setting \lpr {breakafterdirmode} to~\type {1}. The following table shows the
+difference. Watch your spaces.
+
+\def\ShowSome#1{%
+    \BC \type{#1}
+    \NC \breakafterdirmode\zerocount\hsize\zeropoint#1
+    \NC
+    \NC \breakafterdirmode\plusone\hsize\zeropoint#1
+    \NC
+    \NC \NR
+}
+
+\starttabulate[|l|Tp(1pt)|w(5em)|Tp(1pt)|w(5em)|]
+    \DB
+    \BC \type{0}
+    \NC
+    \BC \type{1}
+    \NC
+    \NC \NR
+    \TB
+    \ShowSome{pre {\textdir TLT xxx} post}
+    \ShowSome{pre {\textdir TLT xxx }post}
+    \ShowSome{pre{ \textdir TLT xxx} post}
+    \ShowSome{pre{ \textdir TLT xxx }post}
+    \ShowSome{pre { \textdir TLT xxx } post}
+    \ShowSome{pre {\textdir TLT\relax\space xxx} post}
+    \LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={Controling parshapes with \lpr {shapemode}}]
+
+Another adaptation to the \ALEPH\ directional model is control over shapes driven
+by \prm {hangindent} and \prm {parshape}. This is controlled by a new parameter
+\lpr {shapemode}:
+
+\starttabulate[|c|l|l|]
+\DB value    \BC \prm {hangindent} \BC \prm {parshape} \NC \NR
+\TB
+\BC \type{0} \NC  normal             \NC normal            \NC \NR
+\BC \type{1} \NC  mirrored           \NC normal            \NC \NR
+\BC \type{2} \NC  normal             \NC mirrored          \NC \NR
+\BC \type{3} \NC  mirrored           \NC mirrored          \NC \NR
+\LL
+\stoptabulate
+
+The value is reset to zero (like \prm {hangindent} and \prm {parshape})
+after the paragraph is done with. You can use negative values to prevent
+this. In \in {figure} [fig:shapemode] a few examples are given.
+
+\startplacefigure[reference=fig:shapemode,title={The effect of \type {shapemode}.}]
+    \startcombination[2*3]
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+                \pardir TLT \textdir TLT
+                \hangindent 40pt \hangafter -3
+                \leftskip10pt \input tufte \par
+         \egroup} {TLT: hangindent}
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+            \pardir TLT \textdir TLT
+            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize
+            \input tufte \par
+         \egroup} {TLT: parshape}
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+            \pardir TRT \textdir TRT
+            \hangindent 40pt \hangafter -3
+            \leftskip10pt \input tufte \par
+         \egroup} {TRT: hangindent mode 0}
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+            \pardir TRT \textdir TRT
+            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize
+            \input tufte \par
+         \egroup} {TRT: parshape mode 0}
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+            \shapemode=3
+            \pardir TRT \textdir TRT
+            \hangindent 40pt \hangafter -3
+            \leftskip10pt \input tufte \par
+         \egroup} {TRT: hangindent mode 1 & 3}
+        {\ruledvbox \bgroup \setuptolerance[verytolerant]
+            \hsize .45\textwidth \switchtobodyfont[6pt]
+            \shapemode=3
+            \pardir TRT \textdir TRT
+            \parshape 4 0pt .8\hsize 10pt .8\hsize 20pt .8\hsize 0pt \hsize
+            \input tufte \par
+         \egroup} {TRT: parshape mode 2 & 3}
+    \stopcombination
+\stopplacefigure
+
+\stopsubsection
+
+\startsubsection[title={Symbols or numbers}]
+
+Internally the implementation is different from \ALEPH. First of all we use no
+whatsits but dedicated nodes, but also we have only 4 directions that are mapped
+onto 4 numbers. A text direction node can mark the start or end of a sequence of
+nodes, and therefore has two states. At the \TEX\ end we don't see these states
+because \TEX\ itself will add proper end state nodes if needed.
+
+The symbolic names \type {TLT}, \type {TRT}, etc.\ originate in \OMEGA. In
+\LUATEX\ we also have a number based model which sometimes makes more sense.
+
+\starttabulate[|c|l|l|]
+\DB value     \BC equivalent \NC \NR
+\TB
+\BC \type {0} \NC TLT \NC \NR
+\BC \type {1} \NC TRT \NC \NR
+\BC \type {2} \NC LTL \NC \NR
+\BC \type {3} \NC RTT \NC \NR
+\LL
+\stoptabulate
+
+We support the \OMEGA\ primitives \orm {textdir}, \orm {pardir}, \orm {pagedir},
+\orm {pardir} and \orm {mathdir}. These accept three character keywords. The
+primitives that set the direction by number are: \lpr {textdirection}, \lpr
+{pardirection}, \lpr {pagedirection} and \lpr {bodydirection} and \lpr
+{mathdirection}. When specifying a direction for a box you can use \type {bdir}
+instead of \type {dir}.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title=Implementation notes]
+
+\startsubsection[title=Memory allocation]
+
+\topicindex {memory}
+
+The single internal memory heap that traditional \TEX\ used for tokens and nodes
+is split into two separate arrays. Each of these will grow dynamically when
+needed.
+
+The \type {texmf.cnf} settings related to main memory are no longer used (these
+are: \type {main_memory}, \type {mem_bot}, \type {extra_mem_top} and \type
+{extra_mem_bot}). \quote {Out of main memory} errors can still occur, but the
+limiting factor is now the amount of RAM in your system, not a predefined limit.
+
+Also, the memory (de)allocation routines for nodes are completely rewritten. The
+relevant code now lives in the C file \type {texnode.c}, and basically uses a
+dozen or so \quote {avail} lists instead of a doubly|-|linked model. An extra
+function layer is added so that the code can ask for nodes by type instead of
+directly requisitioning a certain amount of memory words.
+
+Because of the split into two arrays and the resulting differences in the data
+structures, some of the macros have been duplicated. For instance, there are now
+\type {vlink} and \type {vinfo} as well as \type {token_link} and \type
+{token_info}. All access to the variable memory array is now hidden behind a
+macro called \type {vmem}. We mention this because using the \TEX book as
+reference is still quite valid but not for memory related details. Another
+significant detail is that we have double linked node lists and that most nodes
+carry more data.
+
+The input line buffer and pool size are now also reallocated when needed, and the
+\type {texmf.cnf} settings \type {buf_size} and \type {pool_size} are silently
+ignored.
+
+\stopsubsection
+
+\startsubsection[title=Sparse arrays]
+
+The \prm {mathcode}, \prm {delcode}, \prm {catcode}, \prm {sfcode}, \prm {lccode}
+and \prm {uccode} (and the new \lpr {hjcode}) tables are now sparse arrays that
+are implemented in~\CCODE. They are no longer part of the \TEX\ \quote
+{equivalence table} and because each had 1.1 million entries with a few memory
+words each, this makes a major difference in memory usage. Performance is not
+really hurt by this.
+
+The \prm {catcode}, \prm {sfcode}, \prm {lccode}, \prm {uccode} and \lpr {hjcode}
+assignments don't show up when using the \ETEX\ tracing routines \prm
+{tracingassigns} and \prm {tracingrestores} but we don't see that as a real
+limitation.
+
+A side|-|effect of the current implementation is that \prm {global} is now more
+expensive in terms of processing than non|-|global assignments but not many users
+will notice that.
+
+The glyph ids within a font are also managed by means of a sparse array as glyph
+ids can go up to index $2^{21}-1$ but these are never accessed directly so again
+users will not notice this.
+
+\stopsubsection
+
+\startsubsection[title=Simple single|-|character csnames]
+
+\topicindex {csnames}
+
+Single|-|character commands are no longer treated specially in the internals,
+they are stored in the hash just like the multiletter csnames.
+
+The code that displays control sequences explicitly checks if the length is one
+when it has to decide whether or not to add a trailing space.
+
+Active characters are internally implemented as a special type of multi|-|letter
+control sequences that uses a prefix that is otherwise impossible to obtain.
+
+\stopsubsection
+
+\startsubsection[title=The compressed format file]
+
+\topicindex {format}
+
+The format is passed through \type {zlib}, allowing it to shrink to roughly half
+of the size it would have had in uncompressed form. This takes a bit more \CPU\
+cycles but much less disk \IO, so it should still be faster. We use a level~3
+compression which we found to be the optimal trade|-|off between filesize and
+decompression speed.
+
+\stopsubsection
+
+\startsubsection[title=Binary file reading]
+
+\topicindex {files+binary}
+
+All of the internal code is changed in such a way that if one of the \type
+{read_xxx_file} callbacks is not set, then the file is read by a \CCODE\ function
+using basically the same convention as the callback: a single read into a buffer
+big enough to hold the entire file contents. While this uses more memory than the
+previous code (that mostly used \type {getc} calls), it can be quite a bit faster
+(depending on your \IO\ subsystem).
+
+\stopsubsection
+
+\startsubsection[title=Tabs and spaces]
+
+\topicindex {space}
+\topicindex {newline}
+
+We conform to the way other \TEX\ engines handle trailing tabs and spaces. For
+decades trailing tabs and spaces (before a newline) were removed from the input
+but this behaviour was changed in September 2017 to only handle spaces. We are
+aware that this can introduce compatibility issues in existing workflows but
+because we don't want too many differences with upstream \TEXLIVE\ we just follow
+up on that patch (which is a functional one and not really a fix). It is up to
+macro packages maintainers to deal with possible compatibility issues and in
+\LUATEX\ they can do so via the callbacks that deal with reading from files.
+
+The previous behaviour was a known side effect and (as that kind of input
+normally comes from generated sources) it was normally dealt with by adding a
+comment token to the line in case the spaces and|/|or tabs were intentional and
+to be kept. We are aware of the fact that this contradicts some of our other
+choices but consistency with other engines and the fact that in \KPSE\ mode a
+common file \IO\ layer is used can have a side effect of breaking compatibility.
+We still stick to our view that at the log level we can (and might be) more
+incompatible. We already expose some more details.
+
+\stopsubsection
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-nodes.tex b/systems/doc/luatex/luatex-nodes.tex
index 1b8de8d767..21e8a2808f 100644
--- a/systems/doc/luatex/luatex-nodes.tex
+++ b/systems/doc/luatex/luatex-nodes.tex
@@ -1,2664 +1,2664 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-nodes

-

-\startchapter[reference=nodes,title={Nodes}]

-

-\startsection[title={\LUA\ node representation}][library=node]

-

-\topicindex {nodes}

-

-\libindex {fields}

-\libindex {subtypes}

-\libindex {values}

-

-\TEX's nodes are represented in \LUA\ as userdata objects with a variable set of

-fields. In the following syntax tables, such as the type of such a userdata object

-is represented as \syntax {<node>}.

-

-The current return value of \type {node.types()} is:

-\startluacode

-    for id, name in table.sortedhash(node.types()) do

-        context.type(name)

-        context(" (%s), ",id)

-    end

-    context.removeunwantedspaces()

-    context.removepunctuation()

-\stopluacode

-. % period

-

-The \prm {lastnodetype} primitive is \ETEX\ compliant. The valid range is still

-$[-1,15]$ and glyph nodes (formerly known as char nodes) have number~0 while

-ligature nodes are mapped to~7. That way macro packages can use the same symbolic

-names as in traditional \ETEX. Keep in mind that these \ETEX\ node numbers are

-different from the real internal ones and that there are more \ETEX\ node types

-than~15.

-

-You can ask for a list of fields with \type {node.fields} and for valid subtypes

-with \type {node.subtypes}. The \type {node.values} function reports some used

-values. Valid arguments are \nod {dir}, \type {direction}, \nod {glue}, \whs

-{pdf_literal}, \whs {pdf_action}, \whs {pdf_window} and \whs {color_stack}. Keep

-in mind that the setters normally expect a number, but this helper gives you a

-list of what numbers matter. For practical reason the \type {pagestate} values

-are also reported with this helper.

-

-\stopsection

-

-\startsection[title={Main text nodes}]

-

-\topicindex {nodes+text}

-

-These are the nodes that comprise actual typesetting commands. A few fields are

-present in all nodes regardless of their type, these are:

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{next}    \NC node   \NC the next node in a list, or nil \NC \NR

-\NC \type{id}      \NC number \NC the node's type (\type {id}) number \NC \NR

-\NC \type{subtype} \NC number \NC the node \type {subtype} identifier \NC \NR

-\LL

-\stoptabulate

-

-The \type {subtype} is sometimes just a dummy entry because not all nodes

-actually use the \type {subtype}, but this way you can be sure that all nodes

-accept it as a valid field name, and that is often handy in node list traversal.

-In the following tables \type {next} and \type {id} are not explicitly mentioned.

-

-Besides these three fields, almost all nodes also have an \type {attr} field, and

-there is a also a field called \type {prev}. That last field is always present,

-but only initialized on explicit request: when the function \type {node.slide()}

-is called, it will set up the \type {prev} fields to be a backwards pointer in

-the argument node list. By now most of \TEX's node processing makes sure that the

-\type {prev} nodes are valid but there can be exceptions, especially when the

-internal magic uses a leading \nod {temp} nodes to temporarily store a state.

-

-\subsection{\nod {hlist} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype}    \NC number \NC \showsubtypes{list} \NC \NR

-\NC \type{attr}       \NC node   \NC list of attributes \NC \NR

-\NC \type{width}      \NC number \NC the width of the box \NC \NR

-\NC \type{height}     \NC number \NC the height of the box \NC \NR

-\NC \type{depth}      \NC number \NC the depth of the box \NC \NR

-\NC \type{shift}      \NC number \NC a displacement perpendicular to the character

-                                     progression direction \NC \NR

-\NC \type{glue_order} \NC number \NC a number in the range $[0,4]$, indicating the

-                                     glue order \NC \NR

-\NC \type{glue_set}   \NC number \NC the calculated glue ratio \NC \NR

-\NC \type{glue_sign}  \NC number \NC 0 = \type {normal}, 1 = \type {stretching}, 2 =

-                                     \type {shrinking} \NC \NR

-\NC \type{head/list}  \NC node   \NC the first node of the body of this list \NC \NR

-\NC \type{dir}        \NC string \NC the direction of this box, see~\in [dirnodes] \NC \NR

-\LL

-\stoptabulate

-

-\topicindex {nodes+lists}

-\topicindex {lists}

-

-A warning: never assign a node list to the \type {head} field unless you are sure

-its internal link structure is correct, otherwise an error may result.

-

-Note: the field name \type {head} and \type {list} are both valid. Sometimes it

-makes more sense to refer to a list by \type {head}, sometimes \type {list} makes

-more sense.

-

-\subsection{\nod {vlist} nodes}

-

-\topicindex {nodes+lists}

-\topicindex {lists}

-

-This node is similar to \nod {hlist}, except that \quote {shift} is a displacement

-perpendicular to the line progression direction, and \quote {subtype} only has

-the values 0, 4, and~5.

-

-\subsection{\nod {rule} nodes}

-

-\topicindex {nodes+rules}

-\topicindex {rules}

-

-Contrary to traditional \TEX, \LUATEX\ has more \prm {rule} subtypes because we

-also use rules to store reuseable objects and images. User nodes are invisible

-and can be intercepted by a callback.

-

-\starttabulate[|l|l|p|]

-\DB field            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype}   \NC number \NC \showsubtypes {rule} \NC \NR

-\NC \type{attr}      \NC node   \NC list of attributes \NC \NR

-\NC \type{width}     \NC number \NC the width of the rule where the special value

-                                    $-1073741824$ is used for \quote {running} glue dimensions \NC \NR

-\NC \type{height}    \NC number \NC the height of the rule (can be negative) \NC \NR

-\NC \type{depth}     \NC number \NC the depth of the rule (can be negative) \NC \NR

-\NC \type{left}      \NC number \NC shift at the left end (also subtracted from width) \NC \NR

-\NC \type{right}     \NC number \NC (subtracted from width) \NC \NR

-\NC \type{dir}       \NC string \NC the direction of this rule, see~\in[dirnodes] \NC \NR

-\NC \type{index}     \NC number \NC an optional index that can be referred to \NC \NR

-\NC \type{transform} \NC number \NC an private variable (also used to specify outline width) \NC \NR

-\LL

-\stoptabulate

-

-The \type {left} and type {right} keys are somewhat special (and experimental).

-When rules are auto adapting to the surrounding box width you can enforce a shift

-to the right by setting \type {left}. The value is also subtracted from the width

-which can be a value set by the engine itself and is not entirely under user

-control. The \type {right} is also subtracted from the width. It all happens in

-the backend so these are not affecting the calculations in the frontend (actually

-the auto settings also happen in the backend). For a vertical rule \type {left}

-affects the height and \type {right} affects the depth. There is no matching

-interface at the \TEX\ end (although we can have more keywords for rules it would

-complicate matters and introduce a speed penalty.) However, you can just

-construct a rule node with \LUA\ and write it to the \TEX\ input. The \type

-{outline} subtype is just a convenient variant and the \type {transform} field

-specifies the width of the outline.

-

-\subsection{\nod {ins} nodes}

-

-\topicindex {nodes+insertions}

-\topicindex {insertions}

-

-This node relates to the \prm {insert} primitive.

-

-\starttabulate[|l|l|p|]

-\DB field            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype}   \NC number \NC the insertion class \NC \NR

-\NC \type{attr}      \NC node   \NC list of attributes \NC \NR

-\NC \type{cost}      \NC number \NC the penalty associated with this insert \NC \NR

-\NC \type{height}    \NC number \NC height of the insert \NC \NR

-\NC \type{depth}     \NC number \NC depth of the insert \NC \NR

-\NC \type{head/list} \NC node   \NC the first node of the body of this insert \NC \NR

-\LL

-\stoptabulate

-

-There is a set of extra fields that concern the associated glue: \type {width},

-\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}.

-These are all numbers.

-

-A warning: never assign a node list to the \type {head} field unless you are sure

-its internal link structure is correct, otherwise an error may result. You can use

-\type {list} instead (often in functions you want to use local variable with similar

-names and both names are equally sensible).

-

-\subsection{\nod {mark} nodes}

-

-\topicindex {nodes+marks}

-\topicindex {marks}

-

-This one relates to the \prm {mark} primitive.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC unused \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{class}   \NC number \NC the mark class \NC \NR

-\NC \type{mark}    \NC table  \NC a table representing a token list \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {adjust} nodes}

-

-\topicindex {nodes+adjust}

-\topicindex {adjust}

-

-This node comes from \prm {vadjust} primitive.

-

-\starttabulate[|l|l|p|]

-\DB field            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype}   \NC number \NC \showsubtypes{adjust} \NC \NR

-\NC \type{attr}      \NC node   \NC list of attributes \NC \NR

-\NC \type{head/list} \NC node   \NC adjusted material \NC \NR

-\LL

-\stoptabulate

-

-A warning: never assign a node list to the \type {head} field unless you are sure

-its internal link structure is correct, otherwise an error may be the result.

-

-\subsection{\nod {disc} nodes}

-

-\topicindex {nodes+discretionaries}

-\topicindex {discretionaries}

-

-The \prm {discretionary} and \prm {-}, the \type {-} character but also the

-hyphenation mechanism produces these nodes.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{disc} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{pre}     \NC node   \NC pointer to the pre|-|break text \NC \NR

-\NC \type{post}    \NC node   \NC pointer to the post|-|break text \NC \NR

-\NC \type{replace} \NC node   \NC pointer to the no|-|break text \NC \NR

-\NC \type{penalty} \NC number \NC the penalty associated with the break, normally

-                                  \prm {hyphenpenalty} or \prm {exhyphenpenalty} \NC \NR

-\LL

-\stoptabulate

-

-The subtype numbers~4 and~5 belong to the \quote {of-f-ice} explanation given

-elsewhere. These disc nodes are kind of special as at some point they also keep

-information about breakpoints and nested ligatures.

-

-The \type {pre}, \type {post} and \type {replace} fields at the \LUA\ end are in

-fact indirectly accessed and have a \type {prev} pointer that is not \type {nil}.

-This means that when you mess around with the head of these (three) lists, you

-also need to reassign them because that will restore the proper \type {prev}

-pointer, so:

-

-\starttyping

-pre = d.pre

--- change the list starting with pre

-d.pre = pre

-\stoptyping

-

-Otherwise you can end up with an invalid internal perception of reality and

-\LUATEX\ might even decide to crash on you. It also means that running forward

-over for instance \type {pre} is ok but backward you need to stop at \type {pre}.

-And you definitely must not mess with the node that \type {prev} points to, if

-only because it is not really a node but part of the disc data structure (so

-freeing it again might crash \LUATEX).

-

-\subsection{\nod {math} nodes}

-

-\topicindex {nodes+math}

-\topicindex {math+nodes}

-

-Math nodes represent the boundaries of a math formula, normally wrapped into

-\type {$} signs.

-

-\starttabulate[|l|l|p|]

-\DB field           \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype}  \NC number \NC \showsubtypes{math} \NC \NR

-\NC \type{attr}     \NC node   \NC list of attributes \NC \NR

-\NC \type{surround} \NC number \NC width of the \prm {mathsurround} kern \NC \NR

-\LL

-\stoptabulate

-

-There is a set of extra fields that concern the associated glue: \type {width},

-\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}.

-These are all numbers.

-

-\subsection{\nod {glue} nodes}

-

-\topicindex {nodes+glue}

-\topicindex {glue}

-

-Skips are about the only type of data objects in traditional \TEX\ that are not a

-simple value. They are inserted when \TEX\ sees a space in the text flow but also

-by \prm {hskip} and \prm {vskip}. The structure that represents the glue

-components of a skip is called a \nod {glue_spec}, and it has the following

-accessible fields:

-

-\starttabulate[|l|l|p|]

-\DB field                \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{width}         \NC number \NC the horizontal or vertical displacement \NC \NR

-\NC \type{stretch}       \NC number \NC extra (positive) displacement or stretch amount \NC \NR

-\NC \type{stretch_order} \NC number \NC factor applied to stretch amount \NC \NR

-\NC \type{shrink}        \NC number \NC extra (negative) displacement or shrink amount\NC \NR

-\NC \type{shrink_order}  \NC number \NC factor applied to shrink amount \NC \NR

-\LL

-\stoptabulate

-

-The effective width of some glue subtypes depends on the stretch or shrink needed

-to make the encapsulating box fit its dimensions. For instance, in a paragraph

-lines normally have glue representing spaces and these stretch or shrink to make

-the content fit in the available space. The \type {effective_glue} function that

-takes a glue node and a parent (hlist or vlist) returns the effective width of

-that glue item. When you pass \type {true} as third argument the value will be

-rounded.

-

-A \nod {glue_spec} node is a special kind of node that is used for storing a set

-of glue values in registers. Originally they were also used to store properties

-of glue nodes (using a system of reference counts) but we now keep these

-properties in the glue nodes themselves, which gives a cleaner interface to \LUA.

-

-The indirect spec approach was in fact an optimization in the original \TEX\

-code. First of all it can save quite some memory because all these spaces that

-become glue now share the same specification (only the reference count is

-incremented), and zero testing is also a bit faster because only the pointer has

-to be checked (this is no longer true for engines that implement for instance

-protrusion where we really need to ensure that zero is zero when we test for

-bounds). Another side effect is that glue specifications are read|-|only, so in

-the end copies need to be made when they are used from \LUA\ (each assignment to

-a field can result in a new copy). So in the end the advantages of sharing are

-not that high (and nowadays memory is less an issue, also given that a glue node

-is only a few memory words larger than a spec).

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{glue} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{leader}  \NC node   \NC pointer to a box or rule for leaders \NC \NR

-\LL

-\stoptabulate

-

-In addition there are the \type {width}, \type {stretch} \type {stretch_order},

-\type {shrink}, and \type {shrink_order} fields. Note that we use the key \type

-{width} in both horizontal and vertical glue. This suits the \TEX\ internals well

-so we decided to stick to that naming.

-

-A regular word space also results in a \type {spaceskip} subtype (this used to be

-a \type {userskip} with subtype zero).

-

-\subsection{\nod {kern} nodes}

-

-\topicindex {nodes+kerns}

-\topicindex {kerns}

-

-The \prm {kern} command creates such nodes but for instance the font and math

-machinery can also add them.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{kern} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{kern}    \NC number \NC fixed horizontal or vertical advance \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {penalty} nodes}

-

-\topicindex {nodes+penalty}

-\topicindex {penalty}

-

-The \prm {penalty} command is one that generates these nodes.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{penalty} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{penalty} \NC number \NC the penalty value \NC \NR

-\LL

-\stoptabulate

-

-The subtypes are just informative and \TEX\ itself doesn't use them. When you

-run into an \type {linebreakpenalty} you need to keep in mind that it's a

-accumulation of \type {club}, \type{widow} and other relevant penalties.

-

-\subsection[glyphnodes]{\nod {glyph} nodes}

-

-\topicindex {nodes+glyph}

-\topicindex {glyphs}

-

-These are probably the mostly used nodes and although you can push them in the

-current list with for instance \prm {char} \TEX\ will normally do it for you when

-it considers some input to be text.

-

-\starttabulate[|l|l|p|]

-\DB field                   \BC type    \BC explanation \NC \NR

-\TB

-\NC \type{subtype}          \NC number  \NC bit field \NC \NR

-\NC \type{attr}             \NC node    \NC list of attributes \NC \NR

-\NC \type{char}             \NC number  \NC the character index in the font \NC \NR

-\NC \type{font}             \NC number  \NC the font identifier \NC \NR

-\NC \type{lang}             \NC number  \NC the language identifier \NC \NR

-\NC \type{left}             \NC number  \NC the frozen \type {\lefthyphenmnin} value \NC \NR

-\NC \type{right}            \NC number  \NC the frozen \type {\righthyphenmnin} value \NC \NR

-\NC \type{uchyph}           \NC boolean \NC the frozen \prm {uchyph} value \NC \NR

-\NC \type{components}       \NC node    \NC pointer to ligature components \NC \NR

-\NC \type{xoffset}          \NC number  \NC a virtual displacement in horizontal direction \NC \NR

-\NC \type{yoffset}          \NC number  \NC a virtual displacement in vertical direction \NC \NR

-\NC \type{width}            \NC number  \NC the (original) width of the character \NC \NR

-\NC \type{height}           \NC number  \NC the (original) height of the character\NC \NR

-\NC \type{depth}            \NC number  \NC the (original) depth of the character\NC \NR

-\NC \type{expansion_factor} \NC number  \NC the to be applied expansion_factor \NC \NR

-\NC \type{data}             \NC number  \NC a general purpose field for users (we had room for it) \NC \NR

-\LL

-\stoptabulate

-

-The \type {width}, \type {height} and \type {depth} values are read|-|only. The

-\type {expansion_factor} is assigned in the par builder and used in the backend.

-

-A warning: never assign a node list to the components field unless you are sure

-its internal link structure is correct, otherwise an error may be result. Valid

-bits for the \type {subtype} field are:

-

-\starttabulate[|c|l|]

-\DB bit \BC meaning   \NC \NR

-\TB

-\NC 0   \NC character \NC \NR

-\NC 1   \NC ligature  \NC \NR

-\NC 2   \NC ghost     \NC \NR

-\NC 3   \NC left      \NC \NR

-\NC 4   \NC right     \NC \NR

-\LL

-\stoptabulate

-

-See \in {section} [charsandglyphs] for a detailed description of the \type

-{subtype} field.

-

-The \type {expansion_factor} has been introduced as part of the separation

-between font- and backend. It is the result of extensive experiments with a more

-efficient implementation of expansion. Early versions of \LUATEX\ already

-replaced multiple instances of fonts in the backend by scaling but contrary to

-\PDFTEX\ in \LUATEX\ we now also got rid of font copies in the frontend and

-replaced them by expansion factors that travel with glyph nodes. Apart from a

-cleaner approach this is also a step towards a better separation between front-

-and backend.

-

-The \type {is_char} function checks if a node is a glyph node with a subtype still

-less than 256. This function can be used to determine if applying font logic to a

-glyph node makes sense. The value \type {nil} gets returned when the node is not

-a glyph, a character number is returned if the node is still tagged as character

-and \type {false} gets returned otherwise. When nil is returned, the id is also

-returned. The \type {is_glyph} variant doesn't check for a subtype being less

-than 256, so it returns either the character value or nil plus the id. These

-helpers are not always faster than separate calls but they sometimes permit

-making more readable tests. The \type {uses_font} helpers takes a node

-and font id and returns true when a glyph or disc node references that font.

-

-\subsection{\nod {boundary} nodes}

-

-\topicindex {nodes+boundary}

-\topicindex {boundary}

-

-This node relates to the \prm {noboundary}, \prm {boundary}, \prm

-{protrusionboundary} and \prm {wordboundary} primitives.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{boundary} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{value}   \NC number \NC values 0--255 are reserved \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {local_par} nodes}

-

-\topicindex {nodes+paragraphs}

-\topicindex {paragraphs}

-

-This node is inserted at the start of a paragraph. You should not mess

-too much with this one.

-

-\starttabulate[|l|l|p|]

-\DB field                  \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}            \NC node   \NC list of attributes \NC \NR

-\NC \type{pen_inter}       \NC number \NC local interline penalty (from \lpr {localinterlinepenalty}) \NC \NR

-\NC \type{pen_broken}      \NC number \NC local broken penalty (from \lpr {localbrokenpenalty}) \NC \NR

-\NC \type{dir}             \NC string \NC the direction of this par. see~\in [dirnodes] \NC \NR

-\NC \type{box_left}        \NC node   \NC the \lpr {localleftbox} \NC \NR

-\NC \type{box_left_width}  \NC number \NC width of the \lpr {localleftbox} \NC \NR

-\NC \type{box_right}       \NC node   \NC the \lpr {localrightbox} \NC \NR

-\NC \type{box_right_width} \NC number \NC width of the \lpr {localrightbox} \NC \NR

-\LL

-\stoptabulate

-

-A warning: never assign a node list to the \type {box_left} or \type {box_right}

-field unless you are sure its internal link structure is correct, otherwise an

-error may result.

-

-\subsection[dirnodes]{\nod {dir} nodes}

-

-\topicindex {nodes+direction}

-\topicindex {directions}

-

-Direction nodes mark parts of the running text that need a change of direction and \

-the \prm {textdir} command generates them.

-

-\starttabulate[|l|l|p|]

-\DB field        \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}  \NC node   \NC list of attributes \NC \NR

-\NC \type{dir}   \NC string \NC the direction (but see below) \NC \NR

-\NC \type{level} \NC number \NC nesting level of this direction whatsit \NC \NR

-\LL

-\stoptabulate

-

-Direction specifiers are three|-|letter combinations of \type {T}, \type {B},

-\type {R}, and \type {L}. These are built up out of three separate items:

-

-\startitemize[packed]

-\startitem

-    the first  is the direction of the \quote{top}   of paragraphs

-\stopitem

-\startitem

-    the second is the direction of the \quote{start} of lines

-\stopitem

-\startitem

-    the third  is the direction of the \quote{top}   of glyphs

-\stopitem

-\stopitemize

-

-However, only four combinations are accepted: \type {TLT}, \type {TRT}, \type

-{RTT}, and \type {LTL}. Inside actual \nod {dir} nodes, the representation of

-\nod {dir} is not a three|-|letter but a combination of numbers. When printed the

-direction is indicated by a \type {+} or \type {-}, indicating whether the value

-is pushed or popped from the direction stack.

-

-\subsection{\nod {marginkern} nodes}

-

-\topicindex {nodes+paragraphs}

-\topicindex {paragraphs}

-\topicindex {protrusion}

-

-Margin kerns result from protrusion.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number \NC \showsubtypes{marginkern} \NC \NR

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{width}   \NC number \NC the advance of the kern \NC \NR

-\NC \type{glyph}   \NC node   \NC the glyph to be used \NC \NR

-\LL

-\stoptabulate

-

-\stopsection

-

-\startsection[title={Math noads}]

-

-\topicindex {nodes+math}

-\topicindex {math+nodes}

-

-These are the so||called \quote {noad}s and the nodes that are specifically

-associated with math processing. Most of these nodes contain subnodes so that the

-list of possible fields is actually quite small. First, the subnodes:

-

-\subsection{Math kernel subnodes}

-

-Many object fields in math mode are either simple characters in a specific family

-or math lists or node lists. There are four associated subnodes that represent

-these cases (in the following node descriptions these are indicated by the word

-\type {<kernel>}).

-

-The \type {next} and \type {prev} fields for these subnodes are unused.

-

-\subsection{\nod {math_char} and \nod {math_text_char} subnodes}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node   \NC list of attributes \NC \NR

-\NC \type{char} \NC number \NC the character index \NC \NR

-\NC \type{fam}  \NC number \NC the family number \NC \NR

-\LL

-\stoptabulate

-

-The \nod {math_char} is the simplest subnode field, it contains the character

-and family for a single glyph object. The \nod {math_text_char} is a special

-case that you will not normally encounter, it arises temporarily during math list

-conversion (its sole function is to suppress a following italic correction).

-

-\subsection{\nod {sub_box} and \nod {sub_mlist} subnodes}

-

-\starttabulate[|l|l|p|]

-\DB field            \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr}      \NC node \NC list of attributes \NC \NR

-\NC \type{head/list} \NC node \NC list of nodes \NC \NR

-\LL

-\stoptabulate

-

-These two subnode types are used for subsidiary list items. For \nod {sub_box},

-the \type {head} points to a \quote {normal} vbox or hbox. For \nod {sub_mlist},

-the \type {head} points to a math list that is yet to be converted.

-

-A warning: never assign a node list to the \type {head} field unless you are sure

-its internal link structure is correct, otherwise an error is triggered.

-

-\subsection{\nod {delim} subnodes}

-

-There is a fifth subnode type that is used exclusively for delimiter fields. As

-before, the \type {next} and \type {prev} fields are unused.

-

-\starttabulate[|l|l|p|]

-\DB field             \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}       \NC node   \NC list of attributes \NC \NR

-\NC \type{small_char} \NC number \NC character index of base character \NC \NR

-\NC \type{small_fam}  \NC number \NC family number of base character \NC \NR

-\NC \type{large_char} \NC number \NC character index of next larger character \NC \NR

-\NC \type{large_fam}  \NC number \NC family number of next larger character \NC \NR

-\LL

-\stoptabulate

-

-The fields \type {large_char} and \type {large_fam} can be zero, in that case the

-font that is set for the \type {small_fam} is expected to provide the large

-version as an extension to the \type {small_char}.

-

-\subsection{Math core nodes}

-

-First, there are the objects (the \TEX book calls them \quote {atoms}) that are

-associated with the simple math objects: ord, op, bin, rel, open, close, punct,

-inner, over, under, vcent. These all have the same fields, and they are combined

-into a single node type with separate subtypes for differentiation.

-

-Some noads have an option field. The values in this bitset are common:

-

-\starttabulate[|l|r|]

-\DB meaning         \BC bits                      \NC \NR

-\TB

-\NC set             \NC               \type{0x08} \NC \NR

-\NC internal        \NC \type{0x00} + \type{0x08} \NC \NR

-\NC internal        \NC \type{0x01} + \type{0x08} \NC \NR

-\NC axis            \NC \type{0x02} + \type{0x08} \NC \NR

-\NC no axis         \NC \type{0x04} + \type{0x08} \NC \NR

-\NC exact           \NC \type{0x10} + \type{0x08} \NC \NR

-\NC left            \NC \type{0x11} + \type{0x08} \NC \NR

-\NC middle          \NC \type{0x12} + \type{0x08} \NC \NR

-\NC right           \NC \type{0x14} + \type{0x08} \NC \NR

-\NC no sub script   \NC \type{0x21} + \type{0x08} \NC \NR

-\NC no super script \NC \type{0x22} + \type{0x08} \NC \NR

-\NC no script       \NC \type{0x23} + \type{0x08} \NC \NR

-\LL

-\stoptabulate

-

-\subsection{simple \nod {noad} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type        \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number      \NC \showsubtypes{noad} \NC \NR

-\NC \type{attr}    \NC node        \NC list of attributes \NC \NR

-\NC \type{nucleus} \NC kernel node \NC base \NC \NR

-\NC \type{sub}     \NC kernel node \NC subscript \NC \NR

-\NC \type{sup}     \NC kernel node \NC superscript \NC \NR

-\NC \type{options} \NC number      \NC bitset of rendering options \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {accent} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field             \BC type        \BC explanation \NC \NR

-\TB

-\NC \type{subtype}    \NC number      \NC \showsubtypes{accent} \NC \NR

-\NC \type{nucleus}    \NC kernel node \NC base \NC \NR

-\NC \type{sub}        \NC kernel node \NC subscript \NC \NR

-\NC \type{sup}        \NC kernel node \NC superscript \NC \NR

-\NC \type{accent}     \NC kernel node \NC top accent \NC \NR

-\NC \type{bot_accent} \NC kernel node \NC bottom accent \NC \NR

-\NC \type{fraction}   \NC number      \NC larger step criterium (divided by 1000) \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {style} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field        \BC type   \BC explanation    \NC \NR

-\TB

-\NC \type{style} \NC string \NC contains the style \NC \NR

-\LL

-\stoptabulate

-

-There are eight possibilities for the string value: one of \type {display},

-\type {text}, \type {script}, or \type {scriptscript}. Each of these can have

-be prefixed by \type {cramped}.

-

-\subsection{\nod {choice} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field               \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr}         \NC node \NC list of attributes \NC \NR

-\NC \type{display}      \NC node \NC list of display size alternatives \NC \NR

-\NC \type{text}         \NC node \NC list of text size alternatives \NC \NR

-\NC \type{script}       \NC node \NC list of scriptsize alternatives \NC \NR

-\NC \type{scriptscript} \NC node \NC list of scriptscriptsize alternatives \NC \NR

-\LL

-\stoptabulate

-

-Warning: never assign a node list to the \type {display}, \type {text}, \type

-{script}, or \type {scriptscript} field unless you are sure its internal link

-structure is correct, otherwise an error can occur.

-

-\subsection{\nod {radical} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type           \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number         \NC \showsubtypes{radical} \NC \NR

-\NC \type{attr}    \NC node           \NC list of attributes \NC \NR

-\NC \type{nucleus} \NC kernel node    \NC base \NC \NR

-\NC \type{sub}     \NC kernel node    \NC subscript \NC \NR

-\NC \type{sup}     \NC kernel node    \NC superscript \NC \NR

-\NC \type{left}    \NC delimiter node \NC \NC \NR

-\NC \type{degree}  \NC kernel node    \NC only set by \lpr {Uroot} \NC \NR

-\NC \type{width}   \NC number         \NC required width \NC \NR

-\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR

-\LL

-\stoptabulate

-

-Warning: never assign a node list to the \type {nucleus}, \type {sub}, \type

-{sup}, \type {left}, or \type {degree} field unless you are sure its internal

-link structure is correct, otherwise an error can be triggered.

-

-\subsection{\nod {fraction} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type           \BC explanation \NC \NR

-\TB

-\NC \type{attr}    \NC node           \NC list of attributes \NC \NR

-\NC \type{width}   \NC number         \NC (optional) width of the fraction \NC \NR

-\NC \type{num}     \NC kernel node    \NC numerator \NC \NR

-\NC \type{denom}   \NC kernel node    \NC denominator \NC \NR

-\NC \type{left}    \NC delimiter node \NC left side symbol \NC \NR

-\NC \type{right}   \NC delimiter node \NC right side symbol \NC \NR

-\NC \type{middle}  \NC delimiter node \NC middle symbol \NC \NR

-\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR

-\LL

-\stoptabulate

-

-Warning: never assign a node list to the \type {num}, or \type {denom} field

-unless you are sure its internal link structure is correct, otherwise an error

-can result.

-

-\subsection{\nod {fence} nodes}

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type           \BC explanation \NC \NR

-\TB

-\NC \type{subtype} \NC number         \NC \showsubtypes{fence} \NC \NR

-\NC \type{attr}    \NC node           \NC list of attributes \NC \NR

-\NC \type{delim}   \NC delimiter node \NC delimiter specification \NC \NR

-\NC \type{italic}  \NC number         \NC italic correction \NC \NR

-\NC \type{height}  \NC number         \NC required height \NC \NR

-\NC \type{depth}   \NC number         \NC required depth \NC \NR

-\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR

-\NC \type{class}   \NC number         \NC spacing related class \NC \NR

-\LL

-\stoptabulate

-

-Warning: some of these fields are used by the renderer and might get adapted in

-the process.

-

-\stopsection

-

-\startsection[title={Front|-|end whatsits}]

-

-Whatsit nodes come in many subtypes that you can ask for them by running

-\type {node.whatsits}:

-\startluacode

-    for id, name in table.sortedpairs(node.whatsits()) do

-        context.type(name)

-        context(" (%s), ",id)

-    end

-    context.removeunwantedspaces()

-    context.removepunctuation()

-\stopluacode

-. % period

-

-Some of them are generic and independent of the output mode and others are

-specific to the chosen backend: \DVI\ or \PDF. Here we discuss the generic

-font|-|end nodes nodes.

-

-\subsection{\whs {open}}

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}   \NC node   \NC list of attributes \NC \NR

-\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR

-\NC \type{name}   \NC string \NC file name \NC \NR

-\NC \type{ext}    \NC string \NC file extension \NC \NR

-\NC \type{area}   \NC string \NC file area (this may become obsolete) \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {write}}

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}   \NC node   \NC list of attributes \NC \NR

-\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR

-\NC \type{data}   \NC table  \NC a table representing the token list to be written \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {close}}

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}   \NC node   \NC list of attributes \NC \NR

-\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {user_defined}}

-

-User|-|defined whatsit nodes can only be created and handled from \LUA\ code. In

-effect, they are an extension to the extension mechanism. The \LUATEX\ engine

-will simply step over such whatsits without ever looking at the contents.

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{user_id} \NC number \NC id number \NC \NR

-\NC \type{type}    \NC number \NC type of the value \NC \NR

-\NC \type{value}   \NC number \NC a \LUA\ number \NC \NR

-\NC                \NC node   \NC a node list \NC \NR

-\NC                \NC string \NC a \LUA\ string \NC \NR

-\NC                \NC table  \NC a \LUA\ table \NC \NR

-\LL

-\stoptabulate

-

-The \type {type} can have one of six distinct values. The number is the \ASCII\

-value if the first character of the type name (so you can use string.byte("l")

-instead of \type {108}).

-

-\starttabulate[|r|c|p|]

-\DB value \BC meaning \BC explanation \NC \NR

-\TB

-\NC   97  \NC a       \NC list of attributes (a node list) \NC \NR

-\NC  100  \NC d       \NC a \LUA\ number \NC \NR

-\NC  108  \NC l       \NC a \LUA\ value (table, number, boolean, etc) \NC \NR

-\NC  110  \NC n       \NC a node list \NC \NR

-\NC  115  \NC s       \NC a \LUA\ string \NC \NR

-\NC  116  \NC t       \NC a \LUA\ token list in \LUA\ table form (a list of triplets) \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {save_pos}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node \NC list of attributes \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {late_lua}}

-

-\starttabulate[|l|l|p|]

-\DB field        \BC type               \BC explanation \NC \NR

-\TB

-\NC \type{attr}  \NC node               \NC list of attributes \NC \NR

-\NC \type{data}  \NC string or function \NC the to be written information stored as \LUA\ value \NC \NR

-\NC \type{token} \NC string             \NC the to be written information stored as token list \NC \NR

-\NC \type{name}  \NC string             \NC the name to use for \LUA\ error reporting \NC \NR

-\LL

-\stoptabulate

-

-The difference between \type {data} and \type {string} is that on assignment, the

-\type {data} field is converted to a token list, cf.\ use as \lpr {latelua}. The

-\type {string} version is treated as a literal string.

-

-\stopsection

-

-\startsection[title={\DVI\ backend whatsits}]

-

-\subsection{\whs {special}}

-

-There is only one \DVI\ backend whatsit, and it just flushes its content to the

-output file.

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node   \NC list of attributes \NC \NR

-\NC \type{data} \NC string \NC the \prm {special} information \NC \NR

-\LL

-\stoptabulate

-

-\stopsection

-

-\startsection[title={\PDF\ backend whatsits}]

-

-\subsection{\whs {pdf_literal}}

-

-\starttabulate[|l|l|p|]

-\DB field        \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}  \NC node   \NC list of attributes \NC \NR

-\NC \type{mode}  \NC number \NC the \quote {mode} setting of this literal \NC \NR

-\NC \type{data}  \NC string \NC the to be written information stored as \LUA\ string \NC \NR

-\NC \type{token} \NC string \NC the to be written information stored as token list \NC \NR

-\LL

-\stoptabulate

-

-Possible mode values are:

-

-\starttabulate[|c|p|]

-\DB value \BC keyword        \NC \NR

-\TB

-\NC 0     \NC \type{origin}  \NC \NR

-\NC 1     \NC \type{page}    \NC \NR

-\NC 2     \NC \type{direct}  \NC \NR

-\NC 3     \NC \type{raw}     \NC \NR

-\NC 4     \NC \type{text}    \NC \NR

-\LL

-\stoptabulate

-

-The higher the number, the less checking and the more you can run into trouble.

-Especially the \type {raw} variant can produce bad \PDF\ so you can best check

-what you generate.

-

-\subsection{\whs {pdf_refobj}}

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}   \NC node   \NC list of attributes \NC \NR

-\NC \type{objnum} \NC number \NC the referenced \PDF\ object number \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_annot}}

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}   \NC node   \NC list of attributes \NC \NR

-\NC \type{width}  \NC number \NC the width (not used in calculations) \NC \NR

-\NC \type{height} \NC number \NC the height (not used in calculations) \NC \NR

-\NC \type{depth}  \NC number \NC the depth (not used in calculations) \NC \NR

-\NC \type{objnum} \NC number \NC the referenced \PDF\ object number \NC \NR

-\NC \type{data}   \NC string \NC the annotation data \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_start_link}}

-

-\starttabulate[|l|l|p|]

-\DB field            \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}      \NC node   \NC list of attributes \NC \NR

-\NC \type{width}     \NC number \NC the width (not used in calculations) \NC \NR

-\NC \type{height}    \NC number \NC the height (not used in calculations) \NC \NR

-\NC \type{depth}     \NC number \NC the depth (not used in calculations) \NC \NR

-\NC \type{objnum}    \NC number \NC the referenced \PDF\ object number \NC \NR

-\NC \type{link_attr} \NC table  \NC the link attribute token list \NC \NR

-\NC \type{action}    \NC node   \NC the action to perform \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_end_link}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node \NC \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_dest}}

-

-\starttabulate[|l|l|p|]

-\DB field              \BC type     \BC explanation \NC \NR

-\TB

-\NC \type{attr}        \NC node     \NC list of attributes \NC \NR

-\NC \type{width}       \NC number   \NC the width (not used in calculations) \NC \NR

-\NC \type{height}      \NC number   \NC the height (not used in calculations) \NC \NR

-\NC \type{depth}       \NC number   \NC the depth (not used in calculations) \NC \NR

-\NC \type{named_id}    \NC number   \NC is the \type {dest_id} a string value? \NC \NR

-\NC \type{dest_id}     \NC number   \NC the destination id \NC \NR

-\NC                    \NC string   \NC the destination name \NC \NR

-\NC \type{dest_type}   \NC number   \NC type of destination \NC \NR

-\NC \type{xyz_zoom}    \NC number   \NC the zoom factor (times 1000) \NC \NR

-\NC \type{objnum}      \NC number   \NC the \PDF\ object number \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_action}}

-

-These are a special kind of items that only appear inside \PDF\ start link

-objects.

-

-\starttabulate[|l|l|p|]

-\DB field              \BC type             \BC explanation \NC \NR

-\TB

-\NC \type{action_type} \NC number           \NC the kind of action involved \NC \NR

-\NC \type{action_id}   \NC number or string \NC token list reference or string \NC \NR

-\NC \type{named_id}    \NC number           \NC the index of the destination \NC \NR

-\NC \type{file}        \NC string           \NC the target filename \NC \NR

-\NC \type{new_window}  \NC number           \NC the window state of the target \NC \NR

-\NC \type{data}        \NC string           \NC the name of the destination \NC \NR

-\LL

-\stoptabulate

-

-Valid action types are:

-

-\starttabulate[|l|l|]

-\DB value \BC meaning       \NC \NR

-\TB

-\NC 0     \NC \type{page}   \NC \NR

-\NC 1     \NC \type{goto}   \NC \NR

-\NC 2     \NC \type{thread} \NC \NR

-\NC 3     \NC \type{user}   \NC \NR

-\LL

-\stoptabulate

-

-Valid window types are:

-

-\starttabulate[|l|l|]

-\DB value \BC meaning       \NC \NR

-\TB

-\NC 0     \NC \type{notset} \NC \NR

-\NC 1     \NC \type{new}    \NC \NR

-\NC 2     \NC \type{nonew}  \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_thread}}

-

-\starttabulate[|l|l|p|]

-\DB field              \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}        \NC node   \NC list of attributes \NC \NR

-\NC \type{width}       \NC number \NC the width (not used in calculations) \NC \NR

-\NC \type{height}      \NC number \NC the height (not used in calculations) \NC \NR

-\NC \type{depth}       \NC number \NC the depth (not used in calculations) \NC \NR

-\NC \type{named_id}    \NC number \NC is \type {tread_id} a string value? \NC \NR

-\NC \type{tread_id}    \NC number \NC the thread id \NC \NR

-\NC                    \NC string \NC the thread name \NC \NR

-\NC \type{thread_attr} \NC number \NC extra thread information \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_start_thread}}

-

-\starttabulate[|l|l|p|]

-\DB field              \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}        \NC node   \NC list of attributes \NC \NR

-\NC \type{width}       \NC number \NC the width (not used in calculations) \NC \NR

-\NC \type{height}      \NC number \NC the height (not used in calculations) \NC \NR

-\NC \type{depth}       \NC number \NC the depth (not used in calculations) \NC \NR

-\NC \type{named_id}    \NC number \NC is \type {tread_id} a string value? \NC \NR

-\NC \type{tread_id}    \NC number \NC the thread id \NC \NR

-\NC                    \NC string \NC the thread name \NC \NR

-\NC \type{thread_attr} \NC number \NC extra thread information \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_end_thread}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node \NC \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_colorstack}}

-

-\starttabulate[|l|l|p|]

-\DB field          \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr}    \NC node   \NC list of attributes \NC \NR

-\NC \type{stack}   \NC number \NC colorstack id number \NC \NR

-\NC \type{command} \NC number \NC command to execute \NC \NR

-\NC \type{data}    \NC string \NC data \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_setmatrix}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node   \NC list of attributes \NC \NR

-\NC \type{data} \NC string \NC data \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_save}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node \NC list of attributes \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\whs {pdf_restore}}

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{attr} \NC node \NC list of attributes \NC \NR

-\LL

-\stoptabulate

-

-\stopsection

-

-\startsection[title={The \type {node} library}][library=node]

-

-\subsection {Introduction}

-

-The \type {node} library contains functions that facilitate dealing with (lists

-of) nodes and their values. They allow you to create, alter, copy, delete, and

-insert \LUATEX\ node objects, the core objects within the typesetter.

-

-\LUATEX\ nodes are represented in \LUA\ as userdata with the metadata type

-\type {luatex.node}. The various parts within a node can be accessed using

-named fields.

-

-Each node has at least the three fields \type {next}, \type {id}, and \type {subtype}:

-

-\startitemize[intro]

-

-\startitem

-    The \type {next} field returns the userdata object for the next node in a

-    linked list of nodes, or \type {nil}, if there is no next node.

-\stopitem

-

-\startitem

-    The \type {id} indicates \TEX's \quote{node type}. The field \type {id} has a

-    numeric value for efficiency reasons, but some of the library functions also

-    accept a string value instead of \type {id}.

-\stopitem

-

-\startitem

-    The \type {subtype} is another number. It often gives further information

-    about a node of a particular \type {id}, but it is most important when

-    dealing with \quote {whatsits}, because they are differentiated solely based

-    on their \type {subtype}.

-\stopitem

-

-\stopitemize

-

-The other available fields depend on the \type {id} (and for \quote {whatsits},

-the \type {subtype}) of the node.

-

-Support for \nod {unset} (alignment) nodes is partial: they can be queried and

-modified from \LUA\ code, but not created.

-

-Nodes can be compared to each other, but: you are actually comparing indices into

-the node memory. This means that equality tests can only be trusted under very

-limited conditions. It will not work correctly in any situation where one of the

-two nodes has been freed and|/|or reallocated: in that case, there will be false

-positives.

-

-At the moment, memory management of nodes should still be done explicitly by the

-user. Nodes are not \quote {seen} by the \LUA\ garbage collector, so you have to

-call the node freeing functions yourself when you are no longer in need of a node

-(list). Nodes form linked lists without reference counting, so you have to be

-careful that when control returns back to \LUATEX\ itself, you have not deleted

-nodes that are still referenced from a \type {next} pointer elsewhere, and that

-you did not create nodes that are referenced more than once. Normally the setters

-and getters handle this for you.

-

-There are statistics available with regards to the allocated node memory, which

-can be handy for tracing.

-

-\subsection{\type {is_node}}

-

-\topicindex {nodes+functions}

-

-\libindex {is_node}

-

-\startfunctioncall

-<boolean|integer> t =

-    node.is_node(<any> item)

-\stopfunctioncall

-

-This function returns a number (the internal index of the node) if the argument

-is a userdata object of type \type {<node>} and false when no node is passed.

-

-\subsection{\type {types} and \type {whatsits}}

-

-\libindex {types}

-\libindex {whatsits}

-

-This function returns an array that maps node id numbers to node type strings,

-providing an overview of the possible top|-|level \type {id} types.

-

-\startfunctioncall

-<table> t =

-    node.types()

-\stopfunctioncall

-

-\TEX's \quote {whatsits} all have the same \type {id}. The various subtypes are

-defined by their \type {subtype} fields. The function is much like \type {types},

-except that it provides an array of \type {subtype} mappings.

-

-\startfunctioncall

-<table> t =

-    node.whatsits()

-\stopfunctioncall

-

-\subsection{\type {id}}

-

-\libindex{id}

-

-This converts a single type name to its internal numeric representation.

-

-\startfunctioncall

-<number> id =

-    node.id(<string> type)

-\stopfunctioncall

-

-\subsection{\type {type} and \type {subtype}}

-

-\libindex {type}

-\libindex {subtype}

-

-In the argument is a number, then the next function converts an internal numeric

-representation to an external string representation. Otherwise, it will return

-the string \type {node} if the object represents a node, and \type {nil}

-otherwise.

-

-\startfunctioncall

-<string> type =

-    node.type(<any> n)

-\stopfunctioncall

-

-This next one converts a single whatsit name to its internal numeric

-representation (\type {subtype}).

-

-\startfunctioncall

-<number> subtype =

-    node.subtype(<string> type)

-\stopfunctioncall

-

-\subsection{\type {fields}}

-

-\libindex {fields}

-

-This function returns an array of valid field names for a particular type of

-node. If you want to get the valid fields for a \quote {whatsit}, you have to

-supply the second argument also. In other cases, any given second argument will

-be silently ignored.

-

-\startfunctioncall

-<table> t =

-    node.fields(<number> id)

-<table> t =

-    node.fields(<number> id, <number> subtype)

-\stopfunctioncall

-

-The function accepts string \type {id} and \type {subtype} values as well.

-

-\subsection{\type {has_field}}

-

-\libindex {has_field}

-

-This function returns a boolean that is only true if \type {n} is

-actually a node, and it has the field.

-

-\startfunctioncall

-<boolean> t =

-    node.has_field(<node> n, <string> field)

-\stopfunctioncall

-

-\subsection{\type {new}}

-

-\libindex{new}

-

-The \type {new} function creates a new node. All its fields are initialized to

-either zero or \type {nil} except for \type {id} and \type {subtype}. Instead of

-numbers you can also use strings (names). If you create a new \nod {whatsit} node

-the second argument is required. As with all node functions, this function

-creates a node at the \TEX\ level.

-

-\startfunctioncall

-<node> n =

-    node.new(<number> id)

-<node> n =

-    node.new(<number> id, <number> subtype)

-\stopfunctioncall

-

-\subsection{\type {free}, \type {flush_node} and \type {flush_list}}

-

-\libindex{free}

-\libindex{flush_node}

-\libindex{flush_list}

-

-The next one the node \type {n} from \TEX's memory. Be careful: no checks are

-done on whether this node is still pointed to from a register or some \type

-{next} field: it is up to you to make sure that the internal data structures

-remain correct.

-

-\startfunctioncall

-<node> next =

-    node.free(<node> n)

-flush_node(<node> n)

-\stopfunctioncall

-

-The \type {free} function returns the next field of the freed node, while the

-\type {flush_node} alternative returns nothing.

-

-A list starting with node \type {n} can be flushed from \TEX's memory too. Be

-careful: no checks are done on whether any of these nodes is still pointed to

-from a register or some \type {next} field: it is up to you to make sure that the

-internal data structures remain correct.

-

-\startfunctioncall

-node.flush_list(<node> n)

-\stopfunctioncall

-

-\subsection{\type {copy} and \type {copy_list}}

-

-\libindex{copy}

-\libindex{copy_list}

-

-This creates a deep copy of node \type {n}, including all nested lists as in the case

-of a hlist or vlist node. Only the \type {next} field is not copied.

-

-\startfunctioncall

-<node> m =

-    node.copy(<node> n)

-\stopfunctioncall

-

-A deep copy of the node list that starts at \type {n} can be created too. If

-\type {m} is also given, the copy stops just before node \type {m}.

-

-\startfunctioncall

-<node> m =

-    node.copy_list(<node> n)

-<node> m =

-    node.copy_list(<node> n, <node> m)

-\stopfunctioncall

-

-Note that you cannot copy attribute lists this way. However, there is normally no

-need to copy attribute lists as when you do assignments to the \type {attr} field

-or make changes to specific attributes, the needed copying and freeing takes

-place automatically.

-

-\subsection{\type {prev} and \type{next}}

-

-\libindex{prev}

-\libindex{next}

-

-These returns the node preceding or following the given node, or \type {nil} if

-there is no such node.

-

-\startfunctioncall

-<node> m =

-    node.next(<node> n)

-<node> m =

-    node.prev(<node> n)

-\stopfunctioncall

-

-\subsection{\type {current_attr}}

-

-\libindex{current_attr}

-

-This returns the currently active list of attributes, if there is one.

-

-\startfunctioncall

-<node> m =

-    node.current_attr()

-\stopfunctioncall

-

-The intended usage of \type {current_attr} is as follows:

-

-\starttyping

-local x1 = node.new("glyph")

-x1.attr = node.current_attr()

-local x2 = node.new("glyph")

-x2.attr = node.current_attr()

-\stoptyping

-

-or:

-

-\starttyping

-local x1 = node.new("glyph")

-local x2 = node.new("glyph")

-local ca = node.current_attr()

-x1.attr = ca

-x2.attr = ca

-\stoptyping

-

-The attribute lists are ref counted and the assignment takes care of incrementing

-the refcount. You cannot expect the value \type {ca} to be valid any more when

-you assign attributes (using \type {tex.setattribute}) or when control has been

-passed back to \TEX.

-

-Note: this function is somewhat experimental, and it returns the {\it actual}

-attribute list, not a copy thereof. Therefore, changing any of the attributes in

-the list will change these values for all nodes that have the current attribute

-list assigned to them.

-

-\subsection{\type {hpack}}

-

-\libindex {hpack}

-

-This function creates a new hlist by packaging the list that begins at node \type

-{n} into a horizontal box. With only a single argument, this box is created using

-the natural width of its components. In the three argument form, \type {info}

-must be either \type {additional} or \type {exactly}, and \type {w} is the

-additional (\type {\hbox spread}) or exact (\type {\hbox to}) width to be used.

-The second return value is the badness of the generated box.

-

-\startfunctioncall

-<node> h, <number> b =

-    node.hpack(<node> n)

-<node> h, <number> b =

-    node.hpack(<node> n, <number> w, <string> info)

-<node> h, <number> b =

-    node.hpack(<node> n, <number> w, <string> info, <string> dir)

-\stopfunctioncall

-

-Caveat: there can be unexpected side|-|effects to this function, like updating

-some of the \prm {marks} and \type {\inserts}. Also note that the content of

-\type {h} is the original node list \type {n}: if you call \type {node.free(h)}

-you will also free the node list itself, unless you explicitly set the \type

-{list} field to \type {nil} beforehand. And in a similar way, calling \type

-{node.free(n)} will invalidate \type {h} as well!

-

-\subsection{\type {vpack}}

-

-\libindex {vpack}

-

-This function creates a new vlist by packaging the list that begins at node \type

-{n} into a vertical box. With only a single argument, this box is created using

-the natural height of its components. In the three argument form, \type {info}

-must be either \type {additional} or \type {exactly}, and \type {w} is the

-additional (\type {\vbox spread}) or exact (\type {\vbox to}) height to be used.

-

-\startfunctioncall

-<node> h, <number> b =

-    node.vpack(<node> n)

-<node> h, <number> b =

-    node.vpack(<node> n, <number> w, <string> info)

-<node> h, <number> b =

-    node.vpack(<node> n, <number> w, <string> info, <string> dir)

-\stopfunctioncall

-

-The second return value is the badness of the generated box. See the description

-of \type {hpack} for a few memory allocation caveats.

-

-\subsection{\type {prepend_prevdepth}}

-

-\libindex {prepend_prevdepth}

-

-This function is somewhat special in the sense that it is an experimental helper

-that adds the interlinespace to a line keeping the baselineskip and lineskip into

-account.

-

-\startfunctioncall

-<node> n, <number> delta =

-    node.prepend_prevdepth(<node> n,<number> prevdepth)

-\stopfunctioncall

-

-\subsection{\type {dimensions} and \type {rangedimensions}}

-

-\libindex{dimensions}

-\libindex{rangedimensions}

-

-\startfunctioncall

-<number> w, <number> h, <number> d  =

-    node.dimensions(<node> n)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<node> n, <string> dir)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<node> n, <node> t)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<node> n, <node> t, <string> dir)

-\stopfunctioncall

-

-This function calculates the natural in|-|line dimensions of the node list starting

-at node \type {n} and terminating just before node \type {t} (or the end of the

-list, if there is no second argument). The return values are scaled points. An

-alternative format that starts with glue parameters as the first three arguments

-is also possible:

-

-\startfunctioncall

-<number> w, <number> h, <number> d  =

-    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,

-        <node> n)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,

-        <node> n, <string> dir)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,

-        <node> n, <node> t)

-<number> w, <number> h, <number> d  =

-    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,

-        <node> n, <node> t, <string> dir)

-\stopfunctioncall

-

-This calling method takes glue settings into account and is especially useful for

-finding the actual width of a sublist of nodes that are already boxed, for

-example in code like this, which prints the width of the space in between the

-\type {a} and \type {b} as it would be if \type {\box0} was used as-is:

-

-\starttyping

-\setbox0 = \hbox to 20pt {a b}

-

-\directlua{print (node.dimensions(

-    tex.box[0].glue_set,

-    tex.box[0].glue_sign,

-    tex.box[0].glue_order,

-    tex.box[0].head.next,

-    node.tail(tex.box[0].head)

-)) }

-\stoptyping

-

-You need to keep in mind that this is one of the few places in \TEX\ where floats

-are used, which means that you can get small differences in rounding when you

-compare the width reported by \type {hpack} with \type {dimensions}.

-

-The second alternative saves a few lookups and can be more convenient in some

-cases:

-

-\startfunctioncall

-<number> w, <number> h, <number> d  =

-    node.rangedimensions(<node> parent, <node> first)

-<number> w, <number> h, <number> d  =

-    node.rangedimensions(<node> parent, <node> first, <node> last)

-\stopfunctioncall

-

-\subsection{\type {mlist_to_hlist}}

-

-\libindex {mlist_to_hlist}

-

-\startfunctioncall

-<node> h =

-    node.mlist_to_hlist(<node> n, <string> display_type, <boolean> penalties)

-\stopfunctioncall

-

-This runs the internal mlist to hlist conversion, converting the math list in

-\type {n} into the horizontal list \type {h}. The interface is exactly the same

-as for the callback \cbk {mlist_to_hlist}.

-

-\subsection{\type {slide}}

-

-\startfunctioncall

-<node> m =

-    node.slide(<node> n)

-\stopfunctioncall

-

-Returns the last node of the node list that starts at \type {n}. As a

-side|-|effect, it also creates a reverse chain of \type {prev} pointers between

-nodes.

-

-\subsection{\type {tail}}

-

-\libindex {tail}

-

-\startfunctioncall

-<node> m =

-    node.tail(<node> n)

-\stopfunctioncall

-

-Returns the last node of the node list that starts at \type {n}.

-

-\subsection{\type {length} and type {count}}

-

-\libindex {length}

-\libindex {count}

-

-\startfunctioncall

-<number> i =

-    node.length(<node> n)

-<number> i =

-    node.length(<node> n, <node> m)

-\stopfunctioncall

-

-Returns the number of nodes contained in the node list that starts at \type {n}.

-If \type {m} is also supplied it stops at \type {m} instead of at the end of the

-list. The node \type {m} is not counted.

-

-\startfunctioncall

-<number> i =

-    node.count(<number> id, <node> n)

-<number> i =

-    node.count(<number> id, <node> n, <node> m)

-\stopfunctioncall

-

-Returns the number of nodes contained in the node list that starts at \type {n}

-that have a matching \type {id} field. If \type {m} is also supplied, counting

-stops at \type {m} instead of at the end of the list. The node \type {m} is not

-counted. This function also accept string \type {id}'s.

-

-\subsection{\type {is_char} and \type {is_glyph}}

-

-\libindex {is_char}

-\libindex {is_glyph}

-

-The subtype of a glyph node signals if the glyph is already turned into a character reference

-or not.

-

-\startfunctioncall

-<boolean> b =

-    node.is_char(<node> n)

-<boolean> b =

-    node.is_glyph(<node> n)

-\stopfunctioncall

-

-\subsection{\type {traverse}}

-

-\libindex {traverse}

-

-\startfunctioncall

-<node> t, id, subtype =

-    node.traverse(<node> n)

-\stopfunctioncall

-

-This is a \LUA\ iterator that loops over the node list that starts at \type {n}.

-Typically code looks like this:

-

-\starttyping

-for n in node.traverse(head) do

-   ...

-end

-\stoptyping

-

-is functionally equivalent to:

-

-\starttyping

-do

-  local n

-  local function f (head,var)

-    local t

-    if var == nil then

-       t = head

-    else

-       t = var.next

-    end

-    return t

-  end

-  while true do

-    n = f (head, n)

-    if n == nil then break end

-    ...

-  end

-end

-\stoptyping

-

-It should be clear from the definition of the function \type {f} that even though

-it is possible to add or remove nodes from the node list while traversing, you

-have to take great care to make sure all the \type {next} (and \type {prev})

-pointers remain valid.

-

-If the above is unclear to you, see the section \quote {For Statement} in the

-\LUA\ Reference Manual.

-

-\subsection{\type {traverse_id}}

-

-\libindex {traverse_id}

-

-\startfunctioncall

-<node> t, subtype =

-    node.traverse_id(<number> id, <node> n)

-\stopfunctioncall

-

-This is an iterator that loops over all the nodes in the list that starts at

-\type {n} that have a matching \type {id} field.

-

-See the previous section for details. The change is in the local function \type

-{f}, which now does an extra while loop checking against the upvalue \type {id}:

-

-\starttyping

- local function f(head,var)

-   local t

-   if var == nil then

-      t = head

-   else

-      t = var.next

-   end

-   while not t.id == id do

-      t = t.next

-   end

-   return t

- end

-\stoptyping

-

-\subsection{\type {traverse_char} and \type {traverse_glyph}}

-

-\libindex {traverse_char}

-\libindex {traverse_glyph}

-

-The \type{traverse_char} iterator loops over the \nod {glyph} nodes in a list.

-Only nodes with a subtype less than 256 are seen.

-

-\startfunctioncall

-<node> n, font, char =

-    node.traverse_char(<node> n)

-\stopfunctioncall

-

-The \type{traverse_glyph} iterator loops over a list and returns the list and

-filters all glyphs:

-

-\startfunctioncall

-<node> n, font, char =

-    node.traverse_glyph(<node> n)

-\stopfunctioncall

-

-\subsection{\type {traverse_list}}

-

-\libindex {traverse_list}

-

-This iterator loops over the \nod {hlist} and \nod {vlist} nodes in a list.

-

-\startfunctioncall

-<node> n, id, subtype, list =

-    node.traverse_list(<node> n)

-\stopfunctioncall

-

-The four return values can save some time compared to fetching these fields but

-in practice you seldom need them all. So consider it a (side effect of

-experimental) convenience.

-

-\subsection{\type {has_glyph}}

-

-\libindex {has_glyph}

-

-This function returns the first glyph or disc node in the given list:

-

-\startfunctioncall

-<node> n =

-    node.has_glyph(<node> n)

-\stopfunctioncall

-

-\subsection{\type {end_of_math}}

-

-\libindex {end_of_math}

-

-\startfunctioncall

-<node> t =

-    node.end_of_math(<node> start)

-\stopfunctioncall

-

-Looks for and returns the next \type {math_node} following the \type {start}. If

-the given node is a math end node this helper returns that node, else it follows

-the list and returns the next math endnote. If no such node is found nil is

-returned.

-

-\subsection{\type {remove}}

-

-\libindex {remove}

-

-\startfunctioncall

-<node> head, current =

-    node.remove(<node> head, <node> current)

-\stopfunctioncall

-

-This function removes the node \type {current} from the list following \type

-{head}. It is your responsibility to make sure it is really part of that list.

-The return values are the new \type {head} and \type {current} nodes. The

-returned \type {current} is the node following the \type {current} in the calling

-argument, and is only passed back as a convenience (or \type {nil}, if there is

-no such node). The returned \type {head} is more important, because if the

-function is called with \type {current} equal to \type {head}, it will be

-changed.

-

-\subsection{\type {insert_before}}

-

-\libindex {insert_before}

-

-\startfunctioncall

-<node> head, new =

-    node.insert_before(<node> head, <node> current, <node> new)

-\stopfunctioncall

-

-This function inserts the node \type {new} before \type {current} into the list

-following \type {head}. It is your responsibility to make sure that \type

-{current} is really part of that list. The return values are the (potentially

-mutated) \type {head} and the node \type {new}, set up to be part of the list

-(with correct \type {next} field). If \type {head} is initially \type {nil}, it

-will become \type {new}.

-

-\subsection{\type {insert_after}}

-

-\libindex {insert_after}

-

-\startfunctioncall

-<node> head, new =

-    node.insert_after(<node> head, <node> current, <node> new)

-\stopfunctioncall

-

-This function inserts the node \type {new} after \type {current} into the list

-following \type {head}. It is your responsibility to make sure that \type

-{current} is really part of that list. The return values are the \type {head} and

-the node \type {new}, set up to be part of the list (with correct \type {next}

-field). If \type {head} is initially \type {nil}, it will become \type {new}.

-

-\subsection{\type {first_glyph}}

-

-\libindex {first_glyph}

-

-\startfunctioncall

-<node> n =

-    node.first_glyph(<node> n)

-<node> n =

-    node.first_glyph(<node> n, <node> m)

-\stopfunctioncall

-

-Returns the first node in the list starting at \type {n} that is a glyph node

-with a subtype indicating it is a glyph, or \type {nil}. If \type {m} is given,

-processing stops at (but including) that node, otherwise processing stops at the

-end of the list.

-

-\subsection{\type {ligaturing}}

-

-\libindex {ligaturing}

-

-\startfunctioncall

-<node> h, <node> t, <boolean> success =

-    node.ligaturing(<node> n)

-<node> h, <node> t, <boolean> success =

-    node.ligaturing(<node> n, <node> m)

-\stopfunctioncall

-

-Apply \TEX-style ligaturing to the specified nodelist. The tail node \type {m} is

-optional. The two returned nodes \type {h} and \type {t} are the new head and

-tail (both \type {n} and \type {m} can change into a new ligature).

-

-\subsection{\type {kerning}}

-

-\libindex {kerning}

-

-\startfunctioncall

-<node> h, <node> t, <boolean> success =

-    node.kerning(<node> n)

-<node> h, <node> t, <boolean> success =

-    node.kerning(<node> n, <node> m)

-\stopfunctioncall

-

-Apply \TEX|-|style kerning to the specified node list. The tail node \type {m} is

-optional. The two returned nodes \type {h} and \type {t} are the head and tail

-(either one of these can be an inserted kern node, because special kernings with

-word boundaries are possible).

-

-\subsection{\type {unprotect_glyph[s]}}

-

-\libindex {unprotect_glyphs}

-\libindex {unprotect_glyph}

-

-\startfunctioncall

-node.unprotect_glyph(<node> n)

-node.unprotect_glyphs(<node> n,[<node> n])

-\stopfunctioncall

-

-Subtracts 256 from all glyph node subtypes. This and the next function are

-helpers to convert from \type {characters} to \type {glyphs} during node

-processing. The second argument is optional and indicates the end of a range.

-

-\subsection{\type {protect_glyph[s]}}

-

-\libindex {protect_glyphs}

-\libindex {protect_glyph}

-

-\startfunctioncall

-node.protect_glyph(<node> n)

-node.protect_glyphs(<node> n,[<node> n])

-\stopfunctioncall

-

-Adds 256 to all glyph node subtypes in the node list starting at \type {n},

-except that if the value is 1, it adds only 255. The special handling of 1 means

-that \type {characters} will become \type {glyphs} after subtraction of 256. A

-single character can be marked by the singular call. The second argument is

-optional and indicates the end of a range.

-

-\subsection{\type {last_node}}

-

-\libindex {last_node}

-

-\startfunctioncall

-<node> n =

-    node.last_node()

-\stopfunctioncall

-

-This function pops the last node from \TEX's \quote{current list}. It returns

-that node, or \type {nil} if the current list is empty.

-

-\subsection{\type {write}}

-

-\libindex {write}

-

-\startfunctioncall

-node.write(<node> n)

-\stopfunctioncall

-

-This function that will append a node list to \TEX's \quote {current list}. The

-node list is not deep|-|copied! There is no error checking either! You mignt need

-to enforce horizontal mode in order for this to work as expected.

-

-\subsection{\type {protrusion_skippable}}

-

-\libindex {protrusion_skippable}

-

-\startfunctioncall

-<boolean> skippable =

-    node.protrusion_skippable(<node> n)

-\stopfunctioncall

-

-Returns \type {true} if, for the purpose of line boundary discovery when

-character protrusion is active, this node can be skipped.

-

-\stopsection

-

-\startsection[title={Glue handling}][library=node]

-

-\subsection{\type {setglue}}

-

-\libindex {setglue}

-

-You can set the properties of a glue in one go. If you pass no values, the glue

-will become a zero glue.

-

-\startfunctioncall

-node.setglue(<node> n)

-node.setglue(<node> n,width,stretch,shrink,stretch_order,shrink_order)

-\stopfunctioncall

-

-When you pass values, only arguments that are numbers are assigned so

-

-\starttyping

-node.setglue(n,655360,false,65536)

-\stoptyping

-

-will only adapt the width and shrink.

-

-When a list node is passed, you set the glue, order and sign instead.

-

-\subsection{\type {getglue}}

-

-\libindex {getglue}

-

-The next call will return 5 values or nothing when no glue is passed.

-

-\startfunctioncall

-<integer> width, <integer> stretch, <integer> shrink, <integer> stretch_order,

-    <integer> shrink_order = node.getglue(<node> n)

-\stopfunctioncall

-

-When the second argument is false, only the width is returned (this is consistent

-with \type {tex.get}).

-

-When a list node is passed, you get back the glue that is set, the order of that

-glue and the sign.

-

-\subsection{\type {is_zero_glue}}

-

-\libindex {is_zero_glue}

-

-This function returns \type {true} when the width, stretch and shrink properties

-are zero.

-

-\startfunctioncall

-<boolean> isglue =

-    node.is_zero_glue(<node> n)

-\stopfunctioncall

-

-\stopsection

-

-\startsection[title={Attribute handling}][library=node]

-

-\subsection{Attributes}

-

-\topicindex {attributes}

-

-The newly introduced attribute registers are non|-|trivial, because the value

-that is attached to a node is essentially a sparse array of key|-|value pairs. It

-is generally easiest to deal with attribute lists and attributes by using the

-dedicated functions in the \type {node} library, but for completeness, here is

-the low|-|level interface.

-

-Attributes appear as linked list of userdata objects in the \type {attr} field of

-individual nodes. They can be handled individually, but it is much safer and more

-efficient to use the dedicated functions associated with them.

-

-\subsection{\nod {attribute_list} nodes}

-

-\topicindex {nodes+attributes}

-

-An \nod {attribute_list} item is used as a head pointer for a list of attribute

-items. It has only one user-visible field:

-

-\starttabulate[|l|l|p|]

-\DB field       \BC type \BC explanation \NC \NR

-\TB

-\NC \type{next} \NC node \NC pointer to the first attribute \NC \NR

-\LL

-\stoptabulate

-

-\subsection{\nod {attr} nodes}

-

-A normal node's attribute field will point to an item of type \nod

-{attribute_list}, and the \type {next} field in that item will point to the first

-defined \quote {attribute} item, whose \type {next} will point to the second

-\quote {attribute} item, etc.

-

-\starttabulate[|l|l|p|]

-\DB field         \BC type   \BC explanation \NC \NR

-\TB

-\NC \type{next}   \NC node   \NC pointer to the next attribute \NC \NR

-\NC \type{number} \NC number \NC the attribute type id \NC \NR

-\NC \type{value}  \NC number \NC the attribute value \NC \NR

-\LL

-\stoptabulate

-

-As mentioned it's better to use the official helpers rather than edit these

-fields directly. For instance the \type {prev} field is used for other purposes

-and there is no double linked list.

-

-\subsection{\type {has_attribute}}

-

-\libindex {has_attribute}

-

-\startfunctioncall

-<number> v =

-    node.has_attribute(<node> n, <number> id)

-<number> v =

-    node.has_attribute(<node> n, <number> id, <number> val)

-\stopfunctioncall

-

-Tests if a node has the attribute with number \type {id} set. If \type {val} is

-also supplied, also tests if the value matches \type {val}. It returns the value,

-or, if no match is found, \type {nil}.

-

-\subsection{\type {get_attribute}}

-

-\libindex {get_attribute}

-

-\startfunctioncall

-<number> v =

-    node.get_attribute(<node> n, <number> id)

-\stopfunctioncall

-

-Tests if a node has an attribute with number \type {id} set. It returns the

-value, or, if no match is found, \type {nil}. If no \type {id} is given then the

-zero attributes is assumed.

-

-\subsection{\type {find_attribute}}

-

-\libindex {find_attribute}

-

-\startfunctioncall

-<number> v, <node> n =

-    node.find_attribute(<node> n, <number> id)

-\stopfunctioncall

-

-Finds the first node that has attribute with number \type {id} set. It returns

-the value and the node if there is a match and otherwise nothing.

-

-\subsection{\type {set_attribute}}

-

-\libindex {set_attribute}

-

-\startfunctioncall

-node.set_attribute(<node> n, <number> id, <number> val)

-\stopfunctioncall

-

-Sets the attribute with number \type {id} to the value \type {val}. Duplicate

-assignments are ignored.

-

-\subsection{\type {unset_attribute}}

-

-\libindex {unset_attribute}

-

-\startfunctioncall

-<number> v =

-    node.unset_attribute(<node> n, <number> id)

-<number> v =

-    node.unset_attribute(<node> n, <number> id, <number> val)

-\stopfunctioncall

-

-Unsets the attribute with number \type {id}. If \type {val} is also supplied, it

-will only perform this operation if the value matches \type {val}. Missing

-attributes or attribute|-|value pairs are ignored.

-

-If the attribute was actually deleted, returns its old value. Otherwise, returns

-\type {nil}.

-

-\subsection{\type {slide}}

-

-\libindex {slide}

-

-This helper makes sure that the node lists is double linked and returns the found

-tail node.

-

-\startfunctioncall

-<node> tail =

-    node.slide(<node> n)

-\stopfunctioncall

-

-After some callbacks automatic sliding takes place. This feature can be turned

-off with \type {node.fix_node_lists(false)} but you better make sure then that

-you don't mess up lists. In most cases \TEX\ itself only uses \type {next}

-pointers but your other callbacks might expect proper \type {prev} pointers too.

-Future versions of \LUATEX\ can add more checking but this will not influence

-usage.

-

-\subsection{\type {check_discretionary}, \type {check_discretionaries}}

-

-\libindex{check_discretionary}

-\libindex{check_discretionaries}

-

-When you fool around with disc nodes you need to be aware of the fact that they

-have a special internal data structure. As long as you reassign the fields when

-you have extended the lists it's ok because then the tail pointers get updated,

-but when you add to list without reassigning you might end up in trouble when

-the linebreak routine kicks in. You can call this function to check the list for

-issues with disc nodes.

-

-\startfunctioncall

-node.check_discretionary(<node> n)

-node.check_discretionaries(<node> head)

-\stopfunctioncall

-

-The plural variant runs over all disc nodes in a list, the singular variant

-checks one node only (it also checks if the node is a disc node).

-

-\subsection{\type {flatten_discretionaries}}

-

-\libindex {flatten_discretionaries}

-

-This function will remove the discretionaries in the list and inject the replace

-field when set.

-

-\startfunctioncall

-<node> head, count = node.flatten_discretionaries(<node> n)

-\stopfunctioncall

-

-\subsection{\type {family_font}}

-

-\libindex {family_font}

-

-When you pass a proper family identifier the next helper will return the font

-currently associated with it. You can normally also access the font with the

-normal font field or getter because it will resolve the family automatically for

-noads.

-

-\startfunctioncall

-<integer> id =

-    node.family_font(<integer> fam)

-\stopfunctioncall

-

-\stopsection

-

-\startsection[title={Two access models}][library=node]

-

-\topicindex{nodes+direct}

-\topicindex{direct nodes}

-

-\libindex {todirect}

-\libindex {tonode}

-\libindex {tostring}

-

-Deep down in \TEX\ a node has a number which is a numeric entry in a memory

-table. In fact, this model, where \TEX\ manages memory is real fast and one of

-the reasons why plugging in callbacks that operate on nodes is quite fast too.

-Each node gets a number that is in fact an index in the memory table and that

-number often is reported when you print node related information. You go from

-userdata nodes and there numeric references and back with:

-

-\startfunctioncall

-<integer> d = node.todirect(<node> n))

-<node> n = node.tonode(<integer> d))

-\stopfunctioncall

-

-The userdata model is rather robust as it is a virtual interface with some

-additional checking while the more direct access which uses the node numbers

-directly. However, even with userdata you can get into troubles when you free

-nodes that are no longer allocated or mess up lists. if you apply \type

-{tostring} to a node you see its internal (direct) number and id.

-

-The first model provides key based access while the second always accesses fields

-via functions:

-

-\starttyping

-nodeobject.char

-getfield(nodenumber,"char")

-\stoptyping

-

-If you use the direct model, even if you know that you deal with numbers, you

-should not depend on that property but treat it as an abstraction just like

-traditional nodes. In fact, the fact that we use a simple basic datatype has the

-penalty that less checking can be done, but less checking is also the reason why

-it's somewhat faster. An important aspect is that one cannot mix both methods,

-but you can cast both models. So, multiplying a node number makes no sense.

-

-So our advice is: use the indexed (table) approach when possible and investigate

-the direct one when speed might be a real issue. For that reason \LUATEX\ also

-provide the \type {get*} and \type {set*} functions in the top level node

-namespace. There is a limited set of getters. When implementing this direct

-approach the regular index by key variant was also optimized, so direct access

-only makes sense when nodes are accessed millions of times (which happens in some

-font processing for instance).

-

-We're talking mostly of getters because setters are less important. Documents

-have not that many content related nodes and setting many thousands of properties

-is hardly a burden contrary to millions of consultations.

-

-Normally you will access nodes like this:

-

-\starttyping

-local next = current.next

-if next then

-    -- do something

-end

-\stoptyping

-

-Here \type {next} is not a real field, but a virtual one. Accessing it results in

-a metatable method being called. In practice it boils down to looking up the node

-type and based on the node type checking for the field name. In a worst case you

-have a node type that sits at the end of the lookup list and a field that is last

-in the lookup chain. However, in successive versions of \LUATEX\ these lookups

-have been optimized and the most frequently accessed nodes and fields have a

-higher priority.

-

-Because in practice the \type {next} accessor results in a function call, there

-is some overhead involved. The next code does the same and performs a tiny bit

-faster (but not that much because it is still a function call but one that knows

-what to look up).

-

-\starttyping

-local next = node.next(current)

-if next then

-    -- do something

-end

-\stoptyping

-

-Some accessors are used frequently and for these we provide more efficient helpers:

-

-\starttabulate[|l|p|]

-\DB function          \BC explanation \NC \NR

-\TB

-\NC \type{getnext}    \NC parsing nodelist always involves this one \NC \NR

-\NC \type{getprev}    \NC used less but a logical companion to \type {getnext} \NC \NR

-\NC \type{getboth}    \NC returns the next and prev pointer of a node \NC \NR

-\NC \type{getid}      \NC consulted a lot \NC \NR

-\NC \type{getsubtype} \NC consulted less but also a topper \NC \NR

-\NC \type{getfont}    \NC used a lot in \OPENTYPE\ handling (glyph nodes are consulted a lot) \NC \NR

-\NC \type{getchar}    \NC idem and also in other places \NC \NR

-\NC \type{getwhd}     \NC returns the \type {width}, \type {height} and \type {depth} of a list, rule or

-                          (unexpanded) glyph as well as glue (its spec is looked at) and unset nodes\NC \NR

-\NC \type{getdisc}    \NC returns the \type {pre}, \type {post} and \type {replace} fields and

-                          optionally when true is passed also the tail fields \NC \NR

-\NC \type{getlist}    \NC we often parse nested lists so this is a convenient one too \NC \NR

-\NC \type{getleader}  \NC comparable to list, seldom used in \TEX\ (but needs frequent consulting

-                          like lists; leaders could have been made a dedicated node type) \NC \NR

-\NC \type{getfield}   \NC generic getter, sufficient for the rest (other field names are

-                          often shared so a specific getter makes no sense then) \NC \NR

-\NC \type{getbox}     \NC gets the given box (a list node) \NC \NR

-\NC \type{getoffsets} \NC gets the \type {xoffset} and \type {yoffset} of a glyph or

-                          \type {left} and \type {right} values of a rule \NC \NR

-\LL

-\stoptabulate

-

-In the direct namespace there are more such helpers and most of them are

-accompanied by setters. The getters and setters are clever enough to see what

-node is meant. We don't deal with whatsit nodes: their fields are always accessed

-by name. It doesn't make sense to add getters for all fields, we just identifier

-the most likely candidates. In complex documents, many node and fields types

-never get seen, or seen only a few times, but for instance glyphs are candidates

-for such optimization. The \type {node.direct} interface has some more helpers.

-\footnote {We can define the helpers in the node namespace with \type {getfield}

-which is about as efficient, so at some point we might provide that as module.}

-

-The \type {setdisc} helper takes three (optional) arguments plus an optional

-fourth indicating the subtype. Its \type {getdisc} takes an optional boolean;

-when its value is \type {true} the tail nodes will also be returned. The \type

-{setfont} helper takes an optional second argument, it being the character. The

-directmode setter \type {setlink} takes a list of nodes and will link them,

-thereby ignoring \type {nil} entries. The first valid node is returned (beware:

-for good reason it assumes single nodes). For rarely used fields no helpers are

-provided and there are a few that probably are used seldom too but were added for

-consistency. You can of course always define additional accessors using \type

-{getfield} and \type {setfield} with little overhead. When the second argument of

-\type {setattributelist} is \type {true} the current attribute list is assumed.

-

-\def\yes{$+$} \def\nop{$-$}

-

-\def\supported#1#2#3%

- {\NC \type{#1}

-  \NC \ifx#2\yes\lix{node}       {#1}\fi #2

-  \NC \ifx#3\yes\lix{node.direct}{#1}\fi #3 \NC

-  \NR}

-

-\starttabulate[|l|c|c|]

-\DB function \BC node \BC direct \NC \NR

-\TB

-\supported {check_discretionaries}   \yes \yes

-\supported {check_discretionary}     \yes \yes

-\supported {copy_list}               \yes \yes

-\supported {copy}                    \yes \yes

-\supported {count}                   \yes \yes

-\supported {current_attr}            \yes \yes

-\supported {dimensions}              \yes \yes

-\supported {effective_glue}          \yes \yes

-\supported {end_of_math}             \yes \yes

-\supported {family_font}             \yes \nop

-\supported {fields}                  \yes \nop

-\supported {find_attribute}          \yes \yes

-\supported {first_glyph}             \yes \yes

-\supported {flatten_discretionaries} \yes \yes

-\supported {flush_list}              \yes \yes

-\supported {flush_node}              \yes \yes

-\supported {free}                    \yes \yes

-\supported {get_attribute}           \yes \yes

-\supported {get_synctex_fields}      \nop \yes

-\supported {getattributelist}        \nop \yes

-\supported {getboth}                 \yes \yes

-\supported {getbox}                  \nop \yes

-\supported {getchar}                 \yes \yes

-\supported {getcomponents}           \nop \yes

-\supported {getdepth}                \nop \yes

-\supported {getdirection}            \nop \yes

-\supported {getdir}                  \nop \yes

-\supported {getdisc}                 \yes \yes

-\supported {getfam}                  \nop \yes

-\supported {getfield}                \yes \yes

-\supported {getfont}                 \yes \yes

-\supported {getglue}                 \yes \yes

-\supported {getheight}               \nop \yes

-\supported {getid}                   \yes \yes

-\supported {getkern}                 \nop \yes

-\supported {getlang}                 \nop \yes

-\supported {getleader}               \yes \yes

-\supported {getlist}                 \yes \yes

-\supported {getnext}                 \yes \yes

-\supported {getnucleus}              \nop \yes

-\supported {getoffsets}              \nop \yes

-\supported {getpenalty}              \nop \yes

-\supported {getprev}                 \yes \yes

-\supported {getproperty}             \yes \yes

-\supported {getshift}                \nop \yes

-\supported {getsubtype}              \yes \yes

-\supported {getsub}                  \nop \yes

-\supported {getsup}                  \nop \yes

-\supported {getdata}                 \nop \yes

-\supported {getwhd}                  \yes \yes

-\supported {getwidth}                \nop \yes

-\supported {has_attribute}           \yes \yes

-\supported {has_field}               \yes \yes

-\supported {has_glyph}               \yes \yes

-\supported {hpack}                   \yes \yes

-\supported {id}                      \yes \nop

-\supported {insert_after}            \yes \yes

-\supported {insert_before}           \yes \yes

-\supported {is_char}                 \yes \yes

-\supported {is_direct}               \nop \yes

-\supported {is_glyph}                \yes \yes

-\supported {is_node}                 \yes \yes

-\supported {is_zero_glue}            \yes \yes

-\supported {kerning}                 \yes \yes

-\supported {last_node}               \yes \yes

-\supported {length}                  \yes \yes

-\supported {ligaturing}              \yes \yes

-\supported {mlist_to_hlist}          \yes \nop

-\supported {new}                     \yes \yes

-\supported {next}                    \yes \nop

-\supported {prepend_prevdepth}       \nop \yes

-\supported {prev}                    \yes \nop

-\supported {protect_glyphs}          \yes \yes

-\supported {protect_glyph}           \yes \yes

-\supported {protrusion_skippable}    \yes \yes

-\supported {rangedimensions}         \yes \yes

-\supported {remove}                  \yes \yes

-\supported {set_attribute}           \yes \yes

-\supported {set_synctex_fields}      \nop \yes

-\supported {setattributelist}        \nop \yes

-\supported {setboth}                 \nop \yes

-\supported {setbox}                  \nop \yes

-\supported {setchar}                 \nop \yes

-\supported {setcomponents}           \nop \yes

-\supported {setdepth}                \nop \yes

-\supported {setdirection}            \nop \yes

-\supported {setdir}                  \nop \yes

-\supported {setdisc}                 \nop \yes

-\supported {setfam}                  \nop \yes

-\supported {setfield}                \yes \yes

-\supported {setfont}                 \nop \yes

-\supported {setexpansion}            \nop \yes

-\supported {setglue}                 \yes \yes

-\supported {setheight}               \nop \yes

-\supported {setkern}                 \nop \yes

-\supported {setlang}                 \nop \yes

-\supported {setleader}               \nop \yes

-\supported {setlink}                 \nop \yes

-\supported {setlist}                 \nop \yes

-\supported {setnext}                 \nop \yes

-\supported {setnucleus}              \nop \yes

-\supported {setoffsets}              \nop \yes

-\supported {setpenalty}              \nop \yes

-\supported {setprev}                 \nop \yes

-\supported {setproperty}             \yes \yes

-\supported {setshift}                \nop \yes

-\supported {setsplit}                \nop \yes

-\supported {setsubtype}              \nop \yes

-\supported {setsub}                  \nop \yes

-\supported {setsup}                  \nop \yes

-\supported {setwhd}                  \nop \yes

-\supported {setwidth}                \nop \yes

-\supported {slide}                   \yes \yes

-\supported {subtypes}                \yes \nop

-\supported {subtype}                 \yes \nop

-\supported {tail}                    \yes \yes

-\supported {todirect}                \yes \yes

-\supported {tonode}                  \yes \yes

-\supported {tostring}                \yes \yes

-\supported {traverse_char}           \yes \yes

-\supported {traverse_glyph}          \yes \yes

-\supported {traverse_id}             \yes \yes

-\supported {traverse}                \yes \yes

-\supported {types}                   \yes \nop

-\supported {type}                    \yes \nop

-\supported {unprotect_glyphs}        \yes \yes

-\supported {unprotect_glyph}         \yes \yes

-\supported {unset_attribute}         \yes \yes

-\supported {usedlist}                \yes \yes

-\supported {uses_font}               \yes \yes

-\supported {vpack}                   \yes \yes

-\supported {whatsits}                \yes \nop

-\supported {write}                   \yes \yes

-\LL

-\stoptabulate

-

-The \type {node.next} and \type {node.prev} functions will stay but for

-consistency there are variants called \type {getnext} and \type {getprev}. We had

-to use \type {get} because \type {node.id} and \type {node.subtype} are already

-taken for providing meta information about nodes. Note: The getters do only basic

-checking for valid keys. You should just stick to the keys mentioned in the

-sections that describe node properties.

-

-Some of the getters and setters handle multiple node types, given that the field

-is relevant. In that case, some field names are considered similar (like \type

-{kern} and \type {width}, or \type {data} and \type {value}. In retrospect we

-could have normalized field names better but we decided to stick to the original

-(internal) names as much as possible. After all, at the \LUA\ end one can easily

-create synonyms.

-

-Some nodes have indirect references. For instance a math character refers to a

-family instead of a font. In that case we provide a virtual font field as

-accessor. So, \type {getfont} and \type {.font} can be used on them. The same is

-true for the \type {width}, \type {height} and \type {depth} of glue nodes. These

-actually access the spec node properties, and here we can set as well as get the

-values.

-

-In some places \LUATEX\ can do a bit of extra checking for valid node lists and

-you can enable that with:

-

-\startfunctioncall

-node.fix_node_lists(<boolean> b)

-\stopfunctioncall

-

-You can set and query the \SYNCTEX\ fields, a file number aka tag and a line

-number, for a glue, kern, hlist, vlist, rule and math nodes as well as glyph

-nodes (although this last one is not used in native \SYNCTEX).

-

-\startfunctioncall

-node.set_synctex_fields(<integer> f, <integer> l)

-<integer> f, <integer> l =

-    node.get_synctex_fields(<node> n)

-\stopfunctioncall

-

-Of course you need to know what you're doing as no checking on sane values takes

-place. Also, the synctex interpreter used in editors is rather peculiar and has

-some assumptions (heuristics).

-

-\stopsection

-

-\startsection[title={Properties}][library=node]

-

-\topicindex {nodes+properties}

-\topicindex {properties}

-

-\libindex{flush_properties_table}

-\libindex{get_properties_table}

-\libindex{set_properties_mode}

-

-Attributes are a convenient way to relate extra information to a node. You can

-assign them at the \TEX\ end as well as at the \LUA\ end and and consult them at

-the \LUA\ end. One big advantage is that they obey grouping. They are linked

-lists and normally checking for them is pretty efficient, even if you use a lot

-of them. A macro package has to provide some way to manage these attributes at the

-\TEX\ end because otherwise clashes in their usage can occur.

-

-Each node also can have a properties table and you can assign values to this

-table using the \type {setproperty} function and get properties using the \type

-{getproperty} function. Managing properties is way more demanding than managing

-attributes.

-

-Take the following example:

-

-\starttyping

-\directlua {

-    local n = node.new("glyph")

-

-    node.setproperty(n,"foo")

-    print(node.getproperty(n))

-

-    node.setproperty(n,"bar")

-    print(node.getproperty(n))

-

-    node.free(n)

-}

-\stoptyping

-

-This will print \type {foo} and \type {bar} which in itself is not that useful

-when multiple mechanisms want to use this feature. A variant is:

-

-\starttyping

-\directlua {

-    local n = node.new("glyph")

-

-    node.setproperty(n,{ one = "foo", two = "bar" })

-    print(node.getproperty(n).one)

-    print(node.getproperty(n).two)

-

-    node.free(n)

-}

-\stoptyping

-

-This time we store two properties with the node. It really makes sense to have a

-table as property because that way we can store more. But in order for that to

-work well you need to do it this way:

-

-\starttyping

-\directlua {

-    local n = node.new("glyph")

-

-    local t = node.getproperty(n)

-

-    if not t then

-        t = { }

-        node.setproperty(n,t)

-    end

-    t.one = "foo"

-    t.two = "bar"

-

-    print(node.getproperty(n).one)

-    print(node.getproperty(n).two)

-

-    node.free(n)

-}

-\stoptyping

-

-Here our own properties will not overwrite other users properties unless of

-course they use the same keys. So, eventually you will end up with something:

-

-\starttyping

-\directlua {

-    local n = node.new("glyph")

-

-    local t = node.getproperty(n)

-

-    if not t then

-        t = { }

-        node.setproperty(n,t)

-    end

-    t.myself = { one = "foo", two = "bar" }

-

-    print(node.getproperty(n).myself.one)

-    print(node.getproperty(n).myself.two)

-

-    node.free(n)

-}

-\stoptyping

-

-This assumes that only you use \type {myself} as subtable. The possibilities are

-endless but care is needed. For instance, the generic font handler that ships

-with \CONTEXT\ uses the \type {injections} subtable and you should not mess with

-that one!

-

-There are a few helper functions that you normally should not touch as user: \typ

-{flush_properties_table} will wipe the table (normally a bad idea), \typ

-{get_properties_table} and will give the table that stores properties (using

-direct entries) and you can best not mess too much with that one either because

-\LUATEX\ itself will make sure that entries related to nodes will get wiped when

-nodes get freed, so that the \LUA\ garbage collector can do its job. In fact, the

-main reason why we have this mechanism is that it saves the user (or macro

-package) some work. One can easily write a property mechanism in \LUA\ where

-after a shipout properties gets cleaned up but it's not entirely trivial to make

-sure that with each freed node also its properties get freed, due to the fact

-that there can be nodes left over for a next page. And having a callback bound to

-the node deallocator would add way to much overhead.

-

-Managing properties in the node (de)allocator functions is disabled by default

-and is enabled by:

-

-\starttyping

-node.set_properties_mode(true)

-\stoptyping

-

-When we copy a node list that has a table as property, there are several possibilities: we do the same as

-a new node, we copy the entry to the table in properties (a reference), we do

-a deep copy of a table in the properties, we create a new table and give it

-the original one as a metatable. After some experiments (that also included

-timing) with these scenarios we decided that a deep copy made no sense, nor

-did nilling. In the end both the shallow copy and the metatable variant were

-both ok, although the second one is slower. The most important aspect to keep

-in mind is that references to other nodes in properties no longer can be

-valid for that copy. We could use two tables (one unique and one shared) or

-metatables but that only complicates matters.

-

-When defining a new node, we could already allocate a table but it is rather easy

-to do that at the lua end e.g.\ using a metatable \type {__index} method. That

-way it is under macro package control. When deleting a node, we could keep the

-slot (e.g. setting it to false) but it could make memory consumption raise

-unneeded when we have temporary large node lists and after that only small lists.

-Both are not done.

-

-So in the end this is what happens now: when a node is copied, and it has a table

-as property, the new node will share that table. If the second argument of \typ

-{set_properties_mode} is \type {true} then a metatable approach is chosen: the

-copy gets its own table with the original table as metatable. If you use the

-generic font loader the mode is enabled that way.

-

-A few more xperiments were done. For instance: copy attributes to the properties

-so that we have fast access at the \LUA\ end. In the end the overhead is not

-compensated by speed and convenience, in fact, attributes are not that slow when

-it comes to accessing them. So this was rejected.

-

-Another experiment concerned a bitset in the node but again the gain compared to

-attributes was neglectable and given the small amount of available bits it also

-demands a pretty strong agreement over what bit represents what, and this is

-unlikely to succeed in the \TEX\ community. It doesn't pay off.

-

-Just in case one wonders why properties make sense: it is not so much speed that

-we gain, but more convenience: storing all kind of (temporary) data in attributes

-is no fun and this mechanism makes sure that properties are cleaned up when a

-node is freed. Also, the advantage of a more or less global properties table is

-that we stay at the \LUA\ end. An alternative is to store a reference in the node

-itself but that is complicated by the fact that the register has some limitations

-(no numeric keys) and we also don't want to mess with it too much.

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-nodes
+
+\startchapter[reference=nodes,title={Nodes}]
+
+\startsection[title={\LUA\ node representation}][library=node]
+
+\topicindex {nodes}
+
+\libindex {fields}
+\libindex {subtypes}
+\libindex {values}
+
+\TEX's nodes are represented in \LUA\ as userdata objects with a variable set of
+fields. In the following syntax tables, such as the type of such a userdata object
+is represented as \syntax {<node>}.
+
+The current return value of \type {node.types()} is:
+\startluacode
+    for id, name in table.sortedhash(node.types()) do
+        context.type(name)
+        context(" (%s), ",id)
+    end
+    context.removeunwantedspaces()
+    context.removepunctuation()
+\stopluacode
+. % period
+
+The \prm {lastnodetype} primitive is \ETEX\ compliant. The valid range is still
+$[-1,15]$ and glyph nodes (formerly known as char nodes) have number~0 while
+ligature nodes are mapped to~7. That way macro packages can use the same symbolic
+names as in traditional \ETEX. Keep in mind that these \ETEX\ node numbers are
+different from the real internal ones and that there are more \ETEX\ node types
+than~15.
+
+You can ask for a list of fields with \type {node.fields} and for valid subtypes
+with \type {node.subtypes}. The \type {node.values} function reports some used
+values. Valid arguments are \nod {dir}, \type {direction}, \nod {glue}, \whs
+{pdf_literal}, \whs {pdf_action}, \whs {pdf_window} and \whs {color_stack}. Keep
+in mind that the setters normally expect a number, but this helper gives you a
+list of what numbers matter. For practical reason the \type {pagestate} values
+are also reported with this helper.
+
+\stopsection
+
+\startsection[title={Main text nodes}]
+
+\topicindex {nodes+text}
+
+These are the nodes that comprise actual typesetting commands. A few fields are
+present in all nodes regardless of their type, these are:
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{next}    \NC node   \NC the next node in a list, or nil \NC \NR
+\NC \type{id}      \NC number \NC the node's type (\type {id}) number \NC \NR
+\NC \type{subtype} \NC number \NC the node \type {subtype} identifier \NC \NR
+\LL
+\stoptabulate
+
+The \type {subtype} is sometimes just a dummy entry because not all nodes
+actually use the \type {subtype}, but this way you can be sure that all nodes
+accept it as a valid field name, and that is often handy in node list traversal.
+In the following tables \type {next} and \type {id} are not explicitly mentioned.
+
+Besides these three fields, almost all nodes also have an \type {attr} field, and
+there is a also a field called \type {prev}. That last field is always present,
+but only initialized on explicit request: when the function \type {node.slide()}
+is called, it will set up the \type {prev} fields to be a backwards pointer in
+the argument node list. By now most of \TEX's node processing makes sure that the
+\type {prev} nodes are valid but there can be exceptions, especially when the
+internal magic uses a leading \nod {temp} nodes to temporarily store a state.
+
+\subsection{\nod {hlist} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype}    \NC number \NC \showsubtypes{list} \NC \NR
+\NC \type{attr}       \NC node   \NC list of attributes \NC \NR
+\NC \type{width}      \NC number \NC the width of the box \NC \NR
+\NC \type{height}     \NC number \NC the height of the box \NC \NR
+\NC \type{depth}      \NC number \NC the depth of the box \NC \NR
+\NC \type{shift}      \NC number \NC a displacement perpendicular to the character
+                                     progression direction \NC \NR
+\NC \type{glue_order} \NC number \NC a number in the range $[0,4]$, indicating the
+                                     glue order \NC \NR
+\NC \type{glue_set}   \NC number \NC the calculated glue ratio \NC \NR
+\NC \type{glue_sign}  \NC number \NC 0 = \type {normal}, 1 = \type {stretching}, 2 =
+                                     \type {shrinking} \NC \NR
+\NC \type{head/list}  \NC node   \NC the first node of the body of this list \NC \NR
+\NC \type{dir}        \NC string \NC the direction of this box, see~\in [dirnodes] \NC \NR
+\LL
+\stoptabulate
+
+\topicindex {nodes+lists}
+\topicindex {lists}
+
+A warning: never assign a node list to the \type {head} field unless you are sure
+its internal link structure is correct, otherwise an error may result.
+
+Note: the field name \type {head} and \type {list} are both valid. Sometimes it
+makes more sense to refer to a list by \type {head}, sometimes \type {list} makes
+more sense.
+
+\subsection{\nod {vlist} nodes}
+
+\topicindex {nodes+lists}
+\topicindex {lists}
+
+This node is similar to \nod {hlist}, except that \quote {shift} is a displacement
+perpendicular to the line progression direction, and \quote {subtype} only has
+the values 0, 4, and~5.
+
+\subsection{\nod {rule} nodes}
+
+\topicindex {nodes+rules}
+\topicindex {rules}
+
+Contrary to traditional \TEX, \LUATEX\ has more \prm {rule} subtypes because we
+also use rules to store reuseable objects and images. User nodes are invisible
+and can be intercepted by a callback.
+
+\starttabulate[|l|l|p|]
+\DB field            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype}   \NC number \NC \showsubtypes {rule} \NC \NR
+\NC \type{attr}      \NC node   \NC list of attributes \NC \NR
+\NC \type{width}     \NC number \NC the width of the rule where the special value
+                                    $-1073741824$ is used for \quote {running} glue dimensions \NC \NR
+\NC \type{height}    \NC number \NC the height of the rule (can be negative) \NC \NR
+\NC \type{depth}     \NC number \NC the depth of the rule (can be negative) \NC \NR
+\NC \type{left}      \NC number \NC shift at the left end (also subtracted from width) \NC \NR
+\NC \type{right}     \NC number \NC (subtracted from width) \NC \NR
+\NC \type{dir}       \NC string \NC the direction of this rule, see~\in[dirnodes] \NC \NR
+\NC \type{index}     \NC number \NC an optional index that can be referred to \NC \NR
+\NC \type{transform} \NC number \NC an private variable (also used to specify outline width) \NC \NR
+\LL
+\stoptabulate
+
+The \type {left} and type {right} keys are somewhat special (and experimental).
+When rules are auto adapting to the surrounding box width you can enforce a shift
+to the right by setting \type {left}. The value is also subtracted from the width
+which can be a value set by the engine itself and is not entirely under user
+control. The \type {right} is also subtracted from the width. It all happens in
+the backend so these are not affecting the calculations in the frontend (actually
+the auto settings also happen in the backend). For a vertical rule \type {left}
+affects the height and \type {right} affects the depth. There is no matching
+interface at the \TEX\ end (although we can have more keywords for rules it would
+complicate matters and introduce a speed penalty.) However, you can just
+construct a rule node with \LUA\ and write it to the \TEX\ input. The \type
+{outline} subtype is just a convenient variant and the \type {transform} field
+specifies the width of the outline.
+
+\subsection{\nod {ins} nodes}
+
+\topicindex {nodes+insertions}
+\topicindex {insertions}
+
+This node relates to the \prm {insert} primitive.
+
+\starttabulate[|l|l|p|]
+\DB field            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype}   \NC number \NC the insertion class \NC \NR
+\NC \type{attr}      \NC node   \NC list of attributes \NC \NR
+\NC \type{cost}      \NC number \NC the penalty associated with this insert \NC \NR
+\NC \type{height}    \NC number \NC height of the insert \NC \NR
+\NC \type{depth}     \NC number \NC depth of the insert \NC \NR
+\NC \type{head/list} \NC node   \NC the first node of the body of this insert \NC \NR
+\LL
+\stoptabulate
+
+There is a set of extra fields that concern the associated glue: \type {width},
+\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}.
+These are all numbers.
+
+A warning: never assign a node list to the \type {head} field unless you are sure
+its internal link structure is correct, otherwise an error may result. You can use
+\type {list} instead (often in functions you want to use local variable with similar
+names and both names are equally sensible).
+
+\subsection{\nod {mark} nodes}
+
+\topicindex {nodes+marks}
+\topicindex {marks}
+
+This one relates to the \prm {mark} primitive.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC unused \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{class}   \NC number \NC the mark class \NC \NR
+\NC \type{mark}    \NC table  \NC a table representing a token list \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {adjust} nodes}
+
+\topicindex {nodes+adjust}
+\topicindex {adjust}
+
+This node comes from \prm {vadjust} primitive.
+
+\starttabulate[|l|l|p|]
+\DB field            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype}   \NC number \NC \showsubtypes{adjust} \NC \NR
+\NC \type{attr}      \NC node   \NC list of attributes \NC \NR
+\NC \type{head/list} \NC node   \NC adjusted material \NC \NR
+\LL
+\stoptabulate
+
+A warning: never assign a node list to the \type {head} field unless you are sure
+its internal link structure is correct, otherwise an error may be the result.
+
+\subsection{\nod {disc} nodes}
+
+\topicindex {nodes+discretionaries}
+\topicindex {discretionaries}
+
+The \prm {discretionary} and \prm {-}, the \type {-} character but also the
+hyphenation mechanism produces these nodes.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{disc} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{pre}     \NC node   \NC pointer to the pre|-|break text \NC \NR
+\NC \type{post}    \NC node   \NC pointer to the post|-|break text \NC \NR
+\NC \type{replace} \NC node   \NC pointer to the no|-|break text \NC \NR
+\NC \type{penalty} \NC number \NC the penalty associated with the break, normally
+                                  \prm {hyphenpenalty} or \prm {exhyphenpenalty} \NC \NR
+\LL
+\stoptabulate
+
+The subtype numbers~4 and~5 belong to the \quote {of-f-ice} explanation given
+elsewhere. These disc nodes are kind of special as at some point they also keep
+information about breakpoints and nested ligatures.
+
+The \type {pre}, \type {post} and \type {replace} fields at the \LUA\ end are in
+fact indirectly accessed and have a \type {prev} pointer that is not \type {nil}.
+This means that when you mess around with the head of these (three) lists, you
+also need to reassign them because that will restore the proper \type {prev}
+pointer, so:
+
+\starttyping
+pre = d.pre
+-- change the list starting with pre
+d.pre = pre
+\stoptyping
+
+Otherwise you can end up with an invalid internal perception of reality and
+\LUATEX\ might even decide to crash on you. It also means that running forward
+over for instance \type {pre} is ok but backward you need to stop at \type {pre}.
+And you definitely must not mess with the node that \type {prev} points to, if
+only because it is not really a node but part of the disc data structure (so
+freeing it again might crash \LUATEX).
+
+\subsection{\nod {math} nodes}
+
+\topicindex {nodes+math}
+\topicindex {math+nodes}
+
+Math nodes represent the boundaries of a math formula, normally wrapped into
+\type {$} signs.
+
+\starttabulate[|l|l|p|]
+\DB field           \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype}  \NC number \NC \showsubtypes{math} \NC \NR
+\NC \type{attr}     \NC node   \NC list of attributes \NC \NR
+\NC \type{surround} \NC number \NC width of the \prm {mathsurround} kern \NC \NR
+\LL
+\stoptabulate
+
+There is a set of extra fields that concern the associated glue: \type {width},
+\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}.
+These are all numbers.
+
+\subsection{\nod {glue} nodes}
+
+\topicindex {nodes+glue}
+\topicindex {glue}
+
+Skips are about the only type of data objects in traditional \TEX\ that are not a
+simple value. They are inserted when \TEX\ sees a space in the text flow but also
+by \prm {hskip} and \prm {vskip}. The structure that represents the glue
+components of a skip is called a \nod {glue_spec}, and it has the following
+accessible fields:
+
+\starttabulate[|l|l|p|]
+\DB field                \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{width}         \NC number \NC the horizontal or vertical displacement \NC \NR
+\NC \type{stretch}       \NC number \NC extra (positive) displacement or stretch amount \NC \NR
+\NC \type{stretch_order} \NC number \NC factor applied to stretch amount \NC \NR
+\NC \type{shrink}        \NC number \NC extra (negative) displacement or shrink amount\NC \NR
+\NC \type{shrink_order}  \NC number \NC factor applied to shrink amount \NC \NR
+\LL
+\stoptabulate
+
+The effective width of some glue subtypes depends on the stretch or shrink needed
+to make the encapsulating box fit its dimensions. For instance, in a paragraph
+lines normally have glue representing spaces and these stretch or shrink to make
+the content fit in the available space. The \type {effective_glue} function that
+takes a glue node and a parent (hlist or vlist) returns the effective width of
+that glue item. When you pass \type {true} as third argument the value will be
+rounded.
+
+A \nod {glue_spec} node is a special kind of node that is used for storing a set
+of glue values in registers. Originally they were also used to store properties
+of glue nodes (using a system of reference counts) but we now keep these
+properties in the glue nodes themselves, which gives a cleaner interface to \LUA.
+
+The indirect spec approach was in fact an optimization in the original \TEX\
+code. First of all it can save quite some memory because all these spaces that
+become glue now share the same specification (only the reference count is
+incremented), and zero testing is also a bit faster because only the pointer has
+to be checked (this is no longer true for engines that implement for instance
+protrusion where we really need to ensure that zero is zero when we test for
+bounds). Another side effect is that glue specifications are read|-|only, so in
+the end copies need to be made when they are used from \LUA\ (each assignment to
+a field can result in a new copy). So in the end the advantages of sharing are
+not that high (and nowadays memory is less an issue, also given that a glue node
+is only a few memory words larger than a spec).
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{glue} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{leader}  \NC node   \NC pointer to a box or rule for leaders \NC \NR
+\LL
+\stoptabulate
+
+In addition there are the \type {width}, \type {stretch} \type {stretch_order},
+\type {shrink}, and \type {shrink_order} fields. Note that we use the key \type
+{width} in both horizontal and vertical glue. This suits the \TEX\ internals well
+so we decided to stick to that naming.
+
+A regular word space also results in a \type {spaceskip} subtype (this used to be
+a \type {userskip} with subtype zero).
+
+\subsection{\nod {kern} nodes}
+
+\topicindex {nodes+kerns}
+\topicindex {kerns}
+
+The \prm {kern} command creates such nodes but for instance the font and math
+machinery can also add them.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{kern} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{kern}    \NC number \NC fixed horizontal or vertical advance \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {penalty} nodes}
+
+\topicindex {nodes+penalty}
+\topicindex {penalty}
+
+The \prm {penalty} command is one that generates these nodes.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{penalty} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{penalty} \NC number \NC the penalty value \NC \NR
+\LL
+\stoptabulate
+
+The subtypes are just informative and \TEX\ itself doesn't use them. When you
+run into an \type {linebreakpenalty} you need to keep in mind that it's a
+accumulation of \type {club}, \type{widow} and other relevant penalties.
+
+\subsection[glyphnodes]{\nod {glyph} nodes}
+
+\topicindex {nodes+glyph}
+\topicindex {glyphs}
+
+These are probably the mostly used nodes and although you can push them in the
+current list with for instance \prm {char} \TEX\ will normally do it for you when
+it considers some input to be text.
+
+\starttabulate[|l|l|p|]
+\DB field                   \BC type    \BC explanation \NC \NR
+\TB
+\NC \type{subtype}          \NC number  \NC bit field \NC \NR
+\NC \type{attr}             \NC node    \NC list of attributes \NC \NR
+\NC \type{char}             \NC number  \NC the character index in the font \NC \NR
+\NC \type{font}             \NC number  \NC the font identifier \NC \NR
+\NC \type{lang}             \NC number  \NC the language identifier \NC \NR
+\NC \type{left}             \NC number  \NC the frozen \type {\lefthyphenmnin} value \NC \NR
+\NC \type{right}            \NC number  \NC the frozen \type {\righthyphenmnin} value \NC \NR
+\NC \type{uchyph}           \NC boolean \NC the frozen \prm {uchyph} value \NC \NR
+\NC \type{components}       \NC node    \NC pointer to ligature components \NC \NR
+\NC \type{xoffset}          \NC number  \NC a virtual displacement in horizontal direction \NC \NR
+\NC \type{yoffset}          \NC number  \NC a virtual displacement in vertical direction \NC \NR
+\NC \type{width}            \NC number  \NC the (original) width of the character \NC \NR
+\NC \type{height}           \NC number  \NC the (original) height of the character\NC \NR
+\NC \type{depth}            \NC number  \NC the (original) depth of the character\NC \NR
+\NC \type{expansion_factor} \NC number  \NC the to be applied expansion_factor \NC \NR
+\NC \type{data}             \NC number  \NC a general purpose field for users (we had room for it) \NC \NR
+\LL
+\stoptabulate
+
+The \type {width}, \type {height} and \type {depth} values are read|-|only. The
+\type {expansion_factor} is assigned in the par builder and used in the backend.
+
+A warning: never assign a node list to the components field unless you are sure
+its internal link structure is correct, otherwise an error may be result. Valid
+bits for the \type {subtype} field are:
+
+\starttabulate[|c|l|]
+\DB bit \BC meaning   \NC \NR
+\TB
+\NC 0   \NC character \NC \NR
+\NC 1   \NC ligature  \NC \NR
+\NC 2   \NC ghost     \NC \NR
+\NC 3   \NC left      \NC \NR
+\NC 4   \NC right     \NC \NR
+\LL
+\stoptabulate
+
+See \in {section} [charsandglyphs] for a detailed description of the \type
+{subtype} field.
+
+The \type {expansion_factor} has been introduced as part of the separation
+between font- and backend. It is the result of extensive experiments with a more
+efficient implementation of expansion. Early versions of \LUATEX\ already
+replaced multiple instances of fonts in the backend by scaling but contrary to
+\PDFTEX\ in \LUATEX\ we now also got rid of font copies in the frontend and
+replaced them by expansion factors that travel with glyph nodes. Apart from a
+cleaner approach this is also a step towards a better separation between front-
+and backend.
+
+The \type {is_char} function checks if a node is a glyph node with a subtype still
+less than 256. This function can be used to determine if applying font logic to a
+glyph node makes sense. The value \type {nil} gets returned when the node is not
+a glyph, a character number is returned if the node is still tagged as character
+and \type {false} gets returned otherwise. When nil is returned, the id is also
+returned. The \type {is_glyph} variant doesn't check for a subtype being less
+than 256, so it returns either the character value or nil plus the id. These
+helpers are not always faster than separate calls but they sometimes permit
+making more readable tests. The \type {uses_font} helpers takes a node
+and font id and returns true when a glyph or disc node references that font.
+
+\subsection{\nod {boundary} nodes}
+
+\topicindex {nodes+boundary}
+\topicindex {boundary}
+
+This node relates to the \prm {noboundary}, \prm {boundary}, \prm
+{protrusionboundary} and \prm {wordboundary} primitives.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{boundary} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{value}   \NC number \NC values 0--255 are reserved \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {local_par} nodes}
+
+\topicindex {nodes+paragraphs}
+\topicindex {paragraphs}
+
+This node is inserted at the start of a paragraph. You should not mess
+too much with this one.
+
+\starttabulate[|l|l|p|]
+\DB field                  \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}            \NC node   \NC list of attributes \NC \NR
+\NC \type{pen_inter}       \NC number \NC local interline penalty (from \lpr {localinterlinepenalty}) \NC \NR
+\NC \type{pen_broken}      \NC number \NC local broken penalty (from \lpr {localbrokenpenalty}) \NC \NR
+\NC \type{dir}             \NC string \NC the direction of this par. see~\in [dirnodes] \NC \NR
+\NC \type{box_left}        \NC node   \NC the \lpr {localleftbox} \NC \NR
+\NC \type{box_left_width}  \NC number \NC width of the \lpr {localleftbox} \NC \NR
+\NC \type{box_right}       \NC node   \NC the \lpr {localrightbox} \NC \NR
+\NC \type{box_right_width} \NC number \NC width of the \lpr {localrightbox} \NC \NR
+\LL
+\stoptabulate
+
+A warning: never assign a node list to the \type {box_left} or \type {box_right}
+field unless you are sure its internal link structure is correct, otherwise an
+error may result.
+
+\subsection[dirnodes]{\nod {dir} nodes}
+
+\topicindex {nodes+direction}
+\topicindex {directions}
+
+Direction nodes mark parts of the running text that need a change of direction and \
+the \prm {textdir} command generates them.
+
+\starttabulate[|l|l|p|]
+\DB field        \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}  \NC node   \NC list of attributes \NC \NR
+\NC \type{dir}   \NC string \NC the direction (but see below) \NC \NR
+\NC \type{level} \NC number \NC nesting level of this direction whatsit \NC \NR
+\LL
+\stoptabulate
+
+Direction specifiers are three|-|letter combinations of \type {T}, \type {B},
+\type {R}, and \type {L}. These are built up out of three separate items:
+
+\startitemize[packed]
+\startitem
+    the first  is the direction of the \quote{top}   of paragraphs
+\stopitem
+\startitem
+    the second is the direction of the \quote{start} of lines
+\stopitem
+\startitem
+    the third  is the direction of the \quote{top}   of glyphs
+\stopitem
+\stopitemize
+
+However, only four combinations are accepted: \type {TLT}, \type {TRT}, \type
+{RTT}, and \type {LTL}. Inside actual \nod {dir} nodes, the representation of
+\nod {dir} is not a three|-|letter but a combination of numbers. When printed the
+direction is indicated by a \type {+} or \type {-}, indicating whether the value
+is pushed or popped from the direction stack.
+
+\subsection{\nod {marginkern} nodes}
+
+\topicindex {nodes+paragraphs}
+\topicindex {paragraphs}
+\topicindex {protrusion}
+
+Margin kerns result from protrusion.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number \NC \showsubtypes{marginkern} \NC \NR
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{width}   \NC number \NC the advance of the kern \NC \NR
+\NC \type{glyph}   \NC node   \NC the glyph to be used \NC \NR
+\LL
+\stoptabulate
+
+\stopsection
+
+\startsection[title={Math noads}]
+
+\topicindex {nodes+math}
+\topicindex {math+nodes}
+
+These are the so||called \quote {noad}s and the nodes that are specifically
+associated with math processing. Most of these nodes contain subnodes so that the
+list of possible fields is actually quite small. First, the subnodes:
+
+\subsection{Math kernel subnodes}
+
+Many object fields in math mode are either simple characters in a specific family
+or math lists or node lists. There are four associated subnodes that represent
+these cases (in the following node descriptions these are indicated by the word
+\type {<kernel>}).
+
+The \type {next} and \type {prev} fields for these subnodes are unused.
+
+\subsection{\nod {math_char} and \nod {math_text_char} subnodes}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node   \NC list of attributes \NC \NR
+\NC \type{char} \NC number \NC the character index \NC \NR
+\NC \type{fam}  \NC number \NC the family number \NC \NR
+\LL
+\stoptabulate
+
+The \nod {math_char} is the simplest subnode field, it contains the character
+and family for a single glyph object. The \nod {math_text_char} is a special
+case that you will not normally encounter, it arises temporarily during math list
+conversion (its sole function is to suppress a following italic correction).
+
+\subsection{\nod {sub_box} and \nod {sub_mlist} subnodes}
+
+\starttabulate[|l|l|p|]
+\DB field            \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr}      \NC node \NC list of attributes \NC \NR
+\NC \type{head/list} \NC node \NC list of nodes \NC \NR
+\LL
+\stoptabulate
+
+These two subnode types are used for subsidiary list items. For \nod {sub_box},
+the \type {head} points to a \quote {normal} vbox or hbox. For \nod {sub_mlist},
+the \type {head} points to a math list that is yet to be converted.
+
+A warning: never assign a node list to the \type {head} field unless you are sure
+its internal link structure is correct, otherwise an error is triggered.
+
+\subsection{\nod {delim} subnodes}
+
+There is a fifth subnode type that is used exclusively for delimiter fields. As
+before, the \type {next} and \type {prev} fields are unused.
+
+\starttabulate[|l|l|p|]
+\DB field             \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}       \NC node   \NC list of attributes \NC \NR
+\NC \type{small_char} \NC number \NC character index of base character \NC \NR
+\NC \type{small_fam}  \NC number \NC family number of base character \NC \NR
+\NC \type{large_char} \NC number \NC character index of next larger character \NC \NR
+\NC \type{large_fam}  \NC number \NC family number of next larger character \NC \NR
+\LL
+\stoptabulate
+
+The fields \type {large_char} and \type {large_fam} can be zero, in that case the
+font that is set for the \type {small_fam} is expected to provide the large
+version as an extension to the \type {small_char}.
+
+\subsection{Math core nodes}
+
+First, there are the objects (the \TEX book calls them \quote {atoms}) that are
+associated with the simple math objects: ord, op, bin, rel, open, close, punct,
+inner, over, under, vcent. These all have the same fields, and they are combined
+into a single node type with separate subtypes for differentiation.
+
+Some noads have an option field. The values in this bitset are common:
+
+\starttabulate[|l|r|]
+\DB meaning         \BC bits                      \NC \NR
+\TB
+\NC set             \NC               \type{0x08} \NC \NR
+\NC internal        \NC \type{0x00} + \type{0x08} \NC \NR
+\NC internal        \NC \type{0x01} + \type{0x08} \NC \NR
+\NC axis            \NC \type{0x02} + \type{0x08} \NC \NR
+\NC no axis         \NC \type{0x04} + \type{0x08} \NC \NR
+\NC exact           \NC \type{0x10} + \type{0x08} \NC \NR
+\NC left            \NC \type{0x11} + \type{0x08} \NC \NR
+\NC middle          \NC \type{0x12} + \type{0x08} \NC \NR
+\NC right           \NC \type{0x14} + \type{0x08} \NC \NR
+\NC no sub script   \NC \type{0x21} + \type{0x08} \NC \NR
+\NC no super script \NC \type{0x22} + \type{0x08} \NC \NR
+\NC no script       \NC \type{0x23} + \type{0x08} \NC \NR
+\LL
+\stoptabulate
+
+\subsection{simple \nod {noad} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type        \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number      \NC \showsubtypes{noad} \NC \NR
+\NC \type{attr}    \NC node        \NC list of attributes \NC \NR
+\NC \type{nucleus} \NC kernel node \NC base \NC \NR
+\NC \type{sub}     \NC kernel node \NC subscript \NC \NR
+\NC \type{sup}     \NC kernel node \NC superscript \NC \NR
+\NC \type{options} \NC number      \NC bitset of rendering options \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {accent} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field             \BC type        \BC explanation \NC \NR
+\TB
+\NC \type{subtype}    \NC number      \NC \showsubtypes{accent} \NC \NR
+\NC \type{nucleus}    \NC kernel node \NC base \NC \NR
+\NC \type{sub}        \NC kernel node \NC subscript \NC \NR
+\NC \type{sup}        \NC kernel node \NC superscript \NC \NR
+\NC \type{accent}     \NC kernel node \NC top accent \NC \NR
+\NC \type{bot_accent} \NC kernel node \NC bottom accent \NC \NR
+\NC \type{fraction}   \NC number      \NC larger step criterium (divided by 1000) \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {style} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field        \BC type   \BC explanation    \NC \NR
+\TB
+\NC \type{style} \NC string \NC contains the style \NC \NR
+\LL
+\stoptabulate
+
+There are eight possibilities for the string value: one of \type {display},
+\type {text}, \type {script}, or \type {scriptscript}. Each of these can have
+be prefixed by \type {cramped}.
+
+\subsection{\nod {choice} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field               \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr}         \NC node \NC list of attributes \NC \NR
+\NC \type{display}      \NC node \NC list of display size alternatives \NC \NR
+\NC \type{text}         \NC node \NC list of text size alternatives \NC \NR
+\NC \type{script}       \NC node \NC list of scriptsize alternatives \NC \NR
+\NC \type{scriptscript} \NC node \NC list of scriptscriptsize alternatives \NC \NR
+\LL
+\stoptabulate
+
+Warning: never assign a node list to the \type {display}, \type {text}, \type
+{script}, or \type {scriptscript} field unless you are sure its internal link
+structure is correct, otherwise an error can occur.
+
+\subsection{\nod {radical} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type           \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number         \NC \showsubtypes{radical} \NC \NR
+\NC \type{attr}    \NC node           \NC list of attributes \NC \NR
+\NC \type{nucleus} \NC kernel node    \NC base \NC \NR
+\NC \type{sub}     \NC kernel node    \NC subscript \NC \NR
+\NC \type{sup}     \NC kernel node    \NC superscript \NC \NR
+\NC \type{left}    \NC delimiter node \NC \NC \NR
+\NC \type{degree}  \NC kernel node    \NC only set by \lpr {Uroot} \NC \NR
+\NC \type{width}   \NC number         \NC required width \NC \NR
+\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR
+\LL
+\stoptabulate
+
+Warning: never assign a node list to the \type {nucleus}, \type {sub}, \type
+{sup}, \type {left}, or \type {degree} field unless you are sure its internal
+link structure is correct, otherwise an error can be triggered.
+
+\subsection{\nod {fraction} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type           \BC explanation \NC \NR
+\TB
+\NC \type{attr}    \NC node           \NC list of attributes \NC \NR
+\NC \type{width}   \NC number         \NC (optional) width of the fraction \NC \NR
+\NC \type{num}     \NC kernel node    \NC numerator \NC \NR
+\NC \type{denom}   \NC kernel node    \NC denominator \NC \NR
+\NC \type{left}    \NC delimiter node \NC left side symbol \NC \NR
+\NC \type{right}   \NC delimiter node \NC right side symbol \NC \NR
+\NC \type{middle}  \NC delimiter node \NC middle symbol \NC \NR
+\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR
+\LL
+\stoptabulate
+
+Warning: never assign a node list to the \type {num}, or \type {denom} field
+unless you are sure its internal link structure is correct, otherwise an error
+can result.
+
+\subsection{\nod {fence} nodes}
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type           \BC explanation \NC \NR
+\TB
+\NC \type{subtype} \NC number         \NC \showsubtypes{fence} \NC \NR
+\NC \type{attr}    \NC node           \NC list of attributes \NC \NR
+\NC \type{delim}   \NC delimiter node \NC delimiter specification \NC \NR
+\NC \type{italic}  \NC number         \NC italic correction \NC \NR
+\NC \type{height}  \NC number         \NC required height \NC \NR
+\NC \type{depth}   \NC number         \NC required depth \NC \NR
+\NC \type{options} \NC number         \NC bitset of rendering options \NC \NR
+\NC \type{class}   \NC number         \NC spacing related class \NC \NR
+\LL
+\stoptabulate
+
+Warning: some of these fields are used by the renderer and might get adapted in
+the process.
+
+\stopsection
+
+\startsection[title={Front|-|end whatsits}]
+
+Whatsit nodes come in many subtypes that you can ask for them by running
+\type {node.whatsits}:
+\startluacode
+    for id, name in table.sortedpairs(node.whatsits()) do
+        context.type(name)
+        context(" (%s), ",id)
+    end
+    context.removeunwantedspaces()
+    context.removepunctuation()
+\stopluacode
+. % period
+
+Some of them are generic and independent of the output mode and others are
+specific to the chosen backend: \DVI\ or \PDF. Here we discuss the generic
+font|-|end nodes nodes.
+
+\subsection{\whs {open}}
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}   \NC node   \NC list of attributes \NC \NR
+\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR
+\NC \type{name}   \NC string \NC file name \NC \NR
+\NC \type{ext}    \NC string \NC file extension \NC \NR
+\NC \type{area}   \NC string \NC file area (this may become obsolete) \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {write}}
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}   \NC node   \NC list of attributes \NC \NR
+\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR
+\NC \type{data}   \NC table  \NC a table representing the token list to be written \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {close}}
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}   \NC node   \NC list of attributes \NC \NR
+\NC \type{stream} \NC number \NC \TEX's stream id number \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {user_defined}}
+
+User|-|defined whatsit nodes can only be created and handled from \LUA\ code. In
+effect, they are an extension to the extension mechanism. The \LUATEX\ engine
+will simply step over such whatsits without ever looking at the contents.
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{user_id} \NC number \NC id number \NC \NR
+\NC \type{type}    \NC number \NC type of the value \NC \NR
+\NC \type{value}   \NC number \NC a \LUA\ number \NC \NR
+\NC                \NC node   \NC a node list \NC \NR
+\NC                \NC string \NC a \LUA\ string \NC \NR
+\NC                \NC table  \NC a \LUA\ table \NC \NR
+\LL
+\stoptabulate
+
+The \type {type} can have one of six distinct values. The number is the \ASCII\
+value if the first character of the type name (so you can use string.byte("l")
+instead of \type {108}).
+
+\starttabulate[|r|c|p|]
+\DB value \BC meaning \BC explanation \NC \NR
+\TB
+\NC   97  \NC a       \NC list of attributes (a node list) \NC \NR
+\NC  100  \NC d       \NC a \LUA\ number \NC \NR
+\NC  108  \NC l       \NC a \LUA\ value (table, number, boolean, etc) \NC \NR
+\NC  110  \NC n       \NC a node list \NC \NR
+\NC  115  \NC s       \NC a \LUA\ string \NC \NR
+\NC  116  \NC t       \NC a \LUA\ token list in \LUA\ table form (a list of triplets) \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {save_pos}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node \NC list of attributes \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {late_lua}}
+
+\starttabulate[|l|l|p|]
+\DB field        \BC type               \BC explanation \NC \NR
+\TB
+\NC \type{attr}  \NC node               \NC list of attributes \NC \NR
+\NC \type{data}  \NC string or function \NC the to be written information stored as \LUA\ value \NC \NR
+\NC \type{token} \NC string             \NC the to be written information stored as token list \NC \NR
+\NC \type{name}  \NC string             \NC the name to use for \LUA\ error reporting \NC \NR
+\LL
+\stoptabulate
+
+The difference between \type {data} and \type {string} is that on assignment, the
+\type {data} field is converted to a token list, cf.\ use as \lpr {latelua}. The
+\type {string} version is treated as a literal string.
+
+\stopsection
+
+\startsection[title={\DVI\ backend whatsits}]
+
+\subsection{\whs {special}}
+
+There is only one \DVI\ backend whatsit, and it just flushes its content to the
+output file.
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node   \NC list of attributes \NC \NR
+\NC \type{data} \NC string \NC the \prm {special} information \NC \NR
+\LL
+\stoptabulate
+
+\stopsection
+
+\startsection[title={\PDF\ backend whatsits}]
+
+\subsection{\whs {pdf_literal}}
+
+\starttabulate[|l|l|p|]
+\DB field        \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}  \NC node   \NC list of attributes \NC \NR
+\NC \type{mode}  \NC number \NC the \quote {mode} setting of this literal \NC \NR
+\NC \type{data}  \NC string \NC the to be written information stored as \LUA\ string \NC \NR
+\NC \type{token} \NC string \NC the to be written information stored as token list \NC \NR
+\LL
+\stoptabulate
+
+Possible mode values are:
+
+\starttabulate[|c|p|]
+\DB value \BC keyword        \NC \NR
+\TB
+\NC 0     \NC \type{origin}  \NC \NR
+\NC 1     \NC \type{page}    \NC \NR
+\NC 2     \NC \type{direct}  \NC \NR
+\NC 3     \NC \type{raw}     \NC \NR
+\NC 4     \NC \type{text}    \NC \NR
+\LL
+\stoptabulate
+
+The higher the number, the less checking and the more you can run into trouble.
+Especially the \type {raw} variant can produce bad \PDF\ so you can best check
+what you generate.
+
+\subsection{\whs {pdf_refobj}}
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}   \NC node   \NC list of attributes \NC \NR
+\NC \type{objnum} \NC number \NC the referenced \PDF\ object number \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_annot}}
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}   \NC node   \NC list of attributes \NC \NR
+\NC \type{width}  \NC number \NC the width (not used in calculations) \NC \NR
+\NC \type{height} \NC number \NC the height (not used in calculations) \NC \NR
+\NC \type{depth}  \NC number \NC the depth (not used in calculations) \NC \NR
+\NC \type{objnum} \NC number \NC the referenced \PDF\ object number \NC \NR
+\NC \type{data}   \NC string \NC the annotation data \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_start_link}}
+
+\starttabulate[|l|l|p|]
+\DB field            \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}      \NC node   \NC list of attributes \NC \NR
+\NC \type{width}     \NC number \NC the width (not used in calculations) \NC \NR
+\NC \type{height}    \NC number \NC the height (not used in calculations) \NC \NR
+\NC \type{depth}     \NC number \NC the depth (not used in calculations) \NC \NR
+\NC \type{objnum}    \NC number \NC the referenced \PDF\ object number \NC \NR
+\NC \type{link_attr} \NC table  \NC the link attribute token list \NC \NR
+\NC \type{action}    \NC node   \NC the action to perform \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_end_link}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node \NC \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_dest}}
+
+\starttabulate[|l|l|p|]
+\DB field              \BC type     \BC explanation \NC \NR
+\TB
+\NC \type{attr}        \NC node     \NC list of attributes \NC \NR
+\NC \type{width}       \NC number   \NC the width (not used in calculations) \NC \NR
+\NC \type{height}      \NC number   \NC the height (not used in calculations) \NC \NR
+\NC \type{depth}       \NC number   \NC the depth (not used in calculations) \NC \NR
+\NC \type{named_id}    \NC number   \NC is the \type {dest_id} a string value? \NC \NR
+\NC \type{dest_id}     \NC number   \NC the destination id \NC \NR
+\NC                    \NC string   \NC the destination name \NC \NR
+\NC \type{dest_type}   \NC number   \NC type of destination \NC \NR
+\NC \type{xyz_zoom}    \NC number   \NC the zoom factor (times 1000) \NC \NR
+\NC \type{objnum}      \NC number   \NC the \PDF\ object number \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_action}}
+
+These are a special kind of items that only appear inside \PDF\ start link
+objects.
+
+\starttabulate[|l|l|p|]
+\DB field              \BC type             \BC explanation \NC \NR
+\TB
+\NC \type{action_type} \NC number           \NC the kind of action involved \NC \NR
+\NC \type{action_id}   \NC number or string \NC token list reference or string \NC \NR
+\NC \type{named_id}    \NC number           \NC the index of the destination \NC \NR
+\NC \type{file}        \NC string           \NC the target filename \NC \NR
+\NC \type{new_window}  \NC number           \NC the window state of the target \NC \NR
+\NC \type{data}        \NC string           \NC the name of the destination \NC \NR
+\LL
+\stoptabulate
+
+Valid action types are:
+
+\starttabulate[|l|l|]
+\DB value \BC meaning       \NC \NR
+\TB
+\NC 0     \NC \type{page}   \NC \NR
+\NC 1     \NC \type{goto}   \NC \NR
+\NC 2     \NC \type{thread} \NC \NR
+\NC 3     \NC \type{user}   \NC \NR
+\LL
+\stoptabulate
+
+Valid window types are:
+
+\starttabulate[|l|l|]
+\DB value \BC meaning       \NC \NR
+\TB
+\NC 0     \NC \type{notset} \NC \NR
+\NC 1     \NC \type{new}    \NC \NR
+\NC 2     \NC \type{nonew}  \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_thread}}
+
+\starttabulate[|l|l|p|]
+\DB field              \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}        \NC node   \NC list of attributes \NC \NR
+\NC \type{width}       \NC number \NC the width (not used in calculations) \NC \NR
+\NC \type{height}      \NC number \NC the height (not used in calculations) \NC \NR
+\NC \type{depth}       \NC number \NC the depth (not used in calculations) \NC \NR
+\NC \type{named_id}    \NC number \NC is \type {tread_id} a string value? \NC \NR
+\NC \type{tread_id}    \NC number \NC the thread id \NC \NR
+\NC                    \NC string \NC the thread name \NC \NR
+\NC \type{thread_attr} \NC number \NC extra thread information \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_start_thread}}
+
+\starttabulate[|l|l|p|]
+\DB field              \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}        \NC node   \NC list of attributes \NC \NR
+\NC \type{width}       \NC number \NC the width (not used in calculations) \NC \NR
+\NC \type{height}      \NC number \NC the height (not used in calculations) \NC \NR
+\NC \type{depth}       \NC number \NC the depth (not used in calculations) \NC \NR
+\NC \type{named_id}    \NC number \NC is \type {tread_id} a string value? \NC \NR
+\NC \type{tread_id}    \NC number \NC the thread id \NC \NR
+\NC                    \NC string \NC the thread name \NC \NR
+\NC \type{thread_attr} \NC number \NC extra thread information \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_end_thread}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node \NC \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_colorstack}}
+
+\starttabulate[|l|l|p|]
+\DB field          \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr}    \NC node   \NC list of attributes \NC \NR
+\NC \type{stack}   \NC number \NC colorstack id number \NC \NR
+\NC \type{command} \NC number \NC command to execute \NC \NR
+\NC \type{data}    \NC string \NC data \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_setmatrix}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node   \NC list of attributes \NC \NR
+\NC \type{data} \NC string \NC data \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_save}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node \NC list of attributes \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\whs {pdf_restore}}
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{attr} \NC node \NC list of attributes \NC \NR
+\LL
+\stoptabulate
+
+\stopsection
+
+\startsection[title={The \type {node} library}][library=node]
+
+\subsection {Introduction}
+
+The \type {node} library contains functions that facilitate dealing with (lists
+of) nodes and their values. They allow you to create, alter, copy, delete, and
+insert \LUATEX\ node objects, the core objects within the typesetter.
+
+\LUATEX\ nodes are represented in \LUA\ as userdata with the metadata type
+\type {luatex.node}. The various parts within a node can be accessed using
+named fields.
+
+Each node has at least the three fields \type {next}, \type {id}, and \type {subtype}:
+
+\startitemize[intro]
+
+\startitem
+    The \type {next} field returns the userdata object for the next node in a
+    linked list of nodes, or \type {nil}, if there is no next node.
+\stopitem
+
+\startitem
+    The \type {id} indicates \TEX's \quote{node type}. The field \type {id} has a
+    numeric value for efficiency reasons, but some of the library functions also
+    accept a string value instead of \type {id}.
+\stopitem
+
+\startitem
+    The \type {subtype} is another number. It often gives further information
+    about a node of a particular \type {id}, but it is most important when
+    dealing with \quote {whatsits}, because they are differentiated solely based
+    on their \type {subtype}.
+\stopitem
+
+\stopitemize
+
+The other available fields depend on the \type {id} (and for \quote {whatsits},
+the \type {subtype}) of the node.
+
+Support for \nod {unset} (alignment) nodes is partial: they can be queried and
+modified from \LUA\ code, but not created.
+
+Nodes can be compared to each other, but: you are actually comparing indices into
+the node memory. This means that equality tests can only be trusted under very
+limited conditions. It will not work correctly in any situation where one of the
+two nodes has been freed and|/|or reallocated: in that case, there will be false
+positives.
+
+At the moment, memory management of nodes should still be done explicitly by the
+user. Nodes are not \quote {seen} by the \LUA\ garbage collector, so you have to
+call the node freeing functions yourself when you are no longer in need of a node
+(list). Nodes form linked lists without reference counting, so you have to be
+careful that when control returns back to \LUATEX\ itself, you have not deleted
+nodes that are still referenced from a \type {next} pointer elsewhere, and that
+you did not create nodes that are referenced more than once. Normally the setters
+and getters handle this for you.
+
+There are statistics available with regards to the allocated node memory, which
+can be handy for tracing.
+
+\subsection{\type {is_node}}
+
+\topicindex {nodes+functions}
+
+\libindex {is_node}
+
+\startfunctioncall
+<boolean|integer> t =
+    node.is_node(<any> item)
+\stopfunctioncall
+
+This function returns a number (the internal index of the node) if the argument
+is a userdata object of type \type {<node>} and false when no node is passed.
+
+\subsection{\type {types} and \type {whatsits}}
+
+\libindex {types}
+\libindex {whatsits}
+
+This function returns an array that maps node id numbers to node type strings,
+providing an overview of the possible top|-|level \type {id} types.
+
+\startfunctioncall
+<table> t =
+    node.types()
+\stopfunctioncall
+
+\TEX's \quote {whatsits} all have the same \type {id}. The various subtypes are
+defined by their \type {subtype} fields. The function is much like \type {types},
+except that it provides an array of \type {subtype} mappings.
+
+\startfunctioncall
+<table> t =
+    node.whatsits()
+\stopfunctioncall
+
+\subsection{\type {id}}
+
+\libindex{id}
+
+This converts a single type name to its internal numeric representation.
+
+\startfunctioncall
+<number> id =
+    node.id(<string> type)
+\stopfunctioncall
+
+\subsection{\type {type} and \type {subtype}}
+
+\libindex {type}
+\libindex {subtype}
+
+In the argument is a number, then the next function converts an internal numeric
+representation to an external string representation. Otherwise, it will return
+the string \type {node} if the object represents a node, and \type {nil}
+otherwise.
+
+\startfunctioncall
+<string> type =
+    node.type(<any> n)
+\stopfunctioncall
+
+This next one converts a single whatsit name to its internal numeric
+representation (\type {subtype}).
+
+\startfunctioncall
+<number> subtype =
+    node.subtype(<string> type)
+\stopfunctioncall
+
+\subsection{\type {fields}}
+
+\libindex {fields}
+
+This function returns an array of valid field names for a particular type of
+node. If you want to get the valid fields for a \quote {whatsit}, you have to
+supply the second argument also. In other cases, any given second argument will
+be silently ignored.
+
+\startfunctioncall
+<table> t =
+    node.fields(<number> id)
+<table> t =
+    node.fields(<number> id, <number> subtype)
+\stopfunctioncall
+
+The function accepts string \type {id} and \type {subtype} values as well.
+
+\subsection{\type {has_field}}
+
+\libindex {has_field}
+
+This function returns a boolean that is only true if \type {n} is
+actually a node, and it has the field.
+
+\startfunctioncall
+<boolean> t =
+    node.has_field(<node> n, <string> field)
+\stopfunctioncall
+
+\subsection{\type {new}}
+
+\libindex{new}
+
+The \type {new} function creates a new node. All its fields are initialized to
+either zero or \type {nil} except for \type {id} and \type {subtype}. Instead of
+numbers you can also use strings (names). If you create a new \nod {whatsit} node
+the second argument is required. As with all node functions, this function
+creates a node at the \TEX\ level.
+
+\startfunctioncall
+<node> n =
+    node.new(<number> id)
+<node> n =
+    node.new(<number> id, <number> subtype)
+\stopfunctioncall
+
+\subsection{\type {free}, \type {flush_node} and \type {flush_list}}
+
+\libindex{free}
+\libindex{flush_node}
+\libindex{flush_list}
+
+The next one the node \type {n} from \TEX's memory. Be careful: no checks are
+done on whether this node is still pointed to from a register or some \type
+{next} field: it is up to you to make sure that the internal data structures
+remain correct.
+
+\startfunctioncall
+<node> next =
+    node.free(<node> n)
+flush_node(<node> n)
+\stopfunctioncall
+
+The \type {free} function returns the next field of the freed node, while the
+\type {flush_node} alternative returns nothing.
+
+A list starting with node \type {n} can be flushed from \TEX's memory too. Be
+careful: no checks are done on whether any of these nodes is still pointed to
+from a register or some \type {next} field: it is up to you to make sure that the
+internal data structures remain correct.
+
+\startfunctioncall
+node.flush_list(<node> n)
+\stopfunctioncall
+
+\subsection{\type {copy} and \type {copy_list}}
+
+\libindex{copy}
+\libindex{copy_list}
+
+This creates a deep copy of node \type {n}, including all nested lists as in the case
+of a hlist or vlist node. Only the \type {next} field is not copied.
+
+\startfunctioncall
+<node> m =
+    node.copy(<node> n)
+\stopfunctioncall
+
+A deep copy of the node list that starts at \type {n} can be created too. If
+\type {m} is also given, the copy stops just before node \type {m}.
+
+\startfunctioncall
+<node> m =
+    node.copy_list(<node> n)
+<node> m =
+    node.copy_list(<node> n, <node> m)
+\stopfunctioncall
+
+Note that you cannot copy attribute lists this way. However, there is normally no
+need to copy attribute lists as when you do assignments to the \type {attr} field
+or make changes to specific attributes, the needed copying and freeing takes
+place automatically.
+
+\subsection{\type {prev} and \type{next}}
+
+\libindex{prev}
+\libindex{next}
+
+These returns the node preceding or following the given node, or \type {nil} if
+there is no such node.
+
+\startfunctioncall
+<node> m =
+    node.next(<node> n)
+<node> m =
+    node.prev(<node> n)
+\stopfunctioncall
+
+\subsection{\type {current_attr}}
+
+\libindex{current_attr}
+
+This returns the currently active list of attributes, if there is one.
+
+\startfunctioncall
+<node> m =
+    node.current_attr()
+\stopfunctioncall
+
+The intended usage of \type {current_attr} is as follows:
+
+\starttyping
+local x1 = node.new("glyph")
+x1.attr = node.current_attr()
+local x2 = node.new("glyph")
+x2.attr = node.current_attr()
+\stoptyping
+
+or:
+
+\starttyping
+local x1 = node.new("glyph")
+local x2 = node.new("glyph")
+local ca = node.current_attr()
+x1.attr = ca
+x2.attr = ca
+\stoptyping
+
+The attribute lists are ref counted and the assignment takes care of incrementing
+the refcount. You cannot expect the value \type {ca} to be valid any more when
+you assign attributes (using \type {tex.setattribute}) or when control has been
+passed back to \TEX.
+
+Note: this function is somewhat experimental, and it returns the {\it actual}
+attribute list, not a copy thereof. Therefore, changing any of the attributes in
+the list will change these values for all nodes that have the current attribute
+list assigned to them.
+
+\subsection{\type {hpack}}
+
+\libindex {hpack}
+
+This function creates a new hlist by packaging the list that begins at node \type
+{n} into a horizontal box. With only a single argument, this box is created using
+the natural width of its components. In the three argument form, \type {info}
+must be either \type {additional} or \type {exactly}, and \type {w} is the
+additional (\type {\hbox spread}) or exact (\type {\hbox to}) width to be used.
+The second return value is the badness of the generated box.
+
+\startfunctioncall
+<node> h, <number> b =
+    node.hpack(<node> n)
+<node> h, <number> b =
+    node.hpack(<node> n, <number> w, <string> info)
+<node> h, <number> b =
+    node.hpack(<node> n, <number> w, <string> info, <string> dir)
+\stopfunctioncall
+
+Caveat: there can be unexpected side|-|effects to this function, like updating
+some of the \prm {marks} and \type {\inserts}. Also note that the content of
+\type {h} is the original node list \type {n}: if you call \type {node.free(h)}
+you will also free the node list itself, unless you explicitly set the \type
+{list} field to \type {nil} beforehand. And in a similar way, calling \type
+{node.free(n)} will invalidate \type {h} as well!
+
+\subsection{\type {vpack}}
+
+\libindex {vpack}
+
+This function creates a new vlist by packaging the list that begins at node \type
+{n} into a vertical box. With only a single argument, this box is created using
+the natural height of its components. In the three argument form, \type {info}
+must be either \type {additional} or \type {exactly}, and \type {w} is the
+additional (\type {\vbox spread}) or exact (\type {\vbox to}) height to be used.
+
+\startfunctioncall
+<node> h, <number> b =
+    node.vpack(<node> n)
+<node> h, <number> b =
+    node.vpack(<node> n, <number> w, <string> info)
+<node> h, <number> b =
+    node.vpack(<node> n, <number> w, <string> info, <string> dir)
+\stopfunctioncall
+
+The second return value is the badness of the generated box. See the description
+of \type {hpack} for a few memory allocation caveats.
+
+\subsection{\type {prepend_prevdepth}}
+
+\libindex {prepend_prevdepth}
+
+This function is somewhat special in the sense that it is an experimental helper
+that adds the interlinespace to a line keeping the baselineskip and lineskip into
+account.
+
+\startfunctioncall
+<node> n, <number> delta =
+    node.prepend_prevdepth(<node> n,<number> prevdepth)
+\stopfunctioncall
+
+\subsection{\type {dimensions} and \type {rangedimensions}}
+
+\libindex{dimensions}
+\libindex{rangedimensions}
+
+\startfunctioncall
+<number> w, <number> h, <number> d  =
+    node.dimensions(<node> n)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<node> n, <string> dir)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<node> n, <node> t)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<node> n, <node> t, <string> dir)
+\stopfunctioncall
+
+This function calculates the natural in|-|line dimensions of the node list starting
+at node \type {n} and terminating just before node \type {t} (or the end of the
+list, if there is no second argument). The return values are scaled points. An
+alternative format that starts with glue parameters as the first three arguments
+is also possible:
+
+\startfunctioncall
+<number> w, <number> h, <number> d  =
+    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,
+        <node> n)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,
+        <node> n, <string> dir)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,
+        <node> n, <node> t)
+<number> w, <number> h, <number> d  =
+    node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order,
+        <node> n, <node> t, <string> dir)
+\stopfunctioncall
+
+This calling method takes glue settings into account and is especially useful for
+finding the actual width of a sublist of nodes that are already boxed, for
+example in code like this, which prints the width of the space in between the
+\type {a} and \type {b} as it would be if \type {\box0} was used as-is:
+
+\starttyping
+\setbox0 = \hbox to 20pt {a b}
+
+\directlua{print (node.dimensions(
+    tex.box[0].glue_set,
+    tex.box[0].glue_sign,
+    tex.box[0].glue_order,
+    tex.box[0].head.next,
+    node.tail(tex.box[0].head)
+)) }
+\stoptyping
+
+You need to keep in mind that this is one of the few places in \TEX\ where floats
+are used, which means that you can get small differences in rounding when you
+compare the width reported by \type {hpack} with \type {dimensions}.
+
+The second alternative saves a few lookups and can be more convenient in some
+cases:
+
+\startfunctioncall
+<number> w, <number> h, <number> d  =
+    node.rangedimensions(<node> parent, <node> first)
+<number> w, <number> h, <number> d  =
+    node.rangedimensions(<node> parent, <node> first, <node> last)
+\stopfunctioncall
+
+\subsection{\type {mlist_to_hlist}}
+
+\libindex {mlist_to_hlist}
+
+\startfunctioncall
+<node> h =
+    node.mlist_to_hlist(<node> n, <string> display_type, <boolean> penalties)
+\stopfunctioncall
+
+This runs the internal mlist to hlist conversion, converting the math list in
+\type {n} into the horizontal list \type {h}. The interface is exactly the same
+as for the callback \cbk {mlist_to_hlist}.
+
+\subsection{\type {slide}}
+
+\startfunctioncall
+<node> m =
+    node.slide(<node> n)
+\stopfunctioncall
+
+Returns the last node of the node list that starts at \type {n}. As a
+side|-|effect, it also creates a reverse chain of \type {prev} pointers between
+nodes.
+
+\subsection{\type {tail}}
+
+\libindex {tail}
+
+\startfunctioncall
+<node> m =
+    node.tail(<node> n)
+\stopfunctioncall
+
+Returns the last node of the node list that starts at \type {n}.
+
+\subsection{\type {length} and type {count}}
+
+\libindex {length}
+\libindex {count}
+
+\startfunctioncall
+<number> i =
+    node.length(<node> n)
+<number> i =
+    node.length(<node> n, <node> m)
+\stopfunctioncall
+
+Returns the number of nodes contained in the node list that starts at \type {n}.
+If \type {m} is also supplied it stops at \type {m} instead of at the end of the
+list. The node \type {m} is not counted.
+
+\startfunctioncall
+<number> i =
+    node.count(<number> id, <node> n)
+<number> i =
+    node.count(<number> id, <node> n, <node> m)
+\stopfunctioncall
+
+Returns the number of nodes contained in the node list that starts at \type {n}
+that have a matching \type {id} field. If \type {m} is also supplied, counting
+stops at \type {m} instead of at the end of the list. The node \type {m} is not
+counted. This function also accept string \type {id}'s.
+
+\subsection{\type {is_char} and \type {is_glyph}}
+
+\libindex {is_char}
+\libindex {is_glyph}
+
+The subtype of a glyph node signals if the glyph is already turned into a character reference
+or not.
+
+\startfunctioncall
+<boolean> b =
+    node.is_char(<node> n)
+<boolean> b =
+    node.is_glyph(<node> n)
+\stopfunctioncall
+
+\subsection{\type {traverse}}
+
+\libindex {traverse}
+
+\startfunctioncall
+<node> t, id, subtype =
+    node.traverse(<node> n)
+\stopfunctioncall
+
+This is a \LUA\ iterator that loops over the node list that starts at \type {n}.
+Typically code looks like this:
+
+\starttyping
+for n in node.traverse(head) do
+   ...
+end
+\stoptyping
+
+is functionally equivalent to:
+
+\starttyping
+do
+  local n
+  local function f (head,var)
+    local t
+    if var == nil then
+       t = head
+    else
+       t = var.next
+    end
+    return t
+  end
+  while true do
+    n = f (head, n)
+    if n == nil then break end
+    ...
+  end
+end
+\stoptyping
+
+It should be clear from the definition of the function \type {f} that even though
+it is possible to add or remove nodes from the node list while traversing, you
+have to take great care to make sure all the \type {next} (and \type {prev})
+pointers remain valid.
+
+If the above is unclear to you, see the section \quote {For Statement} in the
+\LUA\ Reference Manual.
+
+\subsection{\type {traverse_id}}
+
+\libindex {traverse_id}
+
+\startfunctioncall
+<node> t, subtype =
+    node.traverse_id(<number> id, <node> n)
+\stopfunctioncall
+
+This is an iterator that loops over all the nodes in the list that starts at
+\type {n} that have a matching \type {id} field.
+
+See the previous section for details. The change is in the local function \type
+{f}, which now does an extra while loop checking against the upvalue \type {id}:
+
+\starttyping
+ local function f(head,var)
+   local t
+   if var == nil then
+      t = head
+   else
+      t = var.next
+   end
+   while not t.id == id do
+      t = t.next
+   end
+   return t
+ end
+\stoptyping
+
+\subsection{\type {traverse_char} and \type {traverse_glyph}}
+
+\libindex {traverse_char}
+\libindex {traverse_glyph}
+
+The \type{traverse_char} iterator loops over the \nod {glyph} nodes in a list.
+Only nodes with a subtype less than 256 are seen.
+
+\startfunctioncall
+<node> n, font, char =
+    node.traverse_char(<node> n)
+\stopfunctioncall
+
+The \type{traverse_glyph} iterator loops over a list and returns the list and
+filters all glyphs:
+
+\startfunctioncall
+<node> n, font, char =
+    node.traverse_glyph(<node> n)
+\stopfunctioncall
+
+\subsection{\type {traverse_list}}
+
+\libindex {traverse_list}
+
+This iterator loops over the \nod {hlist} and \nod {vlist} nodes in a list.
+
+\startfunctioncall
+<node> n, id, subtype, list =
+    node.traverse_list(<node> n)
+\stopfunctioncall
+
+The four return values can save some time compared to fetching these fields but
+in practice you seldom need them all. So consider it a (side effect of
+experimental) convenience.
+
+\subsection{\type {has_glyph}}
+
+\libindex {has_glyph}
+
+This function returns the first glyph or disc node in the given list:
+
+\startfunctioncall
+<node> n =
+    node.has_glyph(<node> n)
+\stopfunctioncall
+
+\subsection{\type {end_of_math}}
+
+\libindex {end_of_math}
+
+\startfunctioncall
+<node> t =
+    node.end_of_math(<node> start)
+\stopfunctioncall
+
+Looks for and returns the next \type {math_node} following the \type {start}. If
+the given node is a math end node this helper returns that node, else it follows
+the list and returns the next math endnote. If no such node is found nil is
+returned.
+
+\subsection{\type {remove}}
+
+\libindex {remove}
+
+\startfunctioncall
+<node> head, current =
+    node.remove(<node> head, <node> current)
+\stopfunctioncall
+
+This function removes the node \type {current} from the list following \type
+{head}. It is your responsibility to make sure it is really part of that list.
+The return values are the new \type {head} and \type {current} nodes. The
+returned \type {current} is the node following the \type {current} in the calling
+argument, and is only passed back as a convenience (or \type {nil}, if there is
+no such node). The returned \type {head} is more important, because if the
+function is called with \type {current} equal to \type {head}, it will be
+changed.
+
+\subsection{\type {insert_before}}
+
+\libindex {insert_before}
+
+\startfunctioncall
+<node> head, new =
+    node.insert_before(<node> head, <node> current, <node> new)
+\stopfunctioncall
+
+This function inserts the node \type {new} before \type {current} into the list
+following \type {head}. It is your responsibility to make sure that \type
+{current} is really part of that list. The return values are the (potentially
+mutated) \type {head} and the node \type {new}, set up to be part of the list
+(with correct \type {next} field). If \type {head} is initially \type {nil}, it
+will become \type {new}.
+
+\subsection{\type {insert_after}}
+
+\libindex {insert_after}
+
+\startfunctioncall
+<node> head, new =
+    node.insert_after(<node> head, <node> current, <node> new)
+\stopfunctioncall
+
+This function inserts the node \type {new} after \type {current} into the list
+following \type {head}. It is your responsibility to make sure that \type
+{current} is really part of that list. The return values are the \type {head} and
+the node \type {new}, set up to be part of the list (with correct \type {next}
+field). If \type {head} is initially \type {nil}, it will become \type {new}.
+
+\subsection{\type {first_glyph}}
+
+\libindex {first_glyph}
+
+\startfunctioncall
+<node> n =
+    node.first_glyph(<node> n)
+<node> n =
+    node.first_glyph(<node> n, <node> m)
+\stopfunctioncall
+
+Returns the first node in the list starting at \type {n} that is a glyph node
+with a subtype indicating it is a glyph, or \type {nil}. If \type {m} is given,
+processing stops at (but including) that node, otherwise processing stops at the
+end of the list.
+
+\subsection{\type {ligaturing}}
+
+\libindex {ligaturing}
+
+\startfunctioncall
+<node> h, <node> t, <boolean> success =
+    node.ligaturing(<node> n)
+<node> h, <node> t, <boolean> success =
+    node.ligaturing(<node> n, <node> m)
+\stopfunctioncall
+
+Apply \TEX-style ligaturing to the specified nodelist. The tail node \type {m} is
+optional. The two returned nodes \type {h} and \type {t} are the new head and
+tail (both \type {n} and \type {m} can change into a new ligature).
+
+\subsection{\type {kerning}}
+
+\libindex {kerning}
+
+\startfunctioncall
+<node> h, <node> t, <boolean> success =
+    node.kerning(<node> n)
+<node> h, <node> t, <boolean> success =
+    node.kerning(<node> n, <node> m)
+\stopfunctioncall
+
+Apply \TEX|-|style kerning to the specified node list. The tail node \type {m} is
+optional. The two returned nodes \type {h} and \type {t} are the head and tail
+(either one of these can be an inserted kern node, because special kernings with
+word boundaries are possible).
+
+\subsection{\type {unprotect_glyph[s]}}
+
+\libindex {unprotect_glyphs}
+\libindex {unprotect_glyph}
+
+\startfunctioncall
+node.unprotect_glyph(<node> n)
+node.unprotect_glyphs(<node> n,[<node> n])
+\stopfunctioncall
+
+Subtracts 256 from all glyph node subtypes. This and the next function are
+helpers to convert from \type {characters} to \type {glyphs} during node
+processing. The second argument is optional and indicates the end of a range.
+
+\subsection{\type {protect_glyph[s]}}
+
+\libindex {protect_glyphs}
+\libindex {protect_glyph}
+
+\startfunctioncall
+node.protect_glyph(<node> n)
+node.protect_glyphs(<node> n,[<node> n])
+\stopfunctioncall
+
+Adds 256 to all glyph node subtypes in the node list starting at \type {n},
+except that if the value is 1, it adds only 255. The special handling of 1 means
+that \type {characters} will become \type {glyphs} after subtraction of 256. A
+single character can be marked by the singular call. The second argument is
+optional and indicates the end of a range.
+
+\subsection{\type {last_node}}
+
+\libindex {last_node}
+
+\startfunctioncall
+<node> n =
+    node.last_node()
+\stopfunctioncall
+
+This function pops the last node from \TEX's \quote{current list}. It returns
+that node, or \type {nil} if the current list is empty.
+
+\subsection{\type {write}}
+
+\libindex {write}
+
+\startfunctioncall
+node.write(<node> n)
+\stopfunctioncall
+
+This function that will append a node list to \TEX's \quote {current list}. The
+node list is not deep|-|copied! There is no error checking either! You mignt need
+to enforce horizontal mode in order for this to work as expected.
+
+\subsection{\type {protrusion_skippable}}
+
+\libindex {protrusion_skippable}
+
+\startfunctioncall
+<boolean> skippable =
+    node.protrusion_skippable(<node> n)
+\stopfunctioncall
+
+Returns \type {true} if, for the purpose of line boundary discovery when
+character protrusion is active, this node can be skipped.
+
+\stopsection
+
+\startsection[title={Glue handling}][library=node]
+
+\subsection{\type {setglue}}
+
+\libindex {setglue}
+
+You can set the properties of a glue in one go. If you pass no values, the glue
+will become a zero glue.
+
+\startfunctioncall
+node.setglue(<node> n)
+node.setglue(<node> n,width,stretch,shrink,stretch_order,shrink_order)
+\stopfunctioncall
+
+When you pass values, only arguments that are numbers are assigned so
+
+\starttyping
+node.setglue(n,655360,false,65536)
+\stoptyping
+
+will only adapt the width and shrink.
+
+When a list node is passed, you set the glue, order and sign instead.
+
+\subsection{\type {getglue}}
+
+\libindex {getglue}
+
+The next call will return 5 values or nothing when no glue is passed.
+
+\startfunctioncall
+<integer> width, <integer> stretch, <integer> shrink, <integer> stretch_order,
+    <integer> shrink_order = node.getglue(<node> n)
+\stopfunctioncall
+
+When the second argument is false, only the width is returned (this is consistent
+with \type {tex.get}).
+
+When a list node is passed, you get back the glue that is set, the order of that
+glue and the sign.
+
+\subsection{\type {is_zero_glue}}
+
+\libindex {is_zero_glue}
+
+This function returns \type {true} when the width, stretch and shrink properties
+are zero.
+
+\startfunctioncall
+<boolean> isglue =
+    node.is_zero_glue(<node> n)
+\stopfunctioncall
+
+\stopsection
+
+\startsection[title={Attribute handling}][library=node]
+
+\subsection{Attributes}
+
+\topicindex {attributes}
+
+The newly introduced attribute registers are non|-|trivial, because the value
+that is attached to a node is essentially a sparse array of key|-|value pairs. It
+is generally easiest to deal with attribute lists and attributes by using the
+dedicated functions in the \type {node} library, but for completeness, here is
+the low|-|level interface.
+
+Attributes appear as linked list of userdata objects in the \type {attr} field of
+individual nodes. They can be handled individually, but it is much safer and more
+efficient to use the dedicated functions associated with them.
+
+\subsection{\nod {attribute_list} nodes}
+
+\topicindex {nodes+attributes}
+
+An \nod {attribute_list} item is used as a head pointer for a list of attribute
+items. It has only one user-visible field:
+
+\starttabulate[|l|l|p|]
+\DB field       \BC type \BC explanation \NC \NR
+\TB
+\NC \type{next} \NC node \NC pointer to the first attribute \NC \NR
+\LL
+\stoptabulate
+
+\subsection{\nod {attr} nodes}
+
+A normal node's attribute field will point to an item of type \nod
+{attribute_list}, and the \type {next} field in that item will point to the first
+defined \quote {attribute} item, whose \type {next} will point to the second
+\quote {attribute} item, etc.
+
+\starttabulate[|l|l|p|]
+\DB field         \BC type   \BC explanation \NC \NR
+\TB
+\NC \type{next}   \NC node   \NC pointer to the next attribute \NC \NR
+\NC \type{number} \NC number \NC the attribute type id \NC \NR
+\NC \type{value}  \NC number \NC the attribute value \NC \NR
+\LL
+\stoptabulate
+
+As mentioned it's better to use the official helpers rather than edit these
+fields directly. For instance the \type {prev} field is used for other purposes
+and there is no double linked list.
+
+\subsection{\type {has_attribute}}
+
+\libindex {has_attribute}
+
+\startfunctioncall
+<number> v =
+    node.has_attribute(<node> n, <number> id)
+<number> v =
+    node.has_attribute(<node> n, <number> id, <number> val)
+\stopfunctioncall
+
+Tests if a node has the attribute with number \type {id} set. If \type {val} is
+also supplied, also tests if the value matches \type {val}. It returns the value,
+or, if no match is found, \type {nil}.
+
+\subsection{\type {get_attribute}}
+
+\libindex {get_attribute}
+
+\startfunctioncall
+<number> v =
+    node.get_attribute(<node> n, <number> id)
+\stopfunctioncall
+
+Tests if a node has an attribute with number \type {id} set. It returns the
+value, or, if no match is found, \type {nil}. If no \type {id} is given then the
+zero attributes is assumed.
+
+\subsection{\type {find_attribute}}
+
+\libindex {find_attribute}
+
+\startfunctioncall
+<number> v, <node> n =
+    node.find_attribute(<node> n, <number> id)
+\stopfunctioncall
+
+Finds the first node that has attribute with number \type {id} set. It returns
+the value and the node if there is a match and otherwise nothing.
+
+\subsection{\type {set_attribute}}
+
+\libindex {set_attribute}
+
+\startfunctioncall
+node.set_attribute(<node> n, <number> id, <number> val)
+\stopfunctioncall
+
+Sets the attribute with number \type {id} to the value \type {val}. Duplicate
+assignments are ignored.
+
+\subsection{\type {unset_attribute}}
+
+\libindex {unset_attribute}
+
+\startfunctioncall
+<number> v =
+    node.unset_attribute(<node> n, <number> id)
+<number> v =
+    node.unset_attribute(<node> n, <number> id, <number> val)
+\stopfunctioncall
+
+Unsets the attribute with number \type {id}. If \type {val} is also supplied, it
+will only perform this operation if the value matches \type {val}. Missing
+attributes or attribute|-|value pairs are ignored.
+
+If the attribute was actually deleted, returns its old value. Otherwise, returns
+\type {nil}.
+
+\subsection{\type {slide}}
+
+\libindex {slide}
+
+This helper makes sure that the node lists is double linked and returns the found
+tail node.
+
+\startfunctioncall
+<node> tail =
+    node.slide(<node> n)
+\stopfunctioncall
+
+After some callbacks automatic sliding takes place. This feature can be turned
+off with \type {node.fix_node_lists(false)} but you better make sure then that
+you don't mess up lists. In most cases \TEX\ itself only uses \type {next}
+pointers but your other callbacks might expect proper \type {prev} pointers too.
+Future versions of \LUATEX\ can add more checking but this will not influence
+usage.
+
+\subsection{\type {check_discretionary}, \type {check_discretionaries}}
+
+\libindex{check_discretionary}
+\libindex{check_discretionaries}
+
+When you fool around with disc nodes you need to be aware of the fact that they
+have a special internal data structure. As long as you reassign the fields when
+you have extended the lists it's ok because then the tail pointers get updated,
+but when you add to list without reassigning you might end up in trouble when
+the linebreak routine kicks in. You can call this function to check the list for
+issues with disc nodes.
+
+\startfunctioncall
+node.check_discretionary(<node> n)
+node.check_discretionaries(<node> head)
+\stopfunctioncall
+
+The plural variant runs over all disc nodes in a list, the singular variant
+checks one node only (it also checks if the node is a disc node).
+
+\subsection{\type {flatten_discretionaries}}
+
+\libindex {flatten_discretionaries}
+
+This function will remove the discretionaries in the list and inject the replace
+field when set.
+
+\startfunctioncall
+<node> head, count = node.flatten_discretionaries(<node> n)
+\stopfunctioncall
+
+\subsection{\type {family_font}}
+
+\libindex {family_font}
+
+When you pass a proper family identifier the next helper will return the font
+currently associated with it. You can normally also access the font with the
+normal font field or getter because it will resolve the family automatically for
+noads.
+
+\startfunctioncall
+<integer> id =
+    node.family_font(<integer> fam)
+\stopfunctioncall
+
+\stopsection
+
+\startsection[title={Two access models}][library=node]
+
+\topicindex{nodes+direct}
+\topicindex{direct nodes}
+
+\libindex {todirect}
+\libindex {tonode}
+\libindex {tostring}
+
+Deep down in \TEX\ a node has a number which is a numeric entry in a memory
+table. In fact, this model, where \TEX\ manages memory is real fast and one of
+the reasons why plugging in callbacks that operate on nodes is quite fast too.
+Each node gets a number that is in fact an index in the memory table and that
+number often is reported when you print node related information. You go from
+userdata nodes and there numeric references and back with:
+
+\startfunctioncall
+<integer> d = node.todirect(<node> n))
+<node> n = node.tonode(<integer> d))
+\stopfunctioncall
+
+The userdata model is rather robust as it is a virtual interface with some
+additional checking while the more direct access which uses the node numbers
+directly. However, even with userdata you can get into troubles when you free
+nodes that are no longer allocated or mess up lists. if you apply \type
+{tostring} to a node you see its internal (direct) number and id.
+
+The first model provides key based access while the second always accesses fields
+via functions:
+
+\starttyping
+nodeobject.char
+getfield(nodenumber,"char")
+\stoptyping
+
+If you use the direct model, even if you know that you deal with numbers, you
+should not depend on that property but treat it as an abstraction just like
+traditional nodes. In fact, the fact that we use a simple basic datatype has the
+penalty that less checking can be done, but less checking is also the reason why
+it's somewhat faster. An important aspect is that one cannot mix both methods,
+but you can cast both models. So, multiplying a node number makes no sense.
+
+So our advice is: use the indexed (table) approach when possible and investigate
+the direct one when speed might be a real issue. For that reason \LUATEX\ also
+provide the \type {get*} and \type {set*} functions in the top level node
+namespace. There is a limited set of getters. When implementing this direct
+approach the regular index by key variant was also optimized, so direct access
+only makes sense when nodes are accessed millions of times (which happens in some
+font processing for instance).
+
+We're talking mostly of getters because setters are less important. Documents
+have not that many content related nodes and setting many thousands of properties
+is hardly a burden contrary to millions of consultations.
+
+Normally you will access nodes like this:
+
+\starttyping
+local next = current.next
+if next then
+    -- do something
+end
+\stoptyping
+
+Here \type {next} is not a real field, but a virtual one. Accessing it results in
+a metatable method being called. In practice it boils down to looking up the node
+type and based on the node type checking for the field name. In a worst case you
+have a node type that sits at the end of the lookup list and a field that is last
+in the lookup chain. However, in successive versions of \LUATEX\ these lookups
+have been optimized and the most frequently accessed nodes and fields have a
+higher priority.
+
+Because in practice the \type {next} accessor results in a function call, there
+is some overhead involved. The next code does the same and performs a tiny bit
+faster (but not that much because it is still a function call but one that knows
+what to look up).
+
+\starttyping
+local next = node.next(current)
+if next then
+    -- do something
+end
+\stoptyping
+
+Some accessors are used frequently and for these we provide more efficient helpers:
+
+\starttabulate[|l|p|]
+\DB function          \BC explanation \NC \NR
+\TB
+\NC \type{getnext}    \NC parsing nodelist always involves this one \NC \NR
+\NC \type{getprev}    \NC used less but a logical companion to \type {getnext} \NC \NR
+\NC \type{getboth}    \NC returns the next and prev pointer of a node \NC \NR
+\NC \type{getid}      \NC consulted a lot \NC \NR
+\NC \type{getsubtype} \NC consulted less but also a topper \NC \NR
+\NC \type{getfont}    \NC used a lot in \OPENTYPE\ handling (glyph nodes are consulted a lot) \NC \NR
+\NC \type{getchar}    \NC idem and also in other places \NC \NR
+\NC \type{getwhd}     \NC returns the \type {width}, \type {height} and \type {depth} of a list, rule or
+                          (unexpanded) glyph as well as glue (its spec is looked at) and unset nodes\NC \NR
+\NC \type{getdisc}    \NC returns the \type {pre}, \type {post} and \type {replace} fields and
+                          optionally when true is passed also the tail fields \NC \NR
+\NC \type{getlist}    \NC we often parse nested lists so this is a convenient one too \NC \NR
+\NC \type{getleader}  \NC comparable to list, seldom used in \TEX\ (but needs frequent consulting
+                          like lists; leaders could have been made a dedicated node type) \NC \NR
+\NC \type{getfield}   \NC generic getter, sufficient for the rest (other field names are
+                          often shared so a specific getter makes no sense then) \NC \NR
+\NC \type{getbox}     \NC gets the given box (a list node) \NC \NR
+\NC \type{getoffsets} \NC gets the \type {xoffset} and \type {yoffset} of a glyph or
+                          \type {left} and \type {right} values of a rule \NC \NR
+\LL
+\stoptabulate
+
+In the direct namespace there are more such helpers and most of them are
+accompanied by setters. The getters and setters are clever enough to see what
+node is meant. We don't deal with whatsit nodes: their fields are always accessed
+by name. It doesn't make sense to add getters for all fields, we just identifier
+the most likely candidates. In complex documents, many node and fields types
+never get seen, or seen only a few times, but for instance glyphs are candidates
+for such optimization. The \type {node.direct} interface has some more helpers.
+\footnote {We can define the helpers in the node namespace with \type {getfield}
+which is about as efficient, so at some point we might provide that as module.}
+
+The \type {setdisc} helper takes three (optional) arguments plus an optional
+fourth indicating the subtype. Its \type {getdisc} takes an optional boolean;
+when its value is \type {true} the tail nodes will also be returned. The \type
+{setfont} helper takes an optional second argument, it being the character. The
+directmode setter \type {setlink} takes a list of nodes and will link them,
+thereby ignoring \type {nil} entries. The first valid node is returned (beware:
+for good reason it assumes single nodes). For rarely used fields no helpers are
+provided and there are a few that probably are used seldom too but were added for
+consistency. You can of course always define additional accessors using \type
+{getfield} and \type {setfield} with little overhead. When the second argument of
+\type {setattributelist} is \type {true} the current attribute list is assumed.
+
+\def\yes{$+$} \def\nop{$-$}
+
+\def\supported#1#2#3%
+ {\NC \type{#1}
+  \NC \ifx#2\yes\lix{node}       {#1}\fi #2
+  \NC \ifx#3\yes\lix{node.direct}{#1}\fi #3 \NC
+  \NR}
+
+\starttabulate[|l|c|c|]
+\DB function \BC node \BC direct \NC \NR
+\TB
+\supported {check_discretionaries}   \yes \yes
+\supported {check_discretionary}     \yes \yes
+\supported {copy_list}               \yes \yes
+\supported {copy}                    \yes \yes
+\supported {count}                   \yes \yes
+\supported {current_attr}            \yes \yes
+\supported {dimensions}              \yes \yes
+\supported {effective_glue}          \yes \yes
+\supported {end_of_math}             \yes \yes
+\supported {family_font}             \yes \nop
+\supported {fields}                  \yes \nop
+\supported {find_attribute}          \yes \yes
+\supported {first_glyph}             \yes \yes
+\supported {flatten_discretionaries} \yes \yes
+\supported {flush_list}              \yes \yes
+\supported {flush_node}              \yes \yes
+\supported {free}                    \yes \yes
+\supported {get_attribute}           \yes \yes
+\supported {get_synctex_fields}      \nop \yes
+\supported {getattributelist}        \nop \yes
+\supported {getboth}                 \yes \yes
+\supported {getbox}                  \nop \yes
+\supported {getchar}                 \yes \yes
+\supported {getcomponents}           \nop \yes
+\supported {getdepth}                \nop \yes
+\supported {getdirection}            \nop \yes
+\supported {getdir}                  \nop \yes
+\supported {getdisc}                 \yes \yes
+\supported {getfam}                  \nop \yes
+\supported {getfield}                \yes \yes
+\supported {getfont}                 \yes \yes
+\supported {getglue}                 \yes \yes
+\supported {getheight}               \nop \yes
+\supported {getid}                   \yes \yes
+\supported {getkern}                 \nop \yes
+\supported {getlang}                 \nop \yes
+\supported {getleader}               \yes \yes
+\supported {getlist}                 \yes \yes
+\supported {getnext}                 \yes \yes
+\supported {getnucleus}              \nop \yes
+\supported {getoffsets}              \nop \yes
+\supported {getpenalty}              \nop \yes
+\supported {getprev}                 \yes \yes
+\supported {getproperty}             \yes \yes
+\supported {getshift}                \nop \yes
+\supported {getsubtype}              \yes \yes
+\supported {getsub}                  \nop \yes
+\supported {getsup}                  \nop \yes
+\supported {getdata}                 \nop \yes
+\supported {getwhd}                  \yes \yes
+\supported {getwidth}                \nop \yes
+\supported {has_attribute}           \yes \yes
+\supported {has_field}               \yes \yes
+\supported {has_glyph}               \yes \yes
+\supported {hpack}                   \yes \yes
+\supported {id}                      \yes \nop
+\supported {insert_after}            \yes \yes
+\supported {insert_before}           \yes \yes
+\supported {is_char}                 \yes \yes
+\supported {is_direct}               \nop \yes
+\supported {is_glyph}                \yes \yes
+\supported {is_node}                 \yes \yes
+\supported {is_zero_glue}            \yes \yes
+\supported {kerning}                 \yes \yes
+\supported {last_node}               \yes \yes
+\supported {length}                  \yes \yes
+\supported {ligaturing}              \yes \yes
+\supported {mlist_to_hlist}          \yes \nop
+\supported {new}                     \yes \yes
+\supported {next}                    \yes \nop
+\supported {prepend_prevdepth}       \nop \yes
+\supported {prev}                    \yes \nop
+\supported {protect_glyphs}          \yes \yes
+\supported {protect_glyph}           \yes \yes
+\supported {protrusion_skippable}    \yes \yes
+\supported {rangedimensions}         \yes \yes
+\supported {remove}                  \yes \yes
+\supported {set_attribute}           \yes \yes
+\supported {set_synctex_fields}      \nop \yes
+\supported {setattributelist}        \nop \yes
+\supported {setboth}                 \nop \yes
+\supported {setbox}                  \nop \yes
+\supported {setchar}                 \nop \yes
+\supported {setcomponents}           \nop \yes
+\supported {setdepth}                \nop \yes
+\supported {setdirection}            \nop \yes
+\supported {setdir}                  \nop \yes
+\supported {setdisc}                 \nop \yes
+\supported {setfam}                  \nop \yes
+\supported {setfield}                \yes \yes
+\supported {setfont}                 \nop \yes
+\supported {setexpansion}            \nop \yes
+\supported {setglue}                 \yes \yes
+\supported {setheight}               \nop \yes
+\supported {setkern}                 \nop \yes
+\supported {setlang}                 \nop \yes
+\supported {setleader}               \nop \yes
+\supported {setlink}                 \nop \yes
+\supported {setlist}                 \nop \yes
+\supported {setnext}                 \nop \yes
+\supported {setnucleus}              \nop \yes
+\supported {setoffsets}              \nop \yes
+\supported {setpenalty}              \nop \yes
+\supported {setprev}                 \nop \yes
+\supported {setproperty}             \yes \yes
+\supported {setshift}                \nop \yes
+\supported {setsplit}                \nop \yes
+\supported {setsubtype}              \nop \yes
+\supported {setsub}                  \nop \yes
+\supported {setsup}                  \nop \yes
+\supported {setwhd}                  \nop \yes
+\supported {setwidth}                \nop \yes
+\supported {slide}                   \yes \yes
+\supported {subtypes}                \yes \nop
+\supported {subtype}                 \yes \nop
+\supported {tail}                    \yes \yes
+\supported {todirect}                \yes \yes
+\supported {tonode}                  \yes \yes
+\supported {tostring}                \yes \yes
+\supported {traverse_char}           \yes \yes
+\supported {traverse_glyph}          \yes \yes
+\supported {traverse_id}             \yes \yes
+\supported {traverse}                \yes \yes
+\supported {types}                   \yes \nop
+\supported {type}                    \yes \nop
+\supported {unprotect_glyphs}        \yes \yes
+\supported {unprotect_glyph}         \yes \yes
+\supported {unset_attribute}         \yes \yes
+\supported {usedlist}                \yes \yes
+\supported {uses_font}               \yes \yes
+\supported {vpack}                   \yes \yes
+\supported {whatsits}                \yes \nop
+\supported {write}                   \yes \yes
+\LL
+\stoptabulate
+
+The \type {node.next} and \type {node.prev} functions will stay but for
+consistency there are variants called \type {getnext} and \type {getprev}. We had
+to use \type {get} because \type {node.id} and \type {node.subtype} are already
+taken for providing meta information about nodes. Note: The getters do only basic
+checking for valid keys. You should just stick to the keys mentioned in the
+sections that describe node properties.
+
+Some of the getters and setters handle multiple node types, given that the field
+is relevant. In that case, some field names are considered similar (like \type
+{kern} and \type {width}, or \type {data} and \type {value}. In retrospect we
+could have normalized field names better but we decided to stick to the original
+(internal) names as much as possible. After all, at the \LUA\ end one can easily
+create synonyms.
+
+Some nodes have indirect references. For instance a math character refers to a
+family instead of a font. In that case we provide a virtual font field as
+accessor. So, \type {getfont} and \type {.font} can be used on them. The same is
+true for the \type {width}, \type {height} and \type {depth} of glue nodes. These
+actually access the spec node properties, and here we can set as well as get the
+values.
+
+In some places \LUATEX\ can do a bit of extra checking for valid node lists and
+you can enable that with:
+
+\startfunctioncall
+node.fix_node_lists(<boolean> b)
+\stopfunctioncall
+
+You can set and query the \SYNCTEX\ fields, a file number aka tag and a line
+number, for a glue, kern, hlist, vlist, rule and math nodes as well as glyph
+nodes (although this last one is not used in native \SYNCTEX).
+
+\startfunctioncall
+node.set_synctex_fields(<integer> f, <integer> l)
+<integer> f, <integer> l =
+    node.get_synctex_fields(<node> n)
+\stopfunctioncall
+
+Of course you need to know what you're doing as no checking on sane values takes
+place. Also, the synctex interpreter used in editors is rather peculiar and has
+some assumptions (heuristics).
+
+\stopsection
+
+\startsection[title={Properties}][library=node]
+
+\topicindex {nodes+properties}
+\topicindex {properties}
+
+\libindex{flush_properties_table}
+\libindex{get_properties_table}
+\libindex{set_properties_mode}
+
+Attributes are a convenient way to relate extra information to a node. You can
+assign them at the \TEX\ end as well as at the \LUA\ end and and consult them at
+the \LUA\ end. One big advantage is that they obey grouping. They are linked
+lists and normally checking for them is pretty efficient, even if you use a lot
+of them. A macro package has to provide some way to manage these attributes at the
+\TEX\ end because otherwise clashes in their usage can occur.
+
+Each node also can have a properties table and you can assign values to this
+table using the \type {setproperty} function and get properties using the \type
+{getproperty} function. Managing properties is way more demanding than managing
+attributes.
+
+Take the following example:
+
+\starttyping
+\directlua {
+    local n = node.new("glyph")
+
+    node.setproperty(n,"foo")
+    print(node.getproperty(n))
+
+    node.setproperty(n,"bar")
+    print(node.getproperty(n))
+
+    node.free(n)
+}
+\stoptyping
+
+This will print \type {foo} and \type {bar} which in itself is not that useful
+when multiple mechanisms want to use this feature. A variant is:
+
+\starttyping
+\directlua {
+    local n = node.new("glyph")
+
+    node.setproperty(n,{ one = "foo", two = "bar" })
+    print(node.getproperty(n).one)
+    print(node.getproperty(n).two)
+
+    node.free(n)
+}
+\stoptyping
+
+This time we store two properties with the node. It really makes sense to have a
+table as property because that way we can store more. But in order for that to
+work well you need to do it this way:
+
+\starttyping
+\directlua {
+    local n = node.new("glyph")
+
+    local t = node.getproperty(n)
+
+    if not t then
+        t = { }
+        node.setproperty(n,t)
+    end
+    t.one = "foo"
+    t.two = "bar"
+
+    print(node.getproperty(n).one)
+    print(node.getproperty(n).two)
+
+    node.free(n)
+}
+\stoptyping
+
+Here our own properties will not overwrite other users properties unless of
+course they use the same keys. So, eventually you will end up with something:
+
+\starttyping
+\directlua {
+    local n = node.new("glyph")
+
+    local t = node.getproperty(n)
+
+    if not t then
+        t = { }
+        node.setproperty(n,t)
+    end
+    t.myself = { one = "foo", two = "bar" }
+
+    print(node.getproperty(n).myself.one)
+    print(node.getproperty(n).myself.two)
+
+    node.free(n)
+}
+\stoptyping
+
+This assumes that only you use \type {myself} as subtable. The possibilities are
+endless but care is needed. For instance, the generic font handler that ships
+with \CONTEXT\ uses the \type {injections} subtable and you should not mess with
+that one!
+
+There are a few helper functions that you normally should not touch as user: \typ
+{flush_properties_table} will wipe the table (normally a bad idea), \typ
+{get_properties_table} and will give the table that stores properties (using
+direct entries) and you can best not mess too much with that one either because
+\LUATEX\ itself will make sure that entries related to nodes will get wiped when
+nodes get freed, so that the \LUA\ garbage collector can do its job. In fact, the
+main reason why we have this mechanism is that it saves the user (or macro
+package) some work. One can easily write a property mechanism in \LUA\ where
+after a shipout properties gets cleaned up but it's not entirely trivial to make
+sure that with each freed node also its properties get freed, due to the fact
+that there can be nodes left over for a next page. And having a callback bound to
+the node deallocator would add way to much overhead.
+
+Managing properties in the node (de)allocator functions is disabled by default
+and is enabled by:
+
+\starttyping
+node.set_properties_mode(true)
+\stoptyping
+
+When we copy a node list that has a table as property, there are several possibilities: we do the same as
+a new node, we copy the entry to the table in properties (a reference), we do
+a deep copy of a table in the properties, we create a new table and give it
+the original one as a metatable. After some experiments (that also included
+timing) with these scenarios we decided that a deep copy made no sense, nor
+did nilling. In the end both the shallow copy and the metatable variant were
+both ok, although the second one is slower. The most important aspect to keep
+in mind is that references to other nodes in properties no longer can be
+valid for that copy. We could use two tables (one unique and one shared) or
+metatables but that only complicates matters.
+
+When defining a new node, we could already allocate a table but it is rather easy
+to do that at the lua end e.g.\ using a metatable \type {__index} method. That
+way it is under macro package control. When deleting a node, we could keep the
+slot (e.g. setting it to false) but it could make memory consumption raise
+unneeded when we have temporary large node lists and after that only small lists.
+Both are not done.
+
+So in the end this is what happens now: when a node is copied, and it has a table
+as property, the new node will share that table. If the second argument of \typ
+{set_properties_mode} is \type {true} then a metatable approach is chosen: the
+copy gets its own table with the original table as metatable. If you use the
+generic font loader the mode is enabled that way.
+
+A few more xperiments were done. For instance: copy attributes to the properties
+so that we have fast access at the \LUA\ end. In the end the overhead is not
+compensated by speed and convenience, in fact, attributes are not that slow when
+it comes to accessing them. So this was rejected.
+
+Another experiment concerned a bitset in the node but again the gain compared to
+attributes was neglectable and given the small amount of available bits it also
+demands a pretty strong agreement over what bit represents what, and this is
+unlikely to succeed in the \TEX\ community. It doesn't pay off.
+
+Just in case one wonders why properties make sense: it is not so much speed that
+we gain, but more convenience: storing all kind of (temporary) data in attributes
+is no fun and this mechanism makes sure that properties are cleaned up when a
+node is freed. Also, the advantage of a more or less global properties table is
+that we stay at the \LUA\ end. An alternative is to store a reference in the node
+itself but that is complicated by the fact that the register has some limitations
+(no numeric keys) and we also don't want to mess with it too much.
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-preamble.tex b/systems/doc/luatex/luatex-preamble.tex
index 635ff4134b..8293179776 100644
--- a/systems/doc/luatex/luatex-preamble.tex
+++ b/systems/doc/luatex/luatex-preamble.tex
@@ -1,110 +1,110 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-preamble

-

-\startchapter[reference=preamble,title={Preamble}]

-

-\topicindex{nodes}

-\topicindex{boxes}

-\topicindex{\LUA}

-

-This is a reference manual, not a tutorial. This means that we discuss changes

-relative to traditonal \TEX\ and also present new functionality. As a consequence

-we will refer to concepts that we assume to be known or that might be explained

-later.

-

-The average user doesn't need to know much about what is in this manual. For

-instance fonts and languages are normally dealt with in the macro package that

-you use. Messing around with node lists is also often not really needed at the

-user level. If you do mess around, you'd better know what you're dealing with.

-Reading \quotation {The \TEX\ Book} by Donald Knuth is a good investment of time

-then also because it's good to know where it all started. A more summarizing

-overview is given by \quotation {\TEX\ by Topic} by Victor Eijkhout. You might

-want to peek in \quotation {The \ETEX\ manual} and documentation about \PDFTEX.

-

-But \unknown\ if you're here because of \LUA, then all you need to know is that

-you can call it from within a run. The macro package that you use probably will

-provide a few wrapper mechanisms but the basic \lpr {directlua} command that

-does the job is:

-

-\starttyping

-\directlua{tex.print("Hi there")}

-\stoptyping

-

-You can put code between curly braces but if it's a lot you can also put it in a

-file and load that file with the usual \LUA\ commands.

-

-If you still decide to read on, then it's good to know what nodes are, so we do a

-quick introduction here. If you input this text:

-

-\starttyping

-Hi There

-\stoptyping

-

-eventually we will get a linked lists of nodes, which in \ASCII\ art looks like:

-

-\starttyping

-H <=> i <=> [glue] <=> T <=> h <=> e <=> r <=> e

-\stoptyping

-

-When we have a paragraph, we actually get something:

-

-\starttyping

-[localpar] <=> H <=> i <=> [glue] <=> T <=> h <=> e <=> r <=> e <=> [glue]

-\stoptyping

-

-Each character becomes a so called glyph node, a record with properties like the

-current font, the character code and the current language. Spaces become glue

-nodes. There are many node types that we will discuss later. Each node points

-back to a previous node or next node, given that these exist.

-

-It's also good to know beforehand that \TEX\ is basically centered around

-creating paragraphs and pages. The par builder takes a list and breaks it into

-lines. We turn horizontal material into vertical. Lines are so called boxes and

-can be separated by glue, penalties and more. The page builder accumulates lines

-and when feasible triggers an output routine that will take the list so far.

-Constructing the actual page is not part of \TEX\ but done using primitives that

-permit manipulation of boxes. The result is handled back to \TEX\ and flushed to

-a (often \PDF) file.

-

-The \LUATEX\ engine provides hooks for \LUA\ code at nearly every reasonable

-point in the process: collecting content, hyphenating, applying font features,

-breaking into lines, etc. This means that you can overload \TEX's natural

-behaviour, which still is the benchmark. When we refer to \quote {callbacks} we

-means these hooks.

-

-Where plain \TEX\ is basically a basic framework for writing a specific style,

-macro packages like \CONTEXT\ and \LATEX\ provide the user a whole lot of

-additional tools to make documents look good. They hide the dirty details of font

-management, language demands, turning structure into typeset results, wrapping

-pages, including images, and so on. You should be aware of the fact that when you

-hook in your own code to manipulate lists, this can interfere with the macro

-package that you use.

-

-When you read about nodes in the following chapters it's good to keep in mind their

-commands that relate to then. Here are a few:

-

-\starttabulate[|l|l|p|]

-\DB command                \BC node          \BC explanation \NC \NR

-\TB

-\NC \prm {hbox}            \NC \nod {hlist} \NC horizontal box \NC \NR

-\NC \prm {vbox}            \NC \nod {vlist} \NC vertical box with the baseline at the bottom \NC \NR

-\NC \prm {vtop}            \NC \nod {vlist} \NC vertical box with the baseline at the top \NC \NR

-\NC \prm {hskip}           \NC \nod {glue}  \NC horizontal skip with optional stretch and shrink \NC \NR

-\NC \prm {vskip}           \NC \nod {glue}  \NC vertical skip with optional stretch and shrink \NC \NR

-\NC \prm {kern}            \NC \nod {kern}  \NC horizontal or vertical fixed skip \NC \NR

-\NC \prm {discretionary}   \NC \nod {disc}  \NC hyphenation point (pre, post, replace) \NC \NR

-\NC \prm {char}            \NC \nod {glyph} \NC a character \NC \NR

-\NC \prm {hrule}           \NC \nod {rule}  \NC a horizontal rule \NC \NR

-\NC \prm {vrule}           \NC \nod {rule}  \NC a vertical rule \NC \NR

-\NC \prm {textdir(ection)} \NC \nod {dir}   \NC a change in text direction \NC \NR

-\LL

-\stoptabulate

-

-For now this should be enough to enable you to understand the next chapters.

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-preamble
+
+\startchapter[reference=preamble,title={Preamble}]
+
+\topicindex{nodes}
+\topicindex{boxes}
+\topicindex{\LUA}
+
+This is a reference manual, not a tutorial. This means that we discuss changes
+relative to traditonal \TEX\ and also present new functionality. As a consequence
+we will refer to concepts that we assume to be known or that might be explained
+later.
+
+The average user doesn't need to know much about what is in this manual. For
+instance fonts and languages are normally dealt with in the macro package that
+you use. Messing around with node lists is also often not really needed at the
+user level. If you do mess around, you'd better know what you're dealing with.
+Reading \quotation {The \TEX\ Book} by Donald Knuth is a good investment of time
+then also because it's good to know where it all started. A more summarizing
+overview is given by \quotation {\TEX\ by Topic} by Victor Eijkhout. You might
+want to peek in \quotation {The \ETEX\ manual} and documentation about \PDFTEX.
+
+But \unknown\ if you're here because of \LUA, then all you need to know is that
+you can call it from within a run. The macro package that you use probably will
+provide a few wrapper mechanisms but the basic \lpr {directlua} command that
+does the job is:
+
+\starttyping
+\directlua{tex.print("Hi there")}
+\stoptyping
+
+You can put code between curly braces but if it's a lot you can also put it in a
+file and load that file with the usual \LUA\ commands.
+
+If you still decide to read on, then it's good to know what nodes are, so we do a
+quick introduction here. If you input this text:
+
+\starttyping
+Hi There
+\stoptyping
+
+eventually we will get a linked lists of nodes, which in \ASCII\ art looks like:
+
+\starttyping
+H <=> i <=> [glue] <=> T <=> h <=> e <=> r <=> e
+\stoptyping
+
+When we have a paragraph, we actually get something:
+
+\starttyping
+[localpar] <=> H <=> i <=> [glue] <=> T <=> h <=> e <=> r <=> e <=> [glue]
+\stoptyping
+
+Each character becomes a so called glyph node, a record with properties like the
+current font, the character code and the current language. Spaces become glue
+nodes. There are many node types that we will discuss later. Each node points
+back to a previous node or next node, given that these exist.
+
+It's also good to know beforehand that \TEX\ is basically centered around
+creating paragraphs and pages. The par builder takes a list and breaks it into
+lines. We turn horizontal material into vertical. Lines are so called boxes and
+can be separated by glue, penalties and more. The page builder accumulates lines
+and when feasible triggers an output routine that will take the list so far.
+Constructing the actual page is not part of \TEX\ but done using primitives that
+permit manipulation of boxes. The result is handled back to \TEX\ and flushed to
+a (often \PDF) file.
+
+The \LUATEX\ engine provides hooks for \LUA\ code at nearly every reasonable
+point in the process: collecting content, hyphenating, applying font features,
+breaking into lines, etc. This means that you can overload \TEX's natural
+behaviour, which still is the benchmark. When we refer to \quote {callbacks} we
+means these hooks.
+
+Where plain \TEX\ is basically a basic framework for writing a specific style,
+macro packages like \CONTEXT\ and \LATEX\ provide the user a whole lot of
+additional tools to make documents look good. They hide the dirty details of font
+management, language demands, turning structure into typeset results, wrapping
+pages, including images, and so on. You should be aware of the fact that when you
+hook in your own code to manipulate lists, this can interfere with the macro
+package that you use.
+
+When you read about nodes in the following chapters it's good to keep in mind their
+commands that relate to then. Here are a few:
+
+\starttabulate[|l|l|p|]
+\DB command                \BC node          \BC explanation \NC \NR
+\TB
+\NC \prm {hbox}            \NC \nod {hlist} \NC horizontal box \NC \NR
+\NC \prm {vbox}            \NC \nod {vlist} \NC vertical box with the baseline at the bottom \NC \NR
+\NC \prm {vtop}            \NC \nod {vlist} \NC vertical box with the baseline at the top \NC \NR
+\NC \prm {hskip}           \NC \nod {glue}  \NC horizontal skip with optional stretch and shrink \NC \NR
+\NC \prm {vskip}           \NC \nod {glue}  \NC vertical skip with optional stretch and shrink \NC \NR
+\NC \prm {kern}            \NC \nod {kern}  \NC horizontal or vertical fixed skip \NC \NR
+\NC \prm {discretionary}   \NC \nod {disc}  \NC hyphenation point (pre, post, replace) \NC \NR
+\NC \prm {char}            \NC \nod {glyph} \NC a character \NC \NR
+\NC \prm {hrule}           \NC \nod {rule}  \NC a horizontal rule \NC \NR
+\NC \prm {vrule}           \NC \nod {rule}  \NC a vertical rule \NC \NR
+\NC \prm {textdir(ection)} \NC \nod {dir}   \NC a change in text direction \NC \NR
+\LL
+\stoptabulate
+
+For now this should be enough to enable you to understand the next chapters.
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-registers.tex b/systems/doc/luatex/luatex-registers.tex
index 2930230070..36b1ec0513 100644
--- a/systems/doc/luatex/luatex-registers.tex
+++ b/systems/doc/luatex/luatex-registers.tex
@@ -1,47 +1,47 @@
-\environment luatex-style

-

-\startcomponent luatex-registers

-

-\startchapter[title=Topics]

-

-    \placeregister[topicindex]

-

-\stopchapter

-

-\startchapter[title=Primitives]

-

-    This register contains the primitives that are mentioned in the manual. There

-    are of course many more primitives. The \LUATEX\ primitives are typeset in

-    bold. The primitives from \PDFTEX\ are not supported that way but mentioned

-    anyway.

-

-    \placeregister[primitiveindex][indicator=no]

-

-\stopchapter

-

-\startchapter[title=Callbacks]

-

-    \placeregister[callbackindex]

-

-\stopchapter

-

-\startchapter[title=Nodes]

-

-    This register contains the nodes that are known to \LUATEX. The primary nodes

-    are in bold, whatsits that are determined by their subtype are normal. The

-    names prefixed by \type {pdf_} are backend specific.

-

-    \placeregister[nodeindex]

-

-\stopchapter

-

-\startchapter[title=Libraries]

-

-    This register contains the functions available in libraries. Not all functions

-    are documented, for instance because they can be experimental or obsolete.

-

-    \placeregister[libraryindex]

-

-\stopchapter

-

-\stopcomponent

+\environment luatex-style
+
+\startcomponent luatex-registers
+
+\startchapter[title=Topics]
+
+    \placeregister[topicindex]
+
+\stopchapter
+
+\startchapter[title=Primitives]
+
+    This register contains the primitives that are mentioned in the manual. There
+    are of course many more primitives. The \LUATEX\ primitives are typeset in
+    bold. The primitives from \PDFTEX\ are not supported that way but mentioned
+    anyway.
+
+    \placeregister[primitiveindex][indicator=no]
+
+\stopchapter
+
+\startchapter[title=Callbacks]
+
+    \placeregister[callbackindex]
+
+\stopchapter
+
+\startchapter[title=Nodes]
+
+    This register contains the nodes that are known to \LUATEX. The primary nodes
+    are in bold, whatsits that are determined by their subtype are normal. The
+    names prefixed by \type {pdf_} are backend specific.
+
+    \placeregister[nodeindex]
+
+\stopchapter
+
+\startchapter[title=Libraries]
+
+    This register contains the functions available in libraries. Not all functions
+    are documented, for instance because they can be experimental or obsolete.
+
+    \placeregister[libraryindex]
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-statistics.tex b/systems/doc/luatex/luatex-statistics.tex
index 2428a2929d..efd7f1c75c 100644
--- a/systems/doc/luatex/luatex-statistics.tex
+++ b/systems/doc/luatex/luatex-statistics.tex
@@ -1,17 +1,17 @@
-% language=uk

-

-\environment luatex-style

-

-\startcomponent luatex-statistics

-

-\startchapter[title={Statistics}]

-

-    \topicindex{fonts+used}

-

-    The following fonts are used in this document:

-

-    \showfontusage

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+\environment luatex-style
+
+\startcomponent luatex-statistics
+
+\startchapter[title={Statistics}]
+
+    \topicindex{fonts+used}
+
+    The following fonts are used in this document:
+
+    \showfontusage
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-style.tex b/systems/doc/luatex/luatex-style.tex
index 502e894a8c..aa0a7edc3f 100644
--- a/systems/doc/luatex/luatex-style.tex
+++ b/systems/doc/luatex/luatex-style.tex
@@ -1,443 +1,443 @@
-\startenvironment luatex-style

-

-% todo: use \useMPlibrary[lua]

-

-\enabletrackers[fonts.usage]

-

-\usemodule[fonts-statistics]

-

-\setuplayout

-  [height=middle,

-   width=middle,

-   backspace=2cm,

-   topspace=10mm,

-   bottomspace=10mm,

-   header=10mm,

-   footer=10mm,

-   footerdistance=10mm,

-   headerdistance=10mm]

-

-\setuppagenumbering

-  [alternative=doublesided]

-

-\setuptolerance

-  [stretch,tolerant]

-

-\setuptype

-  [lines=hyphenated]

-

-\setuptyping

-  [lines=hyphenated]

-

-\setupitemize

-  [each]

-  [packed]

-

-\definesymbol[1][\Uchar"2023]

-\definesymbol[2][\endash]

-\definesymbol[3][\wait]      % we want to catch it

-

-\setupitemize

-  [each]

-  [headcolor=maincolor,

-   symbolcolor=maincolor,

-   color=maincolor]

-

-\setupwhitespace

-  [medium]

-

-\setuptabulate

-  [blank={small,samepage},

-   headstyle=bold,

-   rulecolor=maincolor,

-   rulethickness=1pt,

-   foregroundcolor=white,

-   foregroundstyle=\ss\bfx\WORD,

-   backgroundcolor=maincolor]

-

-\setupcaptions

-  [headcolor=darkblue]

-

-\startluacode

-    local skipped = table.tohash { 'id', 'subtype', 'next', 'prev' }

-

-    function document.functions.showfields(s)

-        local t = string.split(s,',')

-        local f = node.fields(t[1],t[2])

-        if f then

-            local d = false

-            for i=1,#f do

-                local fi = f[i]

-                if skipped[fi] then

-                    -- okay

-                elseif d then

-                    context(', {\tttf %s}', fi)

-                else

-                    context('{\tttf %s}', fi)

-                    d = true

-                end

-            end

-        end

-    end

-

-    function document.functions.showid(s)

-        local t = string.split(s,',')

-        context('{tttf %s}',node.id(t[1]))

-        if t[2] then

-            context(', {tttf %s}',node.subtype(t[2]))

-        end

-    end

-

-    function document.functions.showsubtypes(s)

-        local s = node.subtypes(s)

-        local d = false

-        for k, v in table.sortedhash(s) do

-            if d then

-                context(', %s = {\\tttf %s}',k,v)

-            else

-                context('%s = {\\tttf %s}',k,v)

-                d = true

-            end

-        end

-    end

-\stopluacode

-

-\unexpanded\def\showfields  #1{\ctxlua{document.functions.showfields("#1")}}

-\unexpanded\def\showid      #1{\ctxlua{document.functions.showid("#1")}}

-\unexpanded\def\showsubtypes#1{\ctxlua{document.functions.showsubtypes("#1")}}

-

-\definecolor[blue]      [b=.5]

-\definecolor[red]       [r=.5]

-\definecolor[green]     [g=.5]

-\definecolor[maincolor] [b=.5]

-\definecolor[keptcolor] [b=.5]

-\definecolor[othercolor][r=.5,g=.5]

-

-\writestatus{luatex manual}{}

-\writestatus{luatex manual}{defining lucodaot} \usebodyfont  [lucidaot]

-\writestatus{luatex manual}{defining pagella}  \usebodyfont  [pagella]

-\writestatus{luatex manual}{defining cambria}  \usebodyfont  [cambria]

-\writestatus{luatex manual}{defining modern}   \usebodyfont  [modern]

-\writestatus{luatex manual}{defining dejavu}   \setupbodyfont[dejavu,10pt]

-\writestatus{luatex manual}{}

-

-\setuphead [chapter]      [align={flushleft,broad},style=\bfd]

-\setuphead [section]      [align={flushleft,broad},style=\bfb]

-\setuphead [subsection]   [align={flushleft,broad},style=\bfa]

-\setuphead [subsubsection][align={flushleft,broad},style=\bf]

-

-\setuphead [chapter]      [color=maincolor]

-\setuphead [section]      [color=maincolor]

-\setuphead [subsection]   [color=maincolor]

-\setuphead [subsubsection][color=maincolor]

-

-\setupfloats

-  [ntop=4]

-

-\definehead

-  [remark]

-  [subsubsubject]

-

-\setupheadertexts

-  []

-

-% \setuplayout

-%   [style=bold,

-%    color=maincolor]

-

-\definemixedcolumns

-  [twocolumns]

-  [n=2,

-   balance=yes,

-   before=\blank,

-   after=\blank]

-

-\definemixedcolumns

-  [threecolumns]

-  [twocolumns]

-  [n=3]

-

-\definemixedcolumns

-  [fourcolumns]

-  [threecolumns]

-  [n=4]

-

-% if we do this we also need to do it in table cells

-%

-% \setuptyping

-%   [color=maincolor]

-%

-% \setuptype

-%   [color=maincolor]

-

-\definetyping

-  [functioncall]

-

-\startMPdefinitions

-

-    color   luaplanetcolor ; luaplanetcolor := \MPcolor{maincolor} ;

-    color   luaholecolor   ; luaholecolor   := white ;

-    numeric luaextraangle  ; luaextraangle  := 0 ;

-    numeric luaorbitfactor ; luaorbitfactor := .25 ;

-

-    vardef lualogo = image (

-

-        % Graphic design by A. Nakonechnyj. Copyright (c) 1998, All rights reserved.

-

-        save d, r, p ; numeric d, r, p ;

-

-        d := sqrt(2)/4 ; r := 1/4 ; p := r/8 ;

-

-        fill fullcircle scaled 1

-            withcolor luaplanetcolor ;

-        draw fullcircle rotated 40.5 scaled (1+r)

-            dashed evenly scaled p

-            withpen pencircle scaled (p/2)

-            withcolor (luaorbitfactor * luaholecolor) ;

-        fill fullcircle scaled r shifted (d+1/8,d+1/8)

-            rotated - luaextraangle

-            withcolor luaplanetcolor ;

-        fill fullcircle scaled r shifted (d-1/8,d-1/8)

-            withcolor luaholecolor   ;

-        luaorbitfactor := .25 ;

-    ) enddef ;

-

-\stopMPdefinitions

-

-\startuseMPgraphic{luapage}

-    StartPage ;

-

-        fill Page withcolor \MPcolor{othercolor} ;

-

-        luaorbitfactor := 1 ;

-

-        picture p ; p := lualogo ysized (5*\measure{paperheight}/10) ;

-        draw p

-            shifted - center p

-            shifted (

-                \measure{spreadwidth} - .5*\measure{paperwidth} + \measure{spinewidth},

-                .375*\measure{paperheight}

-            )

-        ;

-

-    StopPage ;

-\stopuseMPgraphic

-

-% \starttexdefinition luaextraangle

-%     % we can also just access the last page and so in mp directly

-%     \ctxlua {

-%         context(\lastpage == 0 and 0 or \realfolio*360/\lastpage)

-%     }

-% \stoptexdefinition

-

-\startuseMPgraphic{luanumber}

-  % luaextraangle  := \luaextraangle;

-    luaextraangle  := if (LastPageNumber < 10) : 10 else : (RealPageNumber / LastPageNumber) * 360  fi;

-    luaorbitfactor := 0.25 ;

-    picture p ; p := lualogo ;

-    setbounds p to boundingbox fullcircle ;

-    draw p ysized 1cm ;

-\stopuseMPgraphic

-

-\definelayer

-  [page]

-  [width=\paperwidth,

-   height=\paperheight]

-

-\setupbackgrounds

-  [leftpage]

-  [background=page]

-

-\setupbackgrounds

-  [rightpage]

-  [background=page]

-

-\definemeasure[banneroffset][\bottomspace-\footerheight-\footerdistance+2cm]

-

-\startsetups pagenumber:right

-  \setlayerframed

-    [page]

-    [preset=rightbottom,x=1.0cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,offset=overlay]

-    {\strut\useMPgraphic{luanumber}}

-  \setlayerframed

-    [page]

-    [preset=rightbottom,x=2.5cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,width=1cm,offset=overlay,

-     foregroundstyle=bold,foregroundcolor=maincolor]

-    {\strut\pagenumber}

-  \setlayerframed

-    [page]

-    [preset=rightbottom,x=3.5cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,offset=overlay,

-     foregroundstyle=bold,foregroundcolor=maincolor]

-    {\strut\getmarking[chapter]}

-\stopsetups

-

-\startsetups pagenumber:left

-  \setlayerframed

-    [page]

-    [preset=leftbottom,x=3.5cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,offset=overlay,

-     foregroundstyle=bold,foregroundcolor=maincolor]

-    {\strut\getmarking[chapter]}

-  \setlayerframed

-    [page]

-    [preset=leftbottom,x=2.5cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,width=1cm,offset=overlay,

-     foregroundstyle=bold,foregroundcolor=maincolor]

-    {\strut\pagenumber}

-  \setlayerframed

-    [page]

-    [preset=leftbottom,x=1.0cm,y=\measure{banneroffset}]

-    [frame=off,height=1cm,offset=overlay]

-    {\strut\useMPgraphic{luanumber}}

-\stopsetups

-

-\unexpanded\def\nonterminal#1>{\mathematics{\langle\hbox{\rm #1}\rangle}}

-

-% taco's brainwave -) .. todo: create a typing variant so that we can avoid the !crlf

-

-\newcatcodetable\syntaxcodetable

-

-\unexpanded\def\makesyntaxcodetable

-  {\begingroup

-   \catcode`\<=13 \catcode`\|=12

-   \catcode`\!= 0 \catcode`\\=12

-   \savecatcodetable\syntaxcodetable

-   \endgroup}

-

-\makesyntaxcodetable

-

-\unexpanded\def\startsyntax {\begingroup\catcodetable\syntaxcodetable  \dostartsyntax}

-\unexpanded\def\syntax      {\begingroup\catcodetable\syntaxcodetable  \dosyntax}

-           \let\stopsyntax   \relax

-

-\unexpanded\def\syntaxenvbody#1%

-  {\par

-   \tt

-   \startnarrower

- % \maincolor

-   #1

-   \stopnarrower

-   \par}

-

-\unexpanded\def\syntaxbody#1%

-  {\begingroup

- % \maincolor

-   \tt #1%

-   \endgroup}

-

-\bgroup \catcodetable\syntaxcodetable

-

-!gdef!dostartsyntax#1\stopsyntax{!let<!nonterminal!syntaxenvbody{#1}!endgroup}

-!gdef!dosyntax     #1{!let<!nonterminal!syntaxbody{#1}!endgroup}

-

-!egroup

-

-\definetyping

-  [texsyntax]

-% [color=maincolor]

-

-% end of wave

-

-\setupinteraction

-  [state=start,

-   focus=standard,

-   style=,

-   color=,

-   contrastcolor=]

-

-\placebookmarks

-  [chapter,section,subsection]

-

-\setuplist

-  [chapter,section,subsection,subsubsection]

-  [interaction=all,

-   width=3em]

-

-\setuplist

-  [chapter]

-  [style=bold,

-   before={\testpage[4]\blank},

-   color=keptcolor]

-

-\setuplist

-  [section]

-  [before={\testpage[3]}]

-

-\setuplist

-  [subsection,subsubsection]

-  [margin=3em,

-   width=5em]

-

-\definestartstop

-  [notabene]

-  [style=slanted]

-

-\definestartstop

-  [preamble]

-  [style=normal,

-   before=\blank,

-   after=\blank]

-

-% Hans doesn't like the bookmarks opening by default so we comment this:

-%

-% \setupinteractionscreen

-%   [option=bookmark]

-

-\startbuffer[stylecalculations]

-

-    \normalexpanded{\definemeasure[spinewidth] [0pt]}

-    \normalexpanded{\definemeasure[paperwidth] [\the\paperwidth ]}

-    \normalexpanded{\definemeasure[paperheight][\the\paperheight]}

-    \normalexpanded{\definemeasure[spreadwidth][\measure{paperwidth}]}

-

-\stopbuffer

-

-\getbuffer[stylecalculations]

-

-\dontcomplain

-

-\environment luatex-logos

-

-\defineregister[topicindex]

-\defineregister[primitiveindex]

-\defineregister[callbackindex]

-\defineregister[nodeindex]

-\defineregister[libraryindex]

-

-\unexpanded\def\lpr#1{\doifmode{*bodypart}{\primitiveindex[#1]{\bf\tex {#1}}}\tex {#1}}

-\unexpanded\def\prm#1{\doifmode{*bodypart}{\primitiveindex[#1]{\tex    {#1}}}\tex {#1}}

-\unexpanded\def\orm#1{\doifmode{*bodypart}{\primitiveindex[#1]{\tex    {#1}}}\tex {#1}}

-\unexpanded\def\cbk#1{\doifmode{*bodypart}{\callbackindex [#1]{\type   {#1}}}\type{#1}}

-\unexpanded\def\nod#1{\doifmode{*bodypart}{\nodeindex     [#1]{\bf\type{#1}}}\type{#1}}

-\unexpanded\def\whs#1{\doifmode{*bodypart}{\nodeindex     [#1]{\type   {#1}}}\type{#1}}

-\unexpanded\def\noa#1{\doifmode{*bodypart}{\nodeindex     [#1]{\type   {#1}}}\type{#1}}

-

-\hyphenation{sub-nodes}

-

-\def\currentlibraryindex{\namedstructureuservariable{section}{library}}

-

-\setupregister

-  [libraryindex]

-  [indicator=no,before=]

-

-\setupregister

-  [libraryindex]

-  [1]

-  [textstyle=\ttbf]

-

-\setupregister

-  [libraryindex]

-  [2]

-  [textstyle=\tttf]

-

-\unexpanded\def\lib     #1{\doifmode{*bodypart}{\expanded{\libraryindex{\currentlibraryindex+#1}}\type{\currentlibraryindex.#1}}}

-\unexpanded\def\libindex#1{\doifmode{*bodypart}{\expanded{\libraryindex{\currentlibraryindex+#1}}}}

-\unexpanded\def\libidx#1#2{\doifmode{*bodypart}{\expanded{\libraryindex{#1+#2}}\type{#1.#2}}}

-\unexpanded\def\lix   #1#2{\doifmode{*bodypart}{\expanded{\libraryindex{#1+#2}}}}

-

-% \setstructurepageregister[][keys:1=,entries:1=]

-

-\stopenvironment

+\startenvironment luatex-style
+
+% todo: use \useMPlibrary[lua]
+
+\enabletrackers[fonts.usage]
+
+\usemodule[fonts-statistics]
+
+\setuplayout
+  [height=middle,
+   width=middle,
+   backspace=2cm,
+   topspace=10mm,
+   bottomspace=10mm,
+   header=10mm,
+   footer=10mm,
+   footerdistance=10mm,
+   headerdistance=10mm]
+
+\setuppagenumbering
+  [alternative=doublesided]
+
+\setuptolerance
+  [stretch,tolerant]
+
+\setuptype
+  [lines=hyphenated]
+
+\setuptyping
+  [lines=hyphenated]
+
+\setupitemize
+  [each]
+  [packed]
+
+\definesymbol[1][\Uchar"2023]
+\definesymbol[2][\endash]
+\definesymbol[3][\wait]      % we want to catch it
+
+\setupitemize
+  [each]
+  [headcolor=maincolor,
+   symbolcolor=maincolor,
+   color=maincolor]
+
+\setupwhitespace
+  [medium]
+
+\setuptabulate
+  [blank={small,samepage},
+   headstyle=bold,
+   rulecolor=maincolor,
+   rulethickness=1pt,
+   foregroundcolor=white,
+   foregroundstyle=\ss\bfx\WORD,
+   backgroundcolor=maincolor]
+
+\setupcaptions
+  [headcolor=darkblue]
+
+\startluacode
+    local skipped = table.tohash { 'id', 'subtype', 'next', 'prev' }
+
+    function document.functions.showfields(s)
+        local t = string.split(s,',')
+        local f = node.fields(t[1],t[2])
+        if f then
+            local d = false
+            for i=1,#f do
+                local fi = f[i]
+                if skipped[fi] then
+                    -- okay
+                elseif d then
+                    context(', {\tttf %s}', fi)
+                else
+                    context('{\tttf %s}', fi)
+                    d = true
+                end
+            end
+        end
+    end
+
+    function document.functions.showid(s)
+        local t = string.split(s,',')
+        context('{tttf %s}',node.id(t[1]))
+        if t[2] then
+            context(', {tttf %s}',node.subtype(t[2]))
+        end
+    end
+
+    function document.functions.showsubtypes(s)
+        local s = node.subtypes(s)
+        local d = false
+        for k, v in table.sortedhash(s) do
+            if d then
+                context(', %s = {\\tttf %s}',k,v)
+            else
+                context('%s = {\\tttf %s}',k,v)
+                d = true
+            end
+        end
+    end
+\stopluacode
+
+\unexpanded\def\showfields  #1{\ctxlua{document.functions.showfields("#1")}}
+\unexpanded\def\showid      #1{\ctxlua{document.functions.showid("#1")}}
+\unexpanded\def\showsubtypes#1{\ctxlua{document.functions.showsubtypes("#1")}}
+
+\definecolor[blue]      [b=.5]
+\definecolor[red]       [r=.5]
+\definecolor[green]     [g=.5]
+\definecolor[maincolor] [b=.5]
+\definecolor[keptcolor] [b=.5]
+\definecolor[othercolor][r=.5,g=.5]
+
+\writestatus{luatex manual}{}
+\writestatus{luatex manual}{defining lucodaot} \usebodyfont  [lucidaot]
+\writestatus{luatex manual}{defining pagella}  \usebodyfont  [pagella]
+\writestatus{luatex manual}{defining cambria}  \usebodyfont  [cambria]
+\writestatus{luatex manual}{defining modern}   \usebodyfont  [modern]
+\writestatus{luatex manual}{defining dejavu}   \setupbodyfont[dejavu,10pt]
+\writestatus{luatex manual}{}
+
+\setuphead [chapter]      [align={flushleft,broad},style=\bfd]
+\setuphead [section]      [align={flushleft,broad},style=\bfb]
+\setuphead [subsection]   [align={flushleft,broad},style=\bfa]
+\setuphead [subsubsection][align={flushleft,broad},style=\bf]
+
+\setuphead [chapter]      [color=maincolor]
+\setuphead [section]      [color=maincolor]
+\setuphead [subsection]   [color=maincolor]
+\setuphead [subsubsection][color=maincolor]
+
+\setupfloats
+  [ntop=4]
+
+\definehead
+  [remark]
+  [subsubsubject]
+
+\setupheadertexts
+  []
+
+% \setuplayout
+%   [style=bold,
+%    color=maincolor]
+
+\definemixedcolumns
+  [twocolumns]
+  [n=2,
+   balance=yes,
+   before=\blank,
+   after=\blank]
+
+\definemixedcolumns
+  [threecolumns]
+  [twocolumns]
+  [n=3]
+
+\definemixedcolumns
+  [fourcolumns]
+  [threecolumns]
+  [n=4]
+
+% if we do this we also need to do it in table cells
+%
+% \setuptyping
+%   [color=maincolor]
+%
+% \setuptype
+%   [color=maincolor]
+
+\definetyping
+  [functioncall]
+
+\startMPdefinitions
+
+    color   luaplanetcolor ; luaplanetcolor := \MPcolor{maincolor} ;
+    color   luaholecolor   ; luaholecolor   := white ;
+    numeric luaextraangle  ; luaextraangle  := 0 ;
+    numeric luaorbitfactor ; luaorbitfactor := .25 ;
+
+    vardef lualogo = image (
+
+        % Graphic design by A. Nakonechnyj. Copyright (c) 1998, All rights reserved.
+
+        save d, r, p ; numeric d, r, p ;
+
+        d := sqrt(2)/4 ; r := 1/4 ; p := r/8 ;
+
+        fill fullcircle scaled 1
+            withcolor luaplanetcolor ;
+        draw fullcircle rotated 40.5 scaled (1+r)
+            dashed evenly scaled p
+            withpen pencircle scaled (p/2)
+            withcolor (luaorbitfactor * luaholecolor) ;
+        fill fullcircle scaled r shifted (d+1/8,d+1/8)
+            rotated - luaextraangle
+            withcolor luaplanetcolor ;
+        fill fullcircle scaled r shifted (d-1/8,d-1/8)
+            withcolor luaholecolor   ;
+        luaorbitfactor := .25 ;
+    ) enddef ;
+
+\stopMPdefinitions
+
+\startuseMPgraphic{luapage}
+    StartPage ;
+
+        fill Page withcolor \MPcolor{othercolor} ;
+
+        luaorbitfactor := 1 ;
+
+        picture p ; p := lualogo ysized (5*\measure{paperheight}/10) ;
+        draw p
+            shifted - center p
+            shifted (
+                \measure{spreadwidth} - .5*\measure{paperwidth} + \measure{spinewidth},
+                .375*\measure{paperheight}
+            )
+        ;
+
+    StopPage ;
+\stopuseMPgraphic
+
+% \starttexdefinition luaextraangle
+%     % we can also just access the last page and so in mp directly
+%     \ctxlua {
+%         context(\lastpage == 0 and 0 or \realfolio*360/\lastpage)
+%     }
+% \stoptexdefinition
+
+\startuseMPgraphic{luanumber}
+  % luaextraangle  := \luaextraangle;
+    luaextraangle  := if (LastPageNumber < 10) : 10 else : (RealPageNumber / LastPageNumber) * 360  fi;
+    luaorbitfactor := 0.25 ;
+    picture p ; p := lualogo ;
+    setbounds p to boundingbox fullcircle ;
+    draw p ysized 1cm ;
+\stopuseMPgraphic
+
+\definelayer
+  [page]
+  [width=\paperwidth,
+   height=\paperheight]
+
+\setupbackgrounds
+  [leftpage]
+  [background=page]
+
+\setupbackgrounds
+  [rightpage]
+  [background=page]
+
+\definemeasure[banneroffset][\bottomspace-\footerheight-\footerdistance+2cm]
+
+\startsetups pagenumber:right
+  \setlayerframed
+    [page]
+    [preset=rightbottom,x=1.0cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,offset=overlay]
+    {\strut\useMPgraphic{luanumber}}
+  \setlayerframed
+    [page]
+    [preset=rightbottom,x=2.5cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,width=1cm,offset=overlay,
+     foregroundstyle=bold,foregroundcolor=maincolor]
+    {\strut\pagenumber}
+  \setlayerframed
+    [page]
+    [preset=rightbottom,x=3.5cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,offset=overlay,
+     foregroundstyle=bold,foregroundcolor=maincolor]
+    {\strut\getmarking[chapter]}
+\stopsetups
+
+\startsetups pagenumber:left
+  \setlayerframed
+    [page]
+    [preset=leftbottom,x=3.5cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,offset=overlay,
+     foregroundstyle=bold,foregroundcolor=maincolor]
+    {\strut\getmarking[chapter]}
+  \setlayerframed
+    [page]
+    [preset=leftbottom,x=2.5cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,width=1cm,offset=overlay,
+     foregroundstyle=bold,foregroundcolor=maincolor]
+    {\strut\pagenumber}
+  \setlayerframed
+    [page]
+    [preset=leftbottom,x=1.0cm,y=\measure{banneroffset}]
+    [frame=off,height=1cm,offset=overlay]
+    {\strut\useMPgraphic{luanumber}}
+\stopsetups
+
+\unexpanded\def\nonterminal#1>{\mathematics{\langle\hbox{\rm #1}\rangle}}
+
+% taco's brainwave -) .. todo: create a typing variant so that we can avoid the !crlf
+
+\newcatcodetable\syntaxcodetable
+
+\unexpanded\def\makesyntaxcodetable
+  {\begingroup
+   \catcode`\<=13 \catcode`\|=12
+   \catcode`\!= 0 \catcode`\\=12
+   \savecatcodetable\syntaxcodetable
+   \endgroup}
+
+\makesyntaxcodetable
+
+\unexpanded\def\startsyntax {\begingroup\catcodetable\syntaxcodetable  \dostartsyntax}
+\unexpanded\def\syntax      {\begingroup\catcodetable\syntaxcodetable  \dosyntax}
+           \let\stopsyntax   \relax
+
+\unexpanded\def\syntaxenvbody#1%
+  {\par
+   \tt
+   \startnarrower
+ % \maincolor
+   #1
+   \stopnarrower
+   \par}
+
+\unexpanded\def\syntaxbody#1%
+  {\begingroup
+ % \maincolor
+   \tt #1%
+   \endgroup}
+
+\bgroup \catcodetable\syntaxcodetable
+
+!gdef!dostartsyntax#1\stopsyntax{!let<!nonterminal!syntaxenvbody{#1}!endgroup}
+!gdef!dosyntax     #1{!let<!nonterminal!syntaxbody{#1}!endgroup}
+
+!egroup
+
+\definetyping
+  [texsyntax]
+% [color=maincolor]
+
+% end of wave
+
+\setupinteraction
+  [state=start,
+   focus=standard,
+   style=,
+   color=,
+   contrastcolor=]
+
+\placebookmarks
+  [chapter,section,subsection]
+
+\setuplist
+  [chapter,section,subsection,subsubsection]
+  [interaction=all,
+   width=3em]
+
+\setuplist
+  [chapter]
+  [style=bold,
+   before={\testpage[4]\blank},
+   color=keptcolor]
+
+\setuplist
+  [section]
+  [before={\testpage[3]}]
+
+\setuplist
+  [subsection,subsubsection]
+  [margin=3em,
+   width=5em]
+
+\definestartstop
+  [notabene]
+  [style=slanted]
+
+\definestartstop
+  [preamble]
+  [style=normal,
+   before=\blank,
+   after=\blank]
+
+% Hans doesn't like the bookmarks opening by default so we comment this:
+%
+% \setupinteractionscreen
+%   [option=bookmark]
+
+\startbuffer[stylecalculations]
+
+    \normalexpanded{\definemeasure[spinewidth] [0pt]}
+    \normalexpanded{\definemeasure[paperwidth] [\the\paperwidth ]}
+    \normalexpanded{\definemeasure[paperheight][\the\paperheight]}
+    \normalexpanded{\definemeasure[spreadwidth][\measure{paperwidth}]}
+
+\stopbuffer
+
+\getbuffer[stylecalculations]
+
+\dontcomplain
+
+\environment luatex-logos
+
+\defineregister[topicindex]
+\defineregister[primitiveindex]
+\defineregister[callbackindex]
+\defineregister[nodeindex]
+\defineregister[libraryindex]
+
+\unexpanded\def\lpr#1{\doifmode{*bodypart}{\primitiveindex[#1]{\bf\tex {#1}}}\tex {#1}}
+\unexpanded\def\prm#1{\doifmode{*bodypart}{\primitiveindex[#1]{\tex    {#1}}}\tex {#1}}
+\unexpanded\def\orm#1{\doifmode{*bodypart}{\primitiveindex[#1]{\tex    {#1}}}\tex {#1}}
+\unexpanded\def\cbk#1{\doifmode{*bodypart}{\callbackindex [#1]{\type   {#1}}}\type{#1}}
+\unexpanded\def\nod#1{\doifmode{*bodypart}{\nodeindex     [#1]{\bf\type{#1}}}\type{#1}}
+\unexpanded\def\whs#1{\doifmode{*bodypart}{\nodeindex     [#1]{\type   {#1}}}\type{#1}}
+\unexpanded\def\noa#1{\doifmode{*bodypart}{\nodeindex     [#1]{\type   {#1}}}\type{#1}}
+
+\hyphenation{sub-nodes}
+
+\def\currentlibraryindex{\namedstructureuservariable{section}{library}}
+
+\setupregister
+  [libraryindex]
+  [indicator=no,before=]
+
+\setupregister
+  [libraryindex]
+  [1]
+  [textstyle=\ttbf]
+
+\setupregister
+  [libraryindex]
+  [2]
+  [textstyle=\tttf]
+
+\unexpanded\def\lib     #1{\doifmode{*bodypart}{\expanded{\libraryindex{\currentlibraryindex+#1}}\type{\currentlibraryindex.#1}}}
+\unexpanded\def\libindex#1{\doifmode{*bodypart}{\expanded{\libraryindex{\currentlibraryindex+#1}}}}
+\unexpanded\def\libidx#1#2{\doifmode{*bodypart}{\expanded{\libraryindex{#1+#2}}\type{#1.#2}}}
+\unexpanded\def\lix   #1#2{\doifmode{*bodypart}{\expanded{\libraryindex{#1+#2}}}}
+
+% \setstructurepageregister[][keys:1=,entries:1=]
+
+\stopenvironment
diff --git a/systems/doc/luatex/luatex-tex.tex b/systems/doc/luatex/luatex-tex.tex
index 48bdeef119..65b9458619 100644
--- a/systems/doc/luatex/luatex-tex.tex
+++ b/systems/doc/luatex/luatex-tex.tex
@@ -1,2774 +1,2775 @@
-% language=uk

-

-% lua.newtable

-

-\environment luatex-style

-

-\startcomponent luatex-tex

-

-\startchapter[reference=tex,title={The \TEX\ related libraries}]

-

-\startsection[title={The \type {lua} library}][library=lua]

-

-\startsubsection[title={Version information}]

-

-\topicindex{libraries+\type{lua}}

-\topicindex{version}

-

-\libindex{version}

-

-This library contains one read|-|only item:

-

-\starttyping

-<string> s = lua.version

-\stoptyping

-

-This returns the \LUA\ version identifier string. The value is currently

-\directlua {tex.print(lua.version)}.

-

-\stopsubsection

-

-\startsubsection[title={Bytecode registers}]

-

-\topicindex{bytecodes}

-\topicindex{registers+bytecodes}

-

-\libindex{bytecode}

-\libindex{setbytecode}

-\libindex{getbytecode}

-

-\LUA\ registers can be used to store \LUA\ code chunks. The accepted values for

-assignments are functions and \type {nil}. Likewise, the retrieved value is

-either a function or \type {nil}.

-

-\starttyping

-lua.bytecode[<number> n] = <function> f

-lua.bytecode[<number> n]()

-\stoptyping

-

-The contents of the \type {lua.bytecode} array is stored inside the format file

-as actual \LUA\ bytecode, so it can also be used to preload \LUA\ code. The

-function must not contain any upvalues. The associated function calls are:

-

-\startfunctioncall

-<function> f = lua.getbytecode(<number> n)

-lua.setbytecode(<number> n, <function> f)

-\stopfunctioncall

-

-Note: Since a \LUA\ file loaded using \type {loadfile(filename)} is essentially

-an anonymous function, a complete file can be stored in a bytecode register like

-this:

-

-\startfunctioncall

-lua.bytecode[n] = loadfile(filename)

-\stopfunctioncall

-

-Now all definitions (functions, variables) contained in the file can be

-created by executing this bytecode register:

-

-\startfunctioncall

-lua.bytecode[n]()

-\stopfunctioncall

-

-Note that the path of the file is stored in the \LUA\ bytecode to be used in

-stack backtraces and therefore dumped into the format file if the above code is

-used in \INITEX. If it contains private information, i.e. the user name, this

-information is then contained in the format file as well. This should be kept in

-mind when preloading files into a bytecode register in \INITEX.

-

-\stopsubsection

-

-\startsubsection[title={Chunk name registers}]

-

-\libindex{name}

-\libindex{setluaname}

-\libindex{getluaname}

-

-There is an array of 65536 (0--65535) potential chunk names for use with the

-\prm {directlua} and \lpr {latelua} primitives.

-

-\startfunctioncall

-lua.name[<number> n] = <string> s

-<string> s = lua.name[<number> n]

-\stopfunctioncall

-

-If you want to unset a \LUA\ name, you can assign \type {nil} to it. The function

-accessors are:

-

-\startfunctioncall

-lua.setluaname(<string> s,<number> n])

-<string> s = lua.getluaname(<number> n)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={Introspection}]

-

-\libindex{getstacktop}

-\libindex{getcalllevel}

-

-The \type {getstacktop} and\type {getcalllevel} functions return numbers

-indicating how much nesting is going on. They are only of use as breakpoints when

-checking some mechanism going haywire.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={The \type {status} library}][library=status]

-

-\topicindex{libraries+\type{status}}

-

-\libindex{list}

-\libindex{resetmessages}

-\libindex{setexitcode}

-

-This contains a number of run|-|time configuration items that you may find useful

-in message reporting, as well as an iterator function that gets all of the names

-and values as a table.

-

-\startfunctioncall

-<table> info = status.list()

-\stopfunctioncall

-

-The keys in the table are the known items, the value is the current value. Almost

-all of the values in \type {status} are fetched through a metatable at run|-|time

-whenever they are accessed, so you cannot use \type {pairs} on \type {status},

-but you {\it can\/} use \type {pairs} on \type {info}, of course. If you do not

-need the full list, you can also ask for a single item by using its name as an

-index into \type {status}. The current list is:

-

-\starttabulate[|l|p|]

-\DB key                       \BC explanation \NC \NR

-\TB

-\NC \type{banner}             \NC terminal display banner \NC \NR

-\NC \type{best_page_break}    \NC the current best break (a node) \NC \NR

-\NC \type{buf_size}           \NC current allocated size of the line buffer \NC \NR

-\NC \type{callbacks}          \NC total number of executed callbacks so far \NC \NR

-\NC \type{cs_count}           \NC number of control sequences \NC \NR

-\NC \type{dest_names_size}    \NC \PDF\ destination table size \NC \NR

-\NC \type{dvi_gone}           \NC written \DVI\ bytes \NC \NR

-\NC \type{dvi_ptr}            \NC not yet written \DVI\ bytes \NC \NR

-\NC \type{dyn_used}           \NC token (multi|-|word) memory in use  \NC \NR

-\NC \type{filename}           \NC name of the current input file \NC \NR

-\NC \type{fix_mem_end}        \NC maximum number of used tokens \NC \NR

-\NC \type{fix_mem_min}        \NC minimum number of allocated words for tokens \NC \NR

-\NC \type{fix_mem_max}        \NC maximum number of allocated words for tokens \NC \NR

-\NC \type{font_ptr}           \NC number of active fonts \NC \NR

-\NC \type{hash_extra}         \NC extra allowed hash \NC \NR

-\NC \type{hash_size}          \NC size of hash \NC \NR

-\NC \type{indirect_callbacks} \NC number of those that were themselves a result of other callbacks (e.g. file readers) \NC \NR

-\NC \type{ini_version}        \NC \type {true} if this is an \INITEX\ run \NC \NR

-\NC \type{init_pool_ptr}      \NC \INITEX\ string pool index \NC \NR

-\NC \type{init_str_ptr}       \NC number of \INITEX\ strings \NC \NR

-\NC \type{input_ptr}          \NC the level of input we're at \NC \NR

-\NC \type{inputid}            \NC numeric id of the current input \NC \NR

-\NC \type{largest_used_mark}  \NC max referenced marks class \NC \NR

-\NC \type{lasterrorcontext}   \NC last error context string (with newlines) \NC \NR

-\NC \type{lasterrorstring}    \NC last \TEX\ error string \NC \NR

-\NC \type{lastluaerrorstring} \NC last \LUA\ error string \NC \NR

-\NC \type{lastwarningstring}  \NC last warning tag, normally an indication of in what part\NC \NR

-\NC \type{lastwarningtag}     \NC last warning string\NC \NR

-\NC \type{linenumber}         \NC location in the current input file \NC \NR

-\NC \type{log_name}           \NC name of the log file \NC \NR

-\NC \type{luabytecode_bytes}  \NC number of bytes in \LUA\ bytecode registers \NC \NR

-\NC \type{luabytecodes}       \NC number of active \LUA\ bytecode registers \NC \NR

-\NC \type{luastate_bytes}     \NC number of bytes in use by \LUA\ interpreters \NC \NR

-\NC \type{luatex_engine}      \NC the \LUATEX\ engine identifier \NC \NR

-\NC \type{luatex_hashchars}   \NC length to which \LUA\ hashes strings ($2^n$) \NC \NR

-\NC \type{luatex_hashtype}    \NC the hash method used (in \LUAJITTEX) \NC \NR

-\NC \type{luatex_version}     \NC the \LUATEX\ version number \NC \NR

-\NC \type{luatex_revision}    \NC the \LUATEX\ revision string \NC \NR

-\NC \type{max_buf_stack}      \NC max used buffer position \NC \NR

-\NC \type{max_in_stack}       \NC max used input stack entries \NC \NR

-\NC \type{max_nest_stack}     \NC max used nesting stack entries \NC \NR

-\NC \type{max_param_stack}    \NC max used parameter stack entries \NC \NR

-\NC \type{max_save_stack}     \NC max used save stack entries \NC \NR

-\NC \type{max_strings}        \NC maximum allowed strings \NC \NR

-\NC \type{nest_size}          \NC nesting stack size \NC \NR

-\NC \type{node_mem_usage}     \NC a string giving insight into currently used nodes \NC \NR

-\NC \type{obj_ptr}            \NC max \PDF\ object pointer \NC \NR

-\NC \type{obj_tab_size}       \NC \PDF\ object table size \NC \NR

-\NC \type{output_active}      \NC \type {true} if the \prm {output} routine is active \NC \NR

-\NC \type{output_file_name}   \NC name of the \PDF\ or \DVI\ file \NC \NR

-\NC \type{param_size}         \NC parameter stack size \NC \NR

-\NC \type{pdf_dest_names_ptr} \NC max \PDF\ destination pointer \NC \NR

-\NC \type{pdf_gone}           \NC written \PDF\ bytes \NC \NR

-\NC \type{pdf_mem_ptr}        \NC max \PDF\ memory used \NC \NR

-\NC \type{pdf_mem_size}       \NC \PDF\ memory size \NC \NR

-\NC \type{pdf_os_cntr}        \NC max \PDF\ object stream pointer \NC \NR

-\NC \type{pdf_os_objidx}      \NC \PDF\ object stream index \NC \NR

-\NC \type{pdf_ptr}            \NC not yet written \PDF\ bytes \NC \NR

-\NC \type{pool_ptr}           \NC string pool index \NC \NR

-\NC \type{pool_size}          \NC current size allocated for string characters \NC \NR

-\NC \type{save_size}          \NC save stack size \NC \NR

-\NC \type{shell_escape}       \NC \type {0} means disabled, \type {1} means anything is permitted, and \type {2} is restricted \NC \NR

-\NC \type{safer_option}       \NC \type {1} means safer is enforced \NC \NR

-\NC \type{kpse_used}          \NC \type {1} means that kpse is used \NC \NR

-\NC \type{stack_size}         \NC input stack size \NC \NR

-\NC \type{str_ptr}            \NC number of strings \NC \NR

-\NC \type{total_pages}        \NC number of written pages \NC \NR

-\NC \type{var_mem_max}        \NC number of allocated words for nodes \NC \NR

-\NC \type{var_used}           \NC variable (one|-|word) memory in use \NC \NR

-\NC \type{lc_collate}         \NC the value of \type {LC_COLLATE}  at startup time (becomes \type {C} at startup) \NC \NR

-\NC \type{lc_ctype}           \NC the value of \type {LC_CTYPE}    at startup time (becomes \type {C} at startup) \NC \NR

-%NC \type{lc_monetary}        \NC the value of \type {LC_MONETARY} at startup time \NC \NR

-\NC \type{lc_numeric}         \NC the value of \type {LC_NUMERIC}  at startup time \NC \NR

-%NC \type{lc_time}            \NC the value of \type {LC_TIME}     at startup time (becomes \type {C} at startup) \NC \NR

-\LL

-\stoptabulate

-

-The error and warning messages can be wiped with the \type {resetmessages}

-function. A return value can be set with \type {setexitcode}.

-

-\stopsection

-

-\startsection[title={The \type {tex} library}][library=tex]

-

-\startsubsection[title={Introduction}]

-

-\topicindex{libraries+\type{tex}}

-

-The \type {tex} table contains a large list of virtual internal \TEX\

-parameters that are partially writable.

-

-The designation \quote {virtual} means that these items are not properly defined

-in \LUA, but are only front\-ends that are handled by a metatable that operates

-on the actual \TEX\ values. As a result, most of the \LUA\ table operators (like

-\type {pairs} and \type {#}) do not work on such items.

-

-At the moment, it is possible to access almost every parameter that you can use

-after \prm {the}, is a single tokens or is sort of special in \TEX. This excludes

-parameters that need extra arguments, like \type {\the\scriptfont}. The subset

-comprising simple integer and dimension registers are writable as well as

-readable (like \prm {tracingcommands} and \prm {parindent}).

-

-\stopsubsection

-

-\startsubsection[title={Internal parameter values, \type {set} and \type {get}}]

-

-\topicindex{parameters+internal}

-

-\libindex{set}           \libindex{get}

-

-For all the parameters in this section, it is possible to access them directly

-using their names as index in the \type {tex} table, or by using one of the

-functions \type {tex.get} and \type {tex.set}.

-

-The exact parameters and return values differ depending on the actual parameter,

-and so does whether \type {tex.set} has any effect. For the parameters that {\em

-can} be set, it is possible to use \type {global} as the first argument to \type

-{tex.set}; this makes the assignment global instead of local.

-

-\startfunctioncall

-tex.set (["global",] <string> n, ...)

-... = tex.get (<string> n)

-\stopfunctioncall

-

-Glue is kind of special because there are five values involved. The return value

-is a \nod {glue_spec} node but when you pass \type {false} as last argument to

-\type {tex.get} you get the width of the glue and when you pass \type {true} you

-get all five values. Otherwise you get a node which is a copy of the internal

-value so you are responsible for its freeing at the \LUA\ end. When you set a

-glue quantity you can either pass a \nod {glue_spec} or upto five numbers. If

-you pass \type {true} to \type {get} you get 5 values returned for a glue and

-when you pass \type {false} you only get the width returned.

-

-\subsubsection{Integer parameters}

-

-The integer parameters accept and return \LUA\ numbers. These are read|-|write:

-

-\starttwocolumns

-\starttyping

-tex.adjdemerits

-tex.binoppenalty

-tex.brokenpenalty

-tex.catcodetable

-tex.clubpenalty

-tex.day

-tex.defaulthyphenchar

-tex.defaultskewchar

-tex.delimiterfactor

-tex.displaywidowpenalty

-tex.doublehyphendemerits

-tex.endlinechar

-tex.errorcontextlines

-tex.escapechar

-tex.exhyphenpenalty

-tex.fam

-tex.finalhyphendemerits

-tex.floatingpenalty

-tex.globaldefs

-tex.hangafter

-tex.hbadness

-tex.holdinginserts

-tex.hyphenpenalty

-tex.interlinepenalty

-tex.language

-tex.lastlinefit

-tex.lefthyphenmin

-tex.linepenalty

-tex.localbrokenpenalty

-tex.localinterlinepenalty

-tex.looseness

-tex.mag

-tex.maxdeadcycles

-tex.month

-tex.newlinechar

-tex.outputpenalty

-tex.pausing

-tex.postdisplaypenalty

-tex.predisplaydirection

-tex.predisplaypenalty

-tex.pretolerance

-tex.relpenalty

-tex.righthyphenmin

-tex.savinghyphcodes

-tex.savingvdiscards

-tex.showboxbreadth

-tex.showboxdepth

-tex.time

-tex.tolerance

-tex.tracingassigns

-tex.tracingcommands

-tex.tracinggroups

-tex.tracingifs

-tex.tracinglostchars

-tex.tracingmacros

-tex.tracingnesting

-tex.tracingonline

-tex.tracingoutput

-tex.tracingpages

-tex.tracingparagraphs

-tex.tracingrestores

-tex.tracingscantokens

-tex.tracingstats

-tex.uchyph

-tex.vbadness

-tex.widowpenalty

-tex.year

-\stoptyping

-\stoptwocolumns

-

-These are read|-|only:

-

-\startthreecolumns

-\starttyping

-tex.deadcycles

-tex.insertpenalties

-tex.parshape

-tex.prevgraf

-tex.spacefactor

-\stoptyping

-\stopthreecolumns

-

-\subsubsection{Dimension parameters}

-

-The dimension parameters accept \LUA\ numbers (signifying scaled points) or

-strings (with included dimension). The result is always a number in scaled

-points. These are read|-|write:

-

-\startthreecolumns

-\starttyping

-tex.boxmaxdepth

-tex.delimitershortfall

-tex.displayindent

-tex.displaywidth

-tex.emergencystretch

-tex.hangindent

-tex.hfuzz

-tex.hoffset

-tex.hsize

-tex.lineskiplimit

-tex.mathsurround

-tex.maxdepth

-tex.nulldelimiterspace

-tex.overfullrule

-tex.pagebottomoffset

-tex.pageheight

-tex.pageleftoffset

-tex.pagerightoffset

-tex.pagetopoffset

-tex.pagewidth

-tex.parindent

-tex.predisplaysize

-tex.scriptspace

-tex.splitmaxdepth

-tex.vfuzz

-tex.voffset

-tex.vsize

-tex.prevdepth

-tex.prevgraf

-tex.spacefactor

-\stoptyping

-\stopthreecolumns

-

-These are read|-|only:

-

-\startthreecolumns

-\starttyping

-tex.pagedepth

-tex.pagefilllstretch

-tex.pagefillstretch

-tex.pagefilstretch

-tex.pagegoal

-tex.pageshrink

-tex.pagestretch

-tex.pagetotal

-\stoptyping

-\stopthreecolumns

-

-Beware: as with all \LUA\ tables you can add values to them. So, the following is

-valid:

-

-\starttyping

-tex.foo = 123

-\stoptyping

-

-When you access a \TEX\ parameter a look up takes place. For read||only variables

-that means that you will get something back, but when you set them you create a

-new entry in the table thereby making the original invisible.

-

-There are a few special cases that we make an exception for: \type {prevdepth},

-\type {prevgraf} and \type {spacefactor}. These normally are accessed via the

-\type {tex.nest} table:

-

-\starttyping

-tex.nest[tex.nest.ptr].prevdepth   = p

-tex.nest[tex.nest.ptr].spacefactor = s

-\stoptyping

-

-However, the following also works:

-

-\starttyping

-tex.prevdepth   = p

-tex.spacefactor = s

-\stoptyping

-

-Keep in mind that when you mess with node lists directly at the \LUA\ end you

-might need to update the top of the nesting stack's \type {prevdepth} explicitly

-as there is no way \LUATEX\ can guess your intentions. By using the accessor in

-the \type {tex} tables, you get and set the values at the top of the nesting

-stack.

-

-\subsubsection{Direction parameters}

-

-The direction parameters are read|-|only and return a \LUA\ string.

-

-\startthreecolumns

-\starttyping

-tex.bodydir

-tex.mathdir

-tex.pagedir

-tex.pardir

-tex.textdir

-\stoptyping

-\stopthreecolumns

-

-\subsubsection{Glue parameters}

-

-The glue parameters accept and return a userdata object that represents a \nod {glue_spec} node.

-

-\startthreecolumns

-\starttyping

-tex.abovedisplayshortskip

-tex.abovedisplayskip

-tex.baselineskip

-tex.belowdisplayshortskip

-tex.belowdisplayskip

-tex.leftskip

-tex.lineskip

-tex.parfillskip

-tex.parskip

-tex.rightskip

-tex.spaceskip

-tex.splittopskip

-tex.tabskip

-tex.topskip

-tex.xspaceskip

-\stoptyping

-\stopthreecolumns

-

-\subsubsection{Muglue parameters}

-

-All muglue parameters are to be used read|-|only and return a \LUA\ string.

-

-\startthreecolumns

-\starttyping

-tex.medmuskip

-tex.thickmuskip

-tex.thinmuskip

-\stoptyping

-\stopthreecolumns

-

-\subsubsection{Tokenlist parameters}

-

-The tokenlist parameters accept and return \LUA\ strings. \LUA\ strings are

-converted to and from token lists using \prm {the} \prm {toks} style expansion:

-all category codes are either space (10) or other (12). It follows that assigning

-to some of these, like \quote {tex.output}, is actually useless, but it feels bad

-to make exceptions in view of a coming extension that will accept full|-|blown

-token strings.

-

-\startthreecolumns

-\starttyping

-tex.errhelp

-tex.everycr

-tex.everydisplay

-tex.everyeof

-tex.everyhbox

-tex.everyjob

-tex.everymath

-tex.everypar

-tex.everyvbox

-tex.output

-\stoptyping

-\stopthreecolumns

-

-\stopsubsection

-

-\startsubsection[title={Convert commands}]

-

-\topicindex{convert commands}

-

-All \quote {convert} commands are read|-|only and return a \LUA\ string. The

-supported commands at this moment are:

-

-\starttwocolumns

-\starttyping

-tex.eTeXVersion

-tex.eTeXrevision

-tex.formatname

-tex.jobname

-tex.luatexbanner

-tex.luatexrevision

-tex.fontname(number)

-tex.uniformdeviate(number)

-tex.number(number)

-tex.romannumeral(number)

-tex.fontidentifier(number)

-\stoptyping

-\stoptwocolumns

-

-If you are wondering why this list looks haphazard; these are all the cases of

-the \quote {convert} internal command that do not require an argument, as well as

-the ones that require only a simple numeric value. The special (\LUA|-|only) case

-of \type {tex.fontidentifier} returns the \type {csname} string that matches a

-font id number (if there is one).

-

-\stopsubsection

-

-\startsubsection[title={Last item commands}]

-

-\topicindex{last items}

-

-All \quote {last item} commands are read|-|only and return a number. The

-supported commands at this moment are:

-

-\startthreecolumns

-\starttyping

-tex.lastpenalty

-tex.lastkern

-tex.lastskip

-tex.lastnodetype

-tex.inputlineno

-tex.lastxpos

-tex.lastypos

-tex.randomseed

-tex.luatexversion

-tex.eTeXminorversion

-tex.eTeXversion

-tex.currentgrouplevel

-tex.currentgrouptype

-tex.currentiflevel

-tex.currentiftype

-tex.currentifbranch

-\stoptyping

-\stopthreecolumns

-

-\stopsubsection

-

-\startsubsection[title={Accessing registers: \type {set*}, \type {get*} and \type {is*}}]

-

-\topicindex{attributes}

-\topicindex{registers}

-

-\libindex{attribute}  \libindex{setattribute}  \libindex{getattribute}  \libindex{isattribute}

-\libindex{count}      \libindex{setcount}      \libindex{getcount}      \libindex{iscount}

-\libindex{dimen}      \libindex{setdimen}      \libindex{getdimen}      \libindex{isdimen}

-\libindex{skip}       \libindex{setskip}       \libindex{getskip}       \libindex{isskip}

-\libindex{muskip}     \libindex{setmuskip}     \libindex{getmuskip}     \libindex{ismuskip}

-\libindex{glue}       \libindex{setglue}       \libindex{getglue}       \libindex{isglue}

-\libindex{muglue}     \libindex{setmuglue}     \libindex{getmuglue}     \libindex{ismuglue}

-\libindex{toks}       \libindex{settoks}       \libindex{gettoks}       \libindex{istoks}

-\libindex{box}        \libindex{setbox}        \libindex{getbox}        \libindex{isbox}

-

-\libindex{scantoks}

-

-\TEX's attributes (\lpr {attribute}), counters (\prm {count}), dimensions (\prm

-{dimen}), skips (\prm {skip}, \prm {muskip}) and token (\prm {toks}) registers

-can be accessed and written to using two times five virtual sub|-|tables of the

-\type {tex} table:

-

-\startthreecolumns

-\starttyping

-tex.attribute

-tex.count

-tex.dimen

-tex.skip

-tex.glue

-tex.muskip

-tex.muglue

-tex.toks

-\stoptyping

-\stopthreecolumns

-

-It is possible to use the names of relevant \lpr {attributedef}, \prm {countdef},

-\prm {dimendef}, \prm {skipdef}, or \prm {toksdef} control sequences as indices

-to these tables:

-

-\starttyping

-tex.count.scratchcounter = 0

-enormous = tex.dimen['maxdimen']

-\stoptyping

-

-In this case, \LUATEX\ looks up the value for you on the fly. You have to use a

-valid \prm {countdef} (or \lpr {attributedef}, or \prm {dimendef}, or \prm

-{skipdef}, or \prm {toksdef}), anything else will generate an error (the intent

-is to eventually also allow \type {<chardef tokens>} and even macros that expand

-into a number).

-

-\startitemize

-

-    \startitem

-        The count registers accept and return \LUA\ numbers.

-    \stopitem

-

-    \startitem

-        The dimension registers accept \LUA\ numbers (in scaled points) or

-        strings (with an included absolute dimension; \type {em} and \type {ex}

-        and \type {px} are forbidden). The result is always a number in scaled

-        points.

-    \stopitem

-

-    \startitem

-        The token registers accept and return \LUA\ strings. \LUA\ strings are

-        converted to and from token lists using \prm {the} \prm {toks} style

-        expansion: all category codes are either space (10) or other (12).

-    \stopitem

-

-    \startitem

-        The skip registers accept and return \nod {glue_spec} userdata node

-        objects (see the description of the node interface elsewhere in this

-        manual).

-    \stopitem

-

-    \startitem

-        The glue registers are just skip registers but instead of userdata

-        are verbose.

-    \stopitem

-

-    \startitem

-        Like the counts, the attribute registers accept and return \LUA\ numbers.

-    \stopitem

-

-\stopitemize

-

-As an alternative to array addressing, there are also accessor functions defined

-for all cases, for example, here is the set of possibilities for \prm {skip}

-registers:

-

-\startfunctioncall

-tex.setskip (["global",] <number> n, <node> s)

-tex.setskip (["global",] <string> s, <node> s)

-<node> s = tex.getskip (<number> n)

-<node> s = tex.getskip (<string> s)

-\stopfunctioncall

-

-We have similar setters for \type {count}, \type {dimen}, \type {muskip}, and

-\type {toks}. Counters and dimen are represented by numbers, skips and muskips by

-nodes, and toks by strings.

-

-Again the glue variants are not using the \nod {glue-spec} userdata nodes. The

-\type {setglue} function accepts upto 5 arguments: width, stretch, shrink,

-stretch order and shrink order and the \type {getglue} function reports them,

-unless the second argument is \type {false} in which care only the width is

-returned.

-

-Here is an example usign a threesome:

-

-\startfunctioncall

-local d = tex.getdimen("foo")

-if tex.isdimen("bar") then

-    tex.setdimen("bar",d)

-end

-\stopfunctioncall

-

-There are six extra skip (glue) related helpers:

-

-\startfunctioncall

-tex.setglue (["global"], <number> n,

-    width, stretch, shrink, stretch_order, shrink_order)

-tex.setglue (["global"], <string> s,

-    width, stretch, shrink, stretch_order, shrink_order)

-width, stretch, shrink, stretch_order, shrink_order =

-    tex.getglue (<number> n)

-width, stretch, shrink, stretch_order, shrink_order =

-    tex.getglue (<string> s)

-\stopfunctioncall

-

-The other two are \type {tex.setmuglue} and \type {tex.getmuglue}.

-

-There are such helpers for \type {dimen}, \type {count}, \type {skip}, \type

-{muskip}, \type {box} and \type {attribute} registers but the glue ones

-are special because they have to deal with more properties.

-

-As with the general \type {get} and \type {set} function discussed before, for

-the skip registers \type {getskip} returns a node and \type {getglue} returns

-numbers, while \type {setskip} accepts a node and \type {setglue} expects upto 5

-numbers. Again, when you pass \type {false} as second argument to \type {getglue}

-you only get the width returned. The same is true for the \type {mu} variants

-\type {getmuskip}, \type {setmuskip}, \type {getmuskip} and\type {setmuskip}.

-

-For tokens registers we have an alternative where a catcode table is specified:

-

-\startfunctioncall

-tex.scantoks(0,3,"$e=mc^2$")

-tex.scantoks("global",0,"$\int\limits^1_2$")

-\stopfunctioncall

-

-In the function-based interface, it is possible to define values globally by

-using the string \type {global} as the first function argument.

-

-\stopsubsection

-

-\startsubsection[title={Character code registers: \type {[get|set]*code[s]}}]

-

-\topicindex{characters+codes}

-

-\libindex{lccode}    \libindex{setlccode}    \libindex{getlccode}

-\libindex{uccode}    \libindex{setuccode}    \libindex{getuccode}

-\libindex{sfcode}    \libindex{setsfcode}    \libindex{getsfcode}

-\libindex{catcode}   \libindex{setcatcode}   \libindex{getcatcode}

-\libindex{mathcode}  \libindex{setmathcode}  \libindex{getmathcode}

-\libindex{delcode}   \libindex{setdelcode}   \libindex{getdelcode}

-

-\libindex{setdelcodes}   \libindex{getdelcodes}

-\libindex{setmathcodes}  \libindex{getmathcodes}

-

-\TEX's character code tables (\prm {lccode}, \prm {uccode}, \prm {sfcode}, \prm

-{catcode}, \prm {mathcode}, \prm {delcode}) can be accessed and written to using

-six virtual subtables of the \type {tex} table

-

-\startthreecolumns

-\starttyping

-tex.lccode

-tex.uccode

-tex.sfcode

-tex.catcode

-tex.mathcode

-tex.delcode

-\stoptyping

-\stopthreecolumns

-

-The function call interfaces are roughly as above, but there are a few twists.

-\type {sfcode}s are the simple ones:

-

-\startfunctioncall

-tex.setsfcode (["global",] <number> n, <number> s)

-<number> s = tex.getsfcode (<number> n)

-\stopfunctioncall

-

-The function call interface for \type {lccode} and \type {uccode} additionally

-allows you to set the associated sibling at the same time:

-

-\startfunctioncall

-tex.setlccode (["global"], <number> n, <number> lc)

-tex.setlccode (["global"], <number> n, <number> lc, <number> uc)

-<number> lc = tex.getlccode (<number> n)

-tex.setuccode (["global"], <number> n, <number> uc)

-tex.setuccode (["global"], <number> n, <number> uc, <number> lc)

-<number> uc = tex.getuccode (<number> n)

-\stopfunctioncall

-

-The function call interface for \type {catcode} also allows you to specify a

-category table to use on assignment or on query (default in both cases is the

-current one):

-

-\startfunctioncall

-tex.setcatcode (["global"], <number> n, <number> c)

-tex.setcatcode (["global"], <number> cattable, <number> n, <number> c)

-<number> lc = tex.getcatcode (<number> n)

-<number> lc = tex.getcatcode (<number> cattable, <number> n)

-\stopfunctioncall

-

-The interfaces for \type {delcode} and \type {mathcode} use small array tables to

-set and retrieve values:

-

-\startfunctioncall

-tex.setmathcode (["global"], <number> n, <table> mval )

-<table> mval = tex.getmathcode (<number> n)

-tex.setdelcode (["global"], <number> n, <table> dval )

-<table> dval = tex.getdelcode (<number> n)

-\stopfunctioncall

-

-Where the table for \type {mathcode} is an array of 3 numbers, like this:

-

-\starttyping

-{

-    <number> class,

-    <number> family,

-    <number> character

-}

-\stoptyping

-

-And the table for \type {delcode} is an array with 4 numbers, like this:

-

-\starttyping

-{

-    <number> small_fam,

-    <number> small_char,

-    <number> large_fam,

-    <number> large_char

-}

-\stoptyping

-

-You can also avoid the table:

-

-\startfunctioncall

-tex.setmathcode (["global"], <number> n, <number> class,

-    <number> family, <number> character)

-class, family, char =

-    tex.getmathcodes (<number> n)

-tex.setdelcode (["global"], <number> n, <number> smallfam,

-    <number> smallchar, <number> largefam, <number> largechar)

-smallfam, smallchar, largefam, largechar =

-    tex.getdelcodes (<number> n)

-\stopfunctioncall

-

-Normally, the third and fourth values in a delimiter code assignment will be zero

-according to \lpr {Udelcode} usage, but the returned table can have values there

-(if the delimiter code was set using \prm {delcode}, for example). Unset \type

-{delcode}'s can be recognized because \type {dval[1]} is $-1$.

-

-\stopsubsection

-

-\startsubsection[title={Box registers: \type {[get|set]box}}]

-

-\topicindex{registers}

-\topicindex{boxes}

-

-\libindex{box}

-\libindex{setbox}  \libindex{getbox}

-

-It is possible to set and query actual boxes, coming for instance from \prm

-{hbox}, \prm {vbox} or \prm {vtop}, using the node interface as defined in the

-\type {node} library:

-

-\starttyping

-tex.box

-\stoptyping

-

-for array access, or

-

-\starttyping

-tex.setbox(["global",] <number> n, <node> s)

-tex.setbox(["global",] <string> cs, <node> s)

-<node> n = tex.getbox(<number> n)

-<node> n = tex.getbox(<string> cs)

-\stoptyping

-

-for function|-|based access. In the function-based interface, it is possible to

-define values globally by using the string \type {global} as the first function

-argument.

-

-Be warned that an assignment like

-

-\starttyping

-tex.box[0] = tex.box[2]

-\stoptyping

-

-does not copy the node list, it just duplicates a node pointer. If \type {\box2}

-will be cleared by \TEX\ commands later on, the contents of \type {\box0} becomes

-invalid as well. To prevent this from happening, always use \type

-{node.copy_list} unless you are assigning to a temporary variable:

-

-\starttyping

-tex.box[0] = node.copy_list(tex.box[2])

-\stoptyping

-

-\stopsubsection

-

-\startsubsection[title={Reusing boxes: \type {[use|save]boxresource} and \type {getboxresourcedimensions}}]

-

-\topicindex{boxes+reuse}

-

-\libindex{useboxresource}

-\libindex{saveboxresource}

-\libindex{getboxresourcedimensions}

-

-The following function will register a box for reuse (this is modelled after so

-called xforms in \PDF). You can (re)use the box with \lpr {useboxresource} or

-by creating a rule node with subtype~2.

-

-\starttyping

-local index = tex.saveboxresource(n,attributes,resources,immediate,type,margin)

-\stoptyping

-

-The optional second and third arguments are strings, the fourth is a boolean. The

-fifth argument is a type. When set to non|-|zero the \type {/Type} entry is

-omitted. A value of 1 or 3 still writes a \type {/BBox}, while 2 or 3 will write

-a \type {/Matrix}. The sixth argument is the (virtual) margin that extends beyond

-the effective boundingbox as seen by \TEX. Instead of a box number one can also

-pass a \type {[h|v]list} node.

-

-You can generate the reference (a rule type) with:

-

-\starttyping

-local reused = tex.useboxresource(n,wd,ht,dp)

-\stoptyping

-

-The dimensions are optional and the final ones are returned as extra values. The

-following is just a bonus (no dimensions returned means that the resource is

-unknown):

-

-\starttyping

-local w, h, d, m = tex.getboxresourcedimensions(n)

-\stoptyping

-

-This returns the width, height, depth and margin of the resource.

-

-\stopsubsection

-

-\startsubsection[title={\type {triggerbuildpage}}]

-

-\topicindex{pages}

-

-\libindex{triggerbuildpage}

-

-You should not expect to much from the \type {triggerbuildpage} helpers because

-often \TEX\ doesn't do much if it thinks nothing has to be done, but it might be

-useful for some applications. It just does as it says it calls the internal

-function that build a page, given that there is something to build.

-

-\stopsubsection

-

-\startsubsection[title={\type {splitbox}}]

-

-\topicindex{boxes+split}

-

-\libindex{splitbox}

-

-You can split a box:

-

-\starttyping

-local vlist = tex.splitbox(n,height,mode)

-\stoptyping

-

-The remainder is kept in the original box and a packaged vlist is returned. This

-operation is comparable to the \prm {vsplit} operation. The mode can be \type

-{additional} or \type {exactly} and concerns the split off box.

-

-\stopsubsection

-

-\startsubsection[title={Accessing math parameters: \type {[get|set]math}}]

-

-\topicindex{math+parameters}

-\topicindex{parameters+math}

-

-\libindex{setmath}

-\libindex{getmath}

-

-It is possible to set and query the internal math parameters using:

-

-\startfunctioncall

-tex.setmath(["global",] <string> n, <string> t, <number> n)

-<number> n = tex.getmath(<string> n, <string> t)

-\stopfunctioncall

-

-As before an optional first parameter \type {global} indicates a global

-assignment.

-

-The first string is the parameter name minus the leading \quote {Umath}, and the

-second string is the style name minus the trailing \quote {style}. Just to be

-complete, the values for the math parameter name are:

-

-\starttyping

-quad                axis                operatorsize

-overbarkern         overbarrule         overbarvgap

-underbarkern        underbarrule        underbarvgap

-radicalkern         radicalrule         radicalvgap

-radicaldegreebefore radicaldegreeafter  radicaldegreeraise

-stackvgap           stacknumup          stackdenomdown

-fractionrule        fractionnumvgap     fractionnumup

-fractiondenomvgap   fractiondenomdown   fractiondelsize

-limitabovevgap      limitabovebgap      limitabovekern

-limitbelowvgap      limitbelowbgap      limitbelowkern

-underdelimitervgap  underdelimiterbgap

-overdelimitervgap   overdelimiterbgap

-subshiftdrop        supshiftdrop        subshiftdown

-subsupshiftdown     subtopmax           supshiftup

-supbottommin        supsubbottommax     subsupvgap

-spaceafterscript    connectoroverlapmin

-ordordspacing       ordopspacing        ordbinspacing     ordrelspacing

-ordopenspacing      ordclosespacing     ordpunctspacing   ordinnerspacing

-opordspacing        opopspacing         opbinspacing      oprelspacing

-opopenspacing       opclosespacing      oppunctspacing    opinnerspacing

-binordspacing       binopspacing        binbinspacing     binrelspacing

-binopenspacing      binclosespacing     binpunctspacing   bininnerspacing

-relordspacing       relopspacing        relbinspacing     relrelspacing

-relopenspacing      relclosespacing     relpunctspacing   relinnerspacing

-openordspacing      openopspacing       openbinspacing    openrelspacing

-openopenspacing     openclosespacing    openpunctspacing  openinnerspacing

-closeordspacing     closeopspacing      closebinspacing   closerelspacing

-closeopenspacing    closeclosespacing   closepunctspacing closeinnerspacing

-punctordspacing     punctopspacing      punctbinspacing   punctrelspacing

-punctopenspacing    punctclosespacing   punctpunctspacing punctinnerspacing

-innerordspacing     inneropspacing      innerbinspacing   innerrelspacing

-inneropenspacing    innerclosespacing   innerpunctspacing innerinnerspacing

-\stoptyping

-

-The values for the style parameter are:

-

-\starttyping

-display       crampeddisplay

-text          crampedtext

-script        crampedscript

-scriptscript  crampedscriptscript

-\stoptyping

-

-The value is either a number (representing a dimension or number) or a glue spec

-node representing a muskip for \type {ordordspacing} and similar spacing

-parameters.

-

-\stopsubsection

-

-\startsubsection[title={Special list heads: \type {[get|set]list}}]

-

-\topicindex{lists}

-

-\libindex{lists}

-\libindex{setlist}

-\libindex{getlist}

-

-The virtual table \type {tex.lists} contains the set of internal registers that

-keep track of building page lists.

-

-\starttabulate[|l|p|]

-\DB field                      \BC explanation \NC \NR

-\TB

-\NC \type{page_ins_head}       \NC circular list of pending insertions \NC \NR

-\NC \type{contrib_head}        \NC the recent contributions \NC \NR

-\NC \type{page_head}           \NC the current page content \NC \NR

-%NC \type{temp_head}           \NC \NC \NR

-\NC \type{hold_head}           \NC used for held-over items for next page \NC \NR

-\NC \type{adjust_head}         \NC head of the current \prm {vadjust} list \NC \NR

-\NC \type{pre_adjust_head}     \NC head of the current \type {\vadjust pre} list \NC \NR

-%NC \type{align_head}          \NC \NC \NR

-\NC \type{page_discards_head}  \NC head of the discarded items of a page break \NC \NR

-\NC \type{split_discards_head} \NC head of the discarded items in a vsplit \NC \NR

-\LL

-\stoptabulate

-

-The getter and setter functions are \type {getlist} and \type {setlist}. You have

-to be careful with what you set as \TEX\ can have expectations with regards to

-how a list is constructed or in what state it is.

-

-\stopsubsection

-

-\startsubsection[title={Semantic nest levels: \type {getnest} and \type {ptr}}]

-

-\topicindex{nesting}

-

-\libindex{nest}

-\libindex{ptr}

-%libindex{setnest} % only a message

-\libindex{getnest}

-

-The virtual table \type {nest} contains the currently active semantic nesting

-state. It has two main parts: a zero-based array of userdata for the semantic

-nest itself, and the numerical value \type {ptr}, which gives the highest

-available index. Neither the array items in \type {nest[]} nor \type {ptr} can be

-assigned to (as this would confuse the typesetting engine beyond repair), but you

-can assign to the individual values inside the array items, e.g.\ \type

-{tex.nest[tex.nest.ptr].prevdepth}.

-

-\type {tex.nest[tex.nest.ptr]} is the current nest state, \type {nest[0]} the

-outermost (main vertical list) level. The getter function is \type {getnest}. You

-can pass a number (which gives you a list), nothing or \type {top}, which returns

-the topmost list, or the string \type {ptr} which gives you the index of the

-topmost list.

-

-The known fields are:

-

-\starttabulate[|l|l|l|p|]

-\DB key                \BC type    \BC modes \BC explanation \NC \NR

-\TB

-\NC \type{mode}        \NC number  \NC all   \NC a string:

-                                                 \type {none} (this happens during \prm {write}),

-                                                 \type {vmode}, \type {hmode}, \type {displaymath},

-                                                 \type {innervmode}, \type {innerhmode}, \type {inlinemath};

-                                                 these fields cannot be set \NC \NR

-\NC \type{modeline}    \NC number  \NC all   \NC source input line where this mode was entered in,

-                                                 negative inside the output routine \NC \NR

-\NC \type{head}        \NC node    \NC all   \NC the head of the current list \NC \NR

-\NC \type{tail}        \NC node    \NC all   \NC the tail of the current list \NC \NR

-\NC \type{prevgraf}    \NC number  \NC vmode \NC number of lines in the previous paragraph \NC \NR

-\NC \type{prevdepth}   \NC number  \NC vmode \NC depth of the previous paragraph \NC \NR

-\NC \type{spacefactor} \NC number  \NC hmode \NC the current space factor \NC \NR

-\NC \type{dirs}        \NC node    \NC hmode \NC used for temporary storage by the line break algorithm\NC \NR

-\NC \type{noad}        \NC node    \NC mmode \NC used for temporary storage of a pending fraction numerator,

-                                                 for \prm {over} etc. \NC \NR

-\NC \type{delimptr}    \NC node    \NC mmode \NC used for temporary storage of the previous math delimiter,

-                                                 for \prm {middle} \NC \NR

-\NC \type{mathdir}     \NC boolean \NC mmode \NC true when during math processing the \lpr {mathdir} is not

-                                                 the same as the surrounding \lpr {textdir} \NC \NR

-\NC \type{mathstyle}   \NC number  \NC mmode \NC the current \lpr {mathstyle} \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[reference=sec:luaprint,title={Print functions}]

-

-\topicindex{printing}

-

-The \type {tex} table also contains the three print functions that are the major

-interface from \LUA\ scripting to \TEX. The arguments to these three functions

-are all stored in an in|-|memory virtual file that is fed to the \TEX\ scanner as

-the result of the expansion of \prm {directlua}.

-

-The total amount of returnable text from a \prm {directlua} command is only

-limited by available system \RAM. However, each separate printed string has to

-fit completely in \TEX's input buffer. The result of using these functions from

-inside callbacks is undefined at the moment.

-

-\subsubsection{\type {print}}

-

-\libindex{print}

-

-\startfunctioncall

-tex.print(<string> s, ...)

-tex.print(<number> n, <string> s, ...)

-tex.print(<table> t)

-tex.print(<number> n, <table> t)

-\stopfunctioncall

-

-Each string argument is treated by \TEX\ as a separate input line. If there is a

-table argument instead of a list of strings, this has to be a consecutive array

-of strings to print (the first non-string value will stop the printing process).

-

-The optional parameter can be used to print the strings using the catcode regime

-defined by \lpr {catcodetable}~\type {n}. If \type {n} is $-1$, the currently

-active catcode regime is used. If \type {n} is $-2$, the resulting catcodes are

-the result of \prm {the} \prm {toks}: all category codes are 12 (other) except for

-the space character, that has category code 10 (space). Otherwise, if \type {n}

-is not a valid catcode table, then it is ignored, and the currently active

-catcode regime is used instead.

-

-The very last string of the very last \type {tex.print} command in a \prm

-{directlua} will not have the \prm {endlinechar} appended, all others do.

-

-\subsubsection{\type {sprint}}

-

-\libindex{sprint}

-

-\startfunctioncall

-tex.sprint(<string> s, ...)

-tex.sprint(<number> n, <string> s, ...)

-tex.sprint(<table> t)

-tex.sprint(<number> n, <table> t)

-\stopfunctioncall

-

-Each string argument is treated by \TEX\ as a special kind of input line that

-makes it suitable for use as a partial line input mechanism:

-

-\startitemize[packed]

-\startitem

-    \TEX\ does not switch to the \quote {new line} state, so that leading spaces

-    are not ignored.

-\stopitem

-\startitem

-    No \prm {endlinechar} is inserted.

-\stopitem

-\startitem

-    Trailing spaces are not removed. Note that this does not prevent \TEX\ itself

-    from eating spaces as result of interpreting the line. For example, in

-

-    \starttyping

-    before\directlua{tex.sprint("\\relax")tex.sprint(" inbetween")}after

-    \stoptyping

-

-    the space before \type {in between} will be gobbled as a result of the \quote

-    {normal} scanning of \prm {relax}.

-\stopitem

-\stopitemize

-

-If there is a table argument instead of a list of strings, this has to be a

-consecutive array of strings to print (the first non-string value will stop the

-printing process).

-

-The optional argument sets the catcode regime, as with \type {tex.print}. This

-influences the string arguments (or numbers turned into strings).

-

-Although this needs to be used with care, you can also pass token or node

-userdata objects. These get injected into the stream. Tokens had best be valid

-tokens, while nodes need to be around when they get injected. Therefore it is

-important to realize the following:

-

-\startitemize

-\startitem

-    When you inject a token, you need to pass a valid token userdata object. This

-    object will be collected by \LUA\ when it no longer is referenced. When it gets

-    printed to \TEX\ the token itself gets copied so there is no interference with the

-    \LUA\ garbage collection. You manage the object yourself. Because tokens are

-    actually just numbers, there is no real extra overhead at the \TEX\ end.

-\stopitem

-\startitem

-    When you inject a node, you need to pass a valid node userdata object. The

-    node related to the object will not be collected by \LUA\ when it no longer

-    is referenced. It lives on at the \TEX\ end in its own memory space. When it

-    gets printed to \TEX\ the node reference is used assuming that node stays

-    around. There is no \LUA\ garbage collection involved. Again, you manage the

-    object yourself. The node itself is freed when \TEX\ is done with it.

-\stopitem

-\stopitemize

-

-If you consider the last remark you might realize that we have a problem when a

-printed mix of strings, tokens and nodes is reused. Inside \TEX\ the sequence

-becomes a linked list of input buffers. So, \type {"123"} or \type {"\foo{123}"}

-gets read and parsed on the fly, while \typ {<token userdata>} already is

-tokenized and effectively is a token list now. A \typ {<node userdata>} is also

-tokenized into a token list but it has a reference to a real node. Normally this

-goes fine. But now assume that you store the whole lot in a macro: in that case

-the tokenized node can be flushed many times. But, after the first such flush the

-node is used and its memory freed. You can prevent this by using copies which is

-controlled by setting \lpr {luacopyinputnodes} to a non|-|zero value. This is one

-of these fuzzy areas you have to live with if you really mess with these low

-level issues.

-

-\subsubsection{\type {tprint}}

-

-\libindex{tprint}

-

-\startfunctioncall

-tex.tprint({<number> n, <string> s, ...}, {...})

-\stopfunctioncall

-

-This function is basically a shortcut for repeated calls to \type

-{tex.sprint(<number> n, <string> s, ...)}, once for each of the supplied argument

-tables.

-

-\subsubsection{\type {cprint}}

-

-\libindex{cprint}

-

-This function takes a number indicating the to be used catcode, plus either a

-table of strings or an argument list of strings that will be pushed into the

-input stream.

-

-\startfunctioncall

-tex.cprint( 1," 1: $&{\\foo}") tex.print("\\par") -- a lot of \bgroup s

-tex.cprint( 2," 2: $&{\\foo}") tex.print("\\par") -- matching \egroup s

-tex.cprint( 9," 9: $&{\\foo}") tex.print("\\par") -- all get ignored

-tex.cprint(10,"10: $&{\\foo}") tex.print("\\par") -- all become spaces

-tex.cprint(11,"11: $&{\\foo}") tex.print("\\par") -- letters

-tex.cprint(12,"12: $&{\\foo}") tex.print("\\par") -- other characters

-tex.cprint(14,"12: $&{\\foo}") tex.print("\\par") -- comment triggers

-\stopfunctioncall

-

-% \subsubsection{\type {write}, \type {twrite}, \type {nwrite}}

-\subsubsection{\type {write}}

-

-\libindex{write}

-% \libindex{twrite}

-% \libindex{nwrite}

-

-\startfunctioncall

-tex.write(<string> s, ...)

-tex.write(<table> t)

-\stopfunctioncall

-

-Each string argument is treated by \TEX\ as a special kind of input line that

-makes it suitable for use as a quick way to dump information:

-

-\startitemize

-\item All catcodes on that line are either \quote{space} (for '~') or \quote

-      {character} (for all others).

-\item There is no \prm {endlinechar} appended.

-\stopitemize

-

-If there is a table argument instead of a list of strings, this has to be a

-consecutive array of strings to print (the first non-string value will stop the

-printing process).

-

-% The functions \type {twrite} and \type {nwrite} can be used to write a token or

-% node back to \TEX\, possibly intermixed with regular strings that will be

-% tokenized. You have to make sure that you pass the right data because sometimes

-% \TEX\ has expectations that need to be met.

-

-\stopsubsection

-

-\startsubsection[title={Helper functions}]

-

-\subsubsection{\type {round}}

-

-\topicindex {helpers}

-

-\libindex{round}

-

-\startfunctioncall

-<number> n = tex.round(<number> o)

-\stopfunctioncall

-

-Rounds \LUA\ number \type {o}, and returns a number that is in the range of a

-valid \TEX\ register value. If the number starts out of range, it generates a

-\quote {number too big} error as well.

-

-\subsubsection{\type {scale}}

-

-\libindex{scale}

-

-\startfunctioncall

-<number> n = tex.scale(<number> o, <number> delta)

-<table> n = tex.scale(table o, <number> delta)

-\stopfunctioncall

-

-Multiplies the \LUA\ numbers \type {o} and \nod {delta}, and returns a rounded

-number that is in the range of a valid \TEX\ register value. In the table

-version, it creates a copy of the table with all numeric top||level values scaled

-in that manner. If the multiplied number(s) are of range, it generates

-\quote{number too big} error(s) as well.

-

-Note: the precision of the output of this function will depend on your computer's

-architecture and operating system, so use with care! An interface to \LUATEX's

-internal, 100\% portable scale function will be added at a later date.

-

-\subsubsection{\type {number} and \type {romannumeral}}

-

-\libindex{number}

-\libindex{romannumeral}

-

-These are the companions to the primitives \prm {number} and \prm

-{romannumeral}. They can be used like:

-

-\startfunctioncall

-tex.print(tex.romannumeral(123))

-\stopfunctioncall

-

-\subsubsection{\type {fontidentifier} and \type {fontname}}

-

-\libindex{fontidentifier}

-\libindex{fontname}

-

-The first one returns the name only, the second one reports the size too.

-

-\startfunctioncall

-tex.print(tex.fontname(tex.fontname))

-tex.print(tex.fontname(tex.fontidentidier))

-\stopfunctioncall

-

-\subsubsection{\type {sp}}

-

-\libindex{sp}

-

-\startfunctioncall

-<number> n = tex.sp(<number> o)

-<number> n = tex.sp(<string> s)

-\stopfunctioncall

-

-Converts the number \type {o} or a string \type {s} that represents an explicit

-dimension into an integer number of scaled points.

-

-For parsing the string, the same scanning and conversion rules are used that

-\LUATEX\ would use if it was scanning a dimension specifier in its \TEX|-|like

-input language (this includes generating errors for bad values), expect for the

-following:

-

-\startitemize[n]

-\startitem

-    only explicit values are allowed, control sequences are not handled

-\stopitem

-\startitem

-    infinite dimension units (\type {fil...}) are forbidden

-\stopitem

-\startitem

-    \type {mu} units do not generate an error (but may not be useful either)

-\stopitem

-\stopitemize

-

-\subsubsection{\type {tex.getlinenumber} and \type {tex.setlinenumber}}

-

-\libindex{getlinenumber}

-\libindex{setlinenumber}

-

-You can mess with the current line number:

-

-\startfunctioncall

-local n = tex.getlinenumber()

-tex.setlinenumber(n+10)

-\stopfunctioncall

-

-which can be shortcut to:

-

-\startfunctioncall

-tex.setlinenumber(10,true)

-\stopfunctioncall

-

-This might be handy when you have a callback that read numbers from a file and

-combines them in one line (in which case an error message probably has to refer

-to the original line). Interference with \TEX's internal handling of numbers is

-of course possible.

-

-\subsubsection{\type {error} and \type {show_context}}

-

-\topicindex{errors}

-

-\libindex{error}

-\libindex{show_context}

-

-\startfunctioncall

-tex.error(<string> s)

-tex.error(<string> s, <table> help)

-\stopfunctioncall

-

-This creates an error somewhat like the combination of \prm {errhelp} and \prm

-{errmessage} would. During this error, deletions are disabled.

-

-The array part of the \type {help} table has to contain strings, one for each

-line of error help.

-

-In case of an error the \type {show_context} function will show the current

-context where we're at (in the expansion).

-

-\subsubsection{\type {run}, \type {finish}}

-

-\libindex{run}

-\libindex{finish}

-

-These two functions start the interpretations and force its end. A runs normally

-boils down to \TEX\ entering the so called main loop. A token is fetched and

-depending on it current meaning some actions takes place. Sometimes that actions

-comes immediately, sometimes more scanning is needed. Quite often tokens get

-pushed back into the input. This all means that the \TEX\ scanner is constantly

-pushing and popping input states, but in the end after all the action is done

-returns to the main loop.

-

-\subsubsection{\type {runtoks}}

-

-Because of the fact that \TEX\ is in a complex dance of expanding, dealing with

-fonts, typesetting paragraphs, messing around with boxes, building pages, and so

-on, you cannot easily run a nested \TEX\ run (read nested main loop). However,

-there is an option to force a local run with \type {runtoks}. The content of the

-given token list register gets expanded locally after which we return to where we

-triggered this expansion, at the \LUA\ end. Instead a function can get passed

-that does some work. You have to make sure that at the end \TEX\ is in a sane

-state and this is not always trivial. A more complex mechanism would complicate

-\TEX\ itself (and probably also harm performance) so this simple local expansion

-loop has to do.

-

-\startfunctioncall

-tex.runtoks(<token register>)

-tex.runtoks(<lua function>)

-\stopfunctioncall

-

-When the \prm {tracingnesting} parameter is set to a value larger than~2 some

-information is reported about the state of the local loop.

-

-\subsubsection{\type {forcehmode}}

-

-\libindex{forcehmode}

-

-An example of a (possible error triggering) complication is that \TEX\ expects to

-be in some state, say horizontal mode, and you have to make sure it is when you

-start feeding back something from \LUA\ into \TEX. Normally a user will not run

-into issues but when you start writing tokens or nodes or have a nested run there

-can be situations that you need to run \type {forcehmode}. There is no recipe for

-this and intercepting possible cases would weaken \LUATEX's flexibility.

-

-\subsubsection{\type {hashtokens}}

-

-\libindex{hashtokens}

-

-\topicindex{hash}

-

-\startfunctioncall

-for i,v in pairs (tex.hashtokens()) do ... end

-\stopfunctioncall

-

-Returns a list of names. This can be useful for debugging, but note that this

-also reports control sequences that may be unreachable at this moment due to

-local redefinitions: it is strictly a dump of the hash table. You can use \type

-{token.create} to inspect properties, for instance when the \type {command} key

-in a created table equals \type {123}, you have the \type {cmdname} value \type

-{undefined_cs}.

-

-\subsubsection{\type {definefont}}

-

-\topicindex{fonts+defining}

-

-\libindex{definefont}

-

-\startfunctioncall

-tex.definefont(<string> csname, <number> fontid)

-tex.definefont(<boolean> global, <string> csname, <number> fontid)

-\stopfunctioncall

-

-Associates \type {csname} with the internal font number \type {fontid}. The

-definition is global if (and only if) \type {global} is specified and true (the

-setting of \type {globaldefs} is not taken into account).

-

-\stopsubsection

-

-\startsubsection[reference=luaprimitives,title={Functions for dealing with primitives}]

-

-\subsubsection{\type {enableprimitives}}

-

-\libindex{enableprimitives}

-

-\topicindex{initialization}

-\topicindex{primitives}

-

-\startfunctioncall

-tex.enableprimitives(<string> prefix, <table> primitive names)

-\stopfunctioncall

-

-This function accepts a prefix string and an array of primitive names. For each

-combination of \quote {prefix} and \quote {name}, the \type

-{tex.enableprimitives} first verifies that \quote {name} is an actual primitive

-(it must be returned by one of the \type {tex.extraprimitives} calls explained

-below, or part of \TEX82, or \prm {directlua}). If it is not, \type

-{tex.enableprimitives} does nothing and skips to the next pair.

-

-But if it is, then it will construct a csname variable by concatenating the

-\quote {prefix} and \quote {name}, unless the \quote {prefix} is already the

-actual prefix of \quote {name}. In the latter case, it will discard the \quote

-{prefix}, and just use \quote {name}.

-

-Then it will check for the existence of the constructed csname. If the csname is

-currently undefined (note: that is not the same as \prm {relax}), it will

-globally define the csname to have the meaning: run code belonging to the

-primitive \quote {name}. If for some reason the csname is already defined, it

-does nothing and tries the next pair.

-

-An example:

-

-\starttyping

-tex.enableprimitives('LuaTeX', {'formatname'})

-\stoptyping

-

-will define \type {\LuaTeXformatname} with the same intrinsic meaning as the

-documented primitive \lpr {formatname}, provided that the control sequences \type

-{\LuaTeXformatname} is currently undefined.

-

-When \LUATEX\ is run with \type {--ini} only the \TEX82 primitives and \prm

-{directlua} are available, so no extra primitives {\bf at all}.

-

-If you want to have all the new functionality available using their default

-names, as it is now, you will have to add

-

-\starttyping

-\ifx\directlua\undefined \else

-    \directlua {tex.enableprimitives('',tex.extraprimitives ())}

-\fi

-\stoptyping

-

-near the beginning of your format generation file. Or you can choose different

-prefixes for different subsets, as you see fit.

-

-Calling some form of \type {tex.enableprimitives} is highly important though,

-because if you do not, you will end up with a \TEX82-lookalike that can run \LUA\

-code but not do much else. The defined csnames are (of course) saved in the

-format and will be available at runtime.

-

-\subsubsection{\type {extraprimitives}}

-

-\libindex{extraprimitives}

-

-\startfunctioncall

-<table> t = tex.extraprimitives(<string> s, ...)

-\stopfunctioncall

-

-This function returns a list of the primitives that originate from the engine(s)

-given by the requested string value(s). The possible values and their (current)

-return values are given in the following table. In addition the somewhat special

-primitives \quote{\tex{ }}, \quote{\tex {/}} and \quote{\type {-}} are defined.

-

-\startluacode

-function document.showprimitives(tag)

-    for k, v in table.sortedpairs(tex.extraprimitives(tag)) do

-        if v ~= ' ' and v ~= "/" and v ~= "-" then

-            context.type(v)

-            context.space()

-        end

-    end

-end

-\stopluacode

-

-\starttabulate[|l|pl|]

-\DB name    \BC values \NC \NR

-\TB

-\NC tex     \NC \ctxlua{document.showprimitives('tex')    } \NC \NR

-\NC core    \NC \ctxlua{document.showprimitives('core')   } \NC \NR

-\NC etex    \NC \ctxlua{document.showprimitives('etex')   } \NC \NR

-\NC luatex  \NC \ctxlua{document.showprimitives('luatex') } \NC \NR

-\LL

-\stoptabulate

-

-Note that \type {luatex} does not contain \type {directlua}, as that is

-considered to be a core primitive, along with all the \TEX82 primitives, so it is

-part of the list that is returned from \type {'core'}.

-

-Running \type {tex.extraprimitives} will give you the complete list of

-primitives \type {-ini} startup. It is exactly equivalent to \type

-{tex.extraprimitives("etex","luatex")}.

-

-\subsubsection{\type {primitives}}

-

-\libindex{primitives}

-

-\startfunctioncall

-<table> t = tex.primitives()

-\stopfunctioncall

-

-This function returns a list of all primitives that \LUATEX\ knows about.

-

-\stopsubsection

-

-\startsubsection[title={Core functionality interfaces}]

-

-\subsubsection{\type {badness}}

-

-\libindex{badness}

-

-\startfunctioncall

-<number> b = tex.badness(<number> t, <number> s)

-\stopfunctioncall

-

-This helper function is useful during linebreak calculations. \type {t} and \type

-{s} are scaled values; the function returns the badness for when total \type {t}

-is supposed to be made from amounts that sum to \type {s}. The returned number is

-a reasonable approximation of \mathematics {100(t/s)^3};

-

-\subsubsection{\type {tex.resetparagraph}}

-

-\topicindex {paragraphs+reset}

-

-\libindex{resetparagraph}

-

-This function resets the parameters that \TEX\ normally resets when a new paragraph

-is seen.

-

-\subsubsection{\type {linebreak}}

-

-\topicindex {linebreaks}

-

-\libindex{linebreak}

-

-\startfunctioncall

-local <node> nodelist, <table> info =

-    tex.linebreak(<node> listhead, <table> parameters)

-\stopfunctioncall

-

-The understood parameters are as follows:

-

-\starttabulate[|l|l|p|]

-\DB name                        \BC type            \BC explanation \NC \NR

-\TB

-\NC \type{pardir}               \NC string          \NC \NC \NR

-\NC \type{pretolerance}         \NC number          \NC \NC \NR

-\NC \type{tracingparagraphs}    \NC number          \NC \NC \NR

-\NC \type{tolerance}            \NC number          \NC \NC \NR

-\NC \type{looseness}            \NC number          \NC \NC \NR

-\NC \type{hyphenpenalty}        \NC number          \NC \NC \NR

-\NC \type{exhyphenpenalty}      \NC number          \NC \NC \NR

-\NC \type{pdfadjustspacing}     \NC number          \NC \NC \NR

-\NC \type{adjdemerits}          \NC number          \NC \NC \NR

-\NC \type{pdfprotrudechars}     \NC number          \NC \NC \NR

-\NC \type{linepenalty}          \NC number          \NC \NC \NR

-\NC \type{lastlinefit}          \NC number          \NC \NC \NR

-\NC \type{doublehyphendemerits} \NC number          \NC \NC \NR

-\NC \type{finalhyphendemerits}  \NC number          \NC \NC \NR

-\NC \type{hangafter}            \NC number          \NC \NC \NR

-\NC \type{interlinepenalty}     \NC number or table \NC if a table, then it is an array like \prm {interlinepenalties} \NC \NR

-\NC \type{clubpenalty}          \NC number or table \NC if a table, then it is an array like \prm {clubpenalties} \NC \NR

-\NC \type{widowpenalty}         \NC number or table \NC if a table, then it is an array like \prm {widowpenalties} \NC \NR

-\NC \type{brokenpenalty}        \NC number          \NC \NC \NR

-\NC \type{emergencystretch}     \NC number          \NC in scaled points \NC \NR

-\NC \type{hangindent}           \NC number          \NC in scaled points \NC \NR

-\NC \type{hsize}                \NC number          \NC in scaled points \NC \NR

-\NC \type{leftskip}             \NC glue_spec node  \NC \NC \NR

-\NC \type{rightskip}            \NC glue_spec node  \NC \NC \NR

-\NC \type{parshape}             \NC table           \NC \NC \NR

-\LL

-\stoptabulate

-

-Note that there is no interface for \prm {displaywidowpenalties}, you have to

-pass the right choice for \type {widowpenalties} yourself.

-

-It is your own job to make sure that \type {listhead} is a proper paragraph list:

-this function does not add any nodes to it. To be exact, if you want to replace

-the core line breaking, you may have to do the following (when you are not

-actually working in the \cbk {pre_linebreak_filter} or \cbk {linebreak_filter}

-callbacks, or when the original list starting at listhead was generated in

-horizontal mode):

-

-\startitemize

-\startitem

-    add an \quote {indent box} and perhaps a \nod {local_par} node at the start

-    (only if you need them)

-\stopitem

-\startitem

-    replace any found final glue by an infinite penalty (or add such a penalty,

-    if the last node is not a glue)

-\stopitem

-\startitem

-    add a glue node for the \prm {parfillskip} after that penalty node

-\stopitem

-\startitem

-    make sure all the \type {prev} pointers are OK

-\stopitem

-\stopitemize

-

-The result is a node list, it still needs to be vpacked if you want to assign it

-to a \prm {vbox}. The returned \type {info} table contains four values that are

-all numbers:

-

-\starttabulate[|l|p|]

-\DB name      \BC explanation \NC \NR

-\TB

-\NC prevdepth \NC depth of the last line in the broken paragraph \NC \NR

-\NC prevgraf  \NC number of lines in the broken paragraph \NC \NR

-\NC looseness \NC the actual looseness value in the broken paragraph \NC \NR

-\NC demerits  \NC the total demerits of the chosen solution  \NC \NR

-\LL

-\stoptabulate

-

-Note there are a few things you cannot interface using this function: You cannot

-influence font expansion other than via \type {pdfadjustspacing}, because the

-settings for that take place elsewhere. The same is true for hbadness and hfuzz

-etc. All these are in the \type {hpack} routine, and that fetches its own

-variables via globals.

-

-\subsubsection{\type {shipout}}

-

-\topicindex {shipout}

-

-\libindex{shipout}

-

-\startfunctioncall

-tex.shipout(<number> n)

-\stopfunctioncall

-

-Ships out box number \type {n} to the output file, and clears the box register.

-

-\subsubsection{\type {getpagestate}}

-

-\topicindex {pages}

-

-\libindex{getpagestate}

-

-This helper reports the current page state: \type {empty}, \type {box_there} or

-\type {inserts_only} as integer value.

-

-\subsubsection{\type {getlocallevel}}

-

-\topicindex {nesting}

-

-\libindex{getlocallevel}

-

-This integer reports the current level of the local loop. It's only useful for

-debugging and the (relative state) numbers can change with the implementation.

-

-\stopsubsection

-

-\startsubsection[title={Randomizers}]

-

-\libindex{lua_math_random}

-\libindex{lua_math_randomseed}

-\libindex{init_rand}

-\libindex{normal_rand}

-\libindex{uniform_rand}

-\libindex{uniformdeviate}

-

-For practical reasons \LUATEX\ has its own random number generator. The original

-\LUA\ random function is available as \typ {tex.lua_math_random}. You can

-initialize with a new seed with \type {init_rand} (\typ {lua_math_randomseed} is

-equivalent to this one.

-

-There are three generators: \type {normal_rand} (no argument is used), \type

-{uniform_rand} (takes a number that will get rounded before being used) and \type

-{uniformdeviate} which behaves like the primitive and expects a scaled integer, so

-

-\startfunctioncall

-tex.print(tex.uniformdeviate(65536)/65536)

-\stopfunctioncall

-

-will give a random number between zero and one.

-

-\stopsubsection

-

-\startsubsection[reference=synctex,title={Functions related to synctex}]

-

-\topicindex {synctex}

-

-\libindex{set_synctex_mode}      \libindex{get_synctex_mode}

-\libindex{set_synctex_no_files}

-\libindex{set_synctex_tag}       \libindex{get_synctex_tag}   \libindex{force_synctex_tag}

-\libindex{set_synctex_line}      \libindex{get_synctex_line}  \libindex{force_synctex_line}

-

-The next helpers only make sense when you implement your own synctex logic. Keep in

-mind that the library used in editors assumes a certain logic and is geared for

-plain and \LATEX, so after a decade users expect a certain behaviour.

-

-\starttabulate[|l|p|]

-\DB name                        \BC explanation \NC \NR

-\TB

-\NC \type{set_synctex_mode}     \NC \type {0} is the default and used normal synctex

-                                    logic, \type {1} uses the values set by the next

-                                    helpers while \type {2} also sets these for glyph

-                                    nodes; \type{3} sets glyphs and glue and \type {4}

-                                    sets only glyphs \NC \NR

-\NC \type{set_synctex_tag}      \NC set the current tag (file) value (obeys save stack) \NC \NR

-\NC \type{set_synctex_line}     \NC set the current line value (obeys save stack) \NC \NR

-\NC \type{set_synctex_no_files} \NC disable synctex file logging \NC \NR

-\NC \type{get_synctex_mode}     \NC returns the current mode (for values see above) \NC \NR

-\NC \type{get_synctex_tag}      \NC get the currently set value of tag (file) \NC \NR

-\NC \type{get_synctex_line}     \NC get the currently set value of line \NC \NR

-\NC \type{force_synctex_tag}    \NC overload the tag (file) value (\type {0} resets) \NC \NR

-\NC \type{force_synctex_line}   \NC overload the line value  (\type {0} resets) \NC \NR

-\LL

-\stoptabulate

-

-The last one is somewhat special. Due to the way files are registered in \SYNCTEX\ we need

-to explicitly disable that feature if we provide our own alternative if we want to avoid

-that overhead. Passing a value of 1 disables registering.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={The \type {texconfig} table},reference=texconfig][library=texconfig]

-

-\topicindex{libraries+\type{texconfig}}

-

-\topicindex {configuration}

-

-This is a table that is created empty. A startup \LUA\ script could

-fill this table with a number of settings that are read out by

-the executable after loading and executing the startup file.

-

-\starttabulate[|l|l|l|p|]

-\DB key                   \BC type     \BC default \BC explanation \NC \NR

-\TB

-\NC \type{kpse_init}      \NC boolean  \NC true

-\NC

-    \type {false} totally disables \KPATHSEA\ initialisation, and enables

-    interpretation of the following numeric key--value pairs. (only ever unset

-    this if you implement {\it all\/} file find callbacks!)

-\NC \NR

-\NC

-    \type{shell_escape} \NC string \NC \type {'f'} \NC Use \type {'y'} or \type

-    {'t'} or \type {'1'} to enable \type {\write18} unconditionally, \type {'p'}

-    to enable the commands that are listed in \type {shell_escape_commands}

-\NC \NR

-\NC

-    shell_escape_commands \NC string \NC \NC Comma-separated list of command

-    names that may be executed by \type {\write18} even if \type {shell_escape}

-    is set to \type {'p'}. Do {\it not\/} use spaces around commas, separate any

-    required command arguments by using a space, and use the \ASCII\ double quote

-    (\type {"}) for any needed argument or path quoting

-\NC \NR

-\NC \type{string_vacancies} \NC number   \NC  75000  \NC cf.\ web2c docs \NC \NR

-\NC \type{pool_free}        \NC number   \NC   5000  \NC cf.\ web2c docs \NC \NR

-\NC \type{max_strings}      \NC number   \NC  15000  \NC cf.\ web2c docs \NC \NR

-\NC \type{strings_free}     \NC number   \NC    100  \NC cf.\ web2c docs \NC \NR

-\NC \type{nest_size}        \NC number   \NC     50  \NC cf.\ web2c docs \NC \NR

-\NC \type{max_in_open}      \NC number   \NC     15  \NC cf.\ web2c docs \NC \NR

-\NC \type{param_size}       \NC number   \NC     60  \NC cf.\ web2c docs \NC \NR

-\NC \type{save_size}        \NC number   \NC   4000  \NC cf.\ web2c docs \NC \NR

-\NC \type{stack_size}       \NC number   \NC    300  \NC cf.\ web2c docs \NC \NR

-\NC \type{dvi_buf_size}     \NC number   \NC  16384  \NC cf.\ web2c docs \NC \NR

-\NC \type{error_line}       \NC number   \NC     79  \NC cf.\ web2c docs \NC \NR

-\NC \type{half_error_line}  \NC number   \NC     50  \NC cf.\ web2c docs \NC \NR

-\NC \type{max_print_line}   \NC number   \NC     79  \NC cf.\ web2c docs \NC \NR

-\NC \type{hash_extra}       \NC number   \NC      0  \NC cf.\ web2c docs \NC \NR

-\NC \type{pk_dpi}           \NC number   \NC     72  \NC cf.\ web2c docs \NC \NR

-\NC \type{trace_file_names} \NC boolean  \NC true

-\NC

-    \type {false} disables \TEX's normal file open|-|close feedback (the

-    assumption is that callbacks will take care of that)

-\NC \NR

-\NC \type{file_line_error}  \NC boolean  \NC false

-\NC

-    do \type {file:line} style error messages

-\NC \NR

-\NC \type{halt_on_error}    \NC boolean  \NC false

-\NC

-    abort run on the first encountered error

-\NC \NR

-\NC \type{formatname}       \NC string   \NC

-\NC

-    if no format name was given on the command line, this key will be tested first

-    instead of simply quitting

-\NC \NR

-\NC \type{jobname}        \NC string   \NC

-\NC

-    if no input file name was given on the command line, this key will be tested

-    first instead of simply giving up

-\NC \NR

-\LL

-\stoptabulate

-

-Note: the numeric values that match web2c parameters are only used if \type

-{kpse_init} is explicitly set to \type {false}. In all other cases, the normal

-values from \type {texmf.cnf} are used.

-

-\stopsection

-

-\startsection[title={The \type {texio} library}][library=texio]

-

-\topicindex{libraries+\type{texio}}

-\topicindex{\IO}

-

-This library takes care of the low|-|level I/O interface: writing to the log file

-and|/|or console.

-

-\startsubsection[title={\type {write}}]

-

-\libindex{write}

-

-\startfunctioncall

-texio.write(<string> target, <string> s, ...)

-texio.write(<string> s, ...)

-\stopfunctioncall

-

-Without the \type {target} argument, writes all given strings to the same

-location(s) \TEX\ writes messages to at this moment. If \prm {batchmode} is in

-effect, it writes only to the log, otherwise it writes to the log and the

-terminal. The optional \type {target} can be one of three possibilities: \type

-{term}, \type {log} or \type {term and log}.

-

-Note: If several strings are given, and if the first of these strings is or might

-be one of the targets above, the \type {target} must be specified explicitly to

-prevent \LUA\ from interpreting the first string as the target.

-

-\stopsubsection

-

-\startsubsection[title={\type {write_nl}}]

-

-\libindex{write_nl}

-

-\startfunctioncall

-texio.write_nl(<string> target, <string> s, ...)

-texio.write_nl(<string> s, ...)

-\stopfunctioncall

-

-This function behaves like \type {texio.write}, but make sure that the given

-strings will appear at the beginning of a new line. You can pass a single empty

-string if you only want to move to the next line.

-

-\stopsubsection

-

-\startsubsection[title={\type {setescape}}]

-

-\libindex{setescape}

-

-You can disable \type {^^} escaping of control characters by passing a value of

-zero.

-

-\stopsubsection

-

-\startsubsection[title={\type {closeinput}}]

-

-\libindex{closeinput}

-

-This function that should be used with care. It acts as \prm {endinput} but at

-the \LUA\ end. You can use it to (sort of) force a jump back to \TEX. Normally a

-\LUA\ will just collect prints and at the end bump an input level and flush these

-prints. This function can help you stay at the current level but you need to know

-what you're doing (or more precise: what \TEX\ is doing with input).

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={The \type {token} library}][library=token]

-

-\startsubsection[title={The scanner}]

-

-\topicindex{libraries+\type{token}}

-\topicindex{tokens}

-

-\libindex{scan_keyword}

-\libindex{scan_keywordcs}

-\libindex{scan_int}

-\libindex{scan_real}

-\libindex{scan_float}

-\libindex{scan_dimen}

-\libindex{scan_glue}

-\libindex{scan_toks}

-\libindex{scan_code}

-\libindex{scan_string}

-\libindex{scan_argument}

-\libindex{scan_word}

-\libindex{scan_csname}

-\libindex{scan_list}

-

-The token library provides means to intercept the input and deal with it at the

-\LUA\ level. The library provides a basic scanner infrastructure that can be used

-to write macros that accept a wide range of arguments. This interface is on

-purpose kept general and as performance is quite ok. One can build additional

-parsers without too much overhead. It's up to macro package writers to see how

-they can benefit from this as the main principle behind \LUATEX\ is to provide a

-minimal set of tools and no solutions. The scanner functions are probably the

-most intriguing.

-

-\starttabulate[|l|l|p|]

-\DB function              \BC argument           \BC result \NC \NR

-\TB

-\NC \type{scan_keyword}   \NC string             \NC returns true if the given keyword is gobbled; as with

-                                                     the regular \TEX\ keyword scanner this is case insensitive

-                                                     (and \ASCII\ based) \NC \NR

-\NC \type{scan_keywordcs} \NC string             \NC returns true if the given keyword is gobbled; this variant

-                                                     is case sensitive and also suitable for \UTF8 \NC \NR

-\NC \type{scan_int}       \NC                    \NC returns an integer \NC \NR

-\NC \type{scan_real}      \NC                    \NC returns a number from e.g.\ \type {1},  \type {1.1}, \type {.1} with optional collapsed signs \NC \NR

-\NC \type{scan_float}     \NC                    \NC returns a number from e.g.\ \type {1},  \type {1.1}, \type {.1}, \type {1.1E10}, , \type {.1e-10} with optional collapsed signs \NC \NR

-\NC \type{scan_dimen}     \NC infinity, mu-units \NC returns a number representing a dimension and or two numbers being the filler and order \NC \NR

-\NC \type{scan_glue}      \NC mu-units           \NC returns a glue spec node \NC \NR

-\NC \type{scan_toks}      \NC definer, expand    \NC returns a table of tokens tokens \NC \NR

-\NC \type{scan_code}      \NC bitset             \NC returns a character if its category is in the given bitset (representing catcodes) \NC \NR

-\NC \type{scan_string}    \NC                    \NC returns a string given between \type {{}}, as \type {\macro} or as sequence of characters with catcode 11 or 12 \NC \NR

-\NC \type{scan_argument}  \NC                    \NC this one is simular to \type {scanstring} but also accepts a \type {\cs}

-                                                     (which then get expanded) \NC \NR

-\NC \type{scan_word}      \NC                    \NC returns a sequence of characters with catcode 11 or 12 as string \NC \NR

-\NC \type{scan_csname}    \NC                    \NC returns \type {foo} after scanning \type {\foo} \NC \NR

-\NC \type{scan_list}      \NC                    \NC picks up a box specification and returns a \type {[h|v]list} node \NC \NR

-\LL

-\stoptabulate

-

-The scanners can be considered stable apart from the one scanning for a token.

-The \type {scan_code} function takes an optional number, the \type {keyword}

-function a normal \LUA\ string. The \type {infinity} boolean signals that we also

-permit \type {fill} as dimension and the \type {mu-units} flags the scanner that

-we expect math units. When scanning tokens we can indicate that we are defining a

-macro, in which case the result will also provide information about what

-arguments are expected and in the result this is separated from the meaning by a

-separator token. The \type {expand} flag determines if the list will be expanded.

-

-The string scanner scans for something between curly braces and expands on the

-way, or when it sees a control sequence it will return its meaning. Otherwise it

-will scan characters with catcode \type {letter} or \type {other}. So, given the

-following definition:

-

-\startbuffer

-\def\bar{bar}

-\def\foo{foo-\bar}

-\stopbuffer

-

-\typebuffer \getbuffer

-

-we get:

-

-\starttabulate[|l|Tl|l|]

-\DB name \BC result \NC \NR

-\TB

-\NC \type {\directlua{token.scan_string()}{foo}} \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")} {foo} \NC full expansion \NC \NR

-\NC \type {\directlua{token.scan_string()}foo}   \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")} foo   \NC letters and others \NC \NR

-\NC \type {\directlua{token.scan_string()}\foo}  \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")}\foo   \NC meaning \NC \NR

-\LL

-\stoptabulate

-

-The \type {\foo} case only gives the meaning, but one can pass an already

-expanded definition (\prm {edef}'d). In the case of the braced variant one can of

-course use the \prm {detokenize} and \prm {unexpanded} primitives since there we

-do expand.

-

-The \type {scan_word} scanner can be used to implement for instance a number scanner:

-

-\starttyping

-function token.scan_number(base)

-    return tonumber(token.scan_word(),base)

-end

-\stoptyping

-

-This scanner accepts any valid \LUA\ number so it is a way to pick up floats

-in the input.

-

-You can use the \LUA\ interface as follows:

-

-\starttyping

-\directlua {

-    function mymacro(n)

-        ...

-    end

-}

-

-\def\mymacro#1{%

-    \directlua {

-        mymacro(\number\dimexpr#1)

-    }%

-}

-

-\mymacro{12pt}

-\mymacro{\dimen0}

-\stoptyping

-

-You can also do this:

-

-\starttyping

-\directlua {

-    function mymacro()

-        local d = token.scan_dimen()

-        ...

-    end

-}

-

-\def\mymacro{%

-    \directlua {

-        mymacro()

-    }%

-}

-

-\mymacro 12pt

-\mymacro \dimen0

-\stoptyping

-

-It is quite clear from looking at the code what the first method needs as

-argument(s). For the second method you need to look at the \LUA\ code to see what

-gets picked up. Instead of passing from \TEX\ to \LUA\ we let \LUA\ fetch from

-the input stream.

-

-In the first case the input is tokenized and then turned into a string, then it

-is passed to \LUA\ where it gets interpreted. In the second case only a function

-call gets interpreted but then the input is picked up by explicitly calling the

-scanner functions. These return proper \LUA\ variables so no further conversion

-has to be done. This is more efficient but in practice (given what \TEX\ has to

-do) this effect should not be overestimated. For numbers and dimensions it saves

-a bit but for passing strings conversion to and from tokens has to be done anyway

-(although we can probably speed up the process in later versions if needed).

-

-\stopsubsection

-

-\startsubsection[title= {Picking up one token}]

-

-\libindex {get_next}

-\libindex {scan_token}

-\libindex {expand}

-

-The scanners look for a sequence. When you want to pick up one token from the

-input you use \type {get_next}. This creates a token with the (low level)

-properties as discussed next. This token is just the next one. If you want to

-enforce expansion first you can use \type {scan_token}. Internally tokens are

-characterized by a number that packs a lot of information. In order to access

-the bits of information a token is wrapped in a userdata object.

-

-The \type {expand} function will trigger expansion of the next token in the

-input. This can be quite unpredictable but when you call it you probably know

-enough about \TEX\ not to be too worried about that. It basically is a call to

-the internal expand related function.

-

-\stopsubsection

-

-\startsubsection[title={Creating tokens}]

-

-\libindex{create}

-\libindex{new}

-

-\libindex{is_defined}

-\libindex{is_token}

-\libindex{biggest_char}

-

-\libindex{commands}

-\libindex{command_id}

-

-\libindex{get_command}

-\libindex{get_cmdname}

-\libindex{get_csname}

-\libindex{get_id}

-\libindex{get_active}

-\libindex{get_expandable}

-\libindex{get_protected}

-\libindex{get_mode}

-\libindex{get_index}

-\libindex{get_tok}

-

-\libindex{get_next}

-

-The creator function can be used as follows:

-

-\starttyping

-local t = token.create("relax")

-\stoptyping

-

-This gives back a token object that has the properties of the \prm {relax}

-primitive. The possible properties of tokens are:

-

-\starttabulate[|l|p|]

-\DB name \BC explanation \NC \NR

-\TB

-\NC \type {command}    \NC a number representing the internal command number \NC \NR

-\NC \type {cmdname}    \NC the type of the command (for instance the catcode in case of a

-                           character or the classifier that determines the internal

-                           treatment \NC \NR

-\NC \type {csname}     \NC the associated control sequence (if applicable) \NC \NR

-\NC \type {id}         \NC the unique id of the token \NC \NR

-\NC \type {tok}        \NC the full token number as stored in \TEX \NC \NR

-\NC \type {active}     \NC a boolean indicating the active state of the token \NC \NR

-\NC \type {expandable} \NC a boolean indicating if the token (macro) is expandable \NC \NR

-\NC \type {protected}  \NC a boolean indicating if the token (macro) is protected \NC \NR

-\NC \type {mode}       \NC a number either representing a character or another entity \NC \NR

-\NC \type {index}      \NC a number running from 0x0000 upto 0xFFFF indicating a \TEX\ register index \NC \NR

-\LL

-\stoptabulate

-

-Alternatively you can use a getter \type {get_<fieldname>} to access a property

-of a token.

-

-The numbers that represent a catcode are the same as in \TEX\ itself, so using

-this information assumes that you know a bit about \TEX's internals. The other

-numbers and names are used consistently but are not frozen. So, when you use them

-for comparing you can best query a known primitive or character first to see the

-values.

-

-You can ask for a list of commands:

-

-\starttyping

-local t = token.commands()

-\stoptyping

-

-The id of a token class can be queried as follows:

-

-\starttyping

-local id = token.command_id("math_shift")

-\stoptyping

-

-If you really know what you're doing you can create character tokens by not

-passing a string but a number:

-

-\starttyping

-local letter_x = token.create(string.byte("x"))

-local other_x  = token.create(string.byte("x"),12)

-\stoptyping

-

-Passing weird numbers can give side effects so don't expect too much help with

-that. As said, you need to know what you're doing. The best way to explore the

-way these internals work is to just look at how primitives or macros or \prm

-{chardef}'d commands are tokenized. Just create a known one and inspect its

-fields. A variant that ignores the current catcode table is:

-

-\starttyping

-local whatever = token.new(123,12)

-\stoptyping

-

-You can test if a control sequence is defined with \type {is_defined}, which

-accepts a string and returns a boolean:

-

-\starttyping

-local okay = token.is_defined("foo")

-\stoptyping

-

-The largest character possible is returned by \type {biggest_char}, just in case you

-need to know that boundary condition.

-

-\stopsubsection

-

-\startsubsection[title={Macros}]

-

-\topicindex {macros}

-

-\libindex{set_macro}

-\libindex{get_macro}

-\libindex{get_meaning}

-\libindex{set_char}

-\libindex{set_lua}

-\libindex{get_functions_table}

-

-The \type {set_macro} function can get upto 4 arguments:

-

-\starttyping

-set_macro("csname","content")

-set_macro("csname","content","global")

-set_macro("csname")

-\stoptyping

-

-You can pass a catcodetable identifier as first argument:

-

-\starttyping

-set_macro(catcodetable,"csname","content")

-set_macro(catcodetable,"csname","content","global")

-set_macro(catcodetable,"csname")

-\stoptyping

-

-The results are like:

-

-\starttyping

- \def\csname{content}

-\gdef\csname{content}

- \def\csname{}

-\stoptyping

-

-The \type {get_macro} function can be used to get the content of a macro while

-the \type {get_meaning} function gives the meaning including the argument

-specification (as usual in \TEX\ separated by \type {->}).

-

-The \type {set_char} function can be used to do a \prm {chardef} at the

-\LUA\ end, where invalid assignments are silently ignored:

-

-\starttyping

-set_char("csname",number)

-set_char("csname",number,"global")

-\stoptyping

-

-A special one is the following:

-

-\starttyping

-set_lua("mycode",id)

-set_lua("mycode",id,"global","protected")

-\stoptyping

-

-This creates a token that refers to a \LUA\ function with an entry in the table

-that you can access with \type {lua.get_functions_table}. It is the companion

-to \lpr {luadef}.

-

-\stopsubsection

-

-\startsubsection[title={Pushing back}]

-

-\libindex{get_next}

-\libindex{put_next}

-

-There is a (for now) experimental putter:

-

-\starttyping

-local t1 = token.get_next()

-local t2 = token.get_next()

-local t3 = token.get_next()

-local t4 = token.get_next()

--- watch out, we flush in sequence

-token.put_next { t1, t2 }

--- but this one gets pushed in front

-token.put_next ( t3, t4 )

-\stoptyping

-

-When we scan \type {wxyz!} we get \type {yzwx!} back. The argument is either a table

-with tokens or a list of tokens. The \type {token.expand} function will trigger

-expansion but what happens really depends on what you're doing where.

-

-\stopsubsection

-

-\startsubsection[title={Nota bene}]

-

-When scanning for the next token you need to keep in mind that we're not scanning

-like \TEX\ does: expanding, changing modes and doing things as it goes. When we

-scan with \LUA\ we just pick up tokens. Say that we have:

-

-\starttyping

-\bar

-\stoptyping

-

-but \type {\bar} is undefined. Normally \TEX\ will then issue an error message.

-However, when we have:

-

-\starttyping

-\def\foo{\bar}

-\stoptyping

-

-We get no error, unless we expand \type {\foo} while \type {\bar} is still

-undefined. What happens is that as soon as \TEX\ sees an undefined macro it will

-create a hash entry and when later it gets defined that entry will be reused. So,

-\type {\bar} really exists but can be in an undefined state.

-

-\startbuffer[demo]

-bar        : \directlua{tex.print(token.scan_csname())}\bar

-foo        : \directlua{tex.print(token.scan_csname())}\foo

-myfirstbar : \directlua{tex.print(token.scan_csname())}\myfirstbar

-\stopbuffer

-

-\startlines

-\getbuffer[demo]

-\stoplines

-

-This was entered as:

-

-\typebuffer[demo]

-

-The reason that you see \type {bar} reported and not \type {myfirstbar} is that

-\type {\bar} was already used in a previous paragraph.

-

-If we now say:

-

-\startbuffer

-\def\foo{}

-\stopbuffer

-

-\typebuffer \getbuffer

-

-we get:

-

-\startlines

-\getbuffer[demo]

-\stoplines

-

-And if we say

-

-\startbuffer

-\def\foo{\bar}

-\stopbuffer

-

-\typebuffer \getbuffer

-

-we get:

-

-\startlines

-\getbuffer[demo]

-\stoplines

-

-When scanning from \LUA\ we are not in a mode that defines (undefined) macros at

-all. There we just get the real primitive undefined macro token.

-

-\startbuffer

-\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\myfirstbar

-\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\mysecondbar

-\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\mythirdbar

-\stopbuffer

-

-\startlines

-\getbuffer

-\stoplines

-

-This was generated with:

-

-\typebuffer

-

-So, we do get a unique token because after all we need some kind of \LUA\ object

-that can be used and garbage collected, but it is basically the same one,

-representing an undefined control sequence.

-

-\stopsubsection

-

-\stopsection

-

-\startsection[title={The \type {kpse} library}][library=kpse]

-

-\topicindex{libraries+\type{kpse}}

-

-This library provides two separate, but nearly identical interfaces to the

-\KPATHSEA\ file search functionality: there is a \quote {normal} procedural

-interface that shares its kpathsea instance with \LUATEX\ itself, and an object

-oriented interface that is completely on its own.

-

-\startsubsection[title={\type {set_program_name} and \type {new}}]

-

-\libindex{set_program_name}

-\libindex{default_texmfcnf}

-\libindex{new}

-

-The way the library looks up variables is driven by the \type {texmf.cmf} file

-where the currently set program name acts as filter. You can check what file is

-used by with \type {default_texmfcnf}.

-

-Before the search library can be used at all, its database has to be initialized.

-There are three possibilities, two of which belong to the procedural interface.

-

-First, when \LUATEX\ is used to typeset documents, this initialization happens

-automatically and the \KPATHSEA\ executable and program names are set to \type

-{luatex} (that is, unless explicitly prohibited by the user's startup script.

-See~\in {section} [init] for more details).

-

-Second, in \TEXLUA\ mode, the initialization has to be done explicitly via the

-\type {kpse.set_program_name} function, which sets the \KPATHSEA\ executable

-(and optionally program) name.

-

-\startfunctioncall

-kpse.set_program_name(<string> name)

-kpse.set_program_name(<string> name, <string> progname)

-\stopfunctioncall

-

-The second argument controls the use of the \quote {dotted} values in the \type

-{texmf.cnf} configuration file, and defaults to the first argument.

-

-Third, if you prefer the object oriented interface, you have to call a different

-function. It has the same arguments, but it returns a userdata variable.

-

-\startfunctioncall

-local kpathsea = kpse.new(<string> name)

-local kpathsea = kpse.new(<string> name, <string> progname)

-\stopfunctioncall

-

-Apart from these two functions, the calling conventions of the interfaces are

-identical. Depending on the chosen interface, you either call \type

-{kpse.find_file} or \type {kpathsea:find_file}, with identical arguments and

-return values.

-

-\stopsubsection

-

-\startsubsection[title={\type {record_input_file} and \type {record_output_file}}]

-

-\topicindex {files+recording}

-

-\libindex{record_input_file}

-\libindex{record_output_file}

-

-These two function can be used to register used files. Because callbacks can load

-files themselves you might need these helpers (if you use recording at all).

-

-\startfunctioncall

-kpse.record_input_file(<string> name)

-kpse.record_output_file(<string> name)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {find_file}}]

-

-\topicindex {files+finding}

-

-\libindex {find_file}

-

-The most often used function in the library is \type {find_file}:

-

-\startfunctioncall

-<string> f = kpse.find_file(<string> filename)

-<string> f = kpse.find_file(<string> filename, <string> ftype)

-<string> f = kpse.find_file(<string> filename, <boolean> mustexist)

-<string> f = kpse.find_file(<string> filename, <string> ftype, <boolean> mustexist)

-<string> f = kpse.find_file(<string> filename, <string> ftype, <number> dpi)

-\stopfunctioncall

-

-Arguments:

-

-\startitemize[intro]

-

-\sym{filename}

-

-the name of the file you want to find, with or without extension.

-

-\sym{ftype}

-

-maps to the \type {-format} argument of \KPSEWHICH. The supported \type {ftype}

-values are the same as the ones supported by the standalone \type {kpsewhich}

-program: \startluacode

-    local list = {

-        "afm",

-        "base",

-        "bib",

-        "bitmap font",

-        "bst",

-        "cid maps",

-        "clua",

-        "cmap files",

-        "cnf",

-        "cweb",

-        "dvips config",

-        "enc files",

-        "fmt",

-        "font feature files",

-        "gf",

-        "graphic|/|figure",

-        "ist",

-        "lig files",

-        "ls-R",

-        "lua",

-        "map",

-        "mem",

-        "MetaPost support",

-        "mf",

-        "mfpool",

-        "mft",

-        "misc fonts",

-        "mlbib",

-        "mlbst",

-        "mp",

-        "mppool",

-        "ocp",

-        "ofm",

-        "opentype fonts",

-        "opl",

-        "other binary files",

-        "other text files",

-        "otp",

-        "ovf",

-        "ovp",

-        "pdftex config",

-        "pk",

-        "PostScript header",

-        "subfont definition files",

-        "tex",

-        "TeX system documentation",

-        "TeX system sources",

-        "texmfscripts",

-        "texpool",

-        "tfm",

-        "Troff fonts",

-        "truetype fonts",

-        "type1 fonts",

-        "type42 fonts",

-        "vf",

-        "web",

-        "web2c files",

-    }

-    table.sort(list)

-    context("{\\tttf \letterpercent, t}",list)

-\stopluacode

-

-The default type is \type {tex}. Note: this is different from \KPSEWHICH, which

-tries to deduce the file type itself from looking at the supplied extension.

-

-\sym{mustexist}

-

-is similar to \KPSEWHICH's \type {-must-exist}, and the default is \type {false}.

-If you specify \type {true} (or a non|-|zero integer), then the \KPSE\ library

-will search the disk as well as the \type {ls-R} databases.

-

-\sym{dpi}

-

-This is used for the size argument of the formats \type {pk}, \type {gf}, and

-\type {bitmap font}. \stopitemize

-

-\stopsubsection

-

-\startsubsection[title={\type {lookup}}]

-

-\libindex{lookup}

-

-A more powerful (but slower) generic method for finding files is also available.

-It returns a string for each found file.

-

-\startfunctioncall

-<string> f, ... = kpse.lookup(<string> filename, <table> options)

-\stopfunctioncall

-

-The options match commandline arguments from \type {kpsewhich}:

-

-\starttabulate[|l|l|p|]

-\DB key              \BC type     \BC explanation \NC \NR

-\TB

-\NC \type{debug}     \NC number   \NC set debugging flags for this lookup\NC     \NR

-\NC \type{format}    \NC string   \NC use specific file type (see list above)\NC \NR

-\NC \type{dpi}       \NC number   \NC use this resolution for this lookup; default 600\NC \NR

-\NC \type{path}      \NC string   \NC search in the given path\NC \NR

-\NC \type{all}       \NC boolean  \NC output all matches, not just the first\NC \NR

-\NC \type{mustexist} \NC boolean  \NC search the disk as well as ls-R if necessary\NC \NR

-\NC \type{mktexpk}   \NC boolean  \NC disable/enable mktexpk generation for this lookup\NC \NR

-\NC \type{mktextex}  \NC boolean  \NC disable/enable mktextex generation for this lookup\NC \NR

-\NC \type{mktexmf}   \NC boolean  \NC disable/enable mktexmf generation for this lookup\NC \NR

-\NC \type{mktextfm}  \NC boolean  \NC disable/enable mktextfm generation for this lookup\NC \NR

-\NC \type{subdir}    \NC string

-                         or table \NC only output matches whose directory part

-                                      ends with the given string(s) \NC \NR

-\LL

-\stoptabulate

-

-\stopsubsection

-

-\startsubsection[title={\type {init_prog}}]

-

-\topicindex {initialization+bitmaps}

-

-\libindex{init_prog}

-

-Extra initialization for programs that need to generate bitmap fonts.

-

-\startfunctioncall

-kpse.init_prog(<string> prefix, <number> base_dpi, <string> mfmode)

-kpse.init_prog(<string> prefix, <number> base_dpi, <string> mfmode, <string> fallback)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {readable_file}}]

-

-\libindex{readable_file}

-

-Test if an (absolute) file name is a readable file.

-

-\startfunctioncall

-<string> f = kpse.readable_file(<string> name)

-\stopfunctioncall

-

-The return value is the actual absolute filename you should use, because the disk

-name is not always the same as the requested name, due to aliases and

-system|-|specific handling under e.g.\ \MSDOS. Returns \type {nil} if the file

-does not exist or is not readable.

-

-\stopsubsection

-

-\startsubsection[title={\type {expand_path}}]

-

-\libindex{expand_path}

-

-Like kpsewhich's \type {-expand-path}:

-

-\startfunctioncall

-<string> r = kpse.expand_path(<string> s)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {expand_var}}]

-

-\libindex{expand_var}

-

-Like kpsewhich's  \type {-expand-var}:

-

-\startfunctioncall

-<string> r = kpse.expand_var(<string> s)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {expand_braces}}]

-

-\libindex{expand_braces}

-

-Like kpsewhich's \type {-expand-braces}:

-

-\startfunctioncall

-<string> r = kpse.expand_braces(<string> s)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {show_path}}]

-

-\libindex{show_path}

-

-Like kpsewhich's \type {-show-path}:

-

-\startfunctioncall

-<string> r = kpse.show_path(<string> ftype)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {var_value}}]

-

-\libindex{var_value}

-

-Like kpsewhich's \type {-var-value}:

-

-\startfunctioncall

-<string> r = kpse.var_value(<string> s)

-\stopfunctioncall

-

-\stopsubsection

-

-\startsubsection[title={\type {version}}]

-

-\libindex{version}

-

-Returns the kpathsea version string.

-

-\startfunctioncall

-<string> r = kpse.version()

-\stopfunctioncall

-

-\stopsubsection

-

-\stopsection

-

-\stopchapter

-

-\stopcomponent

+% language=uk
+
+% lua.newtable
+
+\environment luatex-style
+
+\startcomponent luatex-tex
+
+\startchapter[reference=tex,title={The \TEX\ related libraries}]
+
+\startsection[title={The \type {lua} library}][library=lua]
+
+\startsubsection[title={Version information}]
+
+\topicindex{libraries+\type{lua}}
+\topicindex{version}
+
+\libindex{version}
+
+This library contains one read|-|only item:
+
+\starttyping
+<string> s = lua.version
+\stoptyping
+
+This returns the \LUA\ version identifier string. The value is currently
+\directlua {tex.print(lua.version)}.
+
+\stopsubsection
+
+\startsubsection[title={Bytecode registers}]
+
+\topicindex{bytecodes}
+\topicindex{registers+bytecodes}
+
+\libindex{bytecode}
+\libindex{setbytecode}
+\libindex{getbytecode}
+
+\LUA\ registers can be used to store \LUA\ code chunks. The accepted values for
+assignments are functions and \type {nil}. Likewise, the retrieved value is
+either a function or \type {nil}.
+
+\starttyping
+lua.bytecode[<number> n] = <function> f
+lua.bytecode[<number> n]()
+\stoptyping
+
+The contents of the \type {lua.bytecode} array is stored inside the format file
+as actual \LUA\ bytecode, so it can also be used to preload \LUA\ code. The
+function must not contain any upvalues. The associated function calls are:
+
+\startfunctioncall
+<function> f = lua.getbytecode(<number> n)
+lua.setbytecode(<number> n, <function> f)
+\stopfunctioncall
+
+Note: Since a \LUA\ file loaded using \type {loadfile(filename)} is essentially
+an anonymous function, a complete file can be stored in a bytecode register like
+this:
+
+\startfunctioncall
+lua.bytecode[n] = loadfile(filename)
+\stopfunctioncall
+
+Now all definitions (functions, variables) contained in the file can be
+created by executing this bytecode register:
+
+\startfunctioncall
+lua.bytecode[n]()
+\stopfunctioncall
+
+Note that the path of the file is stored in the \LUA\ bytecode to be used in
+stack backtraces and therefore dumped into the format file if the above code is
+used in \INITEX. If it contains private information, i.e. the user name, this
+information is then contained in the format file as well. This should be kept in
+mind when preloading files into a bytecode register in \INITEX.
+
+\stopsubsection
+
+\startsubsection[title={Chunk name registers}]
+
+\libindex{name}
+\libindex{setluaname}
+\libindex{getluaname}
+
+There is an array of 65536 (0--65535) potential chunk names for use with the
+\prm {directlua} and \lpr {latelua} primitives.
+
+\startfunctioncall
+lua.name[<number> n] = <string> s
+<string> s = lua.name[<number> n]
+\stopfunctioncall
+
+If you want to unset a \LUA\ name, you can assign \type {nil} to it. The function
+accessors are:
+
+\startfunctioncall
+lua.setluaname(<string> s,<number> n])
+<string> s = lua.getluaname(<number> n)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={Introspection}]
+
+\libindex{getstacktop}
+\libindex{getcalllevel}
+
+The \type {getstacktop} and\type {getcalllevel} functions return numbers
+indicating how much nesting is going on. They are only of use as breakpoints when
+checking some mechanism going haywire.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={The \type {status} library}][library=status]
+
+\topicindex{libraries+\type{status}}
+
+\libindex{list}
+\libindex{resetmessages}
+\libindex{setexitcode}
+
+This contains a number of run|-|time configuration items that you may find useful
+in message reporting, as well as an iterator function that gets all of the names
+and values as a table.
+
+\startfunctioncall
+<table> info = status.list()
+\stopfunctioncall
+
+The keys in the table are the known items, the value is the current value. Almost
+all of the values in \type {status} are fetched through a metatable at run|-|time
+whenever they are accessed, so you cannot use \type {pairs} on \type {status},
+but you {\it can\/} use \type {pairs} on \type {info}, of course. If you do not
+need the full list, you can also ask for a single item by using its name as an
+index into \type {status}. The current list is:
+
+\starttabulate[|l|p|]
+\DB key                       \BC explanation \NC \NR
+\TB
+\NC \type{banner}             \NC terminal display banner \NC \NR
+\NC \type{best_page_break}    \NC the current best break (a node) \NC \NR
+\NC \type{buf_size}           \NC current allocated size of the line buffer \NC \NR
+\NC \type{callbacks}          \NC total number of executed callbacks so far \NC \NR
+\NC \type{cs_count}           \NC number of control sequences \NC \NR
+\NC \type{dest_names_size}    \NC \PDF\ destination table size \NC \NR
+\NC \type{dvi_gone}           \NC written \DVI\ bytes \NC \NR
+\NC \type{dvi_ptr}            \NC not yet written \DVI\ bytes \NC \NR
+\NC \type{dyn_used}           \NC token (multi|-|word) memory in use  \NC \NR
+\NC \type{filename}           \NC name of the current input file \NC \NR
+\NC \type{fix_mem_end}        \NC maximum number of used tokens \NC \NR
+\NC \type{fix_mem_min}        \NC minimum number of allocated words for tokens \NC \NR
+\NC \type{fix_mem_max}        \NC maximum number of allocated words for tokens \NC \NR
+\NC \type{font_ptr}           \NC number of active fonts \NC \NR
+\NC \type{hash_extra}         \NC extra allowed hash \NC \NR
+\NC \type{hash_size}          \NC size of hash \NC \NR
+\NC \type{indirect_callbacks} \NC number of those that were themselves a result of other callbacks (e.g. file readers) \NC \NR
+\NC \type{ini_version}        \NC \type {true} if this is an \INITEX\ run \NC \NR
+\NC \type{init_pool_ptr}      \NC \INITEX\ string pool index \NC \NR
+\NC \type{init_str_ptr}       \NC number of \INITEX\ strings \NC \NR
+\NC \type{input_ptr}          \NC the level of input we're at \NC \NR
+\NC \type{inputid}            \NC numeric id of the current input \NC \NR
+\NC \type{largest_used_mark}  \NC max referenced marks class \NC \NR
+\NC \type{lasterrorcontext}   \NC last error context string (with newlines) \NC \NR
+\NC \type{lasterrorstring}    \NC last \TEX\ error string \NC \NR
+\NC \type{lastluaerrorstring} \NC last \LUA\ error string \NC \NR
+\NC \type{lastwarningstring}  \NC last warning tag, normally an indication of in what part\NC \NR
+\NC \type{lastwarningtag}     \NC last warning string\NC \NR
+\NC \type{linenumber}         \NC location in the current input file \NC \NR
+\NC \type{log_name}           \NC name of the log file \NC \NR
+\NC \type{luabytecode_bytes}  \NC number of bytes in \LUA\ bytecode registers \NC \NR
+\NC \type{luabytecodes}       \NC number of active \LUA\ bytecode registers \NC \NR
+\NC \type{luastate_bytes}     \NC number of bytes in use by \LUA\ interpreters \NC \NR
+\NC \type{luatex_engine}      \NC the \LUATEX\ engine identifier \NC \NR
+\NC \type{luatex_hashchars}   \NC length to which \LUA\ hashes strings ($2^n$) \NC \NR
+\NC \type{luatex_hashtype}    \NC the hash method used (in \LUAJITTEX) \NC \NR
+\NC \type{luatex_version}     \NC the \LUATEX\ version number \NC \NR
+\NC \type{luatex_revision}    \NC the \LUATEX\ revision string \NC \NR
+\NC \type{max_buf_stack}      \NC max used buffer position \NC \NR
+\NC \type{max_in_stack}       \NC max used input stack entries \NC \NR
+\NC \type{max_nest_stack}     \NC max used nesting stack entries \NC \NR
+\NC \type{max_param_stack}    \NC max used parameter stack entries \NC \NR
+\NC \type{max_save_stack}     \NC max used save stack entries \NC \NR
+\NC \type{max_strings}        \NC maximum allowed strings \NC \NR
+\NC \type{nest_size}          \NC nesting stack size \NC \NR
+\NC \type{node_mem_usage}     \NC a string giving insight into currently used nodes \NC \NR
+\NC \type{obj_ptr}            \NC max \PDF\ object pointer \NC \NR
+\NC \type{obj_tab_size}       \NC \PDF\ object table size \NC \NR
+\NC \type{output_active}      \NC \type {true} if the \prm {output} routine is active \NC \NR
+\NC \type{output_file_name}   \NC name of the \PDF\ or \DVI\ file \NC \NR
+\NC \type{param_size}         \NC parameter stack size \NC \NR
+\NC \type{pdf_dest_names_ptr} \NC max \PDF\ destination pointer \NC \NR
+\NC \type{pdf_gone}           \NC written \PDF\ bytes \NC \NR
+\NC \type{pdf_mem_ptr}        \NC max \PDF\ memory used \NC \NR
+\NC \type{pdf_mem_size}       \NC \PDF\ memory size \NC \NR
+\NC \type{pdf_os_cntr}        \NC max \PDF\ object stream pointer \NC \NR
+\NC \type{pdf_os_objidx}      \NC \PDF\ object stream index \NC \NR
+\NC \type{pdf_ptr}            \NC not yet written \PDF\ bytes \NC \NR
+\NC \type{pool_ptr}           \NC string pool index \NC \NR
+\NC \type{pool_size}          \NC current size allocated for string characters \NC \NR
+\NC \type{save_size}          \NC save stack size \NC \NR
+\NC \type{shell_escape}       \NC \type {0} means disabled, \type {1} means anything is permitted, and \type {2} is restricted \NC \NR
+\NC \type{safer_option}       \NC \type {1} means safer is enforced \NC \NR
+\NC \type{kpse_used}          \NC \type {1} means that kpse is used \NC \NR
+\NC \type{stack_size}         \NC input stack size \NC \NR
+\NC \type{str_ptr}            \NC number of strings \NC \NR
+\NC \type{total_pages}        \NC number of written pages \NC \NR
+\NC \type{var_mem_max}        \NC number of allocated words for nodes \NC \NR
+\NC \type{var_used}           \NC variable (one|-|word) memory in use \NC \NR
+\NC \type{lc_collate}         \NC the value of \type {LC_COLLATE}  at startup time (becomes \type {C} at startup) \NC \NR
+\NC \type{lc_ctype}           \NC the value of \type {LC_CTYPE}    at startup time (becomes \type {C} at startup) \NC \NR
+%NC \type{lc_monetary}        \NC the value of \type {LC_MONETARY} at startup time \NC \NR
+\NC \type{lc_numeric}         \NC the value of \type {LC_NUMERIC}  at startup time \NC \NR
+%NC \type{lc_time}            \NC the value of \type {LC_TIME}     at startup time (becomes \type {C} at startup) \NC \NR
+\LL
+\stoptabulate
+
+The error and warning messages can be wiped with the \type {resetmessages}
+function. A return value can be set with \type {setexitcode}.
+
+\stopsection
+
+\startsection[title={The \type {tex} library}][library=tex]
+
+\startsubsection[title={Introduction}]
+
+\topicindex{libraries+\type{tex}}
+
+The \type {tex} table contains a large list of virtual internal \TEX\
+parameters that are partially writable.
+
+The designation \quote {virtual} means that these items are not properly defined
+in \LUA, but are only front\-ends that are handled by a metatable that operates
+on the actual \TEX\ values. As a result, most of the \LUA\ table operators (like
+\type {pairs} and \type {#}) do not work on such items.
+
+At the moment, it is possible to access almost every parameter that you can use
+after \prm {the}, is a single tokens or is sort of special in \TEX. This excludes
+parameters that need extra arguments, like \type {\the\scriptfont}. The subset
+comprising simple integer and dimension registers are writable as well as
+readable (like \prm {tracingcommands} and \prm {parindent}).
+
+\stopsubsection
+
+\startsubsection[title={Internal parameter values, \type {set} and \type {get}}]
+
+\topicindex{parameters+internal}
+
+\libindex{set}           \libindex{get}
+
+For all the parameters in this section, it is possible to access them directly
+using their names as index in the \type {tex} table, or by using one of the
+functions \type {tex.get} and \type {tex.set}.
+
+The exact parameters and return values differ depending on the actual parameter,
+and so does whether \type {tex.set} has any effect. For the parameters that {\em
+can} be set, it is possible to use \type {global} as the first argument to \type
+{tex.set}; this makes the assignment global instead of local.
+
+\startfunctioncall
+tex.set (["global",] <string> n, ...)
+... = tex.get (<string> n)
+\stopfunctioncall
+
+Glue is kind of special because there are five values involved. The return value
+is a \nod {glue_spec} node but when you pass \type {false} as last argument to
+\type {tex.get} you get the width of the glue and when you pass \type {true} you
+get all five values. Otherwise you get a node which is a copy of the internal
+value so you are responsible for its freeing at the \LUA\ end. When you set a
+glue quantity you can either pass a \nod {glue_spec} or upto five numbers. If
+you pass \type {true} to \type {get} you get 5 values returned for a glue and
+when you pass \type {false} you only get the width returned.
+
+\subsubsection{Integer parameters}
+
+The integer parameters accept and return \LUA\ numbers. These are read|-|write:
+
+\starttwocolumns
+\starttyping
+tex.adjdemerits
+tex.binoppenalty
+tex.brokenpenalty
+tex.catcodetable
+tex.clubpenalty
+tex.day
+tex.defaulthyphenchar
+tex.defaultskewchar
+tex.delimiterfactor
+tex.displaywidowpenalty
+tex.doublehyphendemerits
+tex.endlinechar
+tex.errorcontextlines
+tex.escapechar
+tex.exhyphenpenalty
+tex.fam
+tex.finalhyphendemerits
+tex.floatingpenalty
+tex.globaldefs
+tex.hangafter
+tex.hbadness
+tex.holdinginserts
+tex.hyphenpenalty
+tex.interlinepenalty
+tex.language
+tex.lastlinefit
+tex.lefthyphenmin
+tex.linepenalty
+tex.localbrokenpenalty
+tex.localinterlinepenalty
+tex.looseness
+tex.mag
+tex.maxdeadcycles
+tex.month
+tex.newlinechar
+tex.outputpenalty
+tex.pausing
+tex.postdisplaypenalty
+tex.predisplaydirection
+tex.predisplaypenalty
+tex.pretolerance
+tex.relpenalty
+tex.righthyphenmin
+tex.savinghyphcodes
+tex.savingvdiscards
+tex.showboxbreadth
+tex.showboxdepth
+tex.time
+tex.tolerance
+tex.tracingassigns
+tex.tracingcommands
+tex.tracinggroups
+tex.tracingifs
+tex.tracinglostchars
+tex.tracingmacros
+tex.tracingnesting
+tex.tracingonline
+tex.tracingoutput
+tex.tracingpages
+tex.tracingparagraphs
+tex.tracingrestores
+tex.tracingscantokens
+tex.tracingstats
+tex.uchyph
+tex.vbadness
+tex.widowpenalty
+tex.year
+\stoptyping
+\stoptwocolumns
+
+These are read|-|only:
+
+\startthreecolumns
+\starttyping
+tex.deadcycles
+tex.insertpenalties
+tex.parshape
+tex.prevgraf
+tex.spacefactor
+\stoptyping
+\stopthreecolumns
+
+\subsubsection{Dimension parameters}
+
+The dimension parameters accept \LUA\ numbers (signifying scaled points) or
+strings (with included dimension). The result is always a number in scaled
+points. These are read|-|write:
+
+\startthreecolumns
+\starttyping
+tex.boxmaxdepth
+tex.delimitershortfall
+tex.displayindent
+tex.displaywidth
+tex.emergencystretch
+tex.hangindent
+tex.hfuzz
+tex.hoffset
+tex.hsize
+tex.lineskiplimit
+tex.mathsurround
+tex.maxdepth
+tex.nulldelimiterspace
+tex.overfullrule
+tex.pagebottomoffset
+tex.pageheight
+tex.pageleftoffset
+tex.pagerightoffset
+tex.pagetopoffset
+tex.pagewidth
+tex.parindent
+tex.predisplaysize
+tex.scriptspace
+tex.splitmaxdepth
+tex.vfuzz
+tex.voffset
+tex.vsize
+tex.prevdepth
+tex.prevgraf
+tex.spacefactor
+\stoptyping
+\stopthreecolumns
+
+These are read|-|only:
+
+\startthreecolumns
+\starttyping
+tex.pagedepth
+tex.pagefilllstretch
+tex.pagefillstretch
+tex.pagefilstretch
+tex.pagegoal
+tex.pageshrink
+tex.pagestretch
+tex.pagetotal
+\stoptyping
+\stopthreecolumns
+
+Beware: as with all \LUA\ tables you can add values to them. So, the following is
+valid:
+
+\starttyping
+tex.foo = 123
+\stoptyping
+
+When you access a \TEX\ parameter a look up takes place. For read||only variables
+that means that you will get something back, but when you set them you create a
+new entry in the table thereby making the original invisible.
+
+There are a few special cases that we make an exception for: \type {prevdepth},
+\type {prevgraf} and \type {spacefactor}. These normally are accessed via the
+\type {tex.nest} table:
+
+\starttyping
+tex.nest[tex.nest.ptr].prevdepth   = p
+tex.nest[tex.nest.ptr].spacefactor = s
+\stoptyping
+
+However, the following also works:
+
+\starttyping
+tex.prevdepth   = p
+tex.spacefactor = s
+\stoptyping
+
+Keep in mind that when you mess with node lists directly at the \LUA\ end you
+might need to update the top of the nesting stack's \type {prevdepth} explicitly
+as there is no way \LUATEX\ can guess your intentions. By using the accessor in
+the \type {tex} tables, you get and set the values at the top of the nesting
+stack.
+
+\subsubsection{Direction parameters}
+
+The direction parameters are read|-|only and return a \LUA\ string.
+
+\startthreecolumns
+\starttyping
+tex.bodydir
+tex.mathdir
+tex.pagedir
+tex.pardir
+tex.textdir
+\stoptyping
+\stopthreecolumns
+
+\subsubsection{Glue parameters}
+
+The glue parameters accept and return a userdata object that represents a \nod {glue_spec} node.
+
+\startthreecolumns
+\starttyping
+tex.abovedisplayshortskip
+tex.abovedisplayskip
+tex.baselineskip
+tex.belowdisplayshortskip
+tex.belowdisplayskip
+tex.leftskip
+tex.lineskip
+tex.parfillskip
+tex.parskip
+tex.rightskip
+tex.spaceskip
+tex.splittopskip
+tex.tabskip
+tex.topskip
+tex.xspaceskip
+\stoptyping
+\stopthreecolumns
+
+\subsubsection{Muglue parameters}
+
+All muglue parameters are to be used read|-|only and return a \LUA\ string.
+
+\startthreecolumns
+\starttyping
+tex.medmuskip
+tex.thickmuskip
+tex.thinmuskip
+\stoptyping
+\stopthreecolumns
+
+\subsubsection{Tokenlist parameters}
+
+The tokenlist parameters accept and return \LUA\ strings. \LUA\ strings are
+converted to and from token lists using \prm {the} \prm {toks} style expansion:
+all category codes are either space (10) or other (12). It follows that assigning
+to some of these, like \quote {tex.output}, is actually useless, but it feels bad
+to make exceptions in view of a coming extension that will accept full|-|blown
+token strings.
+
+\startthreecolumns
+\starttyping
+tex.errhelp
+tex.everycr
+tex.everydisplay
+tex.everyeof
+tex.everyhbox
+tex.everyjob
+tex.everymath
+tex.everypar
+tex.everyvbox
+tex.output
+\stoptyping
+\stopthreecolumns
+
+\stopsubsection
+
+\startsubsection[title={Convert commands}]
+
+\topicindex{convert commands}
+
+All \quote {convert} commands are read|-|only and return a \LUA\ string. The
+supported commands at this moment are:
+
+\starttwocolumns
+\starttyping
+tex.eTeXVersion
+tex.eTeXrevision
+tex.formatname
+tex.jobname
+tex.luatexbanner
+tex.luatexrevision
+tex.fontname(number)
+tex.uniformdeviate(number)
+tex.number(number)
+tex.romannumeral(number)
+tex.fontidentifier(number)
+\stoptyping
+\stoptwocolumns
+
+If you are wondering why this list looks haphazard; these are all the cases of
+the \quote {convert} internal command that do not require an argument, as well as
+the ones that require only a simple numeric value. The special (\LUA|-|only) case
+of \type {tex.fontidentifier} returns the \type {csname} string that matches a
+font id number (if there is one).
+
+\stopsubsection
+
+\startsubsection[title={Last item commands}]
+
+\topicindex{last items}
+
+All \quote {last item} commands are read|-|only and return a number. The
+supported commands at this moment are:
+
+\startthreecolumns
+\starttyping
+tex.lastpenalty
+tex.lastkern
+tex.lastskip
+tex.lastnodetype
+tex.inputlineno
+tex.lastxpos
+tex.lastypos
+tex.randomseed
+tex.luatexversion
+tex.eTeXminorversion
+tex.eTeXversion
+tex.currentgrouplevel
+tex.currentgrouptype
+tex.currentiflevel
+tex.currentiftype
+tex.currentifbranch
+\stoptyping
+\stopthreecolumns
+
+\stopsubsection
+
+\startsubsection[title={Accessing registers: \type {set*}, \type {get*} and \type {is*}}]
+
+\topicindex{attributes}
+\topicindex{registers}
+
+\libindex{attribute}  \libindex{setattribute}  \libindex{getattribute}  \libindex{isattribute}
+\libindex{count}      \libindex{setcount}      \libindex{getcount}      \libindex{iscount}
+\libindex{dimen}      \libindex{setdimen}      \libindex{getdimen}      \libindex{isdimen}
+\libindex{skip}       \libindex{setskip}       \libindex{getskip}       \libindex{isskip}
+\libindex{muskip}     \libindex{setmuskip}     \libindex{getmuskip}     \libindex{ismuskip}
+\libindex{glue}       \libindex{setglue}       \libindex{getglue}       \libindex{isglue}
+\libindex{muglue}     \libindex{setmuglue}     \libindex{getmuglue}     \libindex{ismuglue}
+\libindex{toks}       \libindex{settoks}       \libindex{gettoks}       \libindex{istoks}
+\libindex{box}        \libindex{setbox}        \libindex{getbox}        \libindex{isbox}
+
+\libindex{scantoks}
+
+\TEX's attributes (\lpr {attribute}), counters (\prm {count}), dimensions (\prm
+{dimen}), skips (\prm {skip}, \prm {muskip}) and token (\prm {toks}) registers
+can be accessed and written to using two times five virtual sub|-|tables of the
+\type {tex} table:
+
+\startthreecolumns
+\starttyping
+tex.attribute
+tex.count
+tex.dimen
+tex.skip
+tex.glue
+tex.muskip
+tex.muglue
+tex.toks
+\stoptyping
+\stopthreecolumns
+
+It is possible to use the names of relevant \lpr {attributedef}, \prm {countdef},
+\prm {dimendef}, \prm {skipdef}, or \prm {toksdef} control sequences as indices
+to these tables:
+
+\starttyping
+tex.count.scratchcounter = 0
+enormous = tex.dimen['maxdimen']
+\stoptyping
+
+In this case, \LUATEX\ looks up the value for you on the fly. You have to use a
+valid \prm {countdef} (or \lpr {attributedef}, or \prm {dimendef}, or \prm
+{skipdef}, or \prm {toksdef}), anything else will generate an error (the intent
+is to eventually also allow \type {<chardef tokens>} and even macros that expand
+into a number).
+
+\startitemize
+
+    \startitem
+        The count registers accept and return \LUA\ numbers.
+    \stopitem
+
+    \startitem
+        The dimension registers accept \LUA\ numbers (in scaled points) or
+        strings (with an included absolute dimension; \type {em} and \type {ex}
+        and \type {px} are forbidden). The result is always a number in scaled
+        points.
+    \stopitem
+
+    \startitem
+        The token registers accept and return \LUA\ strings. \LUA\ strings are
+        converted to and from token lists using \prm {the} \prm {toks} style
+        expansion: all category codes are either space (10) or other (12).
+    \stopitem
+
+    \startitem
+        The skip registers accept and return \nod {glue_spec} userdata node
+        objects (see the description of the node interface elsewhere in this
+        manual).
+    \stopitem
+
+    \startitem
+        The glue registers are just skip registers but instead of userdata
+        are verbose.
+    \stopitem
+
+    \startitem
+        Like the counts, the attribute registers accept and return \LUA\ numbers.
+    \stopitem
+
+\stopitemize
+
+As an alternative to array addressing, there are also accessor functions defined
+for all cases, for example, here is the set of possibilities for \prm {skip}
+registers:
+
+\startfunctioncall
+tex.setskip (["global",] <number> n, <node> s)
+tex.setskip (["global",] <string> s, <node> s)
+<node> s = tex.getskip (<number> n)
+<node> s = tex.getskip (<string> s)
+\stopfunctioncall
+
+We have similar setters for \type {count}, \type {dimen}, \type {muskip}, and
+\type {toks}. Counters and dimen are represented by numbers, skips and muskips by
+nodes, and toks by strings.
+
+Again the glue variants are not using the \nod {glue-spec} userdata nodes. The
+\type {setglue} function accepts upto 5 arguments: width, stretch, shrink,
+stretch order and shrink order and the \type {getglue} function reports them,
+unless the second argument is \type {false} in which care only the width is
+returned.
+
+Here is an example usign a threesome:
+
+\startfunctioncall
+local d = tex.getdimen("foo")
+if tex.isdimen("bar") then
+    tex.setdimen("bar",d)
+end
+\stopfunctioncall
+
+There are six extra skip (glue) related helpers:
+
+\startfunctioncall
+tex.setglue (["global"], <number> n,
+    width, stretch, shrink, stretch_order, shrink_order)
+tex.setglue (["global"], <string> s,
+    width, stretch, shrink, stretch_order, shrink_order)
+width, stretch, shrink, stretch_order, shrink_order =
+    tex.getglue (<number> n)
+width, stretch, shrink, stretch_order, shrink_order =
+    tex.getglue (<string> s)
+\stopfunctioncall
+
+The other two are \type {tex.setmuglue} and \type {tex.getmuglue}.
+
+There are such helpers for \type {dimen}, \type {count}, \type {skip}, \type
+{muskip}, \type {box} and \type {attribute} registers but the glue ones
+are special because they have to deal with more properties.
+
+As with the general \type {get} and \type {set} function discussed before, for
+the skip registers \type {getskip} returns a node and \type {getglue} returns
+numbers, while \type {setskip} accepts a node and \type {setglue} expects upto 5
+numbers. Again, when you pass \type {false} as second argument to \type {getglue}
+you only get the width returned. The same is true for the \type {mu} variants
+\type {getmuskip}, \type {setmuskip}, \type {getmuskip} and\type {setmuskip}.
+
+For tokens registers we have an alternative where a catcode table is specified:
+
+\startfunctioncall
+tex.scantoks(0,3,"$e=mc^2$")
+tex.scantoks("global",0,"$\int\limits^1_2$")
+\stopfunctioncall
+
+In the function-based interface, it is possible to define values globally by
+using the string \type {global} as the first function argument.
+
+\stopsubsection
+
+\startsubsection[title={Character code registers: \type {[get|set]*code[s]}}]
+
+\topicindex{characters+codes}
+
+\libindex{lccode}    \libindex{setlccode}    \libindex{getlccode}
+\libindex{uccode}    \libindex{setuccode}    \libindex{getuccode}
+\libindex{sfcode}    \libindex{setsfcode}    \libindex{getsfcode}
+\libindex{catcode}   \libindex{setcatcode}   \libindex{getcatcode}
+\libindex{mathcode}  \libindex{setmathcode}  \libindex{getmathcode}
+\libindex{delcode}   \libindex{setdelcode}   \libindex{getdelcode}
+
+\libindex{setdelcodes}   \libindex{getdelcodes}
+\libindex{setmathcodes}  \libindex{getmathcodes}
+
+\TEX's character code tables (\prm {lccode}, \prm {uccode}, \prm {sfcode}, \prm
+{catcode}, \prm {mathcode}, \prm {delcode}) can be accessed and written to using
+six virtual subtables of the \type {tex} table
+
+\startthreecolumns
+\starttyping
+tex.lccode
+tex.uccode
+tex.sfcode
+tex.catcode
+tex.mathcode
+tex.delcode
+\stoptyping
+\stopthreecolumns
+
+The function call interfaces are roughly as above, but there are a few twists.
+\type {sfcode}s are the simple ones:
+
+\startfunctioncall
+tex.setsfcode (["global",] <number> n, <number> s)
+<number> s = tex.getsfcode (<number> n)
+\stopfunctioncall
+
+The function call interface for \type {lccode} and \type {uccode} additionally
+allows you to set the associated sibling at the same time:
+
+\startfunctioncall
+tex.setlccode (["global"], <number> n, <number> lc)
+tex.setlccode (["global"], <number> n, <number> lc, <number> uc)
+<number> lc = tex.getlccode (<number> n)
+tex.setuccode (["global"], <number> n, <number> uc)
+tex.setuccode (["global"], <number> n, <number> uc, <number> lc)
+<number> uc = tex.getuccode (<number> n)
+\stopfunctioncall
+
+The function call interface for \type {catcode} also allows you to specify a
+category table to use on assignment or on query (default in both cases is the
+current one):
+
+\startfunctioncall
+tex.setcatcode (["global"], <number> n, <number> c)
+tex.setcatcode (["global"], <number> cattable, <number> n, <number> c)
+<number> lc = tex.getcatcode (<number> n)
+<number> lc = tex.getcatcode (<number> cattable, <number> n)
+\stopfunctioncall
+
+The interfaces for \type {delcode} and \type {mathcode} use small array tables to
+set and retrieve values:
+
+\startfunctioncall
+tex.setmathcode (["global"], <number> n, <table> mval )
+<table> mval = tex.getmathcode (<number> n)
+tex.setdelcode (["global"], <number> n, <table> dval )
+<table> dval = tex.getdelcode (<number> n)
+\stopfunctioncall
+
+Where the table for \type {mathcode} is an array of 3 numbers, like this:
+
+\starttyping
+{
+    <number> class,
+    <number> family,
+    <number> character
+}
+\stoptyping
+
+And the table for \type {delcode} is an array with 4 numbers, like this:
+
+\starttyping
+{
+    <number> small_fam,
+    <number> small_char,
+    <number> large_fam,
+    <number> large_char
+}
+\stoptyping
+
+You can also avoid the table:
+
+\startfunctioncall
+tex.setmathcode (["global"], <number> n, <number> class,
+    <number> family, <number> character)
+class, family, char =
+    tex.getmathcodes (<number> n)
+tex.setdelcode (["global"], <number> n, <number> smallfam,
+    <number> smallchar, <number> largefam, <number> largechar)
+smallfam, smallchar, largefam, largechar =
+    tex.getdelcodes (<number> n)
+\stopfunctioncall
+
+Normally, the third and fourth values in a delimiter code assignment will be zero
+according to \lpr {Udelcode} usage, but the returned table can have values there
+(if the delimiter code was set using \prm {delcode}, for example). Unset \type
+{delcode}'s can be recognized because \type {dval[1]} is $-1$.
+
+\stopsubsection
+
+\startsubsection[title={Box registers: \type {[get|set]box}}]
+
+\topicindex{registers}
+\topicindex{boxes}
+
+\libindex{box}
+\libindex{setbox}  \libindex{getbox}
+
+It is possible to set and query actual boxes, coming for instance from \prm
+{hbox}, \prm {vbox} or \prm {vtop}, using the node interface as defined in the
+\type {node} library:
+
+\starttyping
+tex.box
+\stoptyping
+
+for array access, or
+
+\starttyping
+tex.setbox(["global",] <number> n, <node> s)
+tex.setbox(["global",] <string> cs, <node> s)
+<node> n = tex.getbox(<number> n)
+<node> n = tex.getbox(<string> cs)
+\stoptyping
+
+for function|-|based access. In the function-based interface, it is possible to
+define values globally by using the string \type {global} as the first function
+argument.
+
+Be warned that an assignment like
+
+\starttyping
+tex.box[0] = tex.box[2]
+\stoptyping
+
+does not copy the node list, it just duplicates a node pointer. If \type {\box2}
+will be cleared by \TEX\ commands later on, the contents of \type {\box0} becomes
+invalid as well. To prevent this from happening, always use \type
+{node.copy_list} unless you are assigning to a temporary variable:
+
+\starttyping
+tex.box[0] = node.copy_list(tex.box[2])
+\stoptyping
+
+\stopsubsection
+
+\startsubsection[title={Reusing boxes: \type {[use|save]boxresource} and \type {getboxresourcedimensions}}]
+
+\topicindex{boxes+reuse}
+
+\libindex{useboxresource}
+\libindex{saveboxresource}
+\libindex{getboxresourcedimensions}
+
+The following function will register a box for reuse (this is modelled after so
+called xforms in \PDF). You can (re)use the box with \lpr {useboxresource} or
+by creating a rule node with subtype~2.
+
+\starttyping
+local index = tex.saveboxresource(n,attributes,resources,immediate,type,margin)
+\stoptyping
+
+The optional second and third arguments are strings, the fourth is a boolean. The
+fifth argument is a type. When set to non|-|zero the \type {/Type} entry is
+omitted. A value of 1 or 3 still writes a \type {/BBox}, while 2 or 3 will write
+a \type {/Matrix}. The sixth argument is the (virtual) margin that extends beyond
+the effective boundingbox as seen by \TEX. Instead of a box number one can also
+pass a \type {[h|v]list} node.
+
+You can generate the reference (a rule type) with:
+
+\starttyping
+local reused = tex.useboxresource(n,wd,ht,dp)
+\stoptyping
+
+The dimensions are optional and the final ones are returned as extra values. The
+following is just a bonus (no dimensions returned means that the resource is
+unknown):
+
+\starttyping
+local w, h, d, m = tex.getboxresourcedimensions(n)
+\stoptyping
+
+This returns the width, height, depth and margin of the resource.
+
+\stopsubsection
+
+\startsubsection[title={\type {triggerbuildpage}}]
+
+\topicindex{pages}
+
+\libindex{triggerbuildpage}
+
+You should not expect to much from the \type {triggerbuildpage} helpers because
+often \TEX\ doesn't do much if it thinks nothing has to be done, but it might be
+useful for some applications. It just does as it says it calls the internal
+function that build a page, given that there is something to build.
+
+\stopsubsection
+
+\startsubsection[title={\type {splitbox}}]
+
+\topicindex{boxes+split}
+
+\libindex{splitbox}
+
+You can split a box:
+
+\starttyping
+local vlist = tex.splitbox(n,height,mode)
+\stoptyping
+
+The remainder is kept in the original box and a packaged vlist is returned. This
+operation is comparable to the \prm {vsplit} operation. The mode can be \type
+{additional} or \type {exactly} and concerns the split off box.
+
+\stopsubsection
+
+\startsubsection[title={Accessing math parameters: \type {[get|set]math}}]
+
+\topicindex{math+parameters}
+\topicindex{parameters+math}
+
+\libindex{setmath}
+\libindex{getmath}
+
+It is possible to set and query the internal math parameters using:
+
+\startfunctioncall
+tex.setmath(["global",] <string> n, <string> t, <number> n)
+<number> n = tex.getmath(<string> n, <string> t)
+\stopfunctioncall
+
+As before an optional first parameter \type {global} indicates a global
+assignment.
+
+The first string is the parameter name minus the leading \quote {Umath}, and the
+second string is the style name minus the trailing \quote {style}. Just to be
+complete, the values for the math parameter name are:
+
+\starttyping
+quad                axis                operatorsize
+overbarkern         overbarrule         overbarvgap
+underbarkern        underbarrule        underbarvgap
+radicalkern         radicalrule         radicalvgap
+radicaldegreebefore radicaldegreeafter  radicaldegreeraise
+stackvgap           stacknumup          stackdenomdown
+fractionrule        fractionnumvgap     fractionnumup
+fractiondenomvgap   fractiondenomdown   fractiondelsize
+limitabovevgap      limitabovebgap      limitabovekern
+limitbelowvgap      limitbelowbgap      limitbelowkern
+underdelimitervgap  underdelimiterbgap
+overdelimitervgap   overdelimiterbgap
+subshiftdrop        supshiftdrop        subshiftdown
+subsupshiftdown     subtopmax           supshiftup
+supbottommin        supsubbottommax     subsupvgap
+spaceafterscript    connectoroverlapmin
+ordordspacing       ordopspacing        ordbinspacing     ordrelspacing
+ordopenspacing      ordclosespacing     ordpunctspacing   ordinnerspacing
+opordspacing        opopspacing         opbinspacing      oprelspacing
+opopenspacing       opclosespacing      oppunctspacing    opinnerspacing
+binordspacing       binopspacing        binbinspacing     binrelspacing
+binopenspacing      binclosespacing     binpunctspacing   bininnerspacing
+relordspacing       relopspacing        relbinspacing     relrelspacing
+relopenspacing      relclosespacing     relpunctspacing   relinnerspacing
+openordspacing      openopspacing       openbinspacing    openrelspacing
+openopenspacing     openclosespacing    openpunctspacing  openinnerspacing
+closeordspacing     closeopspacing      closebinspacing   closerelspacing
+closeopenspacing    closeclosespacing   closepunctspacing closeinnerspacing
+punctordspacing     punctopspacing      punctbinspacing   punctrelspacing
+punctopenspacing    punctclosespacing   punctpunctspacing punctinnerspacing
+innerordspacing     inneropspacing      innerbinspacing   innerrelspacing
+inneropenspacing    innerclosespacing   innerpunctspacing innerinnerspacing
+\stoptyping
+
+The values for the style parameter are:
+
+\starttyping
+display       crampeddisplay
+text          crampedtext
+script        crampedscript
+scriptscript  crampedscriptscript
+\stoptyping
+
+The value is either a number (representing a dimension or number) or a glue spec
+node representing a muskip for \type {ordordspacing} and similar spacing
+parameters.
+
+\stopsubsection
+
+\startsubsection[title={Special list heads: \type {[get|set]list}}]
+
+\topicindex{lists}
+
+\libindex{lists}
+\libindex{setlist}
+\libindex{getlist}
+
+The virtual table \type {tex.lists} contains the set of internal registers that
+keep track of building page lists.
+
+\starttabulate[|l|p|]
+\DB field                      \BC explanation \NC \NR
+\TB
+\NC \type{page_ins_head}       \NC circular list of pending insertions \NC \NR
+\NC \type{contrib_head}        \NC the recent contributions \NC \NR
+\NC \type{page_head}           \NC the current page content \NC \NR
+%NC \type{temp_head}           \NC \NC \NR
+\NC \type{hold_head}           \NC used for held-over items for next page \NC \NR
+\NC \type{adjust_head}         \NC head of the current \prm {vadjust} list \NC \NR
+\NC \type{pre_adjust_head}     \NC head of the current \type {\vadjust pre} list \NC \NR
+%NC \type{align_head}          \NC \NC \NR
+\NC \type{page_discards_head}  \NC head of the discarded items of a page break \NC \NR
+\NC \type{split_discards_head} \NC head of the discarded items in a vsplit \NC \NR
+\LL
+\stoptabulate
+
+The getter and setter functions are \type {getlist} and \type {setlist}. You have
+to be careful with what you set as \TEX\ can have expectations with regards to
+how a list is constructed or in what state it is.
+
+\stopsubsection
+
+\startsubsection[title={Semantic nest levels: \type {getnest} and \type {ptr}}]
+
+\topicindex{nesting}
+
+\libindex{nest}
+\libindex{ptr}
+%libindex{setnest} % only a message
+\libindex{getnest}
+
+The virtual table \type {nest} contains the currently active semantic nesting
+state. It has two main parts: a zero-based array of userdata for the semantic
+nest itself, and the numerical value \type {ptr}, which gives the highest
+available index. Neither the array items in \type {nest[]} nor \type {ptr} can be
+assigned to (as this would confuse the typesetting engine beyond repair), but you
+can assign to the individual values inside the array items, e.g.\ \type
+{tex.nest[tex.nest.ptr].prevdepth}.
+
+\type {tex.nest[tex.nest.ptr]} is the current nest state, \type {nest[0]} the
+outermost (main vertical list) level. The getter function is \type {getnest}. You
+can pass a number (which gives you a list), nothing or \type {top}, which returns
+the topmost list, or the string \type {ptr} which gives you the index of the
+topmost list.
+
+The known fields are:
+
+\starttabulate[|l|l|l|p|]
+\DB key                \BC type    \BC modes \BC explanation \NC \NR
+\TB
+\NC \type{mode}        \NC number  \NC all   \NC the meaning of these numbers depends on the engine
+                                                 and sometimes even the version; you can use \typ
+                                                 {tex.getmodevalues()} to get the mapping: positive
+                                                 values signal vertical, horizontal and math mode,
+                                                 while negative values indicate inner and inline
+                                                 variants \NC \NR
+\NC \type{modeline}    \NC number  \NC all   \NC source input line where this mode was entered in,
+                                                 negative inside the output routine \NC \NR
+\NC \type{head}        \NC node    \NC all   \NC the head of the current list \NC \NR
+\NC \type{tail}        \NC node    \NC all   \NC the tail of the current list \NC \NR
+\NC \type{prevgraf}    \NC number  \NC vmode \NC number of lines in the previous paragraph \NC \NR
+\NC \type{prevdepth}   \NC number  \NC vmode \NC depth of the previous paragraph \NC \NR
+\NC \type{spacefactor} \NC number  \NC hmode \NC the current space factor \NC \NR
+\NC \type{dirs}        \NC node    \NC hmode \NC used for temporary storage by the line break algorithm\NC \NR
+\NC \type{noad}        \NC node    \NC mmode \NC used for temporary storage of a pending fraction numerator,
+                                                 for \prm {over} etc. \NC \NR
+\NC \type{delimptr}    \NC node    \NC mmode \NC used for temporary storage of the previous math delimiter,
+                                                 for \prm {middle} \NC \NR
+\NC \type{mathdir}     \NC boolean \NC mmode \NC true when during math processing the \lpr {mathdir} is not
+                                                 the same as the surrounding \lpr {textdir} \NC \NR
+\NC \type{mathstyle}   \NC number  \NC mmode \NC the current \lpr {mathstyle} \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[reference=sec:luaprint,title={Print functions}]
+
+\topicindex{printing}
+
+The \type {tex} table also contains the three print functions that are the major
+interface from \LUA\ scripting to \TEX. The arguments to these three functions
+are all stored in an in|-|memory virtual file that is fed to the \TEX\ scanner as
+the result of the expansion of \prm {directlua}.
+
+The total amount of returnable text from a \prm {directlua} command is only
+limited by available system \RAM. However, each separate printed string has to
+fit completely in \TEX's input buffer. The result of using these functions from
+inside callbacks is undefined at the moment.
+
+\subsubsection{\type {print}}
+
+\libindex{print}
+
+\startfunctioncall
+tex.print(<string> s, ...)
+tex.print(<number> n, <string> s, ...)
+tex.print(<table> t)
+tex.print(<number> n, <table> t)
+\stopfunctioncall
+
+Each string argument is treated by \TEX\ as a separate input line. If there is a
+table argument instead of a list of strings, this has to be a consecutive array
+of strings to print (the first non-string value will stop the printing process).
+
+The optional parameter can be used to print the strings using the catcode regime
+defined by \lpr {catcodetable}~\type {n}. If \type {n} is $-1$, the currently
+active catcode regime is used. If \type {n} is $-2$, the resulting catcodes are
+the result of \prm {the} \prm {toks}: all category codes are 12 (other) except for
+the space character, that has category code 10 (space). Otherwise, if \type {n}
+is not a valid catcode table, then it is ignored, and the currently active
+catcode regime is used instead.
+
+The very last string of the very last \type {tex.print} command in a \prm
+{directlua} will not have the \prm {endlinechar} appended, all others do.
+
+\subsubsection{\type {sprint}}
+
+\libindex{sprint}
+
+\startfunctioncall
+tex.sprint(<string> s, ...)
+tex.sprint(<number> n, <string> s, ...)
+tex.sprint(<table> t)
+tex.sprint(<number> n, <table> t)
+\stopfunctioncall
+
+Each string argument is treated by \TEX\ as a special kind of input line that
+makes it suitable for use as a partial line input mechanism:
+
+\startitemize[packed]
+\startitem
+    \TEX\ does not switch to the \quote {new line} state, so that leading spaces
+    are not ignored.
+\stopitem
+\startitem
+    No \prm {endlinechar} is inserted.
+\stopitem
+\startitem
+    Trailing spaces are not removed. Note that this does not prevent \TEX\ itself
+    from eating spaces as result of interpreting the line. For example, in
+
+    \starttyping
+    before\directlua{tex.sprint("\\relax")tex.sprint(" inbetween")}after
+    \stoptyping
+
+    the space before \type {in between} will be gobbled as a result of the \quote
+    {normal} scanning of \prm {relax}.
+\stopitem
+\stopitemize
+
+If there is a table argument instead of a list of strings, this has to be a
+consecutive array of strings to print (the first non-string value will stop the
+printing process).
+
+The optional argument sets the catcode regime, as with \type {tex.print}. This
+influences the string arguments (or numbers turned into strings).
+
+Although this needs to be used with care, you can also pass token or node
+userdata objects. These get injected into the stream. Tokens had best be valid
+tokens, while nodes need to be around when they get injected. Therefore it is
+important to realize the following:
+
+\startitemize
+\startitem
+    When you inject a token, you need to pass a valid token userdata object. This
+    object will be collected by \LUA\ when it no longer is referenced. When it gets
+    printed to \TEX\ the token itself gets copied so there is no interference with the
+    \LUA\ garbage collection. You manage the object yourself. Because tokens are
+    actually just numbers, there is no real extra overhead at the \TEX\ end.
+\stopitem
+\startitem
+    When you inject a node, you need to pass a valid node userdata object. The
+    node related to the object will not be collected by \LUA\ when it no longer
+    is referenced. It lives on at the \TEX\ end in its own memory space. When it
+    gets printed to \TEX\ the node reference is used assuming that node stays
+    around. There is no \LUA\ garbage collection involved. Again, you manage the
+    object yourself. The node itself is freed when \TEX\ is done with it.
+\stopitem
+\stopitemize
+
+If you consider the last remark you might realize that we have a problem when a
+printed mix of strings, tokens and nodes is reused. Inside \TEX\ the sequence
+becomes a linked list of input buffers. So, \type {"123"} or \type {"\foo{123}"}
+gets read and parsed on the fly, while \typ {<token userdata>} already is
+tokenized and effectively is a token list now. A \typ {<node userdata>} is also
+tokenized into a token list but it has a reference to a real node. Normally this
+goes fine. But now assume that you store the whole lot in a macro: in that case
+the tokenized node can be flushed many times. But, after the first such flush the
+node is used and its memory freed. You can prevent this by using copies which is
+controlled by setting \lpr {luacopyinputnodes} to a non|-|zero value. This is one
+of these fuzzy areas you have to live with if you really mess with these low
+level issues.
+
+\subsubsection{\type {tprint}}
+
+\libindex{tprint}
+
+\startfunctioncall
+tex.tprint({<number> n, <string> s, ...}, {...})
+\stopfunctioncall
+
+This function is basically a shortcut for repeated calls to \type
+{tex.sprint(<number> n, <string> s, ...)}, once for each of the supplied argument
+tables.
+
+\subsubsection{\type {cprint}}
+
+\libindex{cprint}
+
+This function takes a number indicating the to be used catcode, plus either a
+table of strings or an argument list of strings that will be pushed into the
+input stream.
+
+\startfunctioncall
+tex.cprint( 1," 1: $&{\\foo}") tex.print("\\par") -- a lot of \bgroup s
+tex.cprint( 2," 2: $&{\\foo}") tex.print("\\par") -- matching \egroup s
+tex.cprint( 9," 9: $&{\\foo}") tex.print("\\par") -- all get ignored
+tex.cprint(10,"10: $&{\\foo}") tex.print("\\par") -- all become spaces
+tex.cprint(11,"11: $&{\\foo}") tex.print("\\par") -- letters
+tex.cprint(12,"12: $&{\\foo}") tex.print("\\par") -- other characters
+tex.cprint(14,"12: $&{\\foo}") tex.print("\\par") -- comment triggers
+\stopfunctioncall
+
+% \subsubsection{\type {write}, \type {twrite}, \type {nwrite}}
+\subsubsection{\type {write}}
+
+\libindex{write}
+% \libindex{twrite}
+% \libindex{nwrite}
+
+\startfunctioncall
+tex.write(<string> s, ...)
+tex.write(<table> t)
+\stopfunctioncall
+
+Each string argument is treated by \TEX\ as a special kind of input line that
+makes it suitable for use as a quick way to dump information:
+
+\startitemize
+\item All catcodes on that line are either \quote{space} (for '~') or \quote
+      {character} (for all others).
+\item There is no \prm {endlinechar} appended.
+\stopitemize
+
+If there is a table argument instead of a list of strings, this has to be a
+consecutive array of strings to print (the first non-string value will stop the
+printing process).
+
+% The functions \type {twrite} and \type {nwrite} can be used to write a token or
+% node back to \TEX\, possibly intermixed with regular strings that will be
+% tokenized. You have to make sure that you pass the right data because sometimes
+% \TEX\ has expectations that need to be met.
+
+\stopsubsection
+
+\startsubsection[title={Helper functions}]
+
+\subsubsection{\type {round}}
+
+\topicindex {helpers}
+
+\libindex{round}
+
+\startfunctioncall
+<number> n = tex.round(<number> o)
+\stopfunctioncall
+
+Rounds \LUA\ number \type {o}, and returns a number that is in the range of a
+valid \TEX\ register value. If the number starts out of range, it generates a
+\quote {number too big} error as well.
+
+\subsubsection{\type {scale}}
+
+\libindex{scale}
+
+\startfunctioncall
+<number> n = tex.scale(<number> o, <number> delta)
+<table> n = tex.scale(table o, <number> delta)
+\stopfunctioncall
+
+Multiplies the \LUA\ numbers \type {o} and \nod {delta}, and returns a rounded
+number that is in the range of a valid \TEX\ register value. In the table
+version, it creates a copy of the table with all numeric top||level values scaled
+in that manner. If the multiplied number(s) are of range, it generates
+\quote{number too big} error(s) as well.
+
+Note: the precision of the output of this function will depend on your computer's
+architecture and operating system, so use with care! An interface to \LUATEX's
+internal, 100\% portable scale function will be added at a later date.
+
+\subsubsection{\type {number} and \type {romannumeral}}
+
+\libindex{number}
+\libindex{romannumeral}
+
+These are the companions to the primitives \prm {number} and \prm
+{romannumeral}. They can be used like:
+
+\startfunctioncall
+tex.print(tex.romannumeral(123))
+\stopfunctioncall
+
+\subsubsection{\type {fontidentifier} and \type {fontname}}
+
+\libindex{fontidentifier}
+\libindex{fontname}
+
+The first one returns the name only, the second one reports the size too.
+
+\startfunctioncall
+tex.print(tex.fontname(tex.fontname))
+tex.print(tex.fontname(tex.fontidentidier))
+\stopfunctioncall
+
+\subsubsection{\type {sp}}
+
+\libindex{sp}
+
+\startfunctioncall
+<number> n = tex.sp(<number> o)
+<number> n = tex.sp(<string> s)
+\stopfunctioncall
+
+Converts the number \type {o} or a string \type {s} that represents an explicit
+dimension into an integer number of scaled points.
+
+For parsing the string, the same scanning and conversion rules are used that
+\LUATEX\ would use if it was scanning a dimension specifier in its \TEX|-|like
+input language (this includes generating errors for bad values), expect for the
+following:
+
+\startitemize[n]
+\startitem
+    only explicit values are allowed, control sequences are not handled
+\stopitem
+\startitem
+    infinite dimension units (\type {fil...}) are forbidden
+\stopitem
+\startitem
+    \type {mu} units do not generate an error (but may not be useful either)
+\stopitem
+\stopitemize
+
+\subsubsection{\type {tex.getlinenumber} and \type {tex.setlinenumber}}
+
+\libindex{getlinenumber}
+\libindex{setlinenumber}
+
+You can mess with the current line number:
+
+\startfunctioncall
+local n = tex.getlinenumber()
+tex.setlinenumber(n+10)
+\stopfunctioncall
+
+which can be shortcut to:
+
+\startfunctioncall
+tex.setlinenumber(10,true)
+\stopfunctioncall
+
+This might be handy when you have a callback that read numbers from a file and
+combines them in one line (in which case an error message probably has to refer
+to the original line). Interference with \TEX's internal handling of numbers is
+of course possible.
+
+\subsubsection{\type {error} and \type {show_context}}
+
+\topicindex{errors}
+
+\libindex{error}
+\libindex{show_context}
+
+\startfunctioncall
+tex.error(<string> s)
+tex.error(<string> s, <table> help)
+\stopfunctioncall
+
+This creates an error somewhat like the combination of \prm {errhelp} and \prm
+{errmessage} would. During this error, deletions are disabled.
+
+The array part of the \type {help} table has to contain strings, one for each
+line of error help.
+
+In case of an error the \type {show_context} function will show the current
+context where we're at (in the expansion).
+
+\subsubsection{\type {run}, \type {finish}}
+
+\libindex{run}
+\libindex{finish}
+
+These two functions start the interpretations and force its end. A runs normally
+boils down to \TEX\ entering the so called main loop. A token is fetched and
+depending on it current meaning some actions takes place. Sometimes that actions
+comes immediately, sometimes more scanning is needed. Quite often tokens get
+pushed back into the input. This all means that the \TEX\ scanner is constantly
+pushing and popping input states, but in the end after all the action is done
+returns to the main loop.
+
+\subsubsection{\type {runtoks}}
+
+Because of the fact that \TEX\ is in a complex dance of expanding, dealing with
+fonts, typesetting paragraphs, messing around with boxes, building pages, and so
+on, you cannot easily run a nested \TEX\ run (read nested main loop). However,
+there is an option to force a local run with \type {runtoks}. The content of the
+given token list register gets expanded locally after which we return to where we
+triggered this expansion, at the \LUA\ end. Instead a function can get passed
+that does some work. You have to make sure that at the end \TEX\ is in a sane
+state and this is not always trivial. A more complex mechanism would complicate
+\TEX\ itself (and probably also harm performance) so this simple local expansion
+loop has to do.
+
+\startfunctioncall
+tex.runtoks(<token register>)
+tex.runtoks(<lua function>)
+\stopfunctioncall
+
+When the \prm {tracingnesting} parameter is set to a value larger than~2 some
+information is reported about the state of the local loop.
+
+\subsubsection{\type {forcehmode}}
+
+\libindex{forcehmode}
+
+An example of a (possible error triggering) complication is that \TEX\ expects to
+be in some state, say horizontal mode, and you have to make sure it is when you
+start feeding back something from \LUA\ into \TEX. Normally a user will not run
+into issues but when you start writing tokens or nodes or have a nested run there
+can be situations that you need to run \type {forcehmode}. There is no recipe for
+this and intercepting possible cases would weaken \LUATEX's flexibility.
+
+\subsubsection{\type {hashtokens}}
+
+\libindex{hashtokens}
+
+\topicindex{hash}
+
+\startfunctioncall
+for i,v in pairs (tex.hashtokens()) do ... end
+\stopfunctioncall
+
+Returns a list of names. This can be useful for debugging, but note that this
+also reports control sequences that may be unreachable at this moment due to
+local redefinitions: it is strictly a dump of the hash table. You can use \type
+{token.create} to inspect properties, for instance when the \type {command} key
+in a created table equals \type {123}, you have the \type {cmdname} value \type
+{undefined_cs}.
+
+\subsubsection{\type {definefont}}
+
+\topicindex{fonts+defining}
+
+\libindex{definefont}
+
+\startfunctioncall
+tex.definefont(<string> csname, <number> fontid)
+tex.definefont(<boolean> global, <string> csname, <number> fontid)
+\stopfunctioncall
+
+Associates \type {csname} with the internal font number \type {fontid}. The
+definition is global if (and only if) \type {global} is specified and true (the
+setting of \type {globaldefs} is not taken into account).
+
+\stopsubsection
+
+\startsubsection[reference=luaprimitives,title={Functions for dealing with primitives}]
+
+\subsubsection{\type {enableprimitives}}
+
+\libindex{enableprimitives}
+
+\topicindex{initialization}
+\topicindex{primitives}
+
+\startfunctioncall
+tex.enableprimitives(<string> prefix, <table> primitive names)
+\stopfunctioncall
+
+This function accepts a prefix string and an array of primitive names. For each
+combination of \quote {prefix} and \quote {name}, the \type
+{tex.enableprimitives} first verifies that \quote {name} is an actual primitive
+(it must be returned by one of the \type {tex.extraprimitives} calls explained
+below, or part of \TEX82, or \prm {directlua}). If it is not, \type
+{tex.enableprimitives} does nothing and skips to the next pair.
+
+But if it is, then it will construct a csname variable by concatenating the
+\quote {prefix} and \quote {name}, unless the \quote {prefix} is already the
+actual prefix of \quote {name}. In the latter case, it will discard the \quote
+{prefix}, and just use \quote {name}.
+
+Then it will check for the existence of the constructed csname. If the csname is
+currently undefined (note: that is not the same as \prm {relax}), it will
+globally define the csname to have the meaning: run code belonging to the
+primitive \quote {name}. If for some reason the csname is already defined, it
+does nothing and tries the next pair.
+
+An example:
+
+\starttyping
+tex.enableprimitives('LuaTeX', {'formatname'})
+\stoptyping
+
+will define \type {\LuaTeXformatname} with the same intrinsic meaning as the
+documented primitive \lpr {formatname}, provided that the control sequences \type
+{\LuaTeXformatname} is currently undefined.
+
+When \LUATEX\ is run with \type {--ini} only the \TEX82 primitives and \prm
+{directlua} are available, so no extra primitives {\bf at all}.
+
+If you want to have all the new functionality available using their default
+names, as it is now, you will have to add
+
+\starttyping
+\ifx\directlua\undefined \else
+    \directlua {tex.enableprimitives('',tex.extraprimitives ())}
+\fi
+\stoptyping
+
+near the beginning of your format generation file. Or you can choose different
+prefixes for different subsets, as you see fit.
+
+Calling some form of \type {tex.enableprimitives} is highly important though,
+because if you do not, you will end up with a \TEX82-lookalike that can run \LUA\
+code but not do much else. The defined csnames are (of course) saved in the
+format and will be available at runtime.
+
+\subsubsection{\type {extraprimitives}}
+
+\libindex{extraprimitives}
+
+\startfunctioncall
+<table> t = tex.extraprimitives(<string> s, ...)
+\stopfunctioncall
+
+This function returns a list of the primitives that originate from the engine(s)
+given by the requested string value(s). The possible values and their (current)
+return values are given in the following table. In addition the somewhat special
+primitives \quote{\tex{ }}, \quote{\tex {/}} and \quote{\type {-}} are defined.
+
+\startluacode
+function document.showprimitives(tag)
+    for k, v in table.sortedpairs(tex.extraprimitives(tag)) do
+        if v ~= ' ' and v ~= "/" and v ~= "-" then
+            context.type(v)
+            context.space()
+        end
+    end
+end
+\stopluacode
+
+\starttabulate[|l|pl|]
+\DB name    \BC values \NC \NR
+\TB
+\NC tex     \NC \ctxlua{document.showprimitives('tex')    } \NC \NR
+\NC core    \NC \ctxlua{document.showprimitives('core')   } \NC \NR
+\NC etex    \NC \ctxlua{document.showprimitives('etex')   } \NC \NR
+\NC luatex  \NC \ctxlua{document.showprimitives('luatex') } \NC \NR
+\LL
+\stoptabulate
+
+Note that \type {luatex} does not contain \type {directlua}, as that is
+considered to be a core primitive, along with all the \TEX82 primitives, so it is
+part of the list that is returned from \type {'core'}.
+
+Running \type {tex.extraprimitives} will give you the complete list of
+primitives \type {-ini} startup. It is exactly equivalent to \type
+{tex.extraprimitives("etex","luatex")}.
+
+\subsubsection{\type {primitives}}
+
+\libindex{primitives}
+
+\startfunctioncall
+<table> t = tex.primitives()
+\stopfunctioncall
+
+This function returns a list of all primitives that \LUATEX\ knows about.
+
+\stopsubsection
+
+\startsubsection[title={Core functionality interfaces}]
+
+\subsubsection{\type {badness}}
+
+\libindex{badness}
+
+\startfunctioncall
+<number> b = tex.badness(<number> t, <number> s)
+\stopfunctioncall
+
+This helper function is useful during linebreak calculations. \type {t} and \type
+{s} are scaled values; the function returns the badness for when total \type {t}
+is supposed to be made from amounts that sum to \type {s}. The returned number is
+a reasonable approximation of \mathematics {100(t/s)^3};
+
+\subsubsection{\type {tex.resetparagraph}}
+
+\topicindex {paragraphs+reset}
+
+\libindex{resetparagraph}
+
+This function resets the parameters that \TEX\ normally resets when a new paragraph
+is seen.
+
+\subsubsection{\type {linebreak}}
+
+\topicindex {linebreaks}
+
+\libindex{linebreak}
+
+\startfunctioncall
+local <node> nodelist, <table> info =
+    tex.linebreak(<node> listhead, <table> parameters)
+\stopfunctioncall
+
+The understood parameters are as follows:
+
+\starttabulate[|l|l|p|]
+\DB name                        \BC type            \BC explanation \NC \NR
+\TB
+\NC \type{pardir}               \NC string          \NC \NC \NR
+\NC \type{pretolerance}         \NC number          \NC \NC \NR
+\NC \type{tracingparagraphs}    \NC number          \NC \NC \NR
+\NC \type{tolerance}            \NC number          \NC \NC \NR
+\NC \type{looseness}            \NC number          \NC \NC \NR
+\NC \type{hyphenpenalty}        \NC number          \NC \NC \NR
+\NC \type{exhyphenpenalty}      \NC number          \NC \NC \NR
+\NC \type{pdfadjustspacing}     \NC number          \NC \NC \NR
+\NC \type{adjdemerits}          \NC number          \NC \NC \NR
+\NC \type{pdfprotrudechars}     \NC number          \NC \NC \NR
+\NC \type{linepenalty}          \NC number          \NC \NC \NR
+\NC \type{lastlinefit}          \NC number          \NC \NC \NR
+\NC \type{doublehyphendemerits} \NC number          \NC \NC \NR
+\NC \type{finalhyphendemerits}  \NC number          \NC \NC \NR
+\NC \type{hangafter}            \NC number          \NC \NC \NR
+\NC \type{interlinepenalty}     \NC number or table \NC if a table, then it is an array like \prm {interlinepenalties} \NC \NR
+\NC \type{clubpenalty}          \NC number or table \NC if a table, then it is an array like \prm {clubpenalties} \NC \NR
+\NC \type{widowpenalty}         \NC number or table \NC if a table, then it is an array like \prm {widowpenalties} \NC \NR
+\NC \type{brokenpenalty}        \NC number          \NC \NC \NR
+\NC \type{emergencystretch}     \NC number          \NC in scaled points \NC \NR
+\NC \type{hangindent}           \NC number          \NC in scaled points \NC \NR
+\NC \type{hsize}                \NC number          \NC in scaled points \NC \NR
+\NC \type{leftskip}             \NC glue_spec node  \NC \NC \NR
+\NC \type{rightskip}            \NC glue_spec node  \NC \NC \NR
+\NC \type{parshape}             \NC table           \NC \NC \NR
+\LL
+\stoptabulate
+
+Note that there is no interface for \prm {displaywidowpenalties}, you have to
+pass the right choice for \type {widowpenalties} yourself.
+
+It is your own job to make sure that \type {listhead} is a proper paragraph list:
+this function does not add any nodes to it. To be exact, if you want to replace
+the core line breaking, you may have to do the following (when you are not
+actually working in the \cbk {pre_linebreak_filter} or \cbk {linebreak_filter}
+callbacks, or when the original list starting at listhead was generated in
+horizontal mode):
+
+\startitemize
+\startitem
+    add an \quote {indent box} and perhaps a \nod {local_par} node at the start
+    (only if you need them)
+\stopitem
+\startitem
+    replace any found final glue by an infinite penalty (or add such a penalty,
+    if the last node is not a glue)
+\stopitem
+\startitem
+    add a glue node for the \prm {parfillskip} after that penalty node
+\stopitem
+\startitem
+    make sure all the \type {prev} pointers are OK
+\stopitem
+\stopitemize
+
+The result is a node list, it still needs to be vpacked if you want to assign it
+to a \prm {vbox}. The returned \type {info} table contains four values that are
+all numbers:
+
+\starttabulate[|l|p|]
+\DB name      \BC explanation \NC \NR
+\TB
+\NC prevdepth \NC depth of the last line in the broken paragraph \NC \NR
+\NC prevgraf  \NC number of lines in the broken paragraph \NC \NR
+\NC looseness \NC the actual looseness value in the broken paragraph \NC \NR
+\NC demerits  \NC the total demerits of the chosen solution  \NC \NR
+\LL
+\stoptabulate
+
+Note there are a few things you cannot interface using this function: You cannot
+influence font expansion other than via \type {pdfadjustspacing}, because the
+settings for that take place elsewhere. The same is true for hbadness and hfuzz
+etc. All these are in the \type {hpack} routine, and that fetches its own
+variables via globals.
+
+\subsubsection{\type {shipout}}
+
+\topicindex {shipout}
+
+\libindex{shipout}
+
+\startfunctioncall
+tex.shipout(<number> n)
+\stopfunctioncall
+
+Ships out box number \type {n} to the output file, and clears the box register.
+
+\subsubsection{\type {getpagestate}}
+
+\topicindex {pages}
+
+\libindex{getpagestate}
+
+This helper reports the current page state: \type {empty}, \type {box_there} or
+\type {inserts_only} as integer value.
+
+\subsubsection{\type {getlocallevel}}
+
+\topicindex {nesting}
+
+\libindex{getlocallevel}
+
+This integer reports the current level of the local loop. It's only useful for
+debugging and the (relative state) numbers can change with the implementation.
+
+\stopsubsection
+
+\startsubsection[title={Randomizers}]
+
+\libindex{lua_math_random}
+\libindex{lua_math_randomseed}
+\libindex{init_rand}
+\libindex{normal_rand}
+\libindex{uniform_rand}
+\libindex{uniformdeviate}
+
+For practical reasons \LUATEX\ has its own random number generator. The original
+\LUA\ random function is available as \typ {tex.lua_math_random}. You can
+initialize with a new seed with \type {init_rand} (\typ {lua_math_randomseed} is
+equivalent to this one.
+
+There are three generators: \type {normal_rand} (no argument is used), \type
+{uniform_rand} (takes a number that will get rounded before being used) and \type
+{uniformdeviate} which behaves like the primitive and expects a scaled integer, so
+
+\startfunctioncall
+tex.print(tex.uniformdeviate(65536)/65536)
+\stopfunctioncall
+
+will give a random number between zero and one.
+
+\stopsubsection
+
+\startsubsection[reference=synctex,title={Functions related to synctex}]
+
+\topicindex {synctex}
+
+\libindex{set_synctex_mode}      \libindex{get_synctex_mode}
+\libindex{set_synctex_no_files}
+\libindex{set_synctex_tag}       \libindex{get_synctex_tag}   \libindex{force_synctex_tag}
+\libindex{set_synctex_line}      \libindex{get_synctex_line}  \libindex{force_synctex_line}
+
+The next helpers only make sense when you implement your own synctex logic. Keep in
+mind that the library used in editors assumes a certain logic and is geared for
+plain and \LATEX, so after a decade users expect a certain behaviour.
+
+\starttabulate[|l|p|]
+\DB name                        \BC explanation \NC \NR
+\TB
+\NC \type{set_synctex_mode}     \NC \type {0} is the default and used normal synctex
+                                    logic, \type {1} uses the values set by the next
+                                    helpers while \type {2} also sets these for glyph
+                                    nodes; \type{3} sets glyphs and glue and \type {4}
+                                    sets only glyphs \NC \NR
+\NC \type{set_synctex_tag}      \NC set the current tag (file) value (obeys save stack) \NC \NR
+\NC \type{set_synctex_line}     \NC set the current line value (obeys save stack) \NC \NR
+\NC \type{set_synctex_no_files} \NC disable synctex file logging \NC \NR
+\NC \type{get_synctex_mode}     \NC returns the current mode (for values see above) \NC \NR
+\NC \type{get_synctex_tag}      \NC get the currently set value of tag (file) \NC \NR
+\NC \type{get_synctex_line}     \NC get the currently set value of line \NC \NR
+\NC \type{force_synctex_tag}    \NC overload the tag (file) value (\type {0} resets) \NC \NR
+\NC \type{force_synctex_line}   \NC overload the line value  (\type {0} resets) \NC \NR
+\LL
+\stoptabulate
+
+The last one is somewhat special. Due to the way files are registered in \SYNCTEX\ we need
+to explicitly disable that feature if we provide our own alternative if we want to avoid
+that overhead. Passing a value of 1 disables registering.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={The \type {texconfig} table},reference=texconfig][library=texconfig]
+
+\topicindex{libraries+\type{texconfig}}
+
+\topicindex {configuration}
+
+This is a table that is created empty. A startup \LUA\ script could
+fill this table with a number of settings that are read out by
+the executable after loading and executing the startup file.
+
+\starttabulate[|l|l|l|p|]
+\DB key                   \BC type     \BC default \BC explanation \NC \NR
+\TB
+\NC \type{kpse_init}      \NC boolean  \NC true
+\NC
+    \type {false} totally disables \KPATHSEA\ initialisation, and enables
+    interpretation of the following numeric key--value pairs. (only ever unset
+    this if you implement {\it all\/} file find callbacks!)
+\NC \NR
+\NC
+    \type{shell_escape} \NC string \NC \type {'f'} \NC Use \type {'y'} or \type
+    {'t'} or \type {'1'} to enable \type {\write18} unconditionally, \type {'p'}
+    to enable the commands that are listed in \type {shell_escape_commands}
+\NC \NR
+\NC
+    shell_escape_commands \NC string \NC \NC Comma-separated list of command
+    names that may be executed by \type {\write18} even if \type {shell_escape}
+    is set to \type {'p'}. Do {\it not\/} use spaces around commas, separate any
+    required command arguments by using a space, and use the \ASCII\ double quote
+    (\type {"}) for any needed argument or path quoting
+\NC \NR
+\NC \type{string_vacancies} \NC number   \NC  75000  \NC cf.\ web2c docs \NC \NR
+\NC \type{pool_free}        \NC number   \NC   5000  \NC cf.\ web2c docs \NC \NR
+\NC \type{max_strings}      \NC number   \NC  15000  \NC cf.\ web2c docs \NC \NR
+\NC \type{strings_free}     \NC number   \NC    100  \NC cf.\ web2c docs \NC \NR
+\NC \type{nest_size}        \NC number   \NC     50  \NC cf.\ web2c docs \NC \NR
+\NC \type{max_in_open}      \NC number   \NC     15  \NC cf.\ web2c docs \NC \NR
+\NC \type{param_size}       \NC number   \NC     60  \NC cf.\ web2c docs \NC \NR
+\NC \type{save_size}        \NC number   \NC   4000  \NC cf.\ web2c docs \NC \NR
+\NC \type{stack_size}       \NC number   \NC    300  \NC cf.\ web2c docs \NC \NR
+\NC \type{dvi_buf_size}     \NC number   \NC  16384  \NC cf.\ web2c docs \NC \NR
+\NC \type{error_line}       \NC number   \NC     79  \NC cf.\ web2c docs \NC \NR
+\NC \type{half_error_line}  \NC number   \NC     50  \NC cf.\ web2c docs \NC \NR
+\NC \type{max_print_line}   \NC number   \NC     79  \NC cf.\ web2c docs \NC \NR
+\NC \type{hash_extra}       \NC number   \NC      0  \NC cf.\ web2c docs \NC \NR
+\NC \type{pk_dpi}           \NC number   \NC     72  \NC cf.\ web2c docs \NC \NR
+\NC \type{trace_file_names} \NC boolean  \NC true
+\NC
+    \type {false} disables \TEX's normal file open|-|close feedback (the
+    assumption is that callbacks will take care of that)
+\NC \NR
+\NC \type{file_line_error}  \NC boolean  \NC false
+\NC
+    do \type {file:line} style error messages
+\NC \NR
+\NC \type{halt_on_error}    \NC boolean  \NC false
+\NC
+    abort run on the first encountered error
+\NC \NR
+\NC \type{formatname}       \NC string   \NC
+\NC
+    if no format name was given on the command line, this key will be tested first
+    instead of simply quitting
+\NC \NR
+\NC \type{jobname}        \NC string   \NC
+\NC
+    if no input file name was given on the command line, this key will be tested
+    first instead of simply giving up
+\NC \NR
+\LL
+\stoptabulate
+
+Note: the numeric values that match web2c parameters are only used if \type
+{kpse_init} is explicitly set to \type {false}. In all other cases, the normal
+values from \type {texmf.cnf} are used.
+
+\stopsection
+
+\startsection[title={The \type {texio} library}][library=texio]
+
+\topicindex{libraries+\type{texio}}
+\topicindex{\IO}
+
+This library takes care of the low|-|level I/O interface: writing to the log file
+and|/|or console.
+
+\startsubsection[title={\type {write}}]
+
+\libindex{write}
+
+\startfunctioncall
+texio.write(<string> target, <string> s, ...)
+texio.write(<string> s, ...)
+\stopfunctioncall
+
+Without the \type {target} argument, writes all given strings to the same
+location(s) \TEX\ writes messages to at this moment. If \prm {batchmode} is in
+effect, it writes only to the log, otherwise it writes to the log and the
+terminal. The optional \type {target} can be one of three possibilities: \type
+{term}, \type {log} or \type {term and log}.
+
+Note: If several strings are given, and if the first of these strings is or might
+be one of the targets above, the \type {target} must be specified explicitly to
+prevent \LUA\ from interpreting the first string as the target.
+
+\stopsubsection
+
+\startsubsection[title={\type {write_nl}}]
+
+\libindex{write_nl}
+
+\startfunctioncall
+texio.write_nl(<string> target, <string> s, ...)
+texio.write_nl(<string> s, ...)
+\stopfunctioncall
+
+This function behaves like \type {texio.write}, but make sure that the given
+strings will appear at the beginning of a new line. You can pass a single empty
+string if you only want to move to the next line.
+
+\stopsubsection
+
+\startsubsection[title={\type {setescape}}]
+
+\libindex{setescape}
+
+You can disable \type {^^} escaping of control characters by passing a value of
+zero.
+
+\stopsubsection
+
+\startsubsection[title={\type {closeinput}}]
+
+\libindex{closeinput}
+
+This function that should be used with care. It acts as \prm {endinput} but at
+the \LUA\ end. You can use it to (sort of) force a jump back to \TEX. Normally a
+\LUA\ will just collect prints and at the end bump an input level and flush these
+prints. This function can help you stay at the current level but you need to know
+what you're doing (or more precise: what \TEX\ is doing with input).
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={The \type {token} library}][library=token]
+
+\startsubsection[title={The scanner}]
+
+\topicindex{libraries+\type{token}}
+\topicindex{tokens}
+
+\libindex{scan_keyword}
+\libindex{scan_keywordcs}
+\libindex{scan_int}
+\libindex{scan_real}
+\libindex{scan_float}
+\libindex{scan_dimen}
+\libindex{scan_glue}
+\libindex{scan_toks}
+\libindex{scan_code}
+\libindex{scan_string}
+\libindex{scan_argument}
+\libindex{scan_word}
+\libindex{scan_csname}
+\libindex{scan_list}
+
+The token library provides means to intercept the input and deal with it at the
+\LUA\ level. The library provides a basic scanner infrastructure that can be used
+to write macros that accept a wide range of arguments. This interface is on
+purpose kept general and as performance is quite ok. One can build additional
+parsers without too much overhead. It's up to macro package writers to see how
+they can benefit from this as the main principle behind \LUATEX\ is to provide a
+minimal set of tools and no solutions. The scanner functions are probably the
+most intriguing.
+
+\starttabulate[|l|l|p|]
+\DB function              \BC argument           \BC result \NC \NR
+\TB
+\NC \type{scan_keyword}   \NC string             \NC returns true if the given keyword is gobbled; as with
+                                                     the regular \TEX\ keyword scanner this is case insensitive
+                                                     (and \ASCII\ based) \NC \NR
+\NC \type{scan_keywordcs} \NC string             \NC returns true if the given keyword is gobbled; this variant
+                                                     is case sensitive and also suitable for \UTF8 \NC \NR
+\NC \type{scan_int}       \NC                    \NC returns an integer \NC \NR
+\NC \type{scan_real}      \NC                    \NC returns a number from e.g.\ \type {1},  \type {1.1}, \type {.1} with optional collapsed signs \NC \NR
+\NC \type{scan_float}     \NC                    \NC returns a number from e.g.\ \type {1},  \type {1.1}, \type {.1}, \type {1.1E10}, , \type {.1e-10} with optional collapsed signs \NC \NR
+\NC \type{scan_dimen}     \NC infinity, mu-units \NC returns a number representing a dimension and or two numbers being the filler and order \NC \NR
+\NC \type{scan_glue}      \NC mu-units           \NC returns a glue spec node \NC \NR
+\NC \type{scan_toks}      \NC definer, expand    \NC returns a table of tokens tokens \NC \NR
+\NC \type{scan_code}      \NC bitset             \NC returns a character if its category is in the given bitset (representing catcodes) \NC \NR
+\NC \type{scan_string}    \NC                    \NC returns a string given between \type {{}}, as \type {\macro} or as sequence of characters with catcode 11 or 12 \NC \NR
+\NC \type{scan_argument}  \NC                    \NC this one is simular to \type {scanstring} but also accepts a \type {\cs}
+                                                     (which then get expanded) \NC \NR
+\NC \type{scan_word}      \NC                    \NC returns a sequence of characters with catcode 11 or 12 as string \NC \NR
+\NC \type{scan_csname}    \NC                    \NC returns \type {foo} after scanning \type {\foo} \NC \NR
+\NC \type{scan_list}      \NC                    \NC picks up a box specification and returns a \type {[h|v]list} node \NC \NR
+\LL
+\stoptabulate
+
+The scanners can be considered stable apart from the one scanning for a token.
+The \type {scan_code} function takes an optional number, the \type {keyword}
+function a normal \LUA\ string. The \type {infinity} boolean signals that we also
+permit \type {fill} as dimension and the \type {mu-units} flags the scanner that
+we expect math units. When scanning tokens we can indicate that we are defining a
+macro, in which case the result will also provide information about what
+arguments are expected and in the result this is separated from the meaning by a
+separator token. The \type {expand} flag determines if the list will be expanded.
+
+The string scanner scans for something between curly braces and expands on the
+way, or when it sees a control sequence it will return its meaning. Otherwise it
+will scan characters with catcode \type {letter} or \type {other}. So, given the
+following definition:
+
+\startbuffer
+\def\bar{bar}
+\def\foo{foo-\bar}
+\stopbuffer
+
+\typebuffer \getbuffer
+
+we get:
+
+\starttabulate[|l|Tl|l|]
+\DB name \BC result \NC \NR
+\TB
+\NC \type {\directlua{token.scan_string()}{foo}} \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")} {foo} \NC full expansion \NC \NR
+\NC \type {\directlua{token.scan_string()}foo}   \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")} foo   \NC letters and others \NC \NR
+\NC \type {\directlua{token.scan_string()}\foo}  \NC \directlua{context("{\\red\\type {"..token.scan_string().."}}")}\foo   \NC meaning \NC \NR
+\LL
+\stoptabulate
+
+The \type {\foo} case only gives the meaning, but one can pass an already
+expanded definition (\prm {edef}'d). In the case of the braced variant one can of
+course use the \prm {detokenize} and \prm {unexpanded} primitives since there we
+do expand.
+
+The \type {scan_word} scanner can be used to implement for instance a number scanner:
+
+\starttyping
+function token.scan_number(base)
+    return tonumber(token.scan_word(),base)
+end
+\stoptyping
+
+This scanner accepts any valid \LUA\ number so it is a way to pick up floats
+in the input.
+
+You can use the \LUA\ interface as follows:
+
+\starttyping
+\directlua {
+    function mymacro(n)
+        ...
+    end
+}
+
+\def\mymacro#1{%
+    \directlua {
+        mymacro(\number\dimexpr#1)
+    }%
+}
+
+\mymacro{12pt}
+\mymacro{\dimen0}
+\stoptyping
+
+You can also do this:
+
+\starttyping
+\directlua {
+    function mymacro()
+        local d = token.scan_dimen()
+        ...
+    end
+}
+
+\def\mymacro{%
+    \directlua {
+        mymacro()
+    }%
+}
+
+\mymacro 12pt
+\mymacro \dimen0
+\stoptyping
+
+It is quite clear from looking at the code what the first method needs as
+argument(s). For the second method you need to look at the \LUA\ code to see what
+gets picked up. Instead of passing from \TEX\ to \LUA\ we let \LUA\ fetch from
+the input stream.
+
+In the first case the input is tokenized and then turned into a string, then it
+is passed to \LUA\ where it gets interpreted. In the second case only a function
+call gets interpreted but then the input is picked up by explicitly calling the
+scanner functions. These return proper \LUA\ variables so no further conversion
+has to be done. This is more efficient but in practice (given what \TEX\ has to
+do) this effect should not be overestimated. For numbers and dimensions it saves
+a bit but for passing strings conversion to and from tokens has to be done anyway
+(although we can probably speed up the process in later versions if needed).
+
+\stopsubsection
+
+\startsubsection[title= {Picking up one token}]
+
+\libindex {get_next}
+\libindex {scan_token}
+\libindex {expand}
+
+The scanners look for a sequence. When you want to pick up one token from the
+input you use \type {get_next}. This creates a token with the (low level)
+properties as discussed next. This token is just the next one. If you want to
+enforce expansion first you can use \type {scan_token}. Internally tokens are
+characterized by a number that packs a lot of information. In order to access
+the bits of information a token is wrapped in a userdata object.
+
+The \type {expand} function will trigger expansion of the next token in the
+input. This can be quite unpredictable but when you call it you probably know
+enough about \TEX\ not to be too worried about that. It basically is a call to
+the internal expand related function.
+
+\stopsubsection
+
+\startsubsection[title={Creating tokens}]
+
+\libindex{create}
+\libindex{new}
+
+\libindex{is_defined}
+\libindex{is_token}
+\libindex{biggest_char}
+
+\libindex{commands}
+\libindex{command_id}
+
+\libindex{get_command}
+\libindex{get_cmdname}
+\libindex{get_csname}
+\libindex{get_id}
+\libindex{get_active}
+\libindex{get_expandable}
+\libindex{get_protected}
+\libindex{get_mode}
+\libindex{get_index}
+\libindex{get_tok}
+
+\libindex{get_next}
+
+The creator function can be used as follows:
+
+\starttyping
+local t = token.create("relax")
+\stoptyping
+
+This gives back a token object that has the properties of the \prm {relax}
+primitive. The possible properties of tokens are:
+
+\starttabulate[|l|p|]
+\DB name \BC explanation \NC \NR
+\TB
+\NC \type {command}    \NC a number representing the internal command number \NC \NR
+\NC \type {cmdname}    \NC the type of the command (for instance the catcode in case of a
+                           character or the classifier that determines the internal
+                           treatment \NC \NR
+\NC \type {csname}     \NC the associated control sequence (if applicable) \NC \NR
+\NC \type {id}         \NC the unique id of the token \NC \NR
+\NC \type {tok}        \NC the full token number as stored in \TEX \NC \NR
+\NC \type {active}     \NC a boolean indicating the active state of the token \NC \NR
+\NC \type {expandable} \NC a boolean indicating if the token (macro) is expandable \NC \NR
+\NC \type {protected}  \NC a boolean indicating if the token (macro) is protected \NC \NR
+\NC \type {mode}       \NC a number either representing a character or another entity \NC \NR
+\NC \type {index}      \NC a number running from 0x0000 upto 0xFFFF indicating a \TEX\ register index \NC \NR
+\LL
+\stoptabulate
+
+Alternatively you can use a getter \type {get_<fieldname>} to access a property
+of a token.
+
+The numbers that represent a catcode are the same as in \TEX\ itself, so using
+this information assumes that you know a bit about \TEX's internals. The other
+numbers and names are used consistently but are not frozen. So, when you use them
+for comparing you can best query a known primitive or character first to see the
+values.
+
+You can ask for a list of commands:
+
+\starttyping
+local t = token.commands()
+\stoptyping
+
+The id of a token class can be queried as follows:
+
+\starttyping
+local id = token.command_id("math_shift")
+\stoptyping
+
+If you really know what you're doing you can create character tokens by not
+passing a string but a number:
+
+\starttyping
+local letter_x = token.create(string.byte("x"))
+local other_x  = token.create(string.byte("x"),12)
+\stoptyping
+
+Passing weird numbers can give side effects so don't expect too much help with
+that. As said, you need to know what you're doing. The best way to explore the
+way these internals work is to just look at how primitives or macros or \prm
+{chardef}'d commands are tokenized. Just create a known one and inspect its
+fields. A variant that ignores the current catcode table is:
+
+\starttyping
+local whatever = token.new(123,12)
+\stoptyping
+
+You can test if a control sequence is defined with \type {is_defined}, which
+accepts a string and returns a boolean:
+
+\starttyping
+local okay = token.is_defined("foo")
+\stoptyping
+
+The largest character possible is returned by \type {biggest_char}, just in case you
+need to know that boundary condition.
+
+\stopsubsection
+
+\startsubsection[title={Macros}]
+
+\topicindex {macros}
+
+\libindex{set_macro}
+\libindex{get_macro}
+\libindex{get_meaning}
+\libindex{set_char}
+\libindex{set_lua}
+\libindex{get_functions_table}
+
+The \type {set_macro} function can get upto 4 arguments:
+
+\starttyping
+set_macro("csname","content")
+set_macro("csname","content","global")
+set_macro("csname")
+\stoptyping
+
+You can pass a catcodetable identifier as first argument:
+
+\starttyping
+set_macro(catcodetable,"csname","content")
+set_macro(catcodetable,"csname","content","global")
+set_macro(catcodetable,"csname")
+\stoptyping
+
+The results are like:
+
+\starttyping
+ \def\csname{content}
+\gdef\csname{content}
+ \def\csname{}
+\stoptyping
+
+The \type {get_macro} function can be used to get the content of a macro while
+the \type {get_meaning} function gives the meaning including the argument
+specification (as usual in \TEX\ separated by \type {->}).
+
+The \type {set_char} function can be used to do a \prm {chardef} at the
+\LUA\ end, where invalid assignments are silently ignored:
+
+\starttyping
+set_char("csname",number)
+set_char("csname",number,"global")
+\stoptyping
+
+A special one is the following:
+
+\starttyping
+set_lua("mycode",id)
+set_lua("mycode",id,"global","protected")
+\stoptyping
+
+This creates a token that refers to a \LUA\ function with an entry in the table
+that you can access with \type {lua.get_functions_table}. It is the companion
+to \lpr {luadef}.
+
+\stopsubsection
+
+\startsubsection[title={Pushing back}]
+
+\libindex{get_next}
+\libindex{put_next}
+
+There is a (for now) experimental putter:
+
+\starttyping
+local t1 = token.get_next()
+local t2 = token.get_next()
+local t3 = token.get_next()
+local t4 = token.get_next()
+-- watch out, we flush in sequence
+token.put_next { t1, t2 }
+-- but this one gets pushed in front
+token.put_next ( t3, t4 )
+\stoptyping
+
+When we scan \type {wxyz!} we get \type {yzwx!} back. The argument is either a table
+with tokens or a list of tokens. The \type {token.expand} function will trigger
+expansion but what happens really depends on what you're doing where.
+
+\stopsubsection
+
+\startsubsection[title={Nota bene}]
+
+When scanning for the next token you need to keep in mind that we're not scanning
+like \TEX\ does: expanding, changing modes and doing things as it goes. When we
+scan with \LUA\ we just pick up tokens. Say that we have:
+
+\starttyping
+\bar
+\stoptyping
+
+but \type {\bar} is undefined. Normally \TEX\ will then issue an error message.
+However, when we have:
+
+\starttyping
+\def\foo{\bar}
+\stoptyping
+
+We get no error, unless we expand \type {\foo} while \type {\bar} is still
+undefined. What happens is that as soon as \TEX\ sees an undefined macro it will
+create a hash entry and when later it gets defined that entry will be reused. So,
+\type {\bar} really exists but can be in an undefined state.
+
+\startbuffer[demo]
+bar        : \directlua{tex.print(token.scan_csname())}\bar
+foo        : \directlua{tex.print(token.scan_csname())}\foo
+myfirstbar : \directlua{tex.print(token.scan_csname())}\myfirstbar
+\stopbuffer
+
+\startlines
+\getbuffer[demo]
+\stoplines
+
+This was entered as:
+
+\typebuffer[demo]
+
+The reason that you see \type {bar} reported and not \type {myfirstbar} is that
+\type {\bar} was already used in a previous paragraph.
+
+If we now say:
+
+\startbuffer
+\def\foo{}
+\stopbuffer
+
+\typebuffer \getbuffer
+
+we get:
+
+\startlines
+\getbuffer[demo]
+\stoplines
+
+And if we say
+
+\startbuffer
+\def\foo{\bar}
+\stopbuffer
+
+\typebuffer \getbuffer
+
+we get:
+
+\startlines
+\getbuffer[demo]
+\stoplines
+
+When scanning from \LUA\ we are not in a mode that defines (undefined) macros at
+all. There we just get the real primitive undefined macro token.
+
+\startbuffer
+\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\myfirstbar
+\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\mysecondbar
+\directlua{local t = token.get_next() tex.print(t.id.." "..t.tok)}\mythirdbar
+\stopbuffer
+
+\startlines
+\getbuffer
+\stoplines
+
+This was generated with:
+
+\typebuffer
+
+So, we do get a unique token because after all we need some kind of \LUA\ object
+that can be used and garbage collected, but it is basically the same one,
+representing an undefined control sequence.
+
+\stopsubsection
+
+\stopsection
+
+\startsection[title={The \type {kpse} library}][library=kpse]
+
+\topicindex{libraries+\type{kpse}}
+
+This library provides two separate, but nearly identical interfaces to the
+\KPATHSEA\ file search functionality: there is a \quote {normal} procedural
+interface that shares its kpathsea instance with \LUATEX\ itself, and an object
+oriented interface that is completely on its own.
+
+\startsubsection[title={\type {set_program_name} and \type {new}}]
+
+\libindex{set_program_name}
+\libindex{default_texmfcnf}
+\libindex{new}
+
+The way the library looks up variables is driven by the \type {texmf.cmf} file
+where the currently set program name acts as filter. You can check what file is
+used by with \type {default_texmfcnf}.
+
+Before the search library can be used at all, its database has to be initialized.
+There are three possibilities, two of which belong to the procedural interface.
+
+First, when \LUATEX\ is used to typeset documents, this initialization happens
+automatically and the \KPATHSEA\ executable and program names are set to \type
+{luatex} (that is, unless explicitly prohibited by the user's startup script.
+See~\in {section} [init] for more details).
+
+Second, in \TEXLUA\ mode, the initialization has to be done explicitly via the
+\type {kpse.set_program_name} function, which sets the \KPATHSEA\ executable
+(and optionally program) name.
+
+\startfunctioncall
+kpse.set_program_name(<string> name)
+kpse.set_program_name(<string> name, <string> progname)
+\stopfunctioncall
+
+The second argument controls the use of the \quote {dotted} values in the \type
+{texmf.cnf} configuration file, and defaults to the first argument.
+
+Third, if you prefer the object oriented interface, you have to call a different
+function. It has the same arguments, but it returns a userdata variable.
+
+\startfunctioncall
+local kpathsea = kpse.new(<string> name)
+local kpathsea = kpse.new(<string> name, <string> progname)
+\stopfunctioncall
+
+Apart from these two functions, the calling conventions of the interfaces are
+identical. Depending on the chosen interface, you either call \type
+{kpse.find_file} or \type {kpathsea:find_file}, with identical arguments and
+return values.
+
+\stopsubsection
+
+\startsubsection[title={\type {record_input_file} and \type {record_output_file}}]
+
+\topicindex {files+recording}
+
+\libindex{record_input_file}
+\libindex{record_output_file}
+
+These two function can be used to register used files. Because callbacks can load
+files themselves you might need these helpers (if you use recording at all).
+
+\startfunctioncall
+kpse.record_input_file(<string> name)
+kpse.record_output_file(<string> name)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {find_file}}]
+
+\topicindex {files+finding}
+
+\libindex {find_file}
+
+The most often used function in the library is \type {find_file}:
+
+\startfunctioncall
+<string> f = kpse.find_file(<string> filename)
+<string> f = kpse.find_file(<string> filename, <string> ftype)
+<string> f = kpse.find_file(<string> filename, <boolean> mustexist)
+<string> f = kpse.find_file(<string> filename, <string> ftype, <boolean> mustexist)
+<string> f = kpse.find_file(<string> filename, <string> ftype, <number> dpi)
+\stopfunctioncall
+
+Arguments:
+
+\startitemize[intro]
+
+\sym{filename}
+
+the name of the file you want to find, with or without extension.
+
+\sym{ftype}
+
+maps to the \type {-format} argument of \KPSEWHICH. The supported \type {ftype}
+values are the same as the ones supported by the standalone \type {kpsewhich}
+program: \startluacode
+    local list = {
+        "afm",
+        "base",
+        "bib",
+        "bitmap font",
+        "bst",
+        "cid maps",
+        "clua",
+        "cmap files",
+        "cnf",
+        "cweb",
+        "dvips config",
+        "enc files",
+        "fmt",
+        "font feature files",
+        "gf",
+        "graphic|/|figure",
+        "ist",
+        "lig files",
+        "ls-R",
+        "lua",
+        "map",
+        "mem",
+        "MetaPost support",
+        "mf",
+        "mfpool",
+        "mft",
+        "misc fonts",
+        "mlbib",
+        "mlbst",
+        "mp",
+        "mppool",
+        "ocp",
+        "ofm",
+        "opentype fonts",
+        "opl",
+        "other binary files",
+        "other text files",
+        "otp",
+        "ovf",
+        "ovp",
+        "pdftex config",
+        "pk",
+        "PostScript header",
+        "subfont definition files",
+        "tex",
+        "TeX system documentation",
+        "TeX system sources",
+        "texmfscripts",
+        "texpool",
+        "tfm",
+        "Troff fonts",
+        "truetype fonts",
+        "type1 fonts",
+        "type42 fonts",
+        "vf",
+        "web",
+        "web2c files",
+    }
+    table.sort(list)
+    context("{\\tttf \letterpercent, t}",list)
+\stopluacode
+
+The default type is \type {tex}. Note: this is different from \KPSEWHICH, which
+tries to deduce the file type itself from looking at the supplied extension.
+
+\sym{mustexist}
+
+is similar to \KPSEWHICH's \type {-must-exist}, and the default is \type {false}.
+If you specify \type {true} (or a non|-|zero integer), then the \KPSE\ library
+will search the disk as well as the \type {ls-R} databases.
+
+\sym{dpi}
+
+This is used for the size argument of the formats \type {pk}, \type {gf}, and
+\type {bitmap font}. \stopitemize
+
+\stopsubsection
+
+\startsubsection[title={\type {lookup}}]
+
+\libindex{lookup}
+
+A more powerful (but slower) generic method for finding files is also available.
+It returns a string for each found file.
+
+\startfunctioncall
+<string> f, ... = kpse.lookup(<string> filename, <table> options)
+\stopfunctioncall
+
+The options match commandline arguments from \type {kpsewhich}:
+
+\starttabulate[|l|l|p|]
+\DB key              \BC type     \BC explanation \NC \NR
+\TB
+\NC \type{debug}     \NC number   \NC set debugging flags for this lookup\NC     \NR
+\NC \type{format}    \NC string   \NC use specific file type (see list above)\NC \NR
+\NC \type{dpi}       \NC number   \NC use this resolution for this lookup; default 600\NC \NR
+\NC \type{path}      \NC string   \NC search in the given path\NC \NR
+\NC \type{all}       \NC boolean  \NC output all matches, not just the first\NC \NR
+\NC \type{mustexist} \NC boolean  \NC search the disk as well as ls-R if necessary\NC \NR
+\NC \type{mktexpk}   \NC boolean  \NC disable/enable mktexpk generation for this lookup\NC \NR
+\NC \type{mktextex}  \NC boolean  \NC disable/enable mktextex generation for this lookup\NC \NR
+\NC \type{mktexmf}   \NC boolean  \NC disable/enable mktexmf generation for this lookup\NC \NR
+\NC \type{mktextfm}  \NC boolean  \NC disable/enable mktextfm generation for this lookup\NC \NR
+\NC \type{subdir}    \NC string
+                         or table \NC only output matches whose directory part
+                                      ends with the given string(s) \NC \NR
+\LL
+\stoptabulate
+
+\stopsubsection
+
+\startsubsection[title={\type {init_prog}}]
+
+\topicindex {initialization+bitmaps}
+
+\libindex{init_prog}
+
+Extra initialization for programs that need to generate bitmap fonts.
+
+\startfunctioncall
+kpse.init_prog(<string> prefix, <number> base_dpi, <string> mfmode)
+kpse.init_prog(<string> prefix, <number> base_dpi, <string> mfmode, <string> fallback)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {readable_file}}]
+
+\libindex{readable_file}
+
+Test if an (absolute) file name is a readable file.
+
+\startfunctioncall
+<string> f = kpse.readable_file(<string> name)
+\stopfunctioncall
+
+The return value is the actual absolute filename you should use, because the disk
+name is not always the same as the requested name, due to aliases and
+system|-|specific handling under e.g.\ \MSDOS. Returns \type {nil} if the file
+does not exist or is not readable.
+
+\stopsubsection
+
+\startsubsection[title={\type {expand_path}}]
+
+\libindex{expand_path}
+
+Like kpsewhich's \type {-expand-path}:
+
+\startfunctioncall
+<string> r = kpse.expand_path(<string> s)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {expand_var}}]
+
+\libindex{expand_var}
+
+Like kpsewhich's  \type {-expand-var}:
+
+\startfunctioncall
+<string> r = kpse.expand_var(<string> s)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {expand_braces}}]
+
+\libindex{expand_braces}
+
+Like kpsewhich's \type {-expand-braces}:
+
+\startfunctioncall
+<string> r = kpse.expand_braces(<string> s)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {show_path}}]
+
+\libindex{show_path}
+
+Like kpsewhich's \type {-show-path}:
+
+\startfunctioncall
+<string> r = kpse.show_path(<string> ftype)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {var_value}}]
+
+\libindex{var_value}
+
+Like kpsewhich's \type {-var-value}:
+
+\startfunctioncall
+<string> r = kpse.var_value(<string> s)
+\stopfunctioncall
+
+\stopsubsection
+
+\startsubsection[title={\type {version}}]
+
+\libindex{version}
+
+Returns the kpathsea version string.
+
+\startfunctioncall
+<string> r = kpse.version()
+\stopfunctioncall
+
+\stopsubsection
+
+\stopsection
+
+\stopchapter
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex-titlepage.tex b/systems/doc/luatex/luatex-titlepage.tex
index 5a91f73e8b..d9ca4b3f93 100644
--- a/systems/doc/luatex/luatex-titlepage.tex
+++ b/systems/doc/luatex/luatex-titlepage.tex
@@ -1,53 +1,53 @@
-\environment luatex-style

-

-\startcomponent luatex-titlepage

-

-\startstandardmakeup

-

-    \switchtobodyfont

-      [mainfacemedium]

-

-    \definedfont[Bold*default at \the\dimexpr.06\paperheight\relax] \setupinterlinespace

-

-    \setlayer

-      [page]

-      {\useMPgraphic{luapage}}

-

-    \setlayerframed

-      [page]

-      [preset=righttop,

-       location=middletop,

-       hoffset=.500\measured{paperwidth},

-       voffset=.175\measured{paperheight}]

-      [align=middle,

-       foregroundcolor=white,

-       frame=off]

-      {\documentvariable{manual}\crlf Reference\crlf Manual}

-

-    \definedfont[Bold*default at 14pt] \setupinterlinespace

-

-    \setlayerframed

-      [page]

-      [preset=rightbottom,

-       offset=.025\measured{paperheight}]

-      [align=flushright,

-       foregroundcolor=white,

-       frame=off]

-      {\doifsomething{\documentvariable{status}}{\documentvariable{status}\par}

-       \currentdate[month,space,year]\par

-       Version \documentvariable{version}}

-

-    \setlayerframed

-      [page]

-      [preset=middle,

-       hoffset=-.5\dimexpr\measured{paperwidth}-\measured{spinewidth}\relax]

-      [width=.7\measured{paperwidth},

-       align=normal,

-       foregroundstyle=\bf,

-       foregroundcolor=white,

-       frame=off]

-      {\getbuffer[backpage]}

-

-\stopstandardmakeup

-

-\stopcomponent

+\environment luatex-style
+
+\startcomponent luatex-titlepage
+
+\startstandardmakeup
+
+    \switchtobodyfont
+      [mainfacemedium]
+
+    \definedfont[Bold*default at \the\dimexpr.06\paperheight\relax] \setupinterlinespace
+
+    \setlayer
+      [page]
+      {\useMPgraphic{luapage}}
+
+    \setlayerframed
+      [page]
+      [preset=righttop,
+       location=middletop,
+       hoffset=.500\measured{paperwidth},
+       voffset=.175\measured{paperheight}]
+      [align=middle,
+       foregroundcolor=white,
+       frame=off]
+      {\documentvariable{manual}\crlf Reference\crlf Manual}
+
+    \definedfont[Bold*default at 14pt] \setupinterlinespace
+
+    \setlayerframed
+      [page]
+      [preset=rightbottom,
+       offset=.025\measured{paperheight}]
+      [align=flushright,
+       foregroundcolor=white,
+       frame=off]
+      {\doifsomething{\documentvariable{status}}{\documentvariable{status}\par}
+       \currentdate[month,space,year]\par
+       Version \documentvariable{version}}
+
+    \setlayerframed
+      [page]
+      [preset=middle,
+       hoffset=-.5\dimexpr\measured{paperwidth}-\measured{spinewidth}\relax]
+      [width=.7\measured{paperwidth},
+       align=normal,
+       foregroundstyle=\bf,
+       foregroundcolor=white,
+       frame=off]
+      {\getbuffer[backpage]}
+
+\stopstandardmakeup
+
+\stopcomponent
diff --git a/systems/doc/luatex/luatex.pdf b/systems/doc/luatex/luatex.pdf
index 572b75d842..23abaa0a55 100644
--- a/systems/doc/luatex/luatex.pdf
+++ b/systems/doc/luatex/luatex.pdf
diff --git a/systems/doc/luatex/luatex.tex b/systems/doc/luatex/luatex.tex
index 2d1d4efec6..0230af7384 100644
--- a/systems/doc/luatex/luatex.tex
+++ b/systems/doc/luatex/luatex.tex
@@ -1,103 +1,103 @@
-% macros=mkvi

-

-% \nopdfcompression

-

-% \disabledirectives[vspacing.synchronizepage]

-

-% wsl /data/context/runcontext.sh --global --path=/mnt/c/data/develop/context/manuals/mkiv/external/luatex luatex.tex

-%

-% same runtime as regular context or linux

-% author    : Hans Hagen with Taco Hoekwater, Luigi Scarso & Hartmut Henkel

-% copyright : PRAGMA ADE & ConTeXt Development Team

-% license   : Creative Commons Attribution ShareAlike 4.0 International

-% reference : pragma-ade.nl | contextgarden.net | texlive (related) distributions

-% origin    : the ConTeXt distribution

-%

-% comment   : Because this manual is distributed with TeX distributions it comes with a rather

-%             liberal license. We try to adapt these documents to upgrades in the (sub)systems

-%             that they describe. Using parts of the content otherwise can therefore conflict

-%             with existing functionality and we cannot be held responsible for that. Many of

-%             the manuals contain characteristic graphics and personal notes or examples that

-%             make no sense when used out-of-context.

-%

-% comment   : Some (parts of) chapters might have been published in TugBoat, the NTG Maps, the

-%             ConTeXt Group journal or otherwise. Thanks to the editors for corrections. Also

-%             thanks to users for testing, feedback and corrections.

-

-% \tex vs \type vs \syntax vs. \luatex

-% \em \it \/

-

-% "context --nodates --nocompression luatex" can be used for comparison

-% runs, not that we do it

-

-% todo: all (sub)section to start/stop

-

-% \enabledirectives[hyphenator.flatten]

-

-% \setupsynctex[state=start,method=max] % adds 5 pct overhead

-

-% compoundhyphenmode      : looks okay

-% endlocalcontrol         : very experimental

-% fixupboxesmode          : very experimental

-% mathflattenmode         : looks okay

-% mathrulethicknessmode   : looks okay

-

-% after adding primitives: context mult-prm.mkiv

-

-\environment luatex-style

-

-\startmode[book]

-    \environment luatex-style-book

-\stopmode

-

-\environment luatex-logos

-\environment luatex-private

-

-\startmode[export]

-

-    \setupbackend

-      [export=luatex]

-

-\stopmode

-

-\startdocument

-  [manual=Lua\TeX,

-   status=stable,

-   version=1.10]

-

-\startnotmode[*export]

-    \component luatex-titlepage

-    \component luatex-firstpage

-\stopnotmode

-

-\startmode[*export]

-    \component luatex-export-titlepage

-\stopmode

-

-\startfrontmatter

-    \component luatex-contents

-    \component luatex-introduction

-\stopfrontmatter

-

-\startbodymatter

-    \component luatex-preamble

-    \component luatex-enhancements

-    \component luatex-modifications

-    \component luatex-lua

-    \component luatex-languages

-    \component luatex-fonts

-    \component luatex-math

-    \component luatex-nodes

-    \component luatex-callbacks

-    \component luatex-tex

-    \component luatex-graphics

-    \component luatex-fontloader

-    \component luatex-backend

-\stopbodymatter

-

-\startbackmatter

-    \component luatex-registers

-    \component luatex-statistics

-\stopbackmatter

-

-\stopdocument

+% macros=mkvi
+
+% \nopdfcompression
+
+% \disabledirectives[vspacing.synchronizepage]
+
+% wsl /data/context/runcontext.sh --global --path=/mnt/c/data/develop/context/manuals/mkiv/external/luatex luatex.tex
+%
+% same runtime as regular context or linux
+% author    : Hans Hagen with Taco Hoekwater, Luigi Scarso & Hartmut Henkel
+% copyright : PRAGMA ADE & ConTeXt Development Team
+% license   : Creative Commons Attribution ShareAlike 4.0 International
+% reference : pragma-ade.nl | contextgarden.net | texlive (related) distributions
+% origin    : the ConTeXt distribution
+%
+% comment   : Because this manual is distributed with TeX distributions it comes with a rather
+%             liberal license. We try to adapt these documents to upgrades in the (sub)systems
+%             that they describe. Using parts of the content otherwise can therefore conflict
+%             with existing functionality and we cannot be held responsible for that. Many of
+%             the manuals contain characteristic graphics and personal notes or examples that
+%             make no sense when used out-of-context.
+%
+% comment   : Some (parts of) chapters might have been published in TugBoat, the NTG Maps, the
+%             ConTeXt Group journal or otherwise. Thanks to the editors for corrections. Also
+%             thanks to users for testing, feedback and corrections.
+
+% \tex vs \type vs \syntax vs. \luatex
+% \em \it \/
+
+% "context --nodates --nocompression luatex" can be used for comparison
+% runs, not that we do it
+
+% todo: all (sub)section to start/stop
+
+% \enabledirectives[hyphenator.flatten]
+
+% \setupsynctex[state=start,method=max] % adds 5 pct overhead
+
+% compoundhyphenmode      : looks okay
+% endlocalcontrol         : very experimental
+% fixupboxesmode          : very experimental
+% mathflattenmode         : looks okay
+% mathrulethicknessmode   : looks okay
+
+% after adding primitives: context mult-prm.mkiv
+
+\environment luatex-style
+
+\startmode[book]
+    \environment luatex-style-book
+\stopmode
+
+\environment luatex-logos
+\environment luatex-private
+
+\startmode[export]
+
+    \setupbackend
+      [export=luatex]
+
+\stopmode
+
+\startdocument
+  [manual=Lua\TeX,
+   status=stable,
+   version=1.10]
+
+\startnotmode[*export]
+    \component luatex-titlepage
+    \component luatex-firstpage
+\stopnotmode
+
+\startmode[*export]
+    \component luatex-export-titlepage
+\stopmode
+
+\startfrontmatter
+    \component luatex-contents
+    \component luatex-introduction
+\stopfrontmatter
+
+\startbodymatter
+    \component luatex-preamble
+    \component luatex-enhancements
+    \component luatex-modifications
+    \component luatex-lua
+    \component luatex-languages
+    \component luatex-fonts
+    \component luatex-math
+    \component luatex-nodes
+    \component luatex-callbacks
+    \component luatex-tex
+    \component luatex-graphics
+    \component luatex-fontloader
+    \component luatex-backend
+\stopbodymatter
+
+\startbackmatter
+    \component luatex-registers
+    \component luatex-statistics
+\stopbackmatter
+
+\stopdocument