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-% engine=luatex language=uk
-% $Id$
-
-% TODO: fix layout of function legend descriptions
-% check numbers
-% check \luatex command
-
-%\nopdfcompression
-%\loggingall
-\environment luatexref-env
-\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}
-
-\setvariables
- [document]
- [beta=0.80.0]
-
-\starttext
-
-\dontcomplain \nonknuthmode
-
-\setups[titlepage]
-
-\title{Contents}
-
-\placecontent[criterium=text,level=subsection]
-
-\chapter{Introduction}
-
-\startframedtext[framecolor=red,foregroundcolor=red,width=\hsize,style=\tfa]
-
-This book will eventually become the reference manual of \LUATEX. At the moment,
-it simply reports the behavior of the executable matching the snapshot or beta
-release date in the title page.
-
-\blank
-
-Features may come and go. The current version of \LUATEX\ is not meant for
-production and users cannot depend on stability, nor on functionality staying the
-same.
-
-\blank
-
-Nothing is considered stable just yet. This manual therefore simply reflects the
-current state of the executable. {\bs Absolutely nothing\/} on the following
-pages is set in stone. When the need arises, anything can (and will) be changed.
-
-\stopframedtext
-
-\blank[2*line]
-
-\LUATEX\ consists of a number of interrelated but (still) distinguishable parts:
-
-\startitemize[packed]
-\item \PDFTEX\ version 1.40.9, converted to C (with patches from later releases).
-\item The direction model and some other bits from \ALEPH\ RC4 converted to C.
-\item \LUA\ 5.2.1
-\item dedicated \LUA\ libraries
-\item various \TEX\ extensions
-\item parts of \FONTFORGE\ 2008.11.17
-\item the \METAPOST\ library
-\item newly written compiled source code to glue it all together
-\stopitemize
-
-Neither \ALEPH's I/O translation processes, nor tcx files, nor \ENCTEX\ can be
-used, these encoding|-|related functions are superseded by a \LUA|-|based
-solution (reader callbacks). Also, some experimental \PDFTEX\ features are
-removed. These can be implemented in \LUA\ instead.
-
-\chapter{Basic \TEX\ enhancements}
-
-\section{Introduction}
-
-From day one, \LUATEX\ has offered extra functionality when compared to the
-superset of \PDFTEX\ and \ALEPH. That has not been limited to the possibility to
-execute \LUA\ code via \type {\directlua}, but \LUATEX\ also adds functionality
-via new \TEX-side primitives.
-
-However, starting with beta \type {0.39.0}, most of that functionality is hidden
-by default. When \LUATEX\ 0.40.0 starts up in \quote {iniluatex} mode (\type
-{luatex -ini}), it defines only the primitive commands known by \TEX82 and the
-one extra command \type {\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 \type{\catcode}
-assigned to them at this early time (giving a 'Missing number' error), so it may
-be needed to put these assignments
-
-\starttyping
-\catcode `\{=1
-\catcode `\}=2
-\stoptyping
-
-before the above line. More fine-grained primitives control is possible, you can
-look up the details in \in{section}[luaprimitives]. For simplicity's sake, this
-manual assumes that you have executed the \type {\directlua} command as given
-above.
-
-The startup behavior documented above is considered stable in the sense that
-there will not be backward-incompatible changes any more.
-
-\section{Version information}
-
-There are three new primitives to test the version of \LUATEX:
-
-\starttabulate[|l|p|p|]
-\NC \bf primitive \NC \bf explanation \NC \bf value \NC \NR
-\NC \tex{luatexbanner} \NC the banner as reported on the command line \NC \luatexbanner \NC \NR
-\NC \tex{luatexversion} \NC a combination of major and minor number \NC \the\luatexversion \NC \NR
-\NC \tex{luatexrevision} \NC the revision number, the current value is \NC \luatexrevision \NC \NR
-\stoptabulate
-
-The official \LUATEX\ version is defined as follows:
-
-\startitemize
-\startitem
- The major version is the integer result of \tex {luatexversion} divided by
- 100. The primitive is an \quote {internal variable}, so you may need to prefix
- its use with \type {\the} depending on the context.
-\stopitem
-\startitem
- The minor version is the two-digit result of \tex {luatexversion} modulo 100.
-\stopitem
-\startitem
- The revision is the given by \tex {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
-
-\section{\UNICODE\ text support}
-
-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 not yet a
-clear separation between the two concepts. Until this is implemented, please do
-not be too harsh on us if we make errors in the usage of the terms.
-
-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, \tex
-{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 equals sign)
-or secondary (right of the equals sign) value are: \tex {char}, \tex {lccode},
-\tex {uccode}, \tex {catcode}, \tex {sfcode}, \tex {efcode}, \tex {lpcode}, \tex
-{rpcode}, \tex {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 \luatex {reader}
-callback. This will be explained in a later chapter.
-
-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.
-
-Normalization of the \UNICODE\ input can be handled by a macro package during
-callback processing (this will be explained in \in{section}[iocallback]).
-
-\section{Extended tables}
-
-All traditional \TEX\ and \ETEX\ registers can be 16-bit numbers as in \ALEPH.
-The affected commands are:
-
-\startcolumns[n=4]
-\starttyping
-\count
-\dimen
-\skip
-\muskip
-\marks
-\toks
-\countdef
-\dimendef
-\skipdef
-\muskipdef
-\toksdef
-\box
-\unhbox
-\unvbox
-\copy
-\unhcopy
-\unvcopy
-\wd
-\ht
-\dp
-\setbox
-\vsplit
-\stoptyping
-\stopcolumns
-
-The glyph properties (like \type {\efcode}) introduced in \PDFTEX\ that deal with
-font expansion (hz) and character protruding are also 16-bit. Because font memory
-management has been rewritten, these character properties are no longer shared
-among fonts instances that originate from the same metric file.
-
-The behavior documented in the above section is considered stable in the sense
-that there will not be backward-incompatible changes any more.
-
-\section{Attribute registers}
-
-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
-\tex {the} etc.\ just like the normal \tex {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\ (prior to 0.37, there could not be valid negative attribute
-values, and the \quote {unset} value was $-1$).
-
-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].
-
-The behavior documented in the above subsection is considered stable in the sense
-that there will not be backward-incompatible changes any more.
-
-\subsection{Box attributes}
-
-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 \tex {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}. An
-example:
-
-\starttyping
-\attribute2=5
-\setbox0=\hbox {Hello}
-\setbox2=\hbox attr1=12 attr2=-"7FFFFFFF{Hello}
-\stoptyping
-
-This will set the attribute list of box~2 to $1=12$, and the attributes of box~0
-will be $2=5$. As you can see, assigning the maximum negative value causes an
-attribute to be ignored.
-
-The \type {attr} keyword(s) should come before a \type {to} or \type {spread}, if
-that is also specified.
-
-\section{\LUA\ related primitives}
-
-In order to merge \LUA\ code with \TEX\ input, a few new primitives are needed.
-
-\subsection{\tex{directlua}}
-
-The primitive \tex {directlua} is used to execute \LUA\ code immediately. The
-syntax is
-
-\startsyntax
-\directlua <general text>!crlf
-\directlua name <general text> <general text>!crlf
-\directlua <16-bit number> <general text>
-\stopsyntax
-
-The last \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 \type {\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.
-
-The \syntax {name <general text>} specifies the name of the \LUA\ chunk, mainly
-shown in the stack backtrace of error messages created by \LUA\ code. The \syntax
-{<general text>} is expanded fully, thus macros can be used to generate the chunk
-name, i.e.
-
-\starttyping
-\directlua name{\jobname:\the\inputlineno} ...
-\stoptyping
-
-to include the name of the input file as well as the input line into the chunk
-name.
-
-Likewise, the \syntax {<16-bit number>} designates a name of a \LUA\ chunk, but
-in this case the name will be taken from the \type {lua.name} array (see the
-documentation of the \type {lua} table further in this manual). This syntax is
-new in version 0.36.0.
-
-The chunk name should not start with a \type {@}, or it will be displayed as a
-file name (this is a quirk in the current \LUA\ implementation).
-
-The \tex {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 \tex {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 \tex {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.
-
-The behavior documented in the above subsection is considered stable in the sense
-that there will not be backward-incompatible changes any more.
-
-\subsection{\tex{luafunction}}
-
-The \type {\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 use this primitive hundreds or
-thousands of times, it can become noticeable. For this reason there is a variant
-call available: \type {\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:
-
-\starttyping
-\directlua {
- local t = lua.get_functions_table()
- t[8] = function(slot) tex.print(slot) end
-}
-\stoptyping
-
-the number \type {8} gets typeset.
-
-\subsection{\tex{latelua}}
-
-\tex{latelua} stores \LUA\ code in a whatsit that will be processed
-at the time of shipping out. Its intended use is a cross between
-\tex{pdfliteral} and \tex{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's I/O routines.
-
-\startsyntax
-\latelua <general text>!crlf
-\latelua name <general text> <general text>!crlf
-\latelua <16-bit number> <general text>
-\stopsyntax
-
-Expansion of macros etcetera in the final \type{<general text>} is delayed
-until just before the whatsit is executed (like in \tex{write}). With
-regard to PDF output stream \tex{latelua} behaves as \tex{pdfliteral page}.
-
-The \syntax{name <general text>} and \syntax{<16-bit number>} behave
-in the same way as they do for \type{\directlua}
-
-\subsection{\tex{luaescapestring}}
-
-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 the \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
-
-
-\section{New \ETEX\ primitives}
-
-\subsection{\tex{clearmarks}}
-
-This primitive clears a mark class completely, resetting all three
-connected mark texts to empty.
-
-\startsyntax
-\clearmarks <16-bit number>
-\stopsyntax
-
-\subsection{\tex{noligs} and \tex{nokerns}}
-
-These primitives prohibit ligature and kerning insertion at the time
-when the initial node list is built by \LUATEX's main control loop.
-They are part of a temporary trick and will be removed in the near
-future. For now, you need to 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 now be implemented by overloading the ligature
-building and kerning functions, i.e.\ by assigning dummy functions
-to their associated callbacks.
-
-\subsection{\tex{formatname}}
-
-\tex{formatname}'s syntax is identical to \tex{jobname}.
-
-In \INITEX, the expansion is empty. Otherwise, the expansion is the
-value that \tex{jobname} had during the \INITEX\ run that dumped the
-currently loaded format.
-
-\subsection{\tex{scantextokens}}
-
-The syntax of \tex{scantextokens} is identical to \tex{scantokens}.
-This primitive is a slightly adapted version of \ETEX's \tex{scantokens}. The
-differences are:
-
-\startitemize
-\item The last (and usually only) line does not have a
- \tex{endlinechar} appended
-\item \tex{scantextokens} never raises an EOF error,
- and it does not execute \tex{everyeof} tokens.
-\item The \quote{\unknown\ while end of file \unknown} error tests are not executed, allowing
- the expansion to end on a different grouping level or while a
- conditional is still incomplete.
-\stopitemize
-
-\subsection {Verbose versions of single-character aligments commands (0.45)}
-
-\LUATEX\ defines two new primitives that have the same function as
-\type{#} and \type{&} in aligments:
-
-\starttabulate[|l|l|l|l|]
-\NC \bf primitive \NC \bf explanation \NC\NR
-\NC \tex{alignmark} \NC Duplicates the functionality of \char`\#~%
- inside alignment preambles\NC\NR
-\NC \tex{aligntab} \NC Duplicates the functionality of \char`\&~%
- inside alignments (and preambles)\NC\NR
-\stoptabulate
-
-
-\subsection{Catcode tables}
-
-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.
-
-The subsystem is backward compatible: if you never use the following
-commands, your document will not notice any difference in behavior
-compared to traditional \TEX.
-
-The contents of each catcode table is independent from any other
-catcode tables, and their contents is stored and retrieved from the
-format file.
-
-\subsubsection{\tex{catcodetable}}
-
-\startsyntax
-\catcodetable <15-bit number>
-\stopsyntax
-
-The primitive \tex{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.
-
-\subsubsection{\tex{initcatcodetable}}
-
-\startsyntax
-\initcatcodetable <15-bit number>
-\stopsyntax
-
-The primitive \tex{initcatcodetable} creates a new table with catcodes
-identical to those defined by \INITEX:
-
-\starttabulate[|l|l|l|l|l|]
-\NC~0\NC \tt\letterbackslash \NC \NC \tt escape \NC\NR
-\NC~5\NC \tt\letterhat\letterhat M \NC return \NC \tt car{\_}ret \NC (this name may change) \NC\NR
-\NC~9\NC \tt\letterhat\letterhat @ \NC null \NC \tt ignore \NC\NR
-\NC10\NC \tt <space> \NC space \NC \tt spacer \NC\NR
-\NC11\NC {\tt a} -- {\tt z} \NC \NC \tt letter \NC\NR
-\NC11\NC {\tt A} -- {\tt Z} \NC \NC \tt letter \NC\NR
-\NC12\NC everything else \NC \NC \tt other \NC\NR
-\NC14\NC \tt\letterpercent \NC \NC \tt comment \NC\NR
-\NC15\NC \tt\letterhat\letterhat ? \NC delete \NC \tt invalid{\_}char \NC\NR
-\stoptabulate
-
-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.
-
-\subsubsection{\tex{savecatcodetable}}
-
-\startsyntax
-\savecatcodetable <15-bit number>
-\stopsyntax
-
-\tex{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.
-
-\subsection{\tex{suppressfontnotfounderror} (0.11)}
-
-\startsyntax
-\suppressfontnotfounderror = 1
-\stopsyntax
-
-If this new 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 \tex{ifx} equal to \tex{nullfont}, so that it can be tested
-against that without bothering the user.
-
-\subsection{\tex{suppresslongerror} (0.36)}
-
-\startsyntax
-\suppresslongerror = 1
-\stopsyntax
-
-If this new integer parameter is non|-|zero, then \LUATEX\ will not
-complain about \type{\par} commands encountered in contexts where
-that is normally prohibited (most prominently in the arguments
-of non-long macros).
-
-\subsection{\tex{suppressifcsnameerror} (0.36)}
-
-\startsyntax
-\suppressifcsnameerror = 1
-\stopsyntax
-
-If this new integer parameter is non|-|zero, then \LUATEX\ will not
-complain about non-expandable commands appearing in the middle of a
-\type{\ifcsname} expansion. Instead, it will keep getting expanded
-tokens from the input until it encounters an \type{\endcsname}
-command. Use with care! This command is experimental: if the input
-expansion is unbalanced wrt. \type{\csname} \ldots \type{\endcsname}
-pairs, the \LUATEX\ process may hang indefinitely.
-
-
-\subsection{\tex{suppressoutererror} (0.36)}
-
-\startsyntax
-\suppressoutererror = 1
-\stopsyntax
-
-If this new integer parameter is non|-|zero, then \LUATEX\ will not
-complain about \type{\outer} commands encountered in contexts where
-that is normally prohibited.
-
-The addition of this command coincides with a change in the
-\LUATEX\ engine: ever since the snapshot of 20060915, \type{\outer}
-was simply ignored. That behavior has now reverted back to be
-\TEX82-compatible by default.
-
-
-
-\subsection{\tex{suppressmathparerror} (0.80)}
-
-The following setting will permit \par tokens in a math formula:
-
-\startsyntax
-\suppressmathparerror = 1
-\stopsyntax
-
-So, the next code is valid then:
-
-\starttyping
-$ x + 1 =
-
-a $
-\stoptyping
-
-
-\subsection{\tex{outputbox} (0.37)}
-
-\startsyntax
-\outputbox = 65535
-\stopsyntax
-
-This new 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.
-
-
-\subsection{Font syntax}
-
-\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.
-
-\subsection{File syntax (0.45)}
-
-\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.
-
-\subsection{Images and Forms}
-
-\LUATEX\ accepts optional dimension parameters for \type{\pdfrefximage}
-and \type{\pdfrefxform} in the same format as for \type{\pdfximage}.
-With images, these dimensions are then used
-instead of the ones given to \type{\pdfximage};
-but the original dimensions are not overwritten,
-so that a \type{\pdfrefximage} without dimensions still provides
-the image with dimensions defined by \type{\pdfximage}.
-These optional parameters are not implemented for \type{\pdfxform}.
-
-\starttyping
-\pdfrefximage width 20mm height 10mm depth 5mm \pdflastximage
-\pdfrefxform width 20mm height 10mm depth 5mm \pdflastxform
-\stoptyping
-
-\section{Debugging}
-
-If \tex{tracingonline} is larger than~2, the node list display will
-also print the node number of the nodes.
-
-\section{Global leaders}
-
-There is a new experimental primitive: \type{\gleaders} (a \LUATEX\
-extension, added in 0.43). This type of leaders is anchored to the
-origin of the box to be shipped out. So they are like normal
-\type{\leaders} in that they align nicely, except that the alignment
-is based on the {\it largest\/} enclosing box instead of the
-{\it smallest\/}.
-
-
-\section{Expandable character codes (0.75)}
-
-The new expandable command \tex{Uchar} reads a number between~0 and
-$1{,}114{,}111$ and expands to the associated Unicode character.
-
-
-\chapter {\LUA\ general}
-
-\section[init]{Initialization}
-
-\subsection{\LUATEX\ as a \LUA\ interpreter}
-
-There are some situations that make \LUATEX\ behave like a standalone \LUA\
-interpreter:
-
-\startitemize[packed]
-\item if a \type{--luaonly} option is given on the commandline, or
-\item if the executable is named \type{texlua} (or \type{luatexlua}), or
-\item if the only non|-|option argument (file) on the commandline has the extension
- \type{lua} or \type{luc}.
-\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
-commandline 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 standalone \LUA\
-interpreter with a bunch of extra preloaded libraries.
-
-\subsection{\LUATEX\ as a \LUA\ byte compiler}
-
-There are two situations that make \LUATEX\ behave like the \LUA\
-byte compiler:
-
-\startitemize[packed]
-\item if a \type{--luaconly} option is given on the commandline, or
-\item if the executable is named \type{texluac}
-\stopitemize
-
-In this mode, \LUATEX\ is exactly like \type{luac} from the standalone
-\LUA\ distribution, except that it does not have the \type{-l} switch,
-and that it accepts (but ignores) the \type{--luaconly} switch.
-
-\subsection{Other commandline processing}
-
-When the \LUATEX\ executable starts, it looks for the \type{--lua}
-commandline option. If there is no \type{--lua} option, the
-commandline is interpreted in a similar fashion as in traditional
-\PDFTEX\ and \ALEPH.
-
-The following command-line switches are understood.
-
-\starttabulate[|lT|p|]
-\NC --fmt=FORMAT \NC load the format file FORMAT \NC\NR
-\NC --lua=FILE \NC load and execute a \LUA\ initialization script\NC\NR
-\NC --safer \NC disable easily exploitable \LUA\ commands \NC\NR
-\NC --nosocket \NC disable the \LUA\ socket library \NC\NR
-\NC --help \NC display help and exit \NC\NR
-\NC --ini \NC be iniluatex, for dumping formats \NC\NR
-\NC --interaction=STRING \NC set interaction mode (STRING=batchmode/nonstopmode/\crlf
- scrollmode/errorstopmode) \NC \NR
-\NC --halt-on-error \NC stop processing at the first error\NC \NR
-\NC --kpathsea-debug=NUMBER \NC set path searching debugging flags according to
- the bits of NUMBER \NC \NR
-\NC --progname=STRING \NC set the program name to STRING \NC \NR
-\NC --version \NC display version and exit \NC\NR
-\NC --credits \NC display credits and exit \NC\NR
-\NC --recorder \NC enable filename recorder \NC \NR
-\NC --etex \NC ignored\NC \NR
-\NC --output-comment=STRING \NC use STRING for DVI file comment instead of date
- (no effect for PDF)\NC \NR
-\NC --output-directory=DIR \NC use DIR as the directory to write files to \NC \NR
-\NC --draftmode \NC switch on draft mode (generates no output PDF)\NC \NR
-\NC --output-format=FORMAT \NC use FORMAT for job output; FORMAT is 'dvi' or 'pdf' \NC \NR
-\NC --[no-]shell-escape \NC disable/enable \type{\write18{SHELL COMMAND}} \NC \NR
-\NC --enable-write18 \NC enable \type{\write18{SHELL COMMAND}} \NC \NR
-\NC --disable-write18 \NC disable \type{\write18{SHELL COMMAND}} \NC \NR
-\NC --shell-restricted \NC restrict \type{\write18} to a list of commands
- given in texmf.cnf \NC \NR
-\NC --debug-format \NC enable format debugging \NC \NR
-\NC --[no-]file-line-error \NC disable/enable file:line:error style messages \NC \NR
-\NC --[no-]file-line-error-style \NC aliases of --[no-]file-line-error \NC \NR
-\NC --jobname=STRING \NC set the job name to STRING \NC \NR
-\NC --[no-]parse-first-line \NC disable/enable parsing of the first line of the
- input file \NC \NR
-\NC --translate-file= \NC ignored \NC \NR
-\NC --default-translate-file= \NC ignored \NC \NR
-\NC --8bit \NC ignored \NC \NR
-\NC --[no-]mktex=FMT \NC disable/enable mktexFMT generation (FMT=tex/tfm)\NC \NR
-\NC --synctex=NUMBER \NC enable synctex \NC \NR
-\stoptabulate
-
-A note on the creation of the various temporary files and the \type{\jobname}.
-The value to use for \type{\jobname} is decided as follows:
-
-\startitemize
-\item If \type{--jobname} is given on the command line, its argument
- will be the value for \tex{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 \tex{jobname} setting.
-\item Otherwise, \tex{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.
-\item 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 \type{\everyjob} either, then the
- \tex{jobname} is set to \type{texput} as a last resort.
-\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 \tex{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.
-
-\blank
-
-Without the \type{--lua} option, command line processing works like it does in
-any other web2c-based typesetting engine, except that \LUATEX\ has a few extra
-switches.
-
-
-If the \type{--lua} option is present, \LUATEX\ will enter an alternative mode
-of commandline processing in comparison to the standard web2c
-programs.
-
-In this mode, a small series of actions is taken in order. First,
-it will parse the commandline 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}.
-
-Now it searches for the requested \LUA\ initialization script. If it
-cannot be found using the actual name given on the commandline, a
-second attempt is made by prepending the value of the environment
-variable \type{LUATEXDIR}, if that variable is defined in the environment.
-
-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:
-
-\starttabulate[|l|l|]
-\NC \bf library \NC \bf functions \NC \NR
-\NC \tt os \NC \tt execute exec setenv rename remove tmpdir \NC \NR
-\NC \tt io \NC \tt popen output tmpfile \NC \NR
-\NC \tt lfs \NC \tt rmdir mkdir chdir lock touch \NC \NR
-\stoptabulate
-
-Furthermore, it disables loading of compiled \LUA\ libraries (support
-for these was added in 0.46.0), and it makes \lua{io.open()} fail on
-files that are opened for anything besides reading.
-
-\type{--nosocket} 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.
-
-Next the initialization script is loaded and executed. From within the
-script, the entire commandline is available in the \LUA\ table
-\lua{arg}, beginning with \lua {arg[0]}, containing the name of the executable.
-
-Commandline 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 \luatex{tex}, \luatex{token},
-\luatex{node} and \luatex{pdf}, are off|-|limits during the execution
-of the startup file (they are nilled). Special care is taken that \luatex{texio.write} and
-\luatex{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 \tex{jobname}
-yet at this point). See \in{chapter}[libraries] for more information
-about the \LUATEX-specific \LUA\ extension tables.
-
-
-Everything you do in the \LUA\ initialization script will remain
-visible during the rest of the run, with the exception of the
-aforementioned \luatex{tex}, \luatex{token}, \luatex{node} and
-\luatex{pdf} tables: those 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
-commandline, set values in the \luatex{texconfig} table, and register
-the callbacks you need.
-
-\LUATEX\ allows some of the commandline options to be overridden
-by reading values from the \luatex{texconfig} table at the end of
-script execution (see the description of the \luatex{texconfig} table
-later on in this document for more details on which ones exactly).
-
-Unless the \luatex{texconfig} table tells \LUATEX\ not to initialize
-\KPATHSEA\ at all (set \luatex{texconfig.kpse_init} to \type{false} for that),
-\LUATEX\ acts on some more commandline 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.
-
-
-\section{\LUA\ changes}
-
-{\bf NOTE:} \LUATEX\ 0.74.0 is the first version with Lua 5.2, and
-this is used without any patches to the core, which has some side
-effects. In particular, Lua's \type{tonumber()} 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 \type{\dimen}
-or \type{\count}.
-
-{\bf NOTE:} Also in \LUATEX\ 0.74.0 (this is a change in Lua 5.2),
-loading dynamic Lua libraries will fail if there are two Lua libraries
-loaded at the same time (which will typically happen on Win32, because
-there is one Lua 5.2 inside luatex, and another will likely be linked
-to the \type{dll} file of the module itself). We plan to fix that later
-by switching \LUATEX\ itself to using de DLL version of Lua 5.2 inside
-\LUATEX\ instead of including a static version in the binary.
-
-Starting from version 0.45, \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()}.
-
-Starting from version 0.46.0 \LUATEX\ is
-also 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 build-in core lua function. As in the previous paragraph, 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:
-
-\startnarrower
-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.
-
-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.
-\stopnarrower
-
-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 I mean that it is called as
-\type{luatex}, as opposed to \type{texlua}, and that the commandline option
-\type{--luaonly} was not given), it will only run the four functions above if the
-matching 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
-function as normal. This change is new in 0.37.0.
-
-
-
-The \lua{f:read("*line")} and \lua{f:lines()} functions from the io library have
-been adjusted so that they are line|-|ending neutral: any of \type{LF}, \type
-{CR} or \type{CR+LF} are acceptable line endings.
-
-\lua{luafilesystem} has been extended: there are two extra boolean functions
-(\luatex{lfs.isdir(filename)} and \luatex{lfs.isfile(filename)}) and
-one extra string field in its attributes table
-(\type{permissions}). There is an additional function (added in 0.51)
-\type{lfs.shortname()} which takes a file name and returns its short
-name on WIN32 platforms. On other platforms, it just returns the given
-argument. The file name is not tested for existence. Finally, for
-non-WIN32 platforms only, there is the new function
-\type{lfs.readlink()} (added in 0.51) that takes an existing symbolic
-link as argument and returns its content. It returns an error on
-WIN32.
-
-The \lua{string} library has an extra function:
-\luatex{string.explode(s[,m])}. This function 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 \lua{string} library also has six extra iterators that return strings
-piecemeal:
-
-\startitemize
-\item \luatex{string.utfvalues(s)} (returns an integer value in the
-\UNICODE\ range)
-\item \luatex{string.utfcharacters(s)} (returns a string with a single
-\UTF-8 token in it)
-\item \luatex{string.characters(s)} (a string containing one byte)
-\item \luatex{string.characterpairs(s)} (two strings each containing one byte) will
-produce an empty second string if the string length was odd.
-\item \luatex{string.bytes(s)} (a single byte value)
-\item \luatex{string.bytepairs(s)} (two byte values) Will produce nil instead of a
-number as its second return value if the string length was odd.
-\stopitemize
-
-The \luatex{string.characterpairs()} and \luatex{string.bytepairs()}
-are useful especially in the conversion of UTF-16 encoded data into UTF-8.
-
-
-Starting with \LUATEX\ 0.74, 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}.
-
-Note: The \lua{string} library functions \luatex{len}, \luatex{lower},
-\luatex{sub} etc. are not \UNICODE|-|aware. For strings in the UTF-8
-encoding, i.e., strings containing characters above code point 127, the
-corresponding functions from the \lua{slnunicode} library can be used,
-e.g., \luatex{unicode.utf8.len}, \luatex{unicode.utf8.lower} etc. The
-exceptions are \luatex{unicode.utf8.find}, that always returns byte
-positions in a string, and \luatex{unicode.utf8.match} and
-\luatex{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 \lua{()} (other captures work as
-expected). For the interpretation of character classes in
-\luatex{unicode.utf8} functions refer to the library sources at
-\hyphenatedurl{http://luaforge.net/projects/sln}. The \lua{slnunicode}
-library will be replaced by an internal \UNICODE\ library in a future
-\LUATEX\ version.
-\blank
-
-The \lua{os} library has a few extra functions and variables:
-
-\startitemize
-\item \luatex{os.selfdir} is a variable that holds the directory path
-of the actual executable. For example: {\tt \directlua{tex.sprint(os.selfdir)}}
-(present since 0.27.0).
-
-\item \luatex{os.exec(commandline)} is a variation on \lua{os.execute}.
-
- The \type{commandline} can be either a single string or a single table.
-
- 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).
-
- 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 pathname.
-
- 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.
-
- 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 \tex{"}, \tex{'} or
- \type{\\} within the quoted text are un-escaped. In the table format, there
- is no string handling taking place.
-
- 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 Windows, 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.
-
-\item \luatex{os.spawn(commandline)} is a returning version of \lua{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'}.
-
-\item \luatex{os.setenv('key','value')}
- This sets a variable in the environment. Passing \lua{nil} instead of a
- value string will remove the variable.
-
-\item \luatex{os.env}
- This 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 {\em not\/} updated automatically.
-
-\item \luatex{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.
-
-\item \luatex{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.
-
-\item \luatex{os.tmpdir()} This will create 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.
-
-\item \luatex{os.type}
-This 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}).
-
-\item \luatex{os.name}
-This 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} (since 0.51), \type{cygwin} (since
-0.53), \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).
-
-(\type{os.version} is planned as a future extension)
-
-\item \luatex{os.uname()}
-This function returns a table with specific operating system
-information acquired at runtime. The keys in the returned table are
-all string valued, and their names are: \type{sysname}, \type{machine},
-\type{release}, \type{version}, and \type{nodename}.
-
-
-\stopitemize
-
-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
-
-\section {\LUA\ modules}
-
-{\bf NOTE}: Starting with \LUATEX\ 0.74, the implied use of the
-built-in Lua modules in this section is deprecated. If you want to use
-one of these libraries, please start your source file with a
-proper \type{require} line. In the near future, \LUATEX\ will switch
-to loading these modules on demand.
-
-Some modules that are normally external to \LUA\ are statically linked
-in with \LUATEX, because they offer useful functionality:
-
-\startitemize
-\item \lua{slnunicode}, from the \type {Selene} libraries, \hyphenatedurl{http://luaforge.net/projects/sln}. (version 1.1)
-
-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.
-
-\item \lua{luazip}, from the kepler project, \hyphenatedurl{http://www.keplerproject.org/luazip/}.
- (version 1.2.1, but patched for compilation with \LUA\ 5.2)
-\item \lua{luafilesystem}, also from the kepler project, \hyphenatedurl{http://www.keplerproject.org/luafilesystem/}.
- (version 1.5.0)
-\item \lua{lpeg}, by Roberto Ierusalimschy, \hyphenatedurl{http://www.inf.puc-rio.br/~roberto/lpeg/lpeg.html}. (version 0.10.2)
-
-Note: \lua{lpeg} is not \UNICODE|-|aware, but interprets strings on a
-byte|-|per|-|byte basis. This mainly means that \luatex{lpeg.S} cannot be
-used with characters above code point 127, since those characters are
-encoded using two bytes, and thus \luatex{lpeg.S} will look for one
-of those two bytes when matching, not the combination of the two.
-
-The same is true for \luatex{lpeg.R}, although the latter will display
-an error message if used with characters above code point 127: I.\,e.\
-\luatex{lpeg.R('aä')} results in the message \type{bad argument #1 to
-'R' (range must have two characters)}, since to \lua{lpeg}, \type{ä}
-is two 'characters' (bytes), so \type{aä} totals three.
-
-\item \lua{lzlib}, by Tiago Dionizio, \hyphenatedurl{http://luaforge.net/projects/lzlib/}. (version 0.2)
-\item \lua{md5}, by Roberto Ierusalimschy \hyphenatedurl{http://www.inf.puc-rio.br/~roberto/md5/md5-5/md5.html}.
-
-\item \lua{luasocket}, by Diego Nehab
-\hyphenatedurl{http://w3.impa.br/~diego/software/luasocket/}
-(version 2.0.2).
-
-Note: the \type{.lua} support modules from \type{luasocket} are also
-preloaded inside the executable, there are no external file dependencies.
-\stopitemize
-
-
-\chapter[libraries]{\LUATEX\ \LUA\ Libraries}
-
-{\bf NOTE}: Starting with \LUATEX\ 0.74, the implied use of the
-built-in Lua modules \type{epdf}, \type{fontloader}, \type{mplib},
-and \type{pdfscanner} is deprecated. If you want to use these, please
-start your source file with a proper \type{require} line. In the near
-future, \LUATEX\ will switch to loading these modules on demand.
-
-
-The interfacing between \TEX\ and \LUA\ is facilitated by a set of
-library modules. The \LUA\ libraries in this chapter are all defined and
-initialized by the \LUATEX\ executable. Together, they allow \LUA\
-scripts to query and change a number of \TEX's internal variables, run
-various internal \TEX\ functions, and set up \LUATEX's hooks to execute
-\LUA\ code.
-
-The following sections are in alphabetical order.
-
-\section{The \luatex{callback} library}
-
-This library has functions that register, find and list callbacks.
-
-A quick note on what callbacks are (thanks, Paul!):
-
-Callbacks are entry points to \LUATEX's internal operations, which can be
-interspersed with additional \LUA\ code, and even replaced altogether.
-In the first case, \TEX\ is simply augmented with new operations
-(for instance, a manipulation of the nodes resulting from the paragraph
-builder); in the second case, its hard-coded behavior (for instance, the
-paragraph builder itself) is ignored and processing relies on user code only.
-
-More precisely, the code to be inserted at a given callback is a function
-(an anonymous function or the name of a function variable); % Is this line useful?
-it will receive the arguments associated with the callback, if any, and must
-frequently return some other arguments for \TEX\ to resume its operations.
-
-The first task 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
-
-where 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 {\it exactly} what you are doing! This functionality
-is present since version 0.38.
-
-Currently, callbacks are not dumped into the format file.
-
-\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, \luatex{callback.find} returns \type{nil}.
-
-\subsection{File discovery callbacks}
-
-The behavior documented in this subsection is considered stable in the
-sense that there will not be backward-incompatible changes any more.
-
-\subsubsection{\luatex{find_read_file} and \luatex{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 \tex{input} files. For \TEX's \tex{read} or
-\tex{write} the number is incremented by one, so \tex{read0} becomes~1.
-
-\sym{asked_name}
-
-This is the user|-|supplied filename, as found by \tex{input}, \tex{openin}
-or \tex{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
-
-\subsubsection{\luatex{find_font_file}}
-
-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.
-
-\subsubsection{\luatex{find_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.
-
-\subsubsection{\luatex{find_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).
-
-\subsubsection{\luatex{find_vf_file}}
-
-Like \luatex{find_font_file}, but for virtual fonts. This applies to
-both \ALEPH's \OVF\ files and traditional Knuthian \VF\ files.
-
-\subsubsection{\luatex{find_map_file}}
-
-Like \luatex{find_font_file}, but for map files.
-
-\subsubsection{\luatex{find_enc_file}}
-
-Like \luatex{find_font_file}, but for enc files.
-
-\subsubsection{\luatex{find_sfd_file}}
-
-Like \luatex{find_font_file}, but for subfont definition files.
-
-\subsubsection{\luatex{find_pk_file}}
-
-Like \luatex{find_font_file}, but for pk bitmap files. The argument
-\type{asked_name} is a bit special in this case. Its form is
-
-\starttyping
-<base res>dpi/<fontname>.<actual res>pk
-\stoptyping
-
-So you may be asked for \type{600dpi/manfnt.720pk}. It is up to you
-to find a \quote{reasonable} bitmap file to go with that specification.
-
-\subsubsection{\luatex{find_data_file}}
-
-Like \luatex{find_font_file}, but for embedded files (\tex{pdfobj file '...'}).
-
-\subsubsection{\luatex{find_opentype_file}}
-
-Like \luatex{find_font_file}, but for \OPENTYPE\ font files.
-
-\subsubsection{\luatex{find_truetype_file} and \luatex{find_type1_file}}
-
-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 \luatex{read_file} callback.
-
-Strangely enough, \luatex{find_type1_file} is also used for \OPENTYPE\
-(\OTF) fonts.
-
-\subsubsection{\luatex{find_image_file}}
-
-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 harddisk, 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.
-
-\subsubsection{\luatex{open_read_file}}
-
-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 \luatex{find_read_file} or the return
-value of \luatex{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
-\luatex{reader} and the associated function will be called once
-for each new line to be read, the optional one is \luatex{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
-
-\subsubsubsection{\luatex{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 \luatex{close} function next.
-
-\subsubsubsection{\luatex{close}}
-
-\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.
-
-\subsubsection{General file 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
-\luatex{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 as follows:
-
-\starttabulate[|l|p|]
-\NC \luatex{read_font_file} \NC ofm or tfm files \NC\NR
-\NC \luatex{read_vf_file} \NC virtual fonts \NC\NR
-\NC \luatex{read_map_file} \NC map files \NC\NR
-\NC \luatex{read_enc_file} \NC encoding files \NC\NR
-\NC \luatex{read_sfd_file} \NC subfont definition files \NC\NR
-\NC \luatex{read_pk_file} \NC pk bitmap files \NC\NR
-\NC \luatex{read_data_file} \NC embedded files (\tex{pdfobj file ...}) \NC\NR
-\NC \luatex{read_truetype_file} \NC \TRUETYPE\ font files \NC\NR
-\NC \luatex{read_type1_file} \NC \TYPEONE\ font files \NC\NR
-\NC \luatex{read_opentype_file} \NC \OPENTYPE\ font files \NC\NR
-\stoptabulate
-
-\subsection{Data processing callbacks}
-
-\subsubsection{\luatex{process_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.
-
-\subsubsection{\luatex{process_output_buffer} (0.43)}
-
-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 \tex{write} command. It is only called for output to an
-actual file (that is, excluding the log, the terminal, and \tex{write18}
-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.
-
-
-\subsubsection{\luatex{process_jobname} (0.71)}
-
-This callback allows you to change the jobname given by \type{\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.
-
-
-\subsubsection{\luatex{token_filter}}
-
-This callback allows you to replace the way \LUATEX\ fetches
-lexical tokens.
-
-\startfunctioncall
-function()
- return <table> token
-end
-\stopfunctioncall
-
-The calling convention for this callback is a bit more complicated than
-for most other callbacks. The function should either return a \LUA\
-table representing a valid to|-|be|-|processed token or tokenlist, or
-something else like \type{nil} or an empty table.
-
-If your \LUA\ function does not return a table representing a valid
-token, it will be immediately called again, until it eventually does
-return a useful token or tokenlist (or until you reset the callback
-value to nil). See the description of \luatex{token} for some
-handy functions to be used in conjunction with this callback.
-
-If your function returns a single usable token, then that token will
-be processed by \LUATEX\ immediately. If the function returns a token
-list (a table consisting of a list of consecutive token tables), then
-that list will be pushed to the input stack at a completely new token
-list level, with its token type set to \quote{inserted}. In either case,
-the returned token(s) will not be fed back into the callback function.
-
-Setting this callback to \type{false} has no effect (because otherwise
-nothing would happen, forever).
-
-\subsection{Node list processing callbacks}
-
-The description of nodes and node lists is in~\in{chapter}[nodes].
-
-\subsubsection{\luatex{buildpage_filter}}
-
-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 are:
-
-\starttabulate[|lT|p|]
-\NC \ssbf value \NC \bf explanation \NC\NR
-\NC alignment \NC a (partial) alignment is being added \NC\NR
-\NC after_output \NC an output routine has just finished \NC\NR
-\NC box \NC a typeset box is being added \NC\NR
-%\NC pre_box \NC interline material is being added \NC\NR
-%\NC adjust \NC \tex{vadjust} material is being added \NC\NR
-\NC new_graf \NC the beginning of a new paragraph \NC\NR
-\NC vmode_par \NC \tex{par} was found in vertical mode \NC\NR
-\NC hmode_par \NC \tex{par} was found in horizontal mode \NC\NR
-\NC insert \NC an insert is added \NC\NR
-\NC penalty \NC a penalty (in vertical mode) \NC\NR
-\NC before_display \NC immediately before a display starts \NC\NR
-\NC after_display \NC a display is finished \NC\NR
-\NC end \NC \LUATEX\ is terminating (it's all over)\NC\NR
-\stoptabulate
-
-This callback does not replace any internal code.
-
-
-\subsubsection{\luatex{pre_linebreak_filter}}
-
-This callback is called just before \LUATEX\ starts converting a list
-of nodes into a stack of \tex{hbox}es, after the addition of
-\type{\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
-\luatex {pre_linebreak_filter}, some are for the
-\luatex {hpack_filter} and \luatex {vpack_filter} callbacks that
-will be explained in the next two paragraphs.
-
-\starttabulate[|lT|p|]
-\NC \ssbf value \NC \bf explanation \NC\NR
-\NC <empty> \NC main vertical list \NC\NR
-\NC hbox \NC \tex{hbox} in horizontal mode \NC\NR
-\NC adjusted_hbox\NC \tex{hbox} in vertical mode \NC\NR
-\NC vbox \NC \tex{vbox} \NC\NR
-\NC vtop \NC \tex{vtop} \NC\NR
-\NC align \NC \tex{halign} or \tex{valign} \NC\NR
-\NC disc \NC discretionaries \NC\NR
-\NC insert \NC packaging an insert \NC\NR
-\NC vcenter \NC \tex{vcenter} \NC\NR
-\NC local_box \NC \tex{localleftbox} or \tex{localrightbox} \NC\NR
-\NC split_off \NC top of a \tex{vsplit} \NC\NR
-\NC split_keep \NC remainder of a \tex{vsplit} \NC\NR
-\NC align_set \NC alignment cell \NC\NR
-\NC fin_row \NC alignment row \NC\NR
-\stoptabulate
-
-As for all the callbacks that deal with nodes, the return value can be one of three things:
-
-\startitemize
-\item boolean \type{true} signals succesful processing
-\item \type{<node>} signals that the \quote{head} node should be replaced by the returned node
-\item boolean \type{false} signals that the \quote{head} node list should be ignored and
-flushed from memory
-\stopitemize
-
-
-This callback does not replace any internal code.
-
-
-\subsubsection{\luatex{linebreak_filter}}
-
-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}.
-
-\subsubsection{\luatex{post_linebreak_filter}}
-
-This callback is called just after \LUATEX\ has converted a list
-of nodes into a stack of \tex{hbox}es.
-
-\startfunctioncall
-function(<node> head, <string> groupcode)
- return true | false | <node> newhead
-end
-\stopfunctioncall
-
-This callback does not replace any internal code.
-
-\subsubsection{\luatex{hpack_filter}}
-
-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])
- 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 \tex{hbox spread ...}
-argument. If \type{exactly}, then the \type{size} is a \tex{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} (added in 0.45).
-
-
-This callback does not replace any internal code.
-
-\subsubsection{\luatex{vpack_filter}}
-
-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 \luatex{hpack_filter}. Besides
-the fact that it is called at different moments, there is an extra
-variable that matches \TEX's \tex{maxdepth} setting.
-
-\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.
-
-\subsubsection{\luatex{pre_output_filter}}
-
-This callback is called when \TEX\ is ready to start boxing the
-box 255 for \tex{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.
-
-\subsubsection{\luatex{hyphenate}}
-
-\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.
-
-\subsubsection{\luatex{ligaturing}}
-
-\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.
-
-\subsubsection{\luatex{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 \type{ligaturing} for calling
-conventions.
-
-Setting this callback to \type{false} will prevent the internal
-kern insertion pass.
-
-\subsubsection{\luatex{mlist_to_hlist}}
-
-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.
-
-\subsection{Information reporting callbacks}
-
-\subsubsection{\luatex{pre_dump} (0.61)}
-
-\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.
-
-\subsubsection{\luatex{start_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.
-
-\subsubsection{\luatex{stop_run}}
-
-\startfunctioncall
-function()
-end
-\stopfunctioncall
-
-This callback replaces the code that prints \LUATEX's statistics and \quote{output written
-to} messages.
-
-\subsubsection{\luatex{start_page_number}}
-
-\startfunctioncall
-function()
-end
-\stopfunctioncall
-
-Replaces the code that prints the \type{[} and the page number at the
-begin of \tex{shipout}. This callback will also override the
-printing of box information that normally takes place when
-\tex{tracingoutput} is positive.
-
-\subsubsection{\luatex{stop_page_number}}
-
-\startfunctioncall
-function()
-end
-\stopfunctioncall
-
-Replaces the code that prints the \type{]} at the end of \tex{shipout}.
-
-\subsubsection{\luatex{show_error_hook}}
-
-\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 \luatex{status} table useful.
-
-This callback does not replace any internal code.
-
-\iffalse % this has been retracted for the moment
-\startitemize
-
-\sym{message}
-
-is the formal error message \TEX\ has given to the user.
-(the line after the '!').
-
-\sym{indicator}
-
-is either a filename (when it is a string) or a location indicator (a
-number) that can mean lots of different things like a token list id
-or a \tex{read} number.
-
-\sym{lineno}
-
-is the current line number.
-\stopitemize
-
-This is an investigative item for 'testing the water' only.
-The final goal is the total replacement of \TEX's error handling
-routines, but that needs lots of adjustments in the web source because
-\TEX\ deals with errors in a somewhat haphazard fashion. This is why the
-exact definition of \type{indicator} is not given here.
-\fi
-
-
-\subsubsection{\luatex{show_error_message}}
-
-\startfunctioncall
-function()
-end
-\stopfunctioncall
-
-This callback replaces the code that prints the error message. The usual
-interaction after the message is not affected.
-
-\subsubsection{\luatex{show_lua_error_hook}}
-
-\startfunctioncall
-function()
-end
-\stopfunctioncall
-
-This callback replaces the code that prints the extra lua error message.
-
-
-\subsubsection{\luatex{start_file}}
-
-\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[|||]
-\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
-\stoptabulate
-
-\subsubsection{\luatex{stop_file}}
-
-\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{PDF-related callbacks}
-
-\subsubsection{\luatex{finish_pdffile}}
-
-\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.
-
-
-\subsubsection{\luatex{finish_pdfpage}}
-
-
-\startfunctioncall
-function(shippingout)
-end
-\stopfunctioncall
-
-This callback is called after the pdf page stream has been assembled and before the
-page object gets finalized. This callback is available in \LUATEX\ 0.78.4 and later.
-
-
-\subsection{Font-related callbacks}
-
-\subsubsection{\luatex{define_font}}
-
-\startfunctioncall
-function(<string> name, <number> size, <number> id)
- return <table> font
-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]
-\item if it is positive, it specifies an \quote{at size} in scaled points.
-\item if it is negative, its absolute value represents a \quote{scaled}
-setting relative to the designsize of the font.
-\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.
-
-Setting this callback to \type{false} is pointless as it will prevent
-font loading completely but will nevertheless generate errors.
-
-\section{The \luatex{epdf} library}
-
-The \type{epdf} library provides Lua bindings to many \PDF\ access functions
-that are defined by the poppler pdf viewer library (written in C$+{}+$
-by Kristian H\o gsberg, based on xpdf by Derek Noonburg).
-Within \LUATEX\ (and \PDFTEX),
-xpdf functionality is being used since long time to embed \PDF\ files.
-The \type{epdf} library shall allow to scrutinize an external \PDF\ file.
-It gives access to its document structure,
-e.\,g., catalog, cross-reference table, individual pages, objects,
-annotations, info, and metadata. The \LUATEX\ team is evaluating
-the possibility of reducing the binding to a basic low level \PDF\
-primitives and delegate the complete set of functions
-to an external shared object module.
-
-
-The \type{epdf} library is still in alpha state:
-\PDF\ access is currently read|-|only
-(it's not yet possible to alter a \PDF\ file or to assemble it from scratch),
-and many function bindings are still missing.
-
-For a start,
-a \PDF\ file is opened by \type{epdf.open()} with file name, e.\,g.:
-
-\starttyping
-doc = epdf.open("foo.pdf")
-\stoptyping
-
-This normally returns a \type{PDFDoc} userdata variable;
-but if the file could not be opened successfully,
-instead of a fatal error just the value \type{nil} is returned.
-
-All Lua functions in the \type{epdf} library are named after the
-poppler functions listed in the poppler header files for the various classes,
-e.\,g., files \type{PDFDoc.h}, \type{Dict.h}, and \type{Array.h}.
-These files can be found in the poppler subdirectory within the \LUATEX\ sources.
-Which functions are already implemented in the \type{epdf} library
-can be found in the \LUATEX\ source file \type{lepdflib.cc}.
-For using the \type{epdf} library,
-knowledge of the \PDF\ file architecture is indispensable.
-
-There are many different userdata types defined
-by the \type{epdf} library, currently these are
-\type{AnnotBorderStyle},
-\type{AnnotBorder},
-\type{Annots},
-\type{Annot},
-\type{Array},
-\type{Attribute},
-\type{Catalog},
-\type{Dict},
-\type{EmbFile},
-\type{GString},
-\type{LinkDest},
-\type{Links},
-\type{Link},
-\type{ObjectStream},
-\type{Object},
-\type{PDFDoc},
-\type{PDFRectangle},
-\type{Page},
-\type{Ref},
-\type{Stream},
-\type{StructElement},
-\type{StructTreeRoot}
-\type{TextSpan},
-\type{XRefEntry}
-and
-\type{XRef}
-
-
-All these userdata names and the Lua access functions closely resemble
-the classes naming from the poppler header files,
-including the choice of mixed upper and lower case letters.
-The Lua function calls use object-oriented syntax, e.\,g.,
-the following calls return the \type{Page} object for page~1:
-
-\starttyping
-pageref = doc:getCatalog():getPageRef(1)
-pageobj = doc:getXRef():fetch(pageref.num, pageref.gen)
-\stoptyping
-
-But writing such chained calls is risky,
-as an intermediate function may return \type{nil} on error;
-therefore between function calls there should be Lua type checks
-(e.\,g., against \type{nil}) done.
-If a non-object item is requested
-(e.\,g., a \type{Dict} item by calling \type{page:getPieceInfo()},
-cf.~\type{Page.h}) but not available,
-the Lua functions return \type{nil} (without error).
-If a function should return an \type{Object}, but it's not existing,
-a \type{Null} object is returned instead
-(also without error; this is in|-|line with poppler behavior).
-
-All library objects have a \type{__gc} metamethod for garbage collection.
-The \type{__tostring} metamethod gives the type name for each object.
-
-All object constructors:
-
-\startfunctioncall
-<PDFDoc> = epdf.open(<string> PDF filename)
-<Annot> = epdf.Annot(<XRef>, <Dict>, <Catalog>, <Ref>)
-<Annots> = epdf.Annots(<XRef>, <Catalog>, <Object>)
-<Array> = epdf.Array(<XRef>)
-<Attribute> = epdf.Attribute(<Type>,<Object>)| epdf.Attribute(<string>, <int>, <Object>)
-<Dict> = epdf.Dict(<XRef>)
-<Object> = epdf.Object()
-<PDFRectangle> = epdf.PDFRectangle()
-\stopfunctioncall
-
-The functions \type{StructElement_Type},
-\type{Attribute_Type} and
-\type{AttributeOwner_Type} return a hash table \type{{<string>,<integer>}}.
-
-
-
-\type{Annot} methods:
-
-\startfunctioncall
-<boolean> = <Annot>:isOK()
-<Object> = <Annot>:getAppearance()
-<AnnotBorder> = <Annot>:getBorder()
-<boolean> = <Annot>:match(<Ref>)
-\stopfunctioncall
-
-\type{AnnotBorderStyle} methods:
-
-\startfunctioncall
-<number> = <AnnotBorderStyle>:getWidth()
-\stopfunctioncall
-
-\type{Annots} methods:
-
-\startfunctioncall
-<integer> = <Annots>:getNumAnnots()
-<Annot> = <Annots>:getAnnot(<integer>)
-\stopfunctioncall
-
-\type{Array} methods:
-
-\startfunctioncall
- <Array>:incRef()
- <Array>:decRef()
-<integer> = <Array>:getLength()
- <Array>:add(<Object>)
-<Object> = <Array>:get(<integer>)
-<Object> = <Array>:getNF(<integer>)
-<string> = <Array>:getString(<integer>)
-\stopfunctioncall
-
-
-\type{Attribute} methods:
-
-\startfunctioncall
-<boolean> = <Attribute>:isOk()
-<integer> = <Attribute>:getType()
-<integer> = <Attribute>:getOwner()
-<string> = <Attribute>:getTypeName()
-<string> = <Attribute>:getOwnerName()
-<Object> = <Attribute>:getValue()
-<Object> = <Attribute>:getDefaultValue
-<string> = <Attribute>:getName()
-<integer> = <Attribute>:getRevision()
- <Attribute>:setRevision(<unsigned integer>)
-<boolean> = <Attribute>:istHidden()
- <Attribute>:setHidden(<boolean>)
-<string> = <Attribute>:getFormattedValue()
-<string> = <Attribute>:setFormattedValue(<string>)
-\stopfunctioncall
-
-
-
-\type{Catalog} methods:
-
-\startfunctioncall
-<boolean> = <Catalog>:isOK()
-<integer> = <Catalog>:getNumPages()
-<Page> = <Catalog>:getPage(<integer>)
-<Ref> = <Catalog>:getPageRef(<integer>)
-<string> = <Catalog>:getBaseURI()
-<string> = <Catalog>:readMetadata()
-<Object> = <Catalog>:getStructTreeRoot()
-<integer> = <Catalog>:findPage(<integer> object number, <integer> object generation)
-<LinkDest> = <Catalog>:findDest(<string> name)
-<Object> = <Catalog>:getDests()
-<integer> = <Catalog>:numEmbeddedFiles()
-<EmbFile> = <Catalog>:embeddedFile(<integer>)
-<integer> = <Catalog>:numJS()
-<string> = <Catalog>:getJS(<integer>)
-<Object> = <Catalog>:getOutline()
-<Object> = <Catalog>:getAcroForm()
-\stopfunctioncall
-
-\type{EmbFile} methods:
-
-\startfunctioncall
-<string> = <EmbFile>:name()
-<string> = <EmbFile>:description()
-<integer> = <EmbFile>:size()
-<string> = <EmbFile>:modDate()
-<string> = <EmbFile>:createDate()
-<string> = <EmbFile>:checksum()
-<string> = <EmbFile>:mimeType()
-<Object> = <EmbFile>:streamObject()
-<boolean> = <EmbFile>:isOk()
-\stopfunctioncall
-
-\type{Dict} methods:
-
-\startfunctioncall
- <Dict>:incRef()
- <Dict>:decRef()
-<integer> = <Dict>:getLength()
- <Dict>:add(<string>, <Object>)
- <Dict>:set(<string>, <Object>)
- <Dict>:remove(<string>)
-<boolean> = <Dict>:is(<string>)
-<Object> = <Dict>:lookup(<string>)
-<Object> = <Dict>:lookupNF(<string>)
-<integer> = <Dict>:lookupInt(<string>, <string>)
-<string> = <Dict>:getKey(<integer>)
-<Object> = <Dict>:getVal(<integer>)
-<Object> = <Dict>:getValNF(<integer>)
-<boolean> = <Dict>:hasKey(<string>)
-\stopfunctioncall
-
-\type{Link} methods:
-
-\startfunctioncall
-<boolean> = <Link>:isOK()
-<boolean> = <Link>:inRect(<number>, <number>)
-\stopfunctioncall
-
-\type{LinkDest} methods:
-
-\startfunctioncall
-<boolean> = <LinkDest>:isOK()
-<integer> = <LinkDest>:getKind()
-<string> = <LinkDest>:getKindName()
-<boolean> = <LinkDest>:isPageRef()
-<integer> = <LinkDest>:getPageNum()
-<Ref> = <LinkDest>:getPageRef()
-<number> = <LinkDest>:getLeft()
-<number> = <LinkDest>:getBottom()
-<number> = <LinkDest>:getRight()
-<number> = <LinkDest>:getTop()
-<number> = <LinkDest>:getZoom()
-<boolean> = <LinkDest>:getChangeLeft()
-<boolean> = <LinkDest>:getChangeTop()
-<boolean> = <LinkDest>:getChangeZoom()
-\stopfunctioncall
-
-\type{Links} methods:
-
-\startfunctioncall
-<integer> = <Links>:getNumLinks()
-<Link> = <Links>:getLink(<integer>)
-\stopfunctioncall
-
-\type{Object} methods:
-
-\startfunctioncall
- <Object>:initBool(<boolean>)
- <Object>:initInt(<integer>)
- <Object>:initReal(<number>)
- <Object>:initString(<string>)
- <Object>:initName(<string>)
- <Object>:initNull()
- <Object>:initArray(<XRef>)
- <Object>:initDict(<XRef>)
- <Object>:initStream(<Stream>)
- <Object>:initRef(<integer> object number, <integer> object generation)
- <Object>:initCmd(<string>)
- <Object>:initError()
- <Object>:initEOF()
-<Object> = <Object>:fetch(<XRef>)
-<integer> = <Object>:getType()
-<string> = <Object>:getTypeName()
-<boolean> = <Object>:isBool()
-<boolean> = <Object>:isInt()
-<boolean> = <Object>:isReal()
-<boolean> = <Object>:isNum()
-<boolean> = <Object>:isString()
-<boolean> = <Object>:isName()
-<boolean> = <Object>:isNull()
-<boolean> = <Object>:isArray()
-<boolean> = <Object>:isDict()
-<boolean> = <Object>:isStream()
-<boolean> = <Object>:isRef()
-<boolean> = <Object>:isCmd()
-<boolean> = <Object>:isError()
-<boolean> = <Object>:isEOF()
-<boolean> = <Object>:isNone()
-<boolean> = <Object>:getBool()
-<integer> = <Object>:getInt()
-<number> = <Object>:getReal()
-<number> = <Object>:getNum()
-<string> = <Object>:getString()
-<string> = <Object>:getName()
-<Array> = <Object>:getArray()
-<Dict> = <Object>:getDict()
-<Stream> = <Object>:getStream()
-<Ref> = <Object>:getRef()
-<integer> = <Object>:getRefNum()
-<integer> = <Object>:getRefGen()
-<string> = <Object>:getCmd()
-<integer> = <Object>:arrayGetLength()
- = <Object>:arrayAdd(<Object>)
-<Object> = <Object>:arrayGet(<integer>)
-<Object> = <Object>:arrayGetNF(<integer>)
-<integer> = <Object>:dictGetLength(<integer>)
- = <Object>:dictAdd(<string>, <Object>)
- = <Object>:dictSet(<string>, <Object>)
-<Object> = <Object>:dictLookup(<string>)
-<Object> = <Object>:dictLookupNF(<string>)
-<string> = <Object>:dictgetKey(<integer>)
-<Object> = <Object>:dictgetVal(<integer>)
-<Object> = <Object>:dictgetValNF(<integer>)
-<boolean> = <Object>:streamIs(<string>)
- = <Object>:streamReset()
-<integer> = <Object>:streamGetChar()
-<integer> = <Object>:streamLookChar()
-<integer> = <Object>:streamGetPos()
- = <Object>:streamSetPos(<integer>)
-<Dict> = <Object>:streamGetDict()
-\stopfunctioncall
-
-\type{Page} methods:
-
-\startfunctioncall
-<boolean> = <Page>:isOk()
-<integer> = <Page>:getNum()
-<PDFRectangle> = <Page>:getMediaBox()
-<PDFRectangle> = <Page>:getCropBox()
-<boolean> = <Page>:isCropped()
-<number> = <Page>:getMediaWidth()
-<number> = <Page>:getMediaHeight()
-<number> = <Page>:getCropWidth()
-<number> = <Page>:getCropHeight()
-<PDFRectangle> = <Page>:getBleedBox()
-<PDFRectangle> = <Page>:getTrimBox()
-<PDFRectangle> = <Page>:getArtBox()
-<integer> = <Page>:getRotate()
-<string> = <Page>:getLastModified()
-<Dict> = <Page>:getBoxColorInfo()
-<Dict> = <Page>:getGroup()
-<Stream> = <Page>:getMetadata()
-<Dict> = <Page>:getPieceInfo()
-<Dict> = <Page>:getSeparationInfo()
-<Dict> = <Page>:getResourceDict()
-<Object> = <Page>:getAnnots()
-<Links> = <Page>:getLinks(<Catalog>)
-<Object> = <Page>:getContents()
-\stopfunctioncall
-
-\type{PDFDoc} methods:
-
-\startfunctioncall
-<boolean> = <PDFDoc>:isOk()
-<integer> = <PDFDoc>:getErrorCode()
-<string> = <PDFDoc>:getErrorCodeName()
-<string> = <PDFDoc>:getFileName()
-<XRef> = <PDFDoc>:getXRef()
-<Catalog> = <PDFDoc>:getCatalog()
-<number> = <PDFDoc>:getPageMediaWidth()
-<number> = <PDFDoc>:getPageMediaHeight()
-<number> = <PDFDoc>:getPageCropWidth()
-<number> = <PDFDoc>:getPageCropHeight()
-<integer> = <PDFDoc>:getNumPages()
-<string> = <PDFDoc>:readMetadata()
-<Object> = <PDFDoc>:getStructTreeRoot()
-<integer> = <PDFDoc>:findPage(<integer> object number, <integer> object generation)
-<Links> = <PDFDoc>:getLinks(<integer>)
-<LinkDest> = <PDFDoc>:findDest(<string>)
-<boolean> = <PDFDoc>:isEncrypted()
-<boolean> = <PDFDoc>:okToPrint()
-<boolean> = <PDFDoc>:okToChange()
-<boolean> = <PDFDoc>:okToCopy()
-<boolean> = <PDFDoc>:okToAddNotes()
-<boolean> = <PDFDoc>:isLinearized()
-<Object> = <PDFDoc>:getDocInfo()
-<Object> = <PDFDoc>:getDocInfoNF()
-<integer> = <PDFDoc>:getPDFMajorVersion()
-<integer> = <PDFDoc>:getPDFMinorVersion()
-\stopfunctioncall
-
-\type{PDFRectangle} methods:
-
-\startfunctioncall
-<boolean> = <PDFRectangle>:isValid()
-\stopfunctioncall
-
-%\type{Ref} methods:
-%
-%\startfunctioncall
-%\stopfunctioncall
-
-\type{Stream} methods:
-
-\startfunctioncall
-<integer> = <Stream>:getKind()
-<string> = <Stream>:getKindName()
- = <Stream>:reset()
- = <Stream>:close()
-<integer> = <Stream>:getChar()
-<integer> = <Stream>:lookChar()
-<integer> = <Stream>:getRawChar()
-<integer> = <Stream>:getUnfilteredChar()
- = <Stream>:unfilteredReset()
-<integer> = <Stream>:getPos()
-<boolean> = <Stream>:isBinary()
-<Stream> = <Stream>:getUndecodedStream()
-<Dict> = <Stream>:getDict()
-\stopfunctioncall
-
-\type{StructElement} methods:
-
-\startfunctioncall
-<string> = <StructElement>:getTypeName()
-<integer> = <StructElement>:getType()
-<boolean> = <StructElement>:isOk()
-<boolean> = <StructElement>:isBlock()
-<boolean> = <StructElement>:isInline()
-<boolean> = <StructElement>:isGrouping()
-<boolean> = <StructElement>:isContent()
-<boolean> = <StructElement>:isObjectRef()
-<integer> = <StructElement>:getMCID()
-<Ref> = <StructElement>:getObjectRef()
-<Ref> = <StructElement>:getParentRef()
-<boolean> = <StructElement>:hasPageRef()
-<Ref> = <StructElement>:getPageRef()
-<StructTreeRoot> = <StructElement>:getStructTreeRoot()
-<string> = <StructElement>:getID()
-<string> = <StructElement>:getLanguage()
-<integer> = <StructElement>:getRevision()
- <StructElement>:setRevision(<unsigned integer>)
-<string> = <StructElement>:getTitle()
-<string> = <StructElement>:getExpandedAbbr()
-<integer> = <StructElement>:getNumChildren()
-<StructElement> = <StructElement>:getChild()
- = <StructElement>:appendChild<StructElement>)
-<integer> = <StructElement>:getNumAttributes()
-<Attribute> = <StructElement>:geAttribute(<integer>)
-<string> = <StructElement>:appendAttribute(<Attribute>)
-<Attribute> = <StructElement>:findAttribute(<Attribute::Type>,boolean,Attribute::Owner)
-<string> = <StructElement>:getAltText()
-<string> = <StructElement>:getActualText()
-<string> = <StructElement>:getText(<boolean>)
-<table> = <StructElement>:getTextSpans()
-\stopfunctioncall
-
-
-\type{StructTreeRoot} methods:
-
-\startfunctioncall
-<StructElement> = <StructTreeRoot>:findParentElement
-<PDFDoc> = <StructTreeRoot>:getDoc
-<Dict> = <StructTreeRoot>:getRoleMap
-<Dict> = <StructTreeRoot>:getClassMap
-<integer> = <StructTreeRoot>:getNumChildren
-<StructElement> = <StructTreeRoot>:getChild
- <StructTreeRoot>:appendChild
-<StructElement> = <StructTreeRoot>:findParentElement
-\stopfunctioncall
-
-
-\type{TextSpan} han only one method:
-
-\startfunctioncall
-<string> = <TestSpan>:getText()
-\stopfunctioncall
-
-
-
-
-\type{XRef} methods:
-
-\startfunctioncall
-<boolean> = <XRef>:isOk()
-<integer> = <XRef>:getErrorCode()
-<boolean> = <XRef>:isEncrypted()
-<boolean> = <XRef>:okToPrint()
-<boolean> = <XRef>:okToPrintHighRes()
-<boolean> = <XRef>:okToChange()
-<boolean> = <XRef>:okToCopy()
-<boolean> = <XRef>:okToAddNotes()
-<boolean> = <XRef>:okToFillForm()
-<boolean> = <XRef>:okToAccessibility()
-<boolean> = <XRef>:okToAssemble()
-<Object> = <XRef>:getCatalog()
-<Object> = <XRef>:fetch(<integer> object number, <integer> object generation)
-<Object> = <XRef>:getDocInfo()
-<Object> = <XRef>:getDocInfoNF()
-<integer> = <XRef>:getNumObjects()
-<integer> = <XRef>:getRootNum()
-<integer> = <XRef>:getRootGen()
-<integer> = <XRef>:getSize()
-<Object> = <XRef>:getTrailerDict()
-\stopfunctioncall
-
-%***********************************************************************
-
-\section{The \luatex{font} library}
-
-The font library provides the interface into the internals of the font
-system, and also it contains helper functions to load traditional
-\TEX\ font metrics formats. Other font loading functionality is
-provided by the \luatex{fontloader} library that will be discussed in
-the next section.
-
-\subsection{Loading a \TFM\ file}
-
-The behavior 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
-\item if it is positive, it specifies an \quote{at size} in scaled points.
-\item if it is negative, its absolute value represents a \quote{scaled}
-setting relative to the designsize of the font.
-\stopitemize
-
-The internal structure of the metrics font table that is returned is
-explained in \in{chapter}[fonts].
-
-\subsection{Loading a \VF\ file}
-
-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 \luatex{read_tfm()} function.
-
-\subsection{The fonts array}
-
-The whole table of \TEX\ fonts is accessible from \LUA\ using a virtual array.
-
-\starttyping
-font.fonts[n] = { ... }
-<table> f = font.fonts[n]
-\stoptyping
-
-See \in{chapter}[fonts] for the structure of the tables. 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. This
-process can be quite slow. In a later version of \LUATEX, this
-interface will change (it will start using userdata objects instead of
-actual tables).
-
-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}
-
-You can define your own font into \luatex{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 \luatex{font.fonts}). If the font creation fails, an error is
-raised. The table is a font structure, as explained in
-\in{chapter}[fonts].
-
-\subsection{Projected next font 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.
-
-\subsection{Font id (0.47)}
-
-\startfunctioncall
-<number> i = font.id(<string> csname)
-\stopfunctioncall
-
-This returns the font id associated with \type{csname} string, or $-1$
-if \type{csname} is not defined; new in 0.47.
-
-\subsection{Currently active font}
-
-\startfunctioncall
-<number> i = font.current()
-font.current(<number> i)
-\stopfunctioncall
-
-This gets or sets the currently used font number.
-
-\subsection{Maximum font id}
-
-\startfunctioncall
-<number> i = font.max()
-\stopfunctioncall
-
-This is the largest used index in \type{font.fonts}.
-
-\subsection{Iterating over all fonts}
-
-\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.
-
-\section{The \luatex{fontloader} library (0.36)}
-
-\subsection{Getting quick information on a font}
-
-\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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC fontname \NC string \NC the \POSTSCRIPT\ name of the font\NC\NR
-\NC fullname \NC string \NC the formal name of the font\NC\NR
-\NC familyname \NC string \NC the family name this font belongs to\NC\NR
-\NC weight \NC string \NC a string indicating the color value of the font\NC\NR
-\NC version \NC string \NC the internal font version\NC\NR
-\NC italicangle \NC float \NC the slant angle\NC\NR
-\NC units_per_em \NC number \NC (since 0.78.2) 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC\NR
-\NC pfminfo \NC table \NC (since 0.78.2) (see \in{section}[fontloaderpfminfotable])\NC\NR
-\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.
-
-\subsection{Loading an \OPENTYPE\ or \TRUETYPE\ file}
-
-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
-
-\item The font is automatically re|-|encoded, so that the \type{metrics}
- table for \TRUETYPE\ and \OPENTYPE\ fonts is using \UNICODE\ for
- the character indices.
-
-\item Many features are pre|-|processed into a format that is easier to handle
- than just the bare tables would be.
-
-\item \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.
-
-\item In the future, it may be interesting to allow \LUA\ scripts access to
- the font program itself, perhaps even creating or changing the font.
-
-\stopitemize
-
-A loaded font is discarded with:
-
-\startfunctioncall
-fontloader.close(<userdata> font)
-\stopfunctioncall
-
-\subsection{Applying a \quote{feature file}}
-
-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\crlf
-\hyphenatedurl {http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html}\crlf
-and\crlf
-\hyphenatedurl {http://fontforge.sourceforge.net/featurefile.html}\crlf
-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. (the return value is new in 0.65)
-
-
-
-\subsection{Applying an \quote{\AFM\ file}}
-
-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 \hyphenatedurl{ftp://ftp.math.utah.edu/u/ma/hohn/linux/postscript/5004.AFM_Spec.pdf}
-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. (the return value is new in 0.65)
-
-\subsection[fontloadertables]{Fontloader font tables}
-
-As mentioned earlier, the return value of \type{fontloader.open()} is
-a userdata object. In \LUATEX\ versions before 0.63, the only way to
-have access to the actual metrics was to call
-\type{fontloader.to_table()} on this object, returning the table
-structure that is explained in the following subsections.
-
-However, 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 starting with \LUATEX\ 0.63,
-it is possible to access the userdata object directly.
-
-In the \LUATEX\ 0.63.0, the following is implemented:
-
-\startitemize
-\item all top-level keys that would be returned by \type{to_table()}
- can also be accessed directly.
-\item the top-level key \quote{glyphs} returns a {\it virtual\/} array that
- allows indices from \type{0} to ($\type{f.glyphmax}-1$).
-\item 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.
-\item 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).
-\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
-while (i < f.glyphmax) do
- local g = f.glyphs[i]
- if g then
- print(g.name)
- end
- i = i + 1
-end
-fontloader.close(f)
-\stoptyping
-
-In this case, the \LUATEX\ memory requirement stays below 100MB on the
-test computer, while the internal stucture generated by
-\type{to_table()} needs more than 2GB of memory (the font itself is
-6.9MB in disk size).
-
-In \LUATEX\ 0.63 only the top-level font, the subfont table entries,
-and the glyphs are virtual objects, everything else still produces
-normal lua values and tables. In future versions, more return values
-may be replaced by userdata objects (as much as needed to keep the
-memory requirements in check).
-
-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 for now, more will be
-implemented later):
-
-\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
-
-
-\subsubsection{Table types}
-
-\subsubsubsection{Top-level}
-
-The top|-|level keys in the returned table are (the explanations in
-this part of the documentation are not yet finished):
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC table_version \NC number \NC indicates the metrics version (currently~0.3)\NC\NR
-\NC fontname \NC string \NC \POSTSCRIPT\ font name\NC\NR
-\NC fullname \NC string \NC official (human-oriented) font name\NC\NR
-\NC familyname \NC string \NC family name\NC\NR
-\NC weight \NC string \NC weight indicator\NC\NR
-\NC copyright \NC string \NC copyright information\NC\NR
-\NC filename \NC string \NC the file name\NC\NR
-\NC version \NC string \NC font version\NC\NR
-\NC italicangle \NC float \NC slant angle\NC\NR
-\NC units_per_em \NC number \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC\NR
-\NC ascent \NC number \NC height of ascender in \type{units_per_em}\NC\NR
-\NC descent \NC number \NC depth of descender in \type{units_per_em}\NC\NR
-\NC upos \NC float \NC \NC\NR
-\NC uwidth \NC float \NC \NC\NR
-\NC uniqueid \NC number \NC \NC\NR
-\NC glyphcnt \NC number \NC number of included glyphs\NC\NR
-\NC glyphs \NC array \NC \NC\NR
-\NC glyphmax \NC number \NC maximum used index the glyphs array\NC\NR
-\NC hasvmetrics \NC number \NC \NC\NR
-\NC onlybitmaps \NC number \NC \NC\NR
-\NC serifcheck \NC number \NC \NC\NR
-\NC isserif \NC number \NC \NC\NR
-\NC issans \NC number \NC \NC\NR
-\NC encodingchanged \NC number \NC \NC\NR
-\NC strokedfont \NC number \NC \NC\NR
-\NC use_typo_metrics \NC number \NC \NC\NR
-\NC weight_width_slope_only \NC number \NC \NC\NR
-\NC head_optimized_for_cleartype \NC number \NC \NC\NR
-\NC uni_interp \NC enum \NC \type {unset}, \type {none}, \type {adobe},
- \type {greek}, \type {japanese}, \type {trad_chinese},
- \type {simp_chinese}, \type {korean}, \type {ams}\NC\NR
-\NC origname \NC string \NC the file name, as supplied by the user\NC\NR
-\NC map \NC table \NC \NC\NR
-\NC private \NC table \NC \NC\NR
-\NC xuid \NC string \NC \NC\NR
-\NC pfminfo \NC table \NC \NC\NR
-\NC names \NC table \NC \NC\NR
-\NC cidinfo \NC table \NC \NC\NR
-\NC subfonts \NC array \NC \NC\NR
-\NC commments \NC string \NC \NC\NR
-\NC fontlog \NC string \NC \NC\NR
-\NC cvt_names \NC string \NC \NC\NR
-\NC anchor_classes \NC table \NC \NC\NR
-\NC ttf_tables \NC table \NC \NC\NR
-\NC ttf_tab_saved \NC table \NC \NC\NR
-\NC kerns \NC table \NC \NC\NR
-\NC vkerns \NC table \NC \NC\NR
-\NC texdata \NC table \NC \NC\NR
-\NC lookups \NC table \NC \NC\NR
-\NC gpos \NC table \NC \NC\NR
-\NC gsub \NC table \NC \NC\NR
-\NC mm \NC table \NC \NC\NR
-\NC chosenname \NC string \NC \NC\NR
-\NC macstyle \NC number \NC \NC\NR
-\NC fondname \NC string \NC \NC\NR
-%\NC design_size \NC number \NC \NC\NR
-\NC fontstyle_id \NC number \NC \NC\NR
-\NC fontstyle_name \NC table \NC \NC\NR
-%\NC design_range_bottom \NC number \NC \NC\NR
-%\NC design_range_top \NC number \NC \NC\NR
-\NC strokewidth \NC float \NC \NC\NR
-\NC mark_classes \NC table \NC \NC\NR
-\NC creationtime \NC number \NC \NC\NR
-\NC modificationtime \NC number \NC \NC\NR
-\NC os2_version \NC number \NC \NC\NR
-\NC sfd_version \NC number \NC \NC\NR
-\NC math \NC table \NC \NC\NR
-\NC validation_state \NC table \NC \NC\NR
-\NC horiz_base \NC table \NC \NC\NR
-\NC vert_base \NC table \NC \NC\NR
-\NC extrema_bound \NC number \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{Glyph items}
-
-The \type{glyphs} is an array containing the per|-|character
-information (quite a few of these are only present if nonzero).
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC name \NC string \NC the glyph name\NC\NR
-\NC unicode \NC number \NC unicode code point, or -1\NC\NR
-\NC boundingbox \NC array \NC array of four numbers, see note below\NC\NR
-\NC width \NC number \NC only for horizontal fonts\NC\NR
-\NC vwidth \NC number \NC only for vertical fonts\NC\NR
-\NC tsidebearing \NC number \NC only for vertical ttf/otf fonts, and only if nonzero (0.79.0)\NC\NR
-\NC lsidebearing \NC number \NC only if nonzero and not equal to boundingbox[1]\NC\NR
-\NC class \NC string \NC one of "none", "base", "ligature", "mark", "component"
- (if not present, the glyph class is \quote{automatic})\NC\NR
-\NC kerns \NC array \NC only for horizontal fonts, if set\NC\NR
-\NC vkerns \NC array \NC only for vertical fonts, if set\NC\NR
-\NC dependents \NC array \NC linear array of glyph name strings, only if nonempty\NC\NR
-\NC lookups \NC table \NC only if nonempty\NC\NR
-\NC ligatures \NC table \NC only if nonempty\NC\NR
-\NC anchors \NC table \NC only if set\NC\NR
-\NC comment \NC string \NC only if set\NC\NR
-\NC tex_height \NC number \NC only if set\NC\NR
-\NC tex_depth \NC number \NC only if set\NC\NR
-\NC italic_correction \NC number \NC only if set\NC\NR
-\NC top_accent \NC number \NC only if set\NC\NR
-\NC is_extended_shape \NC number \NC only if this character is part of a math extension list\NC\NR
-\NC altuni \NC table \NC alternate \UNICODE\ items \NC\NR
-\NC vert_variants \NC table \NC \NC \NR
-\NC horiz_variants \NC table \NC \NC \NR
-\NC mathkern \NC table \NC \NC \NR
-\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 starting from \LUATEX\ 0.45, 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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC char \NC string \NC \NC\NR
-\NC off \NC number \NC \NC\NR
-\NC lookup \NC string \NC \NC\NR
-\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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC type \NC enum \NC \type {position}, \type {pair}, \type {substitution}, \type {alternate},
- \type {multiple}, \type {ligature}, \type {lcaret}, \type {kerning}, \type {vkerning}, \type {anchors},
- \type {contextpos}, \type {contextsub}, \type {chainpos}, \type {chainsub},
- \type {reversesub}, \type {max}, \type {kernback}, \type {vkernback} \NC\NR
-\NC specification \NC table \NC extra data \NC\NR
-\stoptabulate
-
-For the first seven values of \type{type}, there can be additional
-sub|-|information, stored in the sub-table \type{specification}:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf value \NC \bf type \NC \bf explanation \NC\NR
-\NC position \NC table \NC a table of the \type {offset_specs} type\NC\NR
-\NC pair \NC table \NC one string: \type {paired}, and an array of one or
- two \type {offset_specs} tables: \type{offsets}\NC\NR
-\NC substitution \NC table \NC one string: \type {variant}\NC\NR
-\NC alternate \NC table \NC one string: \type {components}\NC\NR
-\NC multiple \NC table \NC one string: \type {components}\NC\NR
-\NC ligature \NC table \NC two strings: \type {components}, \type {char}\NC\NR
-\NC lcaret \NC array \NC linear array of numbers\NC\NR
-\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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC lig \NC table \NC uses the same substructure as a single item in the \type{lookups} table explained above\NC\NR
-\NC char \NC string \NC \NC\NR
-\NC components \NC array \NC linear array of named components\NC\NR
-\NC ccnt \NC number \NC \NC\NR
-\stoptabulate
-
-The \type{anchor} table is indexed by a string signifying the
-anchor type, which is one of
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC mark \NC table \NC placement mark\NC\NR
-\NC basechar \NC table \NC mark for attaching combining items to a base char\NC\NR
-\NC baselig \NC table \NC mark for attaching combining items to a ligature\NC\NR
-\NC basemark \NC table \NC generic mark for attaching combining items to connect to\NC\NR
-\NC centry \NC table \NC cursive entry point\NC\NR
-\NC cexit \NC table \NC cursive exit point\NC\NR
-\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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC x \NC number \NC x location\NC\NR
-\NC y \NC number \NC y location\NC\NR
-\NC ttf_pt_index \NC number \NC truetype point index, only if given\NC\NR
-\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!
-
-
-\subsubsubsection{map table}
-
-The top|-|level map is a list of encoding mappings. Each of those is a table itself.
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC enccount \NC number \NC \NC\NR
-\NC encmax \NC number \NC \NC\NR
-\NC backmax \NC number \NC \NC\NR
-\NC remap \NC table \NC \NC\NR
-\NC map \NC array \NC non|-|linear array of mappings\NC\NR
-\NC backmap \NC array \NC non|-|linear array of backward mappings\NC\NR
-\NC enc \NC table \NC \NC\NR
-\stoptabulate
-
-The \type{remap} table is very small:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC firstenc \NC number \NC \NC\NR
-\NC lastenc \NC number \NC \NC\NR
-\NC infont \NC number \NC \NC\NR
-\stoptabulate
-
-The \type{enc} table is a bit more verbose:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC enc_name \NC string \NC \NC\NR
-\NC char_cnt \NC number \NC \NC\NR
-\NC char_max \NC number \NC \NC\NR
-\NC unicode \NC array \NC of \UNICODE\ position numbers\NC\NR
-\NC psnames \NC array \NC of \POSTSCRIPT\ glyph names\NC\NR
-\NC builtin \NC number \NC \NC\NR
-\NC hidden \NC number \NC \NC\NR
-\NC only_1byte \NC number \NC \NC\NR
-\NC has_1byte \NC number \NC \NC\NR
-\NC has_2byte \NC number \NC \NC\NR
-\NC is_unicodebmp \NC number \NC only if nonzero\NC\NR
-\NC is_unicodefull \NC number \NC only if nonzero\NC\NR
-\NC is_custom \NC number \NC only if nonzero\NC\NR
-\NC is_original \NC number \NC only if nonzero\NC\NR
-\NC is_compact \NC number \NC only if nonzero\NC\NR
-\NC is_japanese \NC number \NC only if nonzero\NC\NR
-\NC is_korean \NC number \NC only if nonzero\NC\NR
-\NC is_tradchinese \NC number \NC only if nonzero [name?]\NC\NR
-\NC is_simplechinese \NC number \NC only if nonzero\NC\NR
-\NC low_page \NC number \NC \NC\NR
-\NC high_page \NC number \NC \NC\NR
-\NC iconv_name \NC string \NC \NC\NR
-\NC iso_2022_escape \NC string \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{private table}
-
-This is the font's private \POSTSCRIPT\ dictionary, if any. Keys and
-values are both strings.
-
-\subsubsubsection{cidinfo table}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC registry \NC string \NC \NC\NR
-\NC ordering \NC string \NC \NC\NR
-\NC supplement \NC number \NC \NC\NR
-\NC version \NC number \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection[fontloaderpfminfotable]{pfminfo table}
-
-The \type{pfminfo} table contains most of the OS/2 information:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC pfmset \NC number \NC \NC\NR
-\NC winascent_add \NC number \NC \NC\NR
-\NC windescent_add \NC number \NC \NC\NR
-\NC hheadascent_add \NC number \NC \NC\NR
-\NC hheaddescent_add \NC number \NC \NC\NR
-\NC typoascent_add \NC number \NC \NC\NR
-\NC typodescent_add \NC number \NC \NC\NR
-\NC subsuper_set \NC number \NC \NC\NR
-\NC panose_set \NC number \NC \NC\NR
-\NC hheadset \NC number \NC \NC\NR
-\NC vheadset \NC number \NC \NC\NR
-\NC pfmfamily \NC number \NC \NC\NR
-\NC weight \NC number \NC \NC\NR
-\NC width \NC number \NC \NC\NR
-\NC avgwidth \NC number \NC \NC\NR
-\NC firstchar \NC number \NC \NC\NR
-\NC lastchar \NC number \NC \NC\NR
-\NC fstype \NC number \NC \NC\NR
-\NC linegap \NC number \NC \NC\NR
-\NC vlinegap \NC number \NC \NC\NR
-\NC hhead_ascent \NC number \NC \NC\NR
-\NC hhead_descent \NC number \NC \NC\NR
-\NC os2_typoascent \NC number \NC \NC\NR
-\NC os2_typodescent \NC number \NC \NC\NR
-\NC os2_typolinegap \NC number \NC \NC\NR
-\NC os2_winascent \NC number \NC \NC\NR
-\NC os2_windescent \NC number \NC \NC\NR
-\NC os2_subxsize \NC number \NC \NC\NR
-\NC os2_subysize \NC number \NC \NC\NR
-\NC os2_subxoff \NC number \NC \NC\NR
-\NC os2_subyoff \NC number \NC \NC\NR
-\NC os2_supxsize \NC number \NC \NC\NR
-\NC os2_supysize \NC number \NC \NC\NR
-\NC os2_supxoff \NC number \NC \NC\NR
-\NC os2_supyoff \NC number \NC \NC\NR
-\NC os2_strikeysize \NC number \NC \NC\NR
-\NC os2_strikeypos \NC number \NC \NC\NR
-\NC os2_family_class \NC number \NC \NC\NR
-\NC os2_xheight \NC number \NC \NC\NR
-\NC os2_capheight \NC number \NC \NC\NR
-\NC os2_defaultchar \NC number \NC \NC\NR
-\NC os2_breakchar \NC number \NC \NC\NR
-\NC os2_vendor \NC string \NC \NC\NR
-\NC codepages \NC table \NC A two-number array of encoded code pages\NC\NR
-\NC unicoderages \NC table \NC A four-number array of encoded unicode ranges\NC\NR
-\NC panose \NC table \NC \NC\NR
-\stoptabulate
-
-The \type{panose} subtable has exactly 10 string keys:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC 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 serifstyle \NC string \NC See the \OPENTYPE\ font specification for values\NC\NR
-\NC weight \NC string \NC id. \NC\NR
-\NC proportion \NC string \NC id. \NC\NR
-\NC contrast \NC string \NC id. \NC\NR
-\NC strokevariation \NC string \NC id. \NC\NR
-\NC armstyle \NC string \NC id. \NC\NR
-\NC letterform \NC string \NC id. \NC\NR
-\NC midline \NC string \NC id. \NC\NR
-\NC xheight \NC string \NC id. \NC\NR
-\stoptabulate
-
-\subsubsubsection[fontloadernamestable]{names table}
-
-Each item has two top|-|level keys:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC lang \NC string \NC language for this entry \NC\NR
-\NC names \NC table \NC \NC\NR
-\stoptabulate
-
-The \type{names} keys are the actual \TRUETYPE\ name strings. The
-possible keys are:
-
-\starttabulate[|lT|p|]
-\NC \ssbf key \NC \bf explanation \NC\NR
-\NC copyright \NC \NC\NR
-\NC family \NC \NC\NR
-\NC subfamily \NC \NC\NR
-\NC uniqueid \NC \NC\NR
-\NC fullname \NC \NC\NR
-\NC version \NC \NC\NR
-\NC postscriptname \NC \NC\NR
-\NC trademark \NC \NC\NR
-\NC manufacturer \NC \NC\NR
-\NC designer \NC \NC\NR
-\NC descriptor \NC \NC\NR
-\NC venderurl \NC \NC\NR
-\NC designerurl \NC \NC\NR
-\NC license \NC \NC\NR
-\NC licenseurl \NC \NC\NR
-\NC idontknow \NC \NC\NR
-\NC preffamilyname \NC \NC\NR
-\NC prefmodifiers \NC \NC\NR
-\NC compatfull \NC \NC\NR
-\NC sampletext \NC \NC\NR
-\NC cidfindfontname \NC \NC\NR
-\NC wwsfamily \NC \NC\NR
-\NC wwssubfamily \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{anchor_classes table}
-
-The anchor_classes classes:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC name \NC string \NC a descriptive id of this anchor class\NC\NR
-\NC lookup \NC string \NC \NC\NR
-\NC type \NC string \NC one of \type {mark}, \type {mkmk}, \type {curs}, \type {mklg} \NC\NR
-\stoptabulate
-
-% type is actually a lookup subtype, not a feature name. Officially, these strings
-% should be gpos_mark2mark etc.
-
-\subsubsubsection{gpos table}
-
-Th gpos table has one array entry for each lookup. (The \type {gpos_} prefix is somewhat redundant.)
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC 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 flags \NC table \NC \NC\NR
-\NC name \NC string \NC \NC\NR
-\NC features \NC array \NC \NC\NR
-\NC subtables \NC array \NC \NC\NR
-\stoptabulate
-
-The flags table has a true value for each of the lookup flags that is
-actually set:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC r2l \NC boolean \NC \NC\NR
-\NC ignorebaseglyphs \NC boolean \NC \NC\NR
-\NC ignoreligatures \NC boolean \NC \NC\NR
-\NC ignorecombiningmarks \NC boolean \NC \NC\NR
-\NC mark_class \NC string \NC (new in 0.44)\NC\NR
-\stoptabulate
-
-
-The features subtable items of gpos have:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC tag \NC string \NC \NC\NR
-\NC scripts \NC table \NC \NC\NR
-\stoptabulate
-
-The scripts table within features has:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC script \NC string \NC \NC\NR
-\NC langs \NC array of strings \NC \NC\NR
-\stoptabulate
-
-
-The subtables table has:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC name \NC string \NC \NC\NR
-\NC suffix \NC string \NC (only if used)\NC\NR % used by gpos_single to get a default
-\NC anchor_classes \NC number \NC (only if used)\NC\NR
-\NC vertical_kerning \NC number \NC (only if used)\NC\NR
-\NC kernclass \NC table \NC (only if used)\NC\NR
-\stoptabulate
-
-
-The kernclass with subtables table has:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC firsts \NC array of strings \NC \NC\NR
-\NC seconds \NC array of strings \NC \NC\NR
-\NC lookup \NC string or array \NC associated lookup(s) \NC \NR
-\NC offsets \NC array of numbers \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{gsub table}
-
-This has identical layout to the \type{gpos} table, except for the
-type:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC 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
-\stoptabulate
-
-
-
-\subsubsubsection{ttf_tables and ttf_tab_saved tables}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC tag \NC string \NC \NC\NR
-\NC len \NC number \NC \NC\NR
-\NC maxlen \NC number \NC \NC\NR
-\NC data \NC number \NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{mm table}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC axes \NC table \NC array of axis names \NC \NR
-\NC instance_count \NC number \NC \NC \NR
-\NC positions \NC table \NC array of instance positions
- (\#axes * instances )\NC \NR
-\NC defweights \NC table \NC array of default weights for instances \NC \NR
-\NC cdv \NC string \NC \NC \NR
-\NC ndv \NC string \NC \NC \NR
-\NC axismaps \NC table \NC \NC \NR
-\stoptabulate
-
-The \type{axismaps}:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC blends \NC table \NC an array of blend points \NC \NR
-\NC designs \NC table \NC an array of design values \NC \NR
-\NC min \NC number \NC \NC \NR
-\NC def \NC number \NC \NC \NR
-\NC max \NC number \NC \NC \NR
-\stoptabulate
-
-
-\subsubsubsection{mark_classes table (0.44)}
-
-The keys in this table are mark class names, and the values
-are a space-separated string of glyph names in this class.
-
-Note: This table is indeed new in 0.44. The manual said it existed
-before then, but in practise it was missing due to a bug.
-
-\subsubsubsection{math table}
-
-\starttabulate[|lT|p|]
-\NC ScriptPercentScaleDown \NC \NC \NR
-\NC ScriptScriptPercentScaleDown \NC \NC \NR
-\NC DelimitedSubFormulaMinHeight \NC \NC \NR
-\NC DisplayOperatorMinHeight \NC \NC \NR
-\NC MathLeading \NC \NC \NR
-\NC AxisHeight \NC \NC \NR
-\NC AccentBaseHeight \NC \NC \NR
-\NC FlattenedAccentBaseHeight \NC \NC \NR
-\NC SubscriptShiftDown \NC \NC \NR
-\NC SubscriptTopMax \NC \NC \NR
-\NC SubscriptBaselineDropMin \NC \NC \NR
-\NC SuperscriptShiftUp \NC \NC \NR
-\NC SuperscriptShiftUpCramped \NC \NC \NR
-\NC SuperscriptBottomMin \NC \NC \NR
-\NC SuperscriptBaselineDropMax \NC \NC \NR
-\NC SubSuperscriptGapMin \NC \NC \NR
-\NC SuperscriptBottomMaxWithSubscript \NC \NC \NR
-\NC SpaceAfterScript \NC \NC \NR
-\NC UpperLimitGapMin \NC \NC \NR
-\NC UpperLimitBaselineRiseMin \NC \NC \NR
-\NC LowerLimitGapMin \NC \NC \NR
-\NC LowerLimitBaselineDropMin \NC \NC \NR
-\NC StackTopShiftUp \NC \NC \NR
-\NC StackTopDisplayStyleShiftUp \NC \NC \NR
-\NC StackBottomShiftDown \NC \NC \NR
-\NC StackBottomDisplayStyleShiftDown \NC \NC \NR
-\NC StackGapMin \NC \NC \NR
-\NC StackDisplayStyleGapMin \NC \NC \NR
-\NC StretchStackTopShiftUp \NC \NC \NR
-\NC StretchStackBottomShiftDown \NC \NC \NR
-\NC StretchStackGapAboveMin \NC \NC \NR
-\NC StretchStackGapBelowMin \NC \NC \NR
-\NC FractionNumeratorShiftUp \NC \NC \NR
-\NC FractionNumeratorDisplayStyleShiftUp \NC \NC \NR
-\NC FractionDenominatorShiftDown \NC \NC \NR
-\NC FractionDenominatorDisplayStyleShiftDown \NC \NC \NR
-\NC FractionNumeratorGapMin \NC \NC \NR
-\NC FractionNumeratorDisplayStyleGapMin \NC \NC \NR
-\NC FractionRuleThickness \NC \NC \NR
-\NC FractionDenominatorGapMin \NC \NC \NR
-\NC FractionDenominatorDisplayStyleGapMin \NC \NC \NR
-\NC SkewedFractionHorizontalGap \NC \NC \NR
-\NC SkewedFractionVerticalGap \NC \NC \NR
-\NC OverbarVerticalGap \NC \NC \NR
-\NC OverbarRuleThickness \NC \NC \NR
-\NC OverbarExtraAscender \NC \NC \NR
-\NC UnderbarVerticalGap \NC \NC \NR
-\NC UnderbarRuleThickness \NC \NC \NR
-\NC UnderbarExtraDescender \NC \NC \NR
-\NC RadicalVerticalGap \NC \NC \NR
-\NC RadicalDisplayStyleVerticalGap \NC \NC \NR
-\NC RadicalRuleThickness \NC \NC \NR
-\NC RadicalExtraAscender \NC \NC \NR
-\NC RadicalKernBeforeDegree \NC \NC \NR
-\NC RadicalKernAfterDegree \NC \NC \NR
-\NC RadicalDegreeBottomRaisePercent \NC \NC \NR
-\NC MinConnectorOverlap \NC \NC \NR
-\NC FractionDelimiterSize \NC (new in 0.47.0)\NC \NR
-\NC FractionDelimiterDisplayStyleSize \NC (new in 0.47.0)\NC \NR
-\stoptabulate
-
-\subsubsubsection{validation_state table}
-
-\starttabulate[|lT|p|]
-\NC \ssbf key \NC \bf explanation \NC\NR
-\NC bad_ps_fontname \NC \NC \NR
-\NC bad_glyph_table \NC \NC \NR
-\NC bad_cff_table \NC \NC \NR
-\NC bad_metrics_table \NC \NC \NR
-\NC bad_cmap_table \NC \NC \NR
-\NC bad_bitmaps_table \NC \NC \NR
-\NC bad_gx_table \NC \NC \NR
-\NC bad_ot_table \NC \NC \NR
-\NC bad_os2_version \NC \NC \NR
-\NC bad_sfnt_header \NC \NC \NR
-\stoptabulate
-
-\subsubsubsection{horiz_base and vert_base table}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC tags \NC table \NC an array of script list tags\NC \NR
-\NC scripts \NC table \NC \NC \NR
-\stoptabulate
-
-
-The \type{scripts} subtable:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC baseline \NC table \NC \NC \NR
-\NC default_baseline \NC number \NC \NC \NR
-\NC lang \NC table \NC \NC \NR
-\stoptabulate
-
-
-The \type{lang} subtable:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC tag \NC string \NC a script tag \NC \NR
-\NC ascent \NC number \NC \NC \NR
-\NC descent \NC number \NC \NC \NR
-\NC features \NC table \NC \NC \NR
-\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.
-
-\subsubsubsection{altuni table}
-
-An array of alternate \UNICODE\ values. Inside that array
-are hashes with:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC unicode \NC number \NC this glyph is also used for this unicode\NC \NR
-\NC variant \NC number \NC the alternative is driven by this unicode selector\NC \NR
-\stoptabulate
-
-\subsubsubsection{vert_variants and horiz_variants table}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC variants \NC string \NC \NC \NR
-\NC italic_correction \NC number \NC \NC \NR
-\NC parts \NC table \NC \NC \NR
-\stoptabulate
-
-The \type{parts} table is an array of smaller tables:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC component \NC string \NC \NC \NR
-\NC extender \NC number \NC \NC \NR
-\NC start \NC number \NC \NC \NR
-\NC end \NC number \NC \NC \NR
-\NC advance \NC number \NC \NC \NR
-\stoptabulate
-
-
-\subsubsubsection{mathkern table}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC top_right \NC table \NC \NC \NR
-\NC bottom_right \NC table \NC \NC \NR
-\NC top_left \NC table \NC \NC \NR
-\NC bottom_left \NC table \NC \NC \NR
-\stoptabulate
-
-Each of the subtables is an array of small hashes with two keys:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC height \NC number \NC \NC \NR
-\NC kern \NC number \NC \NC \NR
-\stoptabulate
-
-\subsubsubsection{kerns table}
-
-Substructure is identical to the per|-|glyph subtable.
-
-\subsubsubsection{vkerns table}
-
-Substructure is identical to the per|-|glyph subtable.
-
-\subsubsubsection{texdata table}
-
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC type \NC string \NC \type {unset}, \type {text}, \type {math}, \type {mathext}\NC\NR
-\NC params \NC array \NC 22 font numeric parameters\NC\NR
-\stoptabulate
-
-\subsubsubsection{lookups table}
-
-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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC type \NC string \NC \NC\NR
-\NC format \NC enum \NC one of \type {glyphs}, \type {class}, \type {coverage}, \type {reversecoverage} \NC\NR
-\NC tag \NC string \NC \NC\NR
-\NC current_class \NC array \NC \NC\NR
-\NC before_class \NC array \NC \NC\NR
-\NC after_class \NC array \NC \NC\NR
-\NC rules \NC array \NC an array of rule items\NC\NR
-\stoptabulate
-
-Rule items have one common item and one specialized item:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC lookups \NC array \NC a linear array of lookup names\NC\NR
-\NC glyphs \NC array \NC only if the parent's format is \type{glyphs}\NC\NR
-\NC class \NC array \NC only if the parent's format is \type{class}\NC\NR
-\NC coverage \NC array \NC only if the parent's format is \type{coverage}\NC\NR
-\NC reversecoverage \NC array \NC only if the parent's format is \type{reversecoverage}\NC\NR
-\stoptabulate
-
-A glyph table is:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC names \NC string \NC \NC\NR
-\NC back \NC string \NC \NC\NR
-\NC fore \NC string \NC \NC\NR
-\stoptabulate
-
-A class table is:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC current \NC array \NC of numbers \NC\NR
-\NC before \NC array \NC of numbers \NC\NR
-\NC after \NC array \NC of numbers \NC\NR
-\stoptabulate
-
-coverage:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC current \NC array \NC of strings \NC\NR
-\NC before \NC array \NC of strings\NC\NR
-\NC after \NC array \NC of strings \NC\NR
-\stoptabulate
-
-reversecoverage:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC current \NC array \NC of strings \NC\NR
-\NC before \NC array \NC of strings\NC\NR
-\NC after \NC array \NC of strings \NC\NR
-\NC replacements \NC string \NC \NC\NR
-\stoptabulate
-
-%***********************************************************************
-
-\section{The \luatex{img} library}
-
-The \type{img} library can be used as an alternative to
-\tex{pdfximage} and \tex{pdfrefximage}, and the associated \quote {satellite}
-commands like \tex{pdfximagebbox}.
-Image objects can also be used within virtual fonts
-via the \type{image} command listed in~\in{section}[virtualfonts].
-
-\subsection{\luatex{img.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.
-
-\subsection{\luatex{img.keys}}
-
-\startfunctioncall
-<table> keys = img.keys()
-\stopfunctioncall
-
-This function returns a list of all the possible \type{image_spec}
-keys, both user-supplied and automatic ones.
-
-% hahe: i need to add r/w ro column...
-\starttabulate[|l|l|p|]
-\NC \bf field name\NC \bf type \NC description \NC \NR
-\NC attr \NC string \NC the image attributes for \LUATEX \NC \NR
-\NC 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 colordepth \NC number \NC the number of bits used by the color space\NC \NR
-\NC colorspace \NC number \NC the color space object number \NC \NR
-\NC depth \NC number \NC the image depth for \LUATEX\
- (in scaled points)\NC \NR
-\NC filename \NC string \NC the image file name \NC \NR
-\NC filepath \NC string \NC the full (expanded) file name of the image\NC \NR
-\NC height \NC number \NC the image height for \LUATEX\
- (in scaled points)\NC \NR
-\NC imagetype \NC string \NC one of \type{pdf}, \type{png}, \type{jpg}, \type{jp2},
- \type{jbig2}, or \type{nil} \NC \NR
-\NC index \NC number \NC the \PDF\ image name suffix \NC \NR
-\NC objnum \NC number \NC the \PDF\ image object number \NC \NR
-\NC page \NC ?? \NC the identifier for the requested image page
- (type is number or string,
- default is the number 1)\NC \NR
-\NC 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 pages \NC number \NC the total number of available pages \NC \NR
-\NC rotation \NC number \NC the image rotation from included \PDF\ file,
- in multiples of 90~deg. \NC \NR
-\NC stream \NC string \NC the raw stream data for an \type{/Xobject}
- \type{/Form} object\NC \NR
-\NC transform \NC number \NC the image transform, integer number 0..7\NC \NR
-\NC width \NC number \NC the image width for \LUATEX\
- (in scaled points)\NC \NR
-\NC xres \NC number \NC the horizontal natural image resolution
- (in \DPI) \NC \NR
-\NC xsize \NC number \NC the natural image width \NC \NR
-\NC yres \NC number \NC the vertical natural image resolution
- (in \DPI) \NC \NR
-\NC ysize \NC number \NC the natural image height \NC \NR
-\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{\luatex{img.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{\luatex{img.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 a \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}.
-
-% Hartmut, I don't know if this makes sense. An example of what
-% can, and what cannot be changed would be helpful.
-% -- will think about it...
-
-\subsection{\luatex{img.write}}
-
-\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 whatsit node of subtype \type{pdf_refximage} 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.
-
-\subsection{\luatex{img.immediatewrite}}
-
-\startfunctioncall
-<image> var = img.immediatewrite(<image> var)
-<image> var = img.immediatewrite(<table> image_spec)
-\stopfunctioncall
-
-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 \tex{immediate}\tex{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
-\luatex{img.write(a)} or \luatex{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.
-
-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.
-
-\subsection{\luatex{img.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{\luatex{img.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{\luatex{img.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 letters).
-
-%***********************************************************************
-
-\section{The \luatex{kpse} library}
-
-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. The object oriented interface and \type{kpse.new} have been added
-in \LUATEX\ 0.37.
-
-\subsection{\luatex{kpse.set_program_name} and \luatex{kpse.new}}
-
-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 \luatex{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 vales.
-
-\subsection{\luatex{find_file}}
-
-The most often used function in the library is 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:
-
-\startsimplecolumns
-\starttyping
-'gf'
-'pk'
-'bitmap font'
-'tfm'
-'afm'
-'base'
-'bib'
-'bst'
-'cnf'
-'ls-R'
-'fmt'
-'map'
-'mem'
-'mf'
-'mfpool'
-'mft'
-'mp'
-'mppool'
-'MetaPost support'
-'ocp'
-'ofm'
-'opl'
-'otp'
-'ovf'
-'ovp'
-'graphic/figure'
-'tex'
-'TeX system documentation'
-'texpool'
-'TeX system sources'
-'PostScript header'
-'Troff fonts'
-'type1 fonts'
-'vf'
-'dvips config'
-'ist'
-'truetype fonts'
-'type42 fonts'
-'web2c files'
-'other text files'
-'other binary files'
-'misc fonts'
-'web'
-'cweb'
-'enc files'
-'cmap files'
-'subfont definition files'
-'opentype fonts'
-'pdftex config'
-'lig files'
-'texmfscripts'
-'lua',
-'font feature files',
-'cid maps',
-'mlbib',
-'mlbst',
-'clua',
-\stoptyping
-\stopsimplecolumns
-
-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. The last four types:
-'font feature files', 'cid maps', 'mlbib', 'mlbst' were new
-additions in \LUATEX\ 0.40.2.
-
-
-\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
-
-\subsection{\luatex{lookup}}
-
-A more powerful (but slower) generic method for finding files is also
-available (since 0.51). 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|]
-\NC \ssbf key \NC \ssbf type \NC \ssbf description \NC \NR
-\NC debug \NC number \NC set debugging flags for this lookup\NC \NR
-\NC format \NC string \NC use specific file type (see list above)\NC \NR
-\NC dpi \NC number \NC use this resolution for this lookup; default 600\NC \NR
-\NC path \NC string \NC search in the given path\NC \NR
-\NC all \NC boolean \NC output all matches, not just the first\NC \NR
-\NC mustexist \NC boolean \NC (0.65 and higher) search the disk as well as ls-R if necessary\NC \NR
-\NC must-exist\NC boolean \NC (0.64 and lower) search the disk as well as ls-R if necessary\NC \NR
-\NC mktexpk \NC boolean \NC disable/enable mktexpk generation for this lookup\NC \NR
-\NC mktextex \NC boolean \NC disable/enable mktextex generation for this lookup\NC \NR
-\NC mktexmf \NC boolean \NC disable/enable mktexmf generation for this lookup\NC \NR
-\NC mktextfm \NC boolean \NC disable/enable mktextfm generation for this lookup\NC \NR
-\NC subdir \NC string
- or table \NC only output matches whose directory part
- ends with the given string(s) \NC \NR
-\stoptabulate
-
-\subsection{\luatex{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
-
-
-\subsection{\luatex{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 \lua {nil} if the file does not exist or is not readable.
-
-\subsection{\luatex{expand_path}}
-
-Like kpsewhich's \type {-expand-path}:
-
-\startfunctioncall
-<string> r = kpse.expand_path(<string> s)
-\stopfunctioncall
-
-\subsection{\luatex{expand_var}}
-
-Like kpsewhich's \type{-expand-var}:
-
-\startfunctioncall
-<string> r = kpse.expand_var(<string> s)
-\stopfunctioncall
-
-\subsection{\luatex{expand_braces}}
-
-Like kpsewhich's \type{-expand-braces}:
-
-\startfunctioncall
-<string> r = kpse.expand_braces(<string> s)
-\stopfunctioncall
-
-\subsection{\luatex{show_path}}
-
-Like kpsewhich's \type{-show-path}:
-
-\startfunctioncall
-<string> r = kpse.show_path(<string> ftype)
-\stopfunctioncall
-
-
-\subsection{\luatex{var_value}}
-
-Like kpsewhich's \type{-var-value}:
-
-\startfunctioncall
-<string> r = kpse.var_value(<string> s)
-\stopfunctioncall
-
-\subsection{\luatex{version}}
-
-Returns the kpathsea version string (new in 0.51)
-
-\startfunctioncall
-<string> r = kpse.version()
-\stopfunctioncall
-
-
-\section{The \luatex{lang} library}
-
-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 \luatex{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
-
-returns the internal \tex{language} id number this object refers to.
-
-\startfunctioncall
-<string> n = lang.hyphenation(<language> l)
-lang.hyphenation(<language> l, <string> n)
-\stopfunctioncall
-
-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
-
-Clears the exception dictionary for this language.
-
-\startfunctioncall
-<string> n = lang.clean(<string> o)
-\stopfunctioncall
-
-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.
-
-\startfunctioncall
-<string> n = lang.patterns(<language> l)
-lang.patterns(<language> l, <string> n)
-\stopfunctioncall
-
-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
-
-Clears the pattern dictionary for this language.
-
-\startfunctioncall
-<number> n = lang.prehyphenchar(<language> l)
-lang.prehyphenchar(<language> l, <number> n)
-\stopfunctioncall
-
-Gets or sets the \quote{pre|-|break} hyphen character for implicit
-hyphenation in this language (initially the hyphen, decimal 45).
-
-\startfunctioncall
-<number> n = lang.posthyphenchar(<language> l)
-lang.posthyphenchar(<language> l, <number> n)
-\stopfunctioncall
-
-Gets or sets the \quote{post|-|break} hyphen character for implicit
-hyphenation in this language (initially null, decimal~0, indicating
-emptiness).
-
-
-\startfunctioncall
-<number> n = lang.preexhyphenchar(<language> l)
-lang.preexhyphenchar(<language> l, <number> n)
-\stopfunctioncall
-
-Gets or sets the \quote{pre|-|break} hyphen character for explicit
-hyphenation in this language (initially null, decimal~0, indicating
-emptiness).
-
-\startfunctioncall
-<number> n = lang.postexhyphenchar(<language> l)
-lang.postexhyphenchar(<language> l, <number> n)
-\stopfunctioncall
-
-Gets or sets the \quote{post|-|break} hyphen character for explicit
-hyphenation in this language (initially null, decimal~0, indicating
-emptiness).
-
-\startfunctioncall
-<boolean> success = lang.hyphenate(<node> head)
-<boolean> success = lang.hyphenate(<node> head, <node> tail)
-\stopfunctioncall
-
-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.
-
-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.
-
-
-\section{The \luatex{lua} library}
-
-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)}.
-
-\subsection{\LUA\ bytecode registers}
-
-\LUA\ registers can be used to communicate \LUA\ functions across \LUA\
-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 \luatex{lua.bytecode} array is stored inside the format
-file as actual \LUA\ bytecode, so it can also be used to preload \LUA\ code.
-
-Note: The function must not contain any upvalues. Currently, functions
-containing upvalues can be stored (and their upvalues are set to
-\type{nil}), but this is an artifact of the current \LUA\
-implementation and thus subject to change.
-
-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 \luatex{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.
-
-\subsection{\LUA\ chunk name registers}
-
-There is an array of 65536 (0--65535) potential chunk names for use with
-the \type{\directlua} and \type{\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.
-
-
-\section{The \luatex{mplib} library}
-
-The \MP\ library interface registers itself in the table \type{mplib}. It
-is based on \MPLIB\ version \ctxlua{tex.sprint(mplib.version())}.
-
-\subsection{\luatex{mplib.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[|lT|l|p|p|]
-\NC \ssbf name \NC \bf type \NC \bf description \NC \bf default \NC\NR
-\NC error_line \NC number \NC error line width \NC 79 \NC\NR
-\NC print_line \NC number \NC line length in ps output \NC 100\NC\NR
-\NC random_seed \NC number \NC the initial random seed \NC variable\NC\NR
-\NC interaction \NC string \NC the interaction mode, one of
-\type {batch}, \type {nonstop}, \type {scroll}, \type {errorstop} \NC \type {errorstop}\NC\NR
-\NC job_name \NC string \NC \type {--jobname} \NC \type {mpout} \NC\NR
-\NC find_file \NC function \NC a function to find files \NC only local files\NC\NR
-\stoptabulate
-
-The \type{find_file} function should be of this form:
-
-\starttyping
-<string> found = finder (<string> name, <string> mode, <string> type)
-\stoptyping
-
-with:
-
-\starttabulate[|lT|l|p|]
-\NC \bf name \NC \bf the requested file \NC \NR
-\NC mode \NC the file mode: \type {r} or \type {w} \NC \NR
-\NC type \NC the kind of file, one of: \type {mp}, \type {tfm}, \type {map}, \type {pfb}, \type {enc} \NC \NR
-\stoptabulate
-
-Return either the full pathname 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{mp:execute()} call.
-
-
-\subsection{\luatex{mp: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[|lT|l|p|]
-\NC main_memory \NC number \NC memory size \NC\NR
-\NC hash_size \NC number \NC hash size\NC\NR
-\NC param_size \NC number \NC simultaneous macro parameters\NC\NR
-\NC max_in_open \NC number \NC input file nesting levels\NC\NR
-\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{\luatex{mp:execute}}
-
-You can ask the \METAPOST\ interpreter to run a chunk of code by calling
-
-\startfunctioncall
-<table> rettable = mp:execute('metapost language chunk')
-\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 standalone \type{mpost} command, there is
-{\em no\/} implied \quote{input} at the start of the first chunk.
-
-\subsection{\luatex{mp:finish}}
-
-\startfunctioncall
-<table> rettable = mp:finish()
-\stopfunctioncall
-
-If for some reason you want to stop using an \MPLIB\ instance while
-processing is not yet actually done, you can call \type{mp:finish}.
-Eventually, used memory will be freed and open files will be closed by
-the \LUA\ garbage collector, but an explicit \type{mp:finish} is the
-only way to capture the final part of the output streams.
-
-\subsection{Result table}
-
-The return value of \type{mp:execute} and \type{mp:finish} is a table
-with a few possible keys (only \type {status} is always guaranteed to be present).
-
-\starttabulate[|l|l|p|]
-\NC log \NC string \NC output to the \quote {log} stream \NC \NR
-\NC term \NC string \NC output to the \quote {term} stream \NC \NR
-\NC error \NC string \NC output to the \quote {error} stream (only used for \quote {out of memory})\NC \NR
-\NC status \NC number \NC the return value: 0=good, 1=warning, 2=errors, 3=fatal error \NC \NR
-\NC fig \NC table \NC an array of generated figures (if any)\NC \NR
-\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|]
-\NC boundingbox \NC function \NC returns the bounding box, as an array of 4 values\NC \NR
-\NC 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 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 objects \NC function \NC returns the actual array of graphic objects in this \type{fig} \NC \NR
-\NC copy_objects \NC function \NC returns a deep copy of the array of graphic objects in this \type{fig} \NC \NR
-\NC filename \NC function \NC the filename this \type{fig}'s \POSTSCRIPT\ output
- would have written to in standalone mode\NC \NR
-\NC width \NC function \NC the \type{charwd} value \NC \NR
-\NC height \NC function \NC the \type{charht} value \NC \NR
-\NC depth \NC function \NC the \type{chardp} value \NC \NR
-\NC italcorr \NC function \NC the \type{charit} value \NC \NR
-\NC charcode \NC function \NC the (rounded) \type{charcode} value \NC \NR
-\stoptabulate
-
-{\bf 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 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|]
-\NC path \NC table \NC the list of knots \NC \NR
-\NC htap \NC table \NC the list of knots for the reversed trajectory \NC \NR
-\NC pen \NC table \NC knots of the pen \NC \NR
-\NC color \NC table \NC the object's color \NC \NR
-\NC linejoin \NC number \NC line join style (bare number)\NC \NR
-\NC miterlimit \NC number \NC miterlimit\NC \NR
-\NC prescript \NC string \NC the prescript text \NC \NR
-\NC postscript \NC string \NC the postscript text \NC \NR
-\stoptabulate
-
-The entries \type{htap} and \type{pen} are optional.
-
-There is helper function (\type{mplib.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|]
-\NC width \NC number \NC width of the pen\NC \NR
-\NC sx \NC number \NC $x$ scale \NC \NR
-\NC rx \NC number \NC $xy$ multiplier \NC \NR
-\NC ry \NC number \NC $yx$ multiplier \NC \NR
-\NC sy \NC number \NC $y$ scale \NC \NR
-\NC tx \NC number \NC $x$ offset \NC \NR
-\NC ty \NC number \NC $y$ offset \NC \NR
-\stoptabulate
-
-\subsubsection{outline}
-
-\starttabulate[|l|l|p|]
-\NC path \NC table \NC the list of knots \NC \NR
-\NC pen \NC table \NC knots of the pen \NC \NR
-\NC color \NC table \NC the object's color \NC \NR
-\NC linejoin \NC number \NC line join style (bare number)\NC \NR
-\NC miterlimit \NC number \NC miterlimit \NC \NR
-\NC linecap \NC number \NC line cap style (bare number)\NC \NR
-\NC dash \NC table \NC representation of a dash list\NC \NR
-\NC prescript \NC string \NC the prescript text \NC \NR
-\NC postscript \NC string \NC the postscript text \NC \NR
-\stoptabulate
-
-The entry \type{dash} is optional.
-
-\subsubsection{text}
-
-\starttabulate[|l|l|p|]
-\NC text \NC string \NC the text \NC \NR
-\NC font \NC string \NC font tfm name \NC \NR
-\NC dsize \NC number \NC font size\NC \NR
-\NC color \NC table \NC the object's color \NC \NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC transform \NC table \NC a text transformation \NC \NR
-\NC prescript \NC string \NC the prescript text \NC \NR
-\NC postscript \NC string \NC the postscript text \NC \NR
-\stoptabulate
-
-\subsubsection{special}
-
-\starttabulate[|l|l|p|]
-\NC prescript \NC string \NC special text \NC \NR
-\stoptabulate
-
-\subsubsection{start_bounds, start_clip}
-
-\starttabulate[|l|l|p|]
-\NC path \NC table \NC the list of knots \NC \NR
-\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[|lT|l|p|]
-\NC left_type \NC string \NC when present: 'endpoint', but usually absent \NC \NR
-\NC right_type \NC string \NC like \type{left_type}\NC \NR
-\NC x_coord \NC number \NC X coordinate of this knot\NC \NR
-\NC y_coord \NC number \NC Y coordinate of this knot\NC \NR
-\NC left_x \NC number \NC X coordinate of the precontrol point of this knot\NC \NR
-\NC left_y \NC number \NC Y coordinate of the precontrol point of this knot\NC \NR
-\NC right_x \NC number \NC X coordinate of the postcontrol point of this knot\NC \NR
-\NC right_y \NC number \NC Y coordinate of the postcontrol point of this knot\NC \NR
-\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|]
-\NC 0 \NC marking only \NC no values \NC\NR
-\NC 1 \NC greyscale \NC one value in the range $(0,1)$, \quote {black} is $0$ \NC\NR
-\NC 3 \NC \RGB \NC three values in the range $(0,1)$, \quote {black} is $0,0,0$ \NC\NR
-\NC 4 \NC \CMYK \NC four values in the range $(0,1)$, \quote {black} is $0,0,0,1$ \NC\NR
-\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|]
-\NC 1 \NC number \NC represents x \NC\NR
-\NC 2 \NC number \NC represents y \NC\NR
-\NC 3 \NC number \NC represents xx \NC\NR
-\NC 4 \NC number \NC represents yx \NC\NR
-\NC 5 \NC number \NC represents xy \NC\NR
-\NC 6 \NC number \NC represents yy \NC\NR
-\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|]
-\NC dashes \NC hash \NC an array of on-off numbers \NC\NR
-\NC offset \NC number \NC the starting offset value \NC\NR
-\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{\luatex{mp:char_width}}
-
-\startfunctioncall
-<number> w = mp:char_width(<string> fontname, <number> char)
-\stopfunctioncall
-
-\subsubsection{\luatex{mp:char_height}}
-
-\startfunctioncall
-<number> w = mp:char_height(<string> fontname, <number> char)
-\stopfunctioncall
-
-\subsubsection{\luatex{mp:char_depth}}
-
-\startfunctioncall
-<number> w = mp:char_depth(<string> fontname, <number> char)
-\stopfunctioncall
-
-\section{The \luatex{node} library}
-
-The \luatex{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 \luatex{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]
-
-\item 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.
-
-\item 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}.
-
-\item 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}.
-\stopitemize
-
-The other available fields depend on the \type{id} (and for \quote{whatsits}, the
-\type{subtype}) of the node. Further details on the various fields and their
-meanings are given in~\in{chapter}[nodes].
-
-Support for \type{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.
-
-There are statistics available with regards to the allocated node memory,
-which can be handy for tracing.
-
-\subsection{Node handling functions}
-
-\subsubsection{\luatex{node.is_node}}
-
-\startfunctioncall
-<boolean> t = node.is_node(<any> item)
-\stopfunctioncall
-
-This function returns true if the argument is a userdata object of
-type \type{<node>}.
-
-\subsubsection{\luatex{node.types}}
-
-\startfunctioncall
-<table> t = node.types()
-\stopfunctioncall
-
-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.
-
-\subsubsection{\luatex{node.whatsits}}
-
-\startfunctioncall
-<table> t = node.whatsits()
-\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
-\luatex{node.types}, except that it provides an array of \type{subtype}
-mappings.
-
-\subsubsection{\luatex{node.id}}
-
-\startfunctioncall
-<number> id = node.id(<string> type)
-\stopfunctioncall
-
-This converts a single type name to its internal numeric
-representation.
-
-\subsubsection{\luatex{node.subtype}}
-
-\startfunctioncall
-<number> subtype = node.subtype(<string> type)
-\stopfunctioncall
-
-This converts a single whatsit name to its internal numeric
-representation (\type{subtype}).
-
-\subsubsection{\luatex{node.type}}
-
-\startfunctioncall
-<string> type = node.type(<any> n)
-\stopfunctioncall
-
-In the argument is a number, then this 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 (this is new in 0.65), and \type{nil} otherwise.
-
-\subsubsection{\luatex{node.fields}}
-
-\startfunctioncall
-<table> t = node.fields(<number> id)
-<table> t = node.fields(<number> id, <number> subtype)
-\stopfunctioncall
-
-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.
-
-This function accepts string \type{id} and \type{subtype} values as
-well.
-
-\subsubsection{\luatex{node.has_field}}
-
-\startfunctioncall
-<boolean> t = node.has_field(<node> n, <string> field)
-\stopfunctioncall
-
-This function returns a boolean that is only true if \type{n} is
-actually a node, and it has the field.
-
-\subsubsection{\luatex{node.new}}
-
-\startfunctioncall
-<node> n = node.new(<number> id)
-<node> n = node.new(<number> id, <number> subtype)
-\stopfunctioncall
-
-Creates a new node. All of the new node's fields are initialized to
-either zero or \type{nil} except for \type{id} and \type{subtype} (if
-supplied). If you want to create a new whatsit, then the second
-argument is required, otherwise it need not be present. As with all
-node functions, this function creates a node on the \TEX\ level.
-
-This function accepts string \type{id} and \type{subtype} values as
-well.
-
-\subsubsection{\luatex{node.free}}
-
-\startfunctioncall
-node.free(<node> n)
-\stopfunctioncall
-
-Removes 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.
-
-\subsubsection{\luatex{node.flush_list}}
-
-\startfunctioncall
-node.flush_list(<node> n)
-\stopfunctioncall
-
-Removes the node list \type{n} and the complete node list following
-\type{n} from \TEX's memory. 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.
-
-\subsubsection{\luatex{node.copy}}
-
-\startfunctioncall
-<node> m = node.copy(<node> n)
-\stopfunctioncall
-
-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.
-
-\subsubsection{\luatex{node.copy_list}}
-
-\startfunctioncall
-<node> m = node.copy_list(<node> n)
-<node> m = node.copy_list(<node> n, <node> m)
-\stopfunctioncall
-
-Creates a deep copy of the node list that starts at \type{n}. If
-\type{m} is also given, the copy stops just before node \type{m}.
-
-Note that you cannot copy attribute lists this way, specialized functions for
-dealing with attribute lists will be provided later but are not there yet.
-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.
-
-\subsubsection{\luatex{node.next} (0.65)}
-
-\startfunctioncall
-<node> m = node.next(<node> n)
-\stopfunctioncall
-
-Returns the node following this node, or \type{nil} if there is no
-such node.
-
-\subsubsection{\luatex{node.prev} (0.65)}
-
-\startfunctioncall
-<node> m = node.prev(<node> n)
-\stopfunctioncall
-
-Returns the node preceding this node, or \type{nil} if there is no
-such node.
-
-
-\subsubsection{\luatex{node.current_attr} (0.66)}
-
-\startfunctioncall
-<node> m = node.current_attr()
-\stopfunctioncall
-
-Returns the currently active list of attributes, if there is one.
-
-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.
-
-
-\subsubsection{\luatex{node.hpack}}
-
-\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
-
-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 (\tex{hbox spread})
-or exact (\tex{hbox to}) width to be used.
-
-Direction support added in \LUATEX\ 0.45.
-
-The second return value is the badness of the generated box,
-this extension was added in 0.51.
-
-Caveat: at this moment, there can be unexpected side|-|effects to this
-function, like updating some of the \tex{marks} and \tex{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!
-
-\subsubsection{\luatex{node.vpack} (since 0.36)}
-
-\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
-
-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 (\tex{vbox spread}) or exact (\tex{vbox to}) height to be used.
-
-Direction support added in \LUATEX\ 0.45.
-
-The second return value is the badness of the generated box,
-this extension was added in 0.51.
-
-See the description of \type{node.hpack()} for a few memory allocation
-caveats.
-
-\subsubsection{\luatex{node.dimensions} (0.43)}
-
-\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 inbetween 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
-
-Direction support added in \LUATEX\ 0.45.
-
-\subsubsection{\luatex{node.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 \type{mlist_to_hlist}.
-
-\subsubsection{\luatex{node.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.
-
-\subsubsection{\luatex{node.tail}}
-
-\startfunctioncall
-<node> m = node.tail(<node> n)
-\stopfunctioncall
-
-Returns the last node of the node list that starts at \type{n}.
-
-
-\subsubsection{\luatex{node.length}}
-
-\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.
-
-\subsubsection{\luatex{node.count}}
-
-\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.
-
-\subsubsection{\luatex{node.traverse}}
-
-\startfunctioncall
-<node> t = node.traverse(<node> n)
-\stopfunctioncall
-
-This is a lua iterator that loops over the node list that starts at \type{n}.
-Typical input code 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.
-
-\subsubsection{\luatex{node.traverse_id}}
-
-\startfunctioncall
-<node> t = 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
-
-\subsubsection{\luatex{node.end_of_math} (0.76)}
-
-\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 endnode this helper return that node, else it follows the list and return the next math endnote. If no such node is found nil is returned.
-
-\subsubsection{\luatex{node.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.
-
-\subsubsection{\luatex{node.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}.
-
-\subsubsection{\luatex{node.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}.
-
-\subsubsection{\luatex{node.first_glyph} (0.65)}
-
-\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.
-
-Note: this function used to be called \type{first_character}. It has
-been renamed in \LUATEX\ 0.65, and the old name is deprecated now.
-
-\subsubsection{\luatex{node.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).
-
-\subsubsection{\luatex{node.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 nodelist. 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).
-
-\subsubsection{\luatex{node.unprotect_glyphs}}
-
-\startfunctioncall
-node.unprotect_glyphs(<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.
-
-\subsubsection{\luatex{node.protect_glyphs}}
-
-\startfunctioncall
-node.protect_glyphs(<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.
-
-\subsubsection{\luatex{node.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.
-
-\subsubsection{\luatex{node.write}}
-
-\startfunctioncall
-node.write(<node> n)
-\stopfunctioncall
-
-This is an experimental function that will append a node list to
-\TEX's \quote {current list} (the node list is not deep-copied
-any more since version 0.38). There is no error checking yet!
-
-\subsubsection{\luatex{node.protrusion_skippable} (0.60.1)}
-\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.
-
-\subsection{Attribute handling}
-
-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.
-
-\subsubsection{\luatex{node.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}.
-
-\subsubsection{\luatex{node.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. {\em [needs explanation]}
-
-\subsubsection{\luatex{node.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}.
-
-\section{The \luatex{pdf} library}
-
-This contains variables and functions that are related to the \PDF\ backend.
-
-%***********************************************************************
-
-\subsection{\luatex{pdf.mapfile}, \luatex{pdf.mapline} (new in 0.53.0)}
-
-\startfunctioncall
-pdf.mapfile(<string> map file)
-pdf.mapfile(<string> map line)
-\stopfunctioncall
-
-These two functions can be used to replace primitives \type{\pdfmapfile}
-and \type{\pdfmapline} from \PDFTEX. They expect a string as only parameter
-and have no return value.
-
-The also functions replace the former variables
-\luatex{pdf.pdfmapfile} and \luatex{pdf.pdfmapline}.
-
-%***********************************************************************
-\subsection{\luatex{pdf.catalog}, \luatex{pdf.info},
- \luatex{pdf.names}, \luatex{pdf.trailer} (new in 0.53.0)}
-
-These variables offer a read|-|write interface to the corresponding
-\PDFTEX\ token lists. The value types are strings and they are
-written out to the \PDF\ file directly after the \PDFTEX\ token registers.
-
-The preferred interface is now \luatex {pdf.setcatalog}, \luatex {pdf.setinfo}
-\luatex {pdf.setnames} and \luatex {pdf.settrailer} for setting these properties
-and \luatex {pdf.getcatalog}, \luatex {pdf.getinfo} \luatex {pdf.getnames} and
-\luatex {pdf.gettrailer} for querying them,
-
-The corresponding \quote {\type{pdf}} parameter names \luatex {pdf.pdfcatalog},
-\luatex {pdf.pdfinfo}, \luatex {pdf.pdfnames}, and \luatex {pdf.pdftrailer} are
-removed in 0.79.0.
-
-%***********************************************************************
-\subsection{\luatex{pdf.<set/get>pageattributes}, \luatex{pdf.<set/get>pageresources},
- \luatex{pdf.<set/get>pagesattributes}}
-
-These variables offer a read|-|write interface to related
-token lists. The value types are strings. The variables have no
-interaction with the corresponding \PDFTEX\ token registers
-\tex{pdfpageattr}, \tex{pdfpageresources}, and \tex{pdfpagesattr}.
-They are written out to the \PDF\ file directly after
-the \PDFTEX\ token registers.
-
-The preferred interface is now \luatex {pdf.setpageattributes}, \luatex
-{pdf.setpagesattributes} and \luatex {pdf.setpageresources} for setting these
-properties and \luatex {pdf.getpageattributes}, \luatex {pdf.getpageattributes} and
-\luatex {pdf.getpageresources} for querying them.
-
-%***********************************************************************
-
-\subsection{\luatex{pdf.h}, \luatex{pdf.v}}
-
-
-These are the \type{h} and \type{v} values that define the current location
-on the output page, measured from its lower left corner. The values can be queried
-using scaled points as units.
-
-\starttyping
-local h = pdf.h
-local v = pdf.v
-\stoptyping
-
-\subsection{\luatex{pdf.getpos}, \luatex{pdf.gethpos}, \luatex{pdf.getvpos}}
-
-These are the function variants of \type {pdf.h} and \type {pdf.v}. Sometimes
-using a function is preferred over a key so this saves wrapping. Also, these
-functions are faster then the key based access, as \type {h} and \type {v}
-keys are not real variables but looked up using a metatable call. The
-\type {getpos} function returns two values, the other return one.
-
-\starttyping
-local h, v = pdf.getpos()
-\stoptyping
-
-\subsection{\luatex{pdf.hasmatrix}, \luatex{pdf.getmatrix}}
-
-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
-
-
-
-\subsection{\luatex{pdf.print}}
-
-A print function to write stuff to the \PDF\ document
-that can be used from within a \tex{latelua} argument.
-This function is not to be used inside \tex{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
-\tex{pdfliteral}: the \type{type} is \type{direct} or \type{page}.
-
-\subsection{\luatex{pdf.immediateobj}}
-
-This function creates a \PDF\ object
-and immediately writes it to the \PDF\ file.
-It is modelled after \PDFTEX's \tex{immediate}\tex{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 provided by the user.
-The second version with keyword \type{"file"} as 1st 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 3rd 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
-
-%***********************************************************************
-
-\subsection{\luatex{pdf.obj}}
-
-This function creates a \PDF\ object,
-which is written to the \PDF\ file only when referenced,
-e.\,g., by \luatex{pdf.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 \tex{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>,
- immmediate = <boolean>,
- objnum = <number>,
- attr = <string>,
- compresslevel = <number>,
- objcompression = <boolean>,
- file = <string>,
- string = <string>}
-\stopfunctioncall
-
-The \type{type} field can have the values \type{raw} and
-\type{stream}, this field is required, the others are optional
-(within constraints).
-
-Note: this mode makes \type{pdf.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.
-
-%***********************************************************************
-
-\subsection{\luatex{pdf.refobj}}
-
-This function,
-the \LUA\ version of the \tex{pdfrefobj} primitive,
-references an object by its object number,
-so that the object will be written out.
-
-\startfunctioncall
-pdf.refobj(<integer> n)
-\stopfunctioncall
-
-This function works in both the \tex{directlua} and \tex{latelua} environment.
-Inside \tex{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 out.
-Inside \tex{latelua} the object will be marked for flushing.
-
-This function has no return values.
-
-%***********************************************************************
-
-\subsection{\luatex{pdf.reserveobj}}
-
-This function creates an empty \PDF\ object and returns its number.
-
-\startfunctioncall
-<number> n = pdf.reserveobj()
-<number> n = pdf.reserveobj("annot")
-\stopfunctioncall
-
-\subsection{\luatex{pdf.registerannot} (new in 0.47.0)}
-
-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 \type{\latelua}.
-
-\startfunctioncall
-pdf.registerannot (<number> objnum)
-\stopfunctioncall
-
-\section{The \luatex{pdfscanner} library (new in 0.72.0)}
-
-The \luatex{pdfscanner} library allows interpretation of PDF content streams
-and \type{/ToUnicode} (cmap) streams. You can get those streams from the
-\luatex{epdf} library, as explained in an earlier section. There is only
-a single top|-|level function in this library:
-
-\startfunctioncall
-pdfscanner.scan (<Object> stream, <table> operatortable, <table> info)
-\stopfunctioncall
-
-The first argument, \type{stream}, should be either a PDF stream
-object, or a PDF array of PDF stream objects (those options comprise
-the possible return values of \type{<Page>:getContents()}
-and \type{<Object>:getStream()} in the \type{epdf} 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. The most important of those functions is
-\type{}
-
-A simple example of processing a PDF's document stream
-could look like this:
-
-\starttyping
-function Do (scanner, info)
- local val = scanner:pop()
- local name = val[2] -- val[1] == 'name'
- print (info.space ..'Use XObject '.. name)
- local resources = info.resources
- local xobject = resources:lookup("XObject"):getDict():lookup(name)
- if (xobject and xobject:isStream()) then
- local dict = xobject:getStream():getDict()
- if dict then
- local name = dict:lookup('Subtype')
- if name:getName() == 'Form' then
- local newinfo = { space = info.space .. " " ,
- resources = dict:lookup('Resources'):getDict() }
- pdfscanner.scan(xobject, operatortable, newinfo)
- end
- end
- end
-end
-operatortable = {Do = Do}
-
-doc = epdf.open(arg[1])
-pagenum = 1
-while pagenum <= doc:getNumPages() do
- local page = doc:getCatalog():getPage(pagenum)
- local info = { space = " " , resources = page:getResourceDict()}
- print ('Page ' .. pagenum)
- pdfscanner.scan(page:getContents(), operatortable, info)
- pagenum = pagenum + 1
-end
-\stoptyping
-
-This example iterates over all the actual content in the PDF, and
-prints out the found XObject names. While the code demonstrates quite
-some of the \type{epdf} functions, let's focus on the type
-\type{pdfscanner} specific code instead.
-
-From the bottom up, the line
-
-\starttyping
- pdfscanner.scan(page:getContents(), operatortable, info)
-\stoptyping
-
-runs the scanner with the PDF page's top-level content.
-
-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 XObject, and
-then starts a new scanner for that object's content stream, under the
-condition that the 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 an new \type{resources} field to help the next
-iteration down to properly process any other, embedded XObjects.
-
-Of course, this is not a very useful example in practise, 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[|lT|p|]
-\NC integer \NC <number> \NC \NR
-\NC real \NC <number> \NC \NR
-\NC boolean \NC <boolean> \NC \NR
-\NC name \NC <string> \NC \NR
-\NC operator \NC <string> \NC \NR
-\NC string \NC <string> \NC \NR
-\NC array \NC <table> \NC \NR
-\NC dict \NC <table> \NC \NR
-\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 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 hexidecimal 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.
-
-In case of \type{dict}, the table keys are PDF name strings
-and the values are \type{pop} return values.
-
-\blank
-
-There are few more methods defined that you can ask \type{scanner}:
-
-\starttabulate[|lT|p|]
-\NC pop \NC as explained above\NC \NR
-\NC popNumber \NC return only the value of a \type{real} or \type{integer}\NC \NR
-\NC popName \NC return only the value of a \type{name} \NC \NR
-\NC popString \NC return only the value of a \type{string} \NC \NR
-\NC popArray \NC return only the value of a \type{array} \NC \NR
-\NC popDict \NC return only the value of a \type{dict} \NC \NR
-\NC popBool \NC return only the value of a \type{boolean} \NC \NR
-\NC done \NC abort further processing of this \type{scan()} call\NC \NR
-\stoptabulate
-
-The \type{popXXX} 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 end at the end of the stream, possibly wasting CPU cycles.
-
-\section{The \luatex{status} library}
-
-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[|lT|p|]
-\NC \ssbf key \NC \bf explanation \NC\NR
-\NC pdf_gone\NC written \PDF\ bytes \NC \NR
-\NC pdf_ptr\NC not yet written \PDF\ bytes \NC \NR
-\NC dvi_gone\NC written \DVI\ bytes \NC \NR
-\NC dvi_ptr\NC not yet written \DVI\ bytes \NC \NR
-\NC total_pages\NC number of written pages \NC \NR
-\NC output_file_name\NC name of the \PDF\ or \DVI\ file \NC \NR
-\NC log_name\NC name of the log file \NC \NR
-\NC banner\NC terminal display banner \NC \NR
-\NC var_used\NC variable (one|-|word) memory in use \NC \NR
-\NC dyn_used\NC token (multi|-|word) memory in use \NC \NR
-\NC str_ptr\NC number of strings \NC \NR
-\NC init_str_ptr\NC number of \INITEX\ strings \NC \NR
-\NC max_strings\NC maximum allowed strings \NC \NR
-\NC pool_ptr\NC string pool index \NC \NR
-\NC init_pool_ptr\NC \INITEX\ string pool index \NC \NR
-\NC pool_size\NC current size allocated for string characters \NC \NR
-\NC node_mem_usage\NC a string giving insight into currently used nodes\NC\NR
-\NC var_mem_max\NC number of allocated words for nodes\NC \NR
-\NC fix_mem_max\NC number of allocated words for tokens\NC \NR
-\NC fix_mem_end\NC maximum number of used tokens\NC \NR
-\NC cs_count\NC number of control sequences \NC \NR
-\NC hash_size\NC size of hash \NC \NR
-\NC hash_extra\NC extra allowed hash \NC \NR
-\NC font_ptr\NC number of active fonts \NC \NR
-\NC max_in_stack\NC max used input stack entries \NC \NR
-\NC max_nest_stack\NC max used nesting stack entries \NC \NR
-\NC max_param_stack\NC max used parameter stack entries \NC \NR
-\NC max_buf_stack\NC max used buffer position \NC \NR
-\NC max_save_stack\NC max used save stack entries \NC \NR
-\NC stack_size\NC input stack size \NC \NR
-\NC nest_size\NC nesting stack size \NC \NR
-\NC param_size\NC parameter stack size \NC \NR
-\NC buf_size\NC current allocated size of the line buffer \NC \NR
-\NC save_size\NC save stack size \NC \NR
-\NC obj_ptr\NC max \PDF\ object pointer \NC \NR
-\NC obj_tab_size\NC \PDF\ object table size \NC \NR
-\NC pdf_os_cntr\NC max \PDF\ object stream pointer \NC \NR
-\NC pdf_os_objidx\NC \PDF\ object stream index \NC \NR
-\NC pdf_dest_names_ptr\NC max \PDF\ destination pointer \NC \NR
-\NC dest_names_size\NC \PDF\ destination table size \NC \NR
-\NC pdf_mem_ptr\NC max \PDF\ memory used \NC \NR
-\NC pdf_mem_size\NC \PDF\ memory size \NC \NR
-\NC largest_used_mark\NC max referenced marks class \NC \NR
-\NC filename\NC name of the current input file \NC \NR
-\NC inputid\NC numeric id of the current input \NC \NR
-\NC linenumber\NC location in the current input file\NC \NR
-\NC lasterrorstring\NC last error string\NC \NR
-\NC luabytecodes\NC number of active \LUA\ bytecode registers\NC \NR
-\NC luabytecode_bytes\NC number of bytes in \LUA\ bytecode registers\NC \NR
-\NC luastate_bytes\NC number of bytes in use by \LUA\ interpreters\NC \NR
-\NC output_active\NC \type{true} if the \tex{output} routine is active\NC \NR
-\NC callbacks\NC total number of executed callbacks so far\NC \NR
-\NC indirect_callbacks\NC number of those that were themselves
- a result of other callbacks (e.g. file readers)\NC \NR
-\NC luatex_svn\NC the luatex repository id (added in 0.51)\NC\NR
-\NC luatex_version\NC the luatex version number (added in 0.38)\NC\NR
-\NC luatex_revision\NC the luatex revision string (added in 0.38)\NC\NR
-\NC ini_version\NC \type{true} if this is an \INITEX\ run (added in 0.38)\NC\NR
-\stoptabulate
-
-
-\section{The \luatex{tex} library}
-
-The \luatex{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 has these characteristics:
-
-\startitemize[packed]
-\item You can use it after \tex{the}
-\item It is a single token.
-\item Some special others, see the list below
-\stopitemize
-
-This excludes parameters that need extra arguments, like
-\tex{the}\tex{scriptfont}.
-
-The subset comprising simple integer and dimension registers are
-writable as well as readable (stuff like \tex{tracingcommands} and
-\tex{parindent}).
-
-\subsection{Internal parameter values}
-
-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 {\it 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 (<string> n, ...)
-tex.set ('global', <string> n, ...)
-... = tex.get (<string> n)
-\stopfunctioncall
-
-\subsubsection{Integer parameters}
-
-The integer parameters accept and return \LUA\ numbers.
-
-Read-write:
-
-\startcolumns[n=2]
-\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.pdfadjustspacing
-tex.pdfcompresslevel
-tex.pdfdecimaldigits
-tex.pdfgamma
-tex.pdfgentounicode
-tex.pdfimageapplygamma
-tex.pdfimagegamma
-tex.pdfimagehicolor
-tex.pdfimageresolution
-tex.pdfinclusionerrorlevel
-tex.pdfminorversion
-tex.pdfobjcompresslevel
-tex.pdfoutput
-tex.pdfpagebox
-tex.pdfpkresolution
-tex.pdfprotrudechars
-tex.pdftracingfonts
-tex.pdfuniqueresname
-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
-\stopcolumns
-
-Read|-|only:
-
-\startcolumns[n=3]
-\starttyping
-tex.deadcycles
-tex.insertpenalties
-tex.parshape
-tex.prevgraf
-tex.spacefactor
-\stoptyping
-\stopcolumns
-
-\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.
-
-Read|-|write:
-
-\startcolumns[n=3]
-\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.pdfdestmargin
-tex.pdfeachlinedepth
-tex.pdfeachlineheight
-tex.pdffirstlineheight
-tex.pdfhorigin
-tex.pdflastlinedepth
-tex.pdflinkmargin
-tex.pdfpageheight
-tex.pdfpagewidth
-tex.pdfpxdimen
-tex.pdfthreadmargin
-tex.pdfvorigin
-tex.predisplaysize
-tex.scriptspace
-tex.splitmaxdepth
-tex.vfuzz
-tex.voffset
-tex.vsize
-\stoptyping
-\stopcolumns
-
-Read|-|only:
-
-\startcolumns[n=3]
-\starttyping
-tex.pagedepth
-tex.pagefilllstretch
-tex.pagefillstretch
-tex.pagefilstretch
-tex.pagegoal
-tex.pageshrink
-tex.pagestretch
-tex.pagetotal
-tex.prevdepth
-\stoptyping
-\stopcolumns
-
-\subsubsection{Direction parameters}
-
-The direction parameters are read|-|only and return a \LUA\ string.
-
-\startcolumns[n=3]
-\starttyping
-tex.bodydir
-tex.mathdir
-tex.pagedir
-tex.pardir
-tex.textdir
-\stoptyping
-\stopcolumns
-
-\subsubsection{Glue parameters}
-
-The glue parameters accept and return a userdata object that
-represents a \type{glue_spec} node.
-
-\startcolumns[n=3]
-\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
-\stopcolumns
-
-\subsubsection{Muglue parameters}
-
-All muglue parameters are to be used read|-|only and return a \LUA\ string.
-
-\startcolumns[n=3]
-\starttyping
-tex.medmuskip
-tex.thickmuskip
-tex.thinmuskip
-\stoptyping
-\stopcolumns
-
-\subsubsection{Tokenlist parameters}
-
-The tokenlist parameters accept and return \LUA\ strings. \LUA\ strings are
-converted to and from token lists using \tex{the}\tex{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.
-
-\startcolumns[n=3]
-\starttyping
-tex.errhelp
-tex.everycr
-tex.everydisplay
-tex.everyeof
-tex.everyhbox
-tex.everyjob
-tex.everymath
-tex.everypar
-tex.everyvbox
-tex.output
-tex.pdfpageattr
-tex.pdfpageresources
-tex.pdfpagesattr
-tex.pdfpkmode
-\stoptyping
-\stopcolumns
-
-
-\subsection{Convert commands}
-
-All \quote{convert} commands are read|-|only and return a \LUA\ string.
-The supported commands at this moment are:
-
-\startcolumns[n=2]
-\starttyping
-tex.eTeXVersion
-tex.eTeXrevision
-tex.formatname
-tex.jobname
-tex.luatexbanner
-tex.luatexrevision
-tex.pdfnormaldeviate
-tex.fontname(number)
-tex.pdffontname(number)
-tex.pdffontobjnum(number)
-tex.pdffontsize(number)
-tex.uniformdeviate(number)
-tex.number(number)
-tex.romannumeral(number)
-tex.pdfpageref(number)
-tex.pdfxformname(number)
-tex.fontidentifier(number)
-\stoptyping
-\stopcolumns
-
-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).
-
-The \PDFTEX\ related primitives will be removed from versions after 0.80. All the
-version related details are available in the \type {status} table at the \LUA\
-end, for instance one can say:
-
-\starttyping
-\let\pdftexbanner \luatexbanner
-\let\pdftexversion \luatexversion
-\let\pdftexrevision\luatexrevision
-\stoptyping
-
-% or maybe in the future:
-%
-% \starttyping
-% \def\pdftexbanner {\directlua{tex.write(status.banner)}}
-% \def\pdftexversion {\directlua{tex.write(status.luatex_version}}
-% \def\pdftexrevision{\directlua{tex.write(status.luatex_revision}}
-% \stoptyping
-
-if these are really needed in a macro package.
-
-\subsection{Last item commands}
-
-All \quote{last item} commands are read|-|only and return a number.
-
-The supported commands at this moment are:
-
-\startcolumns[n=3]
-\starttyping
-tex.lastpenalty
-tex.lastkern
-tex.lastskip
-tex.lastnodetype
-tex.inputlineno
-tex.pdflastobj
-tex.pdflastxform
-tex.pdflastximage
-tex.pdflastximagepages
-tex.pdflastannot
-tex.pdflastxpos
-tex.pdflastypos
-tex.pdfrandomseed
-tex.pdflastlink
-tex.luatexversion
-tex.eTeXminorversion
-tex.eTeXversion
-tex.currentgrouplevel
-tex.currentgrouptype
-tex.currentiflevel
-tex.currentiftype
-tex.currentifbranch
-tex.pdflastximagecolordepth
-\stoptyping
-\stopcolumns
-
-\subsection{Attribute, count, dimension, skip and token registers}
-
-\TEX's attributes (\tex{attribute}), counters (\tex{count}),
-dimensions (\tex{dimen}), skips (\tex{skip}) and token (\tex{toks})
-registers can be accessed and written to using two times five virtual
-sub|-|tables of the \luatex{tex} table:
-
-\startcolumns[n=3]
-\starttyping
-tex.attribute
-tex.count
-tex.dimen
-tex.skip
-tex.toks
-\stoptyping
-\stopcolumns
-
-It is possible to use the names of relevant \tex{attributedef}, \tex{countdef},
-\tex{dimendef}, \tex{skipdef}, or \tex{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 \tex{countdef} (or \tex{attributedef}, or
-\tex{dimendef}, or \tex{skipdef}, or \tex{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).
-
-The attribute and count registers accept and return \LUA\ numbers.
-
-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.
-
-The token registers accept and return \LUA\ strings. \LUA\ strings are
-converted to and from token lists using \tex{the}\tex{toks} style
-expansion: all category codes are either space (10) or other (12).
-
-The skip registers accept and return \type{glue_spec} userdata node
-objects (see the description of the node interface elsewhere in this
-manual).
-
-As an alternative to array addressing, there are also accessor
-functions defined for all cases, for example, here is the set
-of possibilities for \type{\skip} registers:
-
-\startfunctioncall
-tex.setskip (<number> n, <node> s)
-tex.setskip (<string> s, <node> s)
-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
-
-In the function-based interface, it is possible to define values
-globally by using the string \type{'global'} as the first function argument.
-
-\subsection{Character code registers (0.63)}
-
-\TEX's character code tables (\tex{lccode}, \tex{uccode},
-\tex{sfcode}, \tex{catcode}, \tex{mathcode}, \tex{delcode}) can be
-accessed and written to using six virtual subtables of the \type{tex}
-table
-
-\startcolumns[n=3]
-\starttyping
-tex.lccode
-tex.uccode
-tex.sfcode
-tex.catcode
-tex.mathcode
-tex.delcode
-\stoptyping
-\stopcolumns
-
-The function call interfaces are roughly as above, but there are a few twists.
-\type{sfcode}s are the simple ones:
-
-\startfunctioncall
-tex.setsfcode (<number> n, <number> s)
-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> mathclass, <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
-
-Normally, the third and fourth values in a delimiter code assignment
-will be zero according to \tex{Udelcode} usage, but the returned table can have
-values there (if the delimiter code was set using \type{\delcode}, for
-example). Unset \type{delcode}'s can be recognized because
-\type{dval[1]} is $-1$.
-
-\subsection{Box registers}
-
-It is possible to set and query actual boxes, using the node
-interface as defined in the \luatex{node} library:
-
-\starttyping
-tex.box
-\stoptyping
-
-for array access, or
-
-\starttyping
-tex.setbox(<number> n, <node> s)
-tex.setbox(<string> cs, <node> s)
-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
-\tex{box2} will be cleared by \TEX\ commands later on, the contents
-of \tex{box0} becomes invalid as well. To prevent this from
-happening, always use \luatex{node.copy_list()} unless you are
-assigning to a temporary variable:
-
-\starttyping
-tex.box[0] = node.copy_list(tex.box[2])
-\stoptyping
-
-%{\bf note: In previous versions of \LUATEX\ there were also three
-%virtual tables called \type{tex.wd}, \type{tex.ht}, and \type{tex.dp}
-%along with an associated function call interface. These were
-%removed in version 0.63. You should switch to using \type{tex.box[].width}
-%etc. instead.}
-%
-%If for some reason you want the functionality of these tables back,
-%you can add \LUA\ code to do that for you, like this:
-%
-%\starttyping
-%local box = tex.box
-%
-%local wd = {
-% __index = function(t,k) local bk = box[k] return bk and bk.width or 0 end,
-% __newindex = function(t,k,v) local bk = box[k] if bk then bk.width = v end end,
-%}
-%local ht = {
-% __index = function(t,k) local bk = box[k] return bk and bk.height or 0 end,
-% __newindex = function(t,k,v) local bk = box[k] if bk then bk.height = v end end,
-%}
-%local dp = {
-% __index = function(t,k) local bk = box[k] return bk and bk.depth or 0 end,
-% __newindex = function(t,k,v) local bk = box[k] if bk then bk.depth = v end end,
-%}
-%
-%tex.wd = { } setmetatable(tex.wd,wd)
-%tex.ht = { } setmetatable(tex.ht,ht)
-%tex.dp = { } setmetatable(tex.dp,dp)
-%\stoptyping
-
-
-\subsection{Math parameters}
-
-It is possible to set and query the internal math parameters
-using:
-
-\startfunctioncall
-tex.setmath(<string> n, <string> t, <number> n)
-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 name are:
-
-\starttyping
-display crampeddisplay
-text crampedtext
-script crampedscript
-scriptscript crampedscriptscript
-\stoptyping
-
-
-\subsection{Special list heads}
-
-The virtual table \luatex{tex.lists} contains the set of internal
-registers that keep track of building page lists.
-
-
-\starttabulate[|lT|p|]
-\NC \bf field \NC \bf description \NC \NR
-\NC page_ins_head \NC circular list of pending insertions \NC \NR
-\NC contrib_head \NC the recent contributions \NC \NR
-\NC page_head \NC the current page content\NC \NR
-%\NC temp_head \NC \NC \NR
-\NC hold_head \NC used for held-over items for next page\NC \NR
-\NC adjust_head \NC head of the current \tex{vadjust} list \NC \NR
-\NC pre_adjust_head \NC head of the current \tex{vadjust pre} list\NC \NR
-% \NC align_head \NC \NC \NR
-\stoptabulate
-
-\subsection{Semantic nest levels (0.51)}
-
-The virtual table \luatex{tex.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{tex.nest.ptr}, which gives the highest available index. Neither
-the array items in \type{tex.nest[]} nor \type{tex.nest.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{tex.nest[0]}
-the outermost (main vertical list) level.
-
-The known fields are:
-
-\starttabulate[|lT|l|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf modes \NC \bf explanation \NC\NR
-\NC mode \NC number \NC all \NC The current mode. This is a number representing the
- main mode at this level:\crlf
- 0 == no mode (this happens during \type{\write})\crlf
- 1 == vertical,\crlf
- 127 = horizontal,\crlf
- 253 = display math.\crlf
- $-1$ == internal vertical,\crlf
- $-127$ = restricted horizontal,\crlf
- $-253$ = inline math.\NC\NR
-\NC modeline \NC number \NC all \NC source input line where this mode was entered in,
- negative inside the output routine.\NC\NR
-\NC head \NC node \NC all \NC the head of the current list\NC\NR
-\NC tail \NC node \NC all \NC the tail of the current list\NC\NR
-\NC prevgraf \NC number \NC vmode \NC number of lines in the previous paragraph\NC\NR
-\NC prevdepth \NC number \NC vmode \NC depth of the previous paragraph (equal to \type{\pdfignoreddimen}
- when it is to be ignored)\NC\NR
-\NC spacefactor \NC number \NC hmode \NC the current space factor\NC\NR
-\NC dirs \NC node \NC hmode \NC used for temporary storage by the line break algorithm\NC\NR
-\NC noad \NC node \NC mmode \NC used for temporary storage of a pending fraction numerator,
- for \type{\over} etc.\NC\NR
-\NC delimptr \NC node \NC mmode \NC used for temporary storage of the previous math delimiter,
- for \type{\middle}.\NC\NR
-\NC mathdir \NC boolean \NC mmode \NC true when during math processing the \type{\mathdir} is not
- the same as the surrounding \type{\textdir}\NC\NR
-\NC mathstyle \NC number \NC mmode \NC the current \type{\mathstyle} \NC\NR
-\stoptabulate
-
-
-\subsection[sec:luaprint]{Print functions}
-
-The \luatex{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 \tex{directlua}.
-
-The total amount of returnable text from a \tex{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{\luatex{tex.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). This syntax was added in 0.36.
-
-The optional parameter can be used to print the strings using the
-catcode regime defined by \tex{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 \type{\the\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 \luatex{tex.print()} command in a
-\tex{directlua} will not have the \tex{endlinechar} appended, all
-others do.
-
-\subsubsection{\luatex{tex.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]
-\item \TEX\ does not switch to the \quote{new line} state, so
- that leading spaces are not ignored.
-\item No \tex{endlinechar} is inserted.
-\item 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{inbetween} will be gobbled as a result of
-the \quote{normal} scanning of \tex{relax}.
-\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). This syntax was added in 0.36.
-
-The optional argument sets the catcode regime, as with \type{tex.print()}.
-
-\subsubsection{\luatex{tex.tprint}}
-
-\startfunctioncall
-tex.tprint({<number> n, <string> s, ...}, {...})
-\stopfunctioncall
-
-This function is basically a shortcut for repeated calls to
-\luatex{tex.sprint(<number> n, <string> s, ...)}, once for each of
-the supplied argument tables.
-
-\subsubsection{\luatex{tex.write}}
-
-\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 \tex{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). This syntax was added in 0.36.
-
-
-\subsection{Helper functions}
-
-\subsubsection{\luatex{tex.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 to big} error as well.
-
-\subsubsection{\luatex{tex.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 \type{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 to 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{\luatex{tex.sp} (0.51)}
-
-\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]
-\item only explicit values are allowed, control sequences are not handled
-\item infinite dimension units (\type{fil...}) are forbidden
-\item \type{mu} units do not generate an error (but may not be useful either)
-\stopitemize
-
-\subsubsection{\luatex{tex.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).
-
-
-\subsubsection{\luatex{tex.error} (0.61)}
-
-\startfunctioncall
-tex.error(<string> s)
-tex.error(<string> s, <table> help)
-\stopfunctioncall
-
-This creates an error somewhat like the combination of \tex{errhelp}
-and \tex{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.
-
-
-\subsubsection{\luatex{tex.hashtokens} (0.25)}
-
-\startfunctioncall
-for i,v in pairs (tex.hashtokens()) do ... end
-\stopfunctioncall
-
-Returns a name and token table pair (see~\in{section}[luatokens] about
-token tables) iterator for every non-zero entry in the hash table.
-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.
-
-\subsection[luaprimitives]{Functions for dealing with primitives }
-
-\subsubsection{\luatex{tex.enableprimitives}}
-
-\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 \type{\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
-\type{\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 \type{\formatname}, provided that the
-control sequences \type{\LuaTeXformatname} is currently undefined.
-
-Second example:
-
-\starttyping
- tex.enableprimitives('Omega',tex.extraprimitives ('omega'))
-\stoptyping
-
-will define a whole series of csnames like \type{\Omegatextdir},
-\type{\Omegapardir}, etc., but it will stick with \type{\OmegaVersion}
-instead of creating the doubly-prefixed \type{\OmegaOmegaVersion}.
-
-Starting with version 0.39.0 (and this is why the above two functions
-are needed), \LUATEX\ in \type{--ini} mode contains only the \TEX82
-primitives and \type{\directlua}, no extra primitives {\bf at all}.
-
-So, 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{\luatex{tex.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:
-
-\startluacode
-function out_prim (a)
- local v = tex.extraprimitives(a)
- table.sort(v)
- for _,n in pairs(v) do
- if n == ' ' then
- n = '\\normalcontrolspace'
- end
- tex.print(n .. '\\hskip 4pt plus 5em')
- end
-end
-\stopluacode
-
-\starttabulate[|l|p|]
-\NC \bf name\NC \bf values \NC \NR
-\NC tex \NC \ctxlua{out_prim('tex') } \NC \NR
-\NC core \NC \ctxlua{out_prim('core') } \NC \NR
-\NC etex \NC \ctxlua{out_prim('etex') } \NC \NR
-\NC pdftex \NC \ctxlua{out_prim('pdftex') } \NC \NR
-\NC omega \NC \ctxlua{out_prim('omega') } \NC \NR
-\NC aleph \NC \ctxlua{out_prim('aleph') } \NC \NR
-\NC luatex \NC \ctxlua{out_prim('luatex') } \NC \NR
-\NC umath \NC \ctxlua{out_prim('umath') } \NC \NR
-\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'}.
-
-\type{'umath'} is a subset of \type{'luatex'} that covers the Unicode math
-primitives and have been added in \LUATEX\ 0.75.0 as it might be desired to
-handle the prefixing of that subset differently.
-
-Running \type{tex.extraprimitives()} will give you the complete list
-of primitives that are not defined at \LUATEX\ 0.39.0 \type{-ini}
-startup. It is exactly equivalent to \type{tex.extraprimitives('etex',
-'pdftex', 'omega', 'aleph', 'luatex')}
-
-\subsubsection{\luatex{tex.primitives}}
-
-\startfunctioncall
-<table> t = tex.primitives()
-\stopfunctioncall
-
-This function returns a hash table listing all primitives that \LUATEX\
-knows about. The keys in the hash are primitives names, the values are
-tables representing tokens (see~\in{section }[luatokens]). The third value
-is always zero.
-
-\subsection{Core functionality interfaces}
-
-\subsubsection{\luatex{tex.badness} (0.53)}
-
-\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 $100(t/s)^3$;
-
-\subsubsection{\luatex{tex.linebreak} (0.53)}
-
-\startfunctioncall
-local <node> nodelist, <table> info =
- tex.linebreak(<node> listhead, <table> parameters)
-\stopfunctioncall
-
-The understood parameters are as follows:
-
-\starttabulate[|l|l|p|]
-\NC \bf name \NC \bf type \NC \bf description \NC \NR
-\NC pardir \NC string \NC \NC \NR
-\NC pretolerance \NC number \NC \NC \NR
-\NC tracingparagraphs \NC number \NC \NC \NR
-\NC tolerance \NC number \NC \NC \NR
-\NC looseness \NC number \NC \NC \NR
-\NC hyphenpenalty \NC number \NC \NC \NR
-\NC exhyphenpenalty \NC number \NC \NC \NR
-\NC pdfadjustspacing \NC number \NC \NC \NR
-\NC adjdemerits \NC number \NC \NC \NR
-\NC pdfprotrudechars \NC number \NC \NC \NR
-\NC linepenalty \NC number \NC \NC \NR
-\NC lastlinefit \NC number \NC \NC \NR
-\NC doublehyphendemerits \NC number \NC \NC \NR
-\NC finalhyphendemerits \NC number \NC \NC \NR
-\NC hangafter \NC number \NC \NC \NR
-\NC interlinepenalty \NC number or table \NC if a table, then it is an array like \type{\interlinepenalties}\NC \NR
-\NC clubpenalty \NC number or table \NC if a table, then it is an array like \type{\clubpenalties}\NC \NR
-\NC widowpenalty \NC number or table \NC if a table, then it is an array like \type{\widowpenalties}\NC \NR
-\NC brokenpenalty \NC number \NC \NC \NR
-\NC emergencystretch \NC number \NC in scaled points \NC \NR
-\NC hangindent \NC number \NC in scaled points \NC \NR
-\NC hsize \NC number \NC in scaled points \NC \NR
-\NC leftskip \NC glue_spec node \NC \NC \NR
-\NC rightskip \NC glue_spec node \NC \NC \NR
-\NC pdfeachlineheight \NC number \NC in scaled points \NC \NR
-\NC pdfeachlinedepth \NC number \NC in scaled points \NC \NR
-\NC pdffirstlineheight \NC number \NC in scaled points \NC \NR
-\NC pdflastlinedepth \NC number \NC in scaled points \NC \NR
-\NC pdfignoreddimen \NC number \NC in scaled points \NC \NR
-\NC parshape \NC table \NC \NC \NR
-\stoptabulate
-
-Note that there is no interface for \type{\displaywidowpenalties}, you
-have to pass the right choice for \type{widowpenalties} yourself.
-
-The meaning of the various keys should be fairly obvious from the
-table (the names match the \TEX\ and \PDFTEX\ primitives) except for
-the last 5 entries. The four \type{pdf...line...} keys are ignored if
-their value equals \type{pdfignoreddimen}.
-
-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
-\type{pre_linebreak_filter} or \type{linebreak_filter} callbacks, or when the
-original list starting at listhead was generated in horizontal mode):
-
-\startitemize
-\item add an \quote{indent box} and perhaps a \type{local_par} node at
- the start (only if you need them)
-\item replace any found final glue by an infinite penalty (or add such
- a penalty, if the last node is not a glue)
-\item add a glue node for the \type{\parfillskip} after that penalty node
-\item make sure all the \type{prev} pointers are OK
-\stopitemize
-
-The result is a node list, it still needs to be vpacked if you
-want to assign it to a \tex{vbox}.
-
-
-The returned \type{info} table contains four values that are all numbers:
-
-\starttabulate[|l|p|]
-\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
-\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{\luatex{tex.shipout} (0.51)}
-
-\startfunctioncall
-tex.shipout(<number> n)
-\stopfunctioncall
-
-Ships out box number \type{n} to the output file, and clears the box
-register.
-
-
-\section[texconfig]{The \luatex{texconfig} table}
-
-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[|lT|l|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf default \NC \bf explanation \NC\NR
-\NC 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 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} (new in 0.37)\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 (new in 0.37)\NC\NR
-\NC string_vacancies \NC number\NC 75000\NC cf.\ web2c docs \NC \NR
-\NC pool_free \NC number\NC 5000\NC cf.\ web2c docs \NC \NR
-\NC max_strings \NC number\NC 15000\NC cf.\ web2c docs \NC \NR
-\NC strings_free \NC number\NC 100\NC cf.\ web2c docs \NC \NR
-\NC nest_size \NC number\NC 50\NC cf.\ web2c docs \NC \NR
-\NC max_in_open \NC number\NC 15\NC cf.\ web2c docs \NC \NR
-\NC param_size \NC number\NC 60\NC cf.\ web2c docs \NC \NR
-\NC save_size \NC number\NC 4000\NC cf.\ web2c docs \NC \NR
-\NC stack_size \NC number\NC 300\NC cf.\ web2c docs \NC \NR
-\NC dvi_buf_size \NC number\NC 16384\NC cf.\ web2c docs \NC \NR
-\NC error_line \NC number\NC 79\NC cf.\ web2c docs \NC \NR
-\NC half_error_line \NC number\NC 50\NC cf.\ web2c docs \NC \NR
-\NC max_print_line \NC number\NC 79\NC cf.\ web2c docs \NC \NR
-\NC hash_extra \NC number\NC 0\NC cf.\ web2c docs \NC \NR
-\NC pk_dpi \NC number\NC 72\NC cf.\ web2c docs \NC \NR
-\NC 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 file_line_error \NC boolean \NC false \NC do \type{file:line} style error messages\NC \NR
-\NC halt_on_error \NC boolean \NC false \NC abort run on the first encountered error\NC \NR
-\NC formatname \NC string \NC \NC if no format name was given
- on the commandline, this key will be tested first
- instead of simply quitting\NC \NR
-\NC jobname \NC string \NC \NC if no input file name was given
- on the commandline, this key will be tested first
- instead of simply giving up\NC \NR
-\stoptabulate
-
-{\bf 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.
-
-\section{The \luatex{texio} library}
-
-This library takes care of the low|-|level I/O interface.
-
-\subsection{Printing functions}
-
-\subsubsection{\luatex{texio.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
-\tex{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.
-
-\subsubsection{\luatex{texio.write_nl}}
-
-\startfunctioncall
-texio.write_nl(<string> target, <string> s, ...)
-texio.write_nl(<string> s, ...)
-\stopfunctioncall
-
-This function behaves like \luatex{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.
-
-%***********************************************************************
-
-\section[luatokens]{The \luatex{token} library}
-
-The \luatex{token} table contains interface functions to \TEX's
-handling of tokens. These functions are most useful when combined with
-the \luatex{token_filter} callback, but they could be used standalone
-as well.
-
-A token is represented in \LUA\ as a small table. For the moment, this
-table consists of three numeric entries:
-
-\starttabulate[|l|l|p|]
-\NC \bf index\NC \bf meaning \NC \bf description \NC \NR
-\NC 1 \NC command code \NC this is a value between~$0$ and~$130$ (approximately)\NC \NR
-\NC 2 \NC command modifier \NC this is a value between~$0$ and~$2^{21}$ \NC \NR
-\NC 3 \NC control sequence id \NC for commands that are not the result of control
- sequences, like letters and characters, it is zero,
- otherwise, it is a number pointing into the \quote
- {equivalence table} \NC \NR
-\stoptabulate
-
-\subsection{\luatex{token.get_next}}
-
-\startfunctioncall
-token t = token.get_next()
-\stopfunctioncall
-
-This fetches the next input token from the current input source,
-without expansion.
-
-\subsection{\luatex{token.is_expandable}}
-
-\startfunctioncall
-<boolean> b = token.is_expandable(<token> t)
-\stopfunctioncall
-
-This tests if the token \type{t} could be expanded.
-
-\subsection{\luatex{token.expand}}
-
-\startfunctioncall
-token.expand(<token> t)
-\stopfunctioncall
-
-If a token is expandable, this will expand one level of it, so that
-the first token of the expansion will now be the next token to be read
-by \luatex{token.get_next()}.
-
-\subsection{\luatex{token.is_activechar}}
-
-\startfunctioncall
-<boolean> b = token.is_activechar(<token> t)
-\stopfunctioncall
-
-This is a special test that is sometimes handy. Discovering whether
-some control sequence is the result of an active character turned out
-to be very hard otherwise.
-
-\subsection{\luatex{token.create}}
-
-\startfunctioncall
-token t = token.create(<string> csname)
-token t = token.create(<number> charcode)
-token t = token.create(<number> charcode, <number> catcode)
-\stopfunctioncall
-
-This is the token factory. If you feed it a string, then it is the
-name of a control sequence (without leading backslash), and it will be
-looked up in the equivalence table.
-
-If you feed it number, then this is assumed to be an input character,
-and an optional second number gives its category code. This means it
-is possible to overrule a character's category code, with a few
-exceptions: the category codes~0 (escape), 9~(ignored), 13~(active),
-14~(comment), and 15 (invalid) cannot occur inside a token. The values~0, 9, 14
-and~15 are therefore illegal as input to \luatex{token.create()}, and
-active characters will be resolved immediately.
-
-Note: unknown string sequences and never defined active characters
-will result in a token representing an \quote{undefined control sequence}
-with a near|-|random name. It is {\em not} possible to define brand
-new control sequences using \luatex{token.create}!
-
-\subsection{\luatex{token.command_name}}
-
-\startfunctioncall
-<string> commandname = token.command_name(<token> t)
-\stopfunctioncall
-
-This returns the name associated with the \quote{command} value of the token
-in \LUATEX. There is not always a direct connection between these names and
-primitives. For instance, all \tex{ifxxx} tests are grouped under
-\type {if_test}, and the \quote{command modifier} defines which test is to be run.
-
-\subsection{\luatex{token.command_id}}
-
-\startfunctioncall
-<number> i = token.command_id(<string> commandname)
-\stopfunctioncall
-
-This returns a number that is the inverse operation of the previous
-command, to be used as the first item in a token table.
-
-\subsection{\luatex{token.csname_name}}
-
-\startfunctioncall
-<string> csname = token.csname_name(<token> t)
-\stopfunctioncall
-
-This returns the name associated with the \quote{equivalence table} value of
-the token in \LUATEX. It returns the string value of the command used
-to create the current token, or an empty string if there is no
-associated control sequence.
-
-Keep in mind that there are potentially two control sequences that
-return the same csname string: single character control sequences
-and active characters have the same \quote{name}.
-
-\subsection{\luatex{token.csname_id}}
-
-\startfunctioncall
-<number> i = token.csname_id(<string> csname)
-\stopfunctioncall
-
-This returns a number that is the inverse operation of the previous
-command, to be used as the third item in a token table.
-
-\subsection{The \luatex{newtoken} libray}
-
-The current \type {token} library will be replaced by a new one that is more
-flexible and powerful. The transition takes place in steps. In version 0.80 we
-have \type {newtoken} and in version 0.85 the old lib will be replaced
-completely. So if you use this new mechanism in production code you need to be
-aware of incompatible updates between 0.80 and 0.90. Because the related in- and
-output code will also be cleaned up and rewritten you should be aware of
-incompatible logging and error reporting too.
-
-The old library presents tokens as triplets or numbers, the new library presents
-a userdata object. The old library used a callback to intercept tokens in the
-input but the new 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 current functions in the \type {newtoken} namespace are given in the next
-table:
-
-\starttabulate[|lT|lT|p|]
-\NC \bf function \NC \bf argument \NC \bf result \NC \NR
-\HL
-\NC is_token \NC token \NC checks if the given argument is a token userdatum \NC \NR
-\NC get_next \NC \NC returns the next token in the input \NC \NR
-\NC scan_keyword \NC string \NC returns true if the given keyword is gobbled \NC \NR
-\NC scan_int \NC \NC returns a number \NC \NR
-\NC 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 scan_glue \NC mu-units \NC returns a glue spec node \NC \NR
-\NC scan_toks \NC definer, expand \NC returns a table of tokens token list (this can become a linked list in later releases) \NC \NR
-\NC scan_code \NC bitset \NC returns a character if its category is in the given bitset (representing catcodes) \NC \NR
-\NC 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 scan_word \NC \NC returns a sequence of characters with catcode 11 or 12 as string \NC \NR
-\NC create \NC \NC returns a userdata token object of the given control sequence name (or character); this interface can change \NC \NR
-\stoptabulate
-
-The scanners can be considered stable apart from the one scanning for a token.
-This is because futures releases can return a linked list instead of a table (as
-with nodes). 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|]
-\NC \type{\directlua{newtoken.scan_string()}{foo}} \NC \directlua{context("{\\red\\type{"..newtoken.scan_string().."}}")} {foo} \NC full expansion \NR
-\NC \type{\directlua{newtoken.scan_string()}foo} \NC \directlua{context("{\\red\\type{"..newtoken.scan_string().."}}")} foo \NC letters and others \NR
-\NC \type{\directlua{newtoken.scan_string()}\foo} \NC \directlua{context("{\\red\\type{"..newtoken.scan_string().."}}")}\foo \NC meaning \NR
-\stoptabulate
-
-The \type {\foo} case only gives the meaning, but one can pass an already expanded
-definition (\type {\edef}'d). In the case of the braced variant one can of course
-use the \type {\detokenize} and \type {\unexpanded} primitives as there we do
-expand.
-
-The \type {scan_word} scanner can be used to implement for instance a number scanner:
-
-\starttyping
-function newtokens.scan_number(base)
- return tonumber(newtoken.scan_word(),base)
-end
-\stoptyping
-
-This scanner accepts any valid \LUA\ number so it is a way to pick up floats
-in the input.
-
-The creator function can be used as follows:
-
-\starttyping
-local t = newtoken("relax")
-\stoptyping
-
-This gives back a token object that has the properties of the \type {\relax}
-primitive. The possible properties of tokens are:
-
-\starttabulate[|lT|p|]
-\NC command \NC a number representing the internal command number \NC \NR
-\NC 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 csname \NC the associated control sequence (if applicable) \NC \NR
-\NC id \NC the unique id of the token \NC \NR
-%NC tok \NC \NC \NR % might change
-\NC active \NC a boolean indicating the active state of the token \NC \NR
-\NC expandable \NC a boolean indicating if the token (macro) is expandable \NC \NR
-\NC protected \NC a boolean indicating if the token (macro) is protected \NC \NR
-\stoptabulate
-
-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.
-
-More interesting are the scanners. 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
-
-But starting with version 0.80 you can also do this:
-
-\starttyping
-\directlua {
- function mymacro()
- local d = newtoken.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 when it's
-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).
-
-When the interface is stable and has replaced the old one completely we will add
-some more information here. By that time the internals have been cleaned up a bit
-more so we know then what will stay and go. A positive side effect of this
-transition is that we can simplify the input part because we no longer need to
-intercept using callbacks.
-
-\chapter[math]{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 in the past that are now
-added to the engine.
-
-\section{The current math style}
-
-Starting with \LUATEX\ 0.39.0, 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: \type{\mathstyle}. This is a
-\quote{convert command} like e.g. \type{\romannumeral}: its value can
-only be read, not set.
-
-\subsection{\tex{mathstyle}}
-
-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 the 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
-
-\subsection{\tex{Ustack}}
-
-There are a few math commands in \TEX\ where the style that will be used
-is not known straight from the start. These commands (\tex{over},
-\tex{atop}, \tex{overwithdelims}, \tex{atopwithdelims}) would
-therefore normally return wrong values for \type{\mathstyle}. To
-fix this, \LUATEX\ introduces a special prefix command:
-\type{\Ustack}:
-
-\starttyping
-$\Ustack {a \over b}$
-\stoptyping
-
-The \type{\Ustack} command will scan the next brace and start a new
-math group with the correct (numerator) math style.
-
-\section{Unicode math characters}
-
-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 in the second column.
-
-The input for such primitives would look like this:
-
-\starttyping
-\def\overbrace {\Umathaccent 0 1 "23DE }
-\stoptyping
-
-
-Altered \TEX82 primitives:
-
-\starttabulate[|l|l|l|]
-\NC \bf primitive \NC \bf value range (in hex) \NC\NR
-\NC \tex{mathcode} \NC 0--10FFFF = 0--8000 \NC\NR
-\NC \tex{delcode} \NC 0--10FFFF = 0--FFFFFF \NC\NR
-\stoptabulate
-
-Unaltered:
-
-\starttabulate[|l|l|l|]
-\NC \bf primitive \NC \bf value range (in hex) \NC\NR
-\NC \tex{mathchardef} \NC 0--8000 \NC\NR
-\NC \tex{mathchar} \NC 0--7FFF \NC\NR
-\NC \tex{mathaccent} \NC 0--7FFF \NC\NR
-\NC \tex{delimiter} \NC 0--7FFFFFF \NC\NR
-\NC \tex{radical} \NC 0--7FFFFFF \NC\NR
-\stoptabulate
-
-New primitives that are compatible with \XETEX:
-
-\starttabulate[|l|l|l|l|]
-\NC \bf primitive \NC \bf value range (in hex) \NC\NR
-\NC \tex{Umathchardef} \NC 0+0+0--7+FF+10FFFF$^1$ \NC\NR
-\NC \tex{Umathcharnumdef}$^5$ \NC -80000000--7FFFFFFF$^3$ \NC\NR
-\NC \tex{Umathcode} \NC 0--10FFFF = 0+0+0--7+FF+10FFFF$^1$ \NC\NR
-\NC \tex{Udelcode} \NC 0--10FFFF = 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Umathchar} \NC 0+0+0--7+FF+10FFFF \NC\NR
-\NC \tex{Umathaccent} \NC 0+0+0--7+FF+10FFFF$^{2,4}$ \NC\NR
-\NC \tex{Udelimiter} \NC 0+0+0--7+FF+10FFFF$^2$ \NC\NR
-\NC \tex{Uradical} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Umathcharnum} \NC -80000000--7FFFFFFF$^3$ \NC\NR
-\NC \tex{Umathcodenum} \NC 0--10FFFF = -80000000--7FFFFFFF$^3$ \NC\NR
-\NC \tex{Udelcodenum} \NC 0--10FFFF = -80000000--7FFFFFFF$^3$ \NC\NR
-\stoptabulate
-
-Note 1: \type{\Umathchardef<csname>="8"0"0} and \type{\Umathchardef<number>="8"0"0}
-are also accepted.
-
-Note 2: 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
-\tex{Umathoperatorsize} parameter (more information a following section).
-
-Note 3: For these three primitives, all information is packed into a single
-signed integer. For the first two (\tex{Umathcharnum} and
-\tex{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 \tex{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.
-
-Note 4: As of \LUATEX\ 0.65, \tex{Umathaccent} accepts optional
-keywords to control various details regarding math accents. See
-\in{section}[mathacc] below for details.
-
-Note 5: \tex{Umathcharnumdef} was added in release 0.72.
-
-
-New primitives that exist in \LUATEX\ only (all of these will be explained
-in following sections):
-
-
-\starttabulate[|l|l|l|l|]
-\NC \bf primitive \NC \bf value range (in hex) \NC\NR
-\NC \tex{Uroot} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Uoverdelimiter} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Uunderdelimiter} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Udelimiterover} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\NC \tex{Udelimiterunder} \NC 0+0--FF+10FFFF$^2$ \NC\NR
-\stoptabulate
-
-\section{Cramped math styles}
-
-\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.
-
-\section{Math parameter settings}
-
-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 accessible before.
-
-\starttabulate
-\NC \bf primitive name \NC \bf description \NC \NR
-\NC \type{\Umathquad} \NC the width of 18mu's\NC \NR
-\NC \type{\Umathaxis} \NC height of the vertical center axis of
- the math formula above the baseline\NC \NR
-\NC \type{\Umathoperatorsize} \NC minimum size of large operators in display mode \NC \NR
-\NC \type{\Umathoverbarkern} \NC vertical clearance above the rule \NC \NR
-\NC \type{\Umathoverbarrule} \NC the width of the rule \NC \NR
-\NC \type{\Umathoverbarvgap} \NC vertical clearance below the rule \NC \NR
-\NC \type{\Umathunderbarkern} \NC vertical clearance below the rule \NC \NR
-\NC \type{\Umathunderbarrule} \NC the width of the rule \NC \NR
-\NC \type{\Umathunderbarvgap} \NC vertical clearance above the rule \NC \NR
-\NC \type{\Umathradicalkern} \NC vertical clearance above the rule \NC \NR
-\NC \type{\Umathradicalrule} \NC the width of the rule \NC \NR
-\NC \type{\Umathradicalvgap} \NC vertical clearance below the rule \NC \NR
-\NC \type{\Umathradicaldegreebefore}\NC the forward kern that takes place before placement of
- the radical degree \NC \NR
-\NC \type{\Umathradicaldegreeafter} \NC the backward kern that takes place after placement of
- the radical degree \NC \NR
-\NC \type{\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 \type{\Umathstackvgap} \NC vertical clearance between the two
- elements in a \type{\atop} stack \NC \NR
-\NC \type{\Umathstacknumup} \NC numerator shift upward in \type{\atop} stack \NC \NR
-\NC \type{\Umathstackdenomdown} \NC denominator shift downward in \type{\atop} stack\NC \NR
-\NC \type{\Umathfractionrule} \NC the width of the rule in a \type{\over}\NC \NR
-\NC \type{\Umathfractionnumvgap} \NC vertical clearance between the numerator and the rule\NC \NR
-\NC \type{\Umathfractionnumup} \NC numerator shift upward in \type{\over} \NC \NR
-\NC \type{\Umathfractiondenomvgap} \NC vertical clearance between the denominator and the rule\NC \NR
-\NC \type{\Umathfractiondenomdown} \NC denominator shift downward in \type{\over} \NC \NR
-\NC \type{\Umathfractiondelsize} \NC minimum delimiter size for \type{\...withdelims}\NC \NR
-\NC \type{\Umathlimitabovevgap} \NC vertical clearance for limits above operators\NC \NR
-\NC \type{\Umathlimitabovebgap} \NC vertical baseline clearance for limits above operators\NC \NR
-\NC \type{\Umathlimitabovekern} \NC space reserved at the top of the limit\NC \NR
-\NC \type{\Umathlimitbelowvgap} \NC vertical clearance for limits below operators\NC \NR
-\NC \type{\Umathlimitbelowbgap} \NC vertical baseline clearance for limits below operators\NC \NR
-\NC \type{\Umathlimitbelowkern} \NC space reserved at the bottom of the limit\NC \NR
-\NC \type{\Umathoverdelimitervgap} \NC vertical clearance for limits above delimiters\NC \NR
-\NC \type{\Umathoverdelimiterbgap} \NC vertical baseline clearance for limits above delimiters\NC \NR
-\NC \type{\Umathunderdelimitervgap} \NC vertical clearance for limits below delimiters\NC \NR
-\NC \type{\Umathunderdelimiterbgap} \NC vertical baseline clearance for limits below delimiters\NC \NR
-\NC \type{\Umathsubshiftdrop} \NC subscript drop for boxes and subformulas\NC \NR
-\NC \type{\Umathsubshiftdown} \NC subscript drop for characters\NC \NR
-\NC \type{\Umathsupshiftdrop} \NC superscript drop (raise, actually) for boxes and subformulas\NC \NR
-\NC \type{\Umathsupshiftup} \NC superscript raise for characters\NC \NR
-\NC \type{\Umathsubsupshiftdown} \NC subscript drop in the presence of a superscript\NC \NR
-\NC \type{\Umathsubtopmax} \NC the top of standalone subscripts cannot be higher than this above the baseline\NC \NR
-\NC \type{\Umathsupbottommin} \NC the bottom of standalone superscripts cannot be less than this above the baseline\NC \NR
-\NC \type{\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 \type{\Umathsubsupvgap} \NC vertical clearance between super- and subscript\NC \NR
-\NC \type{\Umathspaceafterscript} \NC additional space added after a super- or subscript\NC \NR
-\NC \type{\Umathconnectoroverlapmin}\NC minimum overlap between parts in an extensible recipe\NC \NR
-\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.
-
-\section{Font-based 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 using in the \TeX book. Assignments to
-\tex{textfont} set the values for the cramped and uncramped display and
-text styles. Use \tex{scriptfont} for the script styles, and
-\tex{scriptscriptfont} for the scriptscript styles (totalling 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.
-
-\start
-
-\switchtobodyfont[8pt]
-
-\starttabulate[|l|l|l|p|]
-\NC \bf variable \NC \bf style \NC \bf default value opentype \NC \bf default value tfm \NC\NR
-\NC \tex{Umathaxis} \NC -- \NC AxisHeight \NC axis_height \NC\NR
-\NC \tex{Umathoperatorsize} \NC D, D' \NC DisplayOperatorMinHeight \NC $^6$ \NC\NR
-\NC \tex{Umathfractiondelsize} \NC D, D' \NC FractionDelimiterDisplayStyleSize$^9$ \NC delim1 \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC FractionDelimiterSize$^9$ \NC delim2 \NC\NR
-\NC \tex{Umathfractiondenomdown}\NC D, D' \NC FractionDenominatorDisplayStyleShiftDown \NC denom1 \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC FractionDenominatorShiftDown \NC denom2 \NC\NR
-\NC \tex{Umathfractiondenomvgap}\NC D, D' \NC FractionDenominatorDisplayStyleGapMin \NC 3*default_rule_thickness \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC FractionDenominatorGapMin \NC default_rule_thickness \NC\NR
-\NC \tex{Umathfractionnumup} \NC D, D' \NC FractionNumeratorDisplayStyleShiftUp \NC num1 \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC FractionNumeratorShiftUp \NC num2 \NC\NR
-\NC \tex{Umathfractionnumvgap} \NC D, D' \NC FractionNumeratorDisplayStyleGapMin \NC 3*default_rule_thickness \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC FractionNumeratorGapMin \NC default_rule_thickness \NC\NR
-\NC \tex{Umathfractionrule} \NC -- \NC FractionRuleThickness \NC default_rule_thickness \NC\NR
-\NC \tex{Umathlimitabovebgap} \NC -- \NC UpperLimitBaselineRiseMin \NC big_op_spacing3 \NC\NR
-\NC \tex{Umathlimitabovekern} \NC -- \NC 0$^1$ \NC big_op_spacing5 \NC\NR
-\NC \tex{Umathlimitabovevgap} \NC -- \NC UpperLimitGapMin \NC big_op_spacing1 \NC\NR
-\NC \tex{Umathlimitbelowbgap} \NC -- \NC LowerLimitBaselineDropMin \NC big_op_spacing4 \NC\NR
-\NC \tex{Umathlimitbelowkern} \NC -- \NC 0$^1$ \NC big_op_spacing5 \NC\NR
-\NC \tex{Umathlimitbelowvgap} \NC -- \NC LowerLimitGapMin \NC big_op_spacing2 \NC\NR
-\NC \tex{Umathoverdelimitervgap}\NC -- \NC StretchStackGapBelowMin \NC big_op_spacing1 \NC\NR
-\NC \tex{Umathoverdelimiterbgap}\NC -- \NC StretchStackTopShiftUp \NC big_op_spacing3 \NC\NR
-\NC \tex{Umathunderdelimitervgap}\NC-- \NC StretchStackGapAboveMin \NC big_op_spacing2 \NC\NR
-\NC \tex{Umathunderdelimiterbgap}\NC-- \NC StretchStackBottomShiftDown \NC big_op_spacing4 \NC\NR
-\NC \tex{Umathoverbarkern} \NC -- \NC OverbarExtraAscender \NC default_rule_thickness \NC\NR
-\NC \tex{Umathoverbarrule} \NC -- \NC OverbarRuleThickness \NC default_rule_thickness \NC\NR
-\NC \tex{Umathoverbarvgap} \NC -- \NC OverbarVerticalGap \NC 3*default_rule_thickness \NC\NR
-\NC \tex{Umathquad} \NC -- \NC <font_size(f)>$^1$ \NC math_quad \NC\NR
-\NC \tex{Umathradicalkern} \NC -- \NC RadicalExtraAscender \NC default_rule_thickness \NC\NR
-\NC \tex{Umathradicalrule} \NC -- \NC RadicalRuleThickness \NC <not set>$^2$ \NC\NR
-\NC \tex{Umathradicalvgap} \NC D, D' \NC RadicalDisplayStyleVerticalGap \NC (default_rule_thickness+\crlf
- (abs(math_x_height)/4))$^3$ \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC RadicalVerticalGap \NC (default_rule_thickness+\crlf
- (abs(default_rule_thickness)/4))$^3$ \NC\NR
-\NC \tex{Umathradicaldegreebefore}\NC -- \NC RadicalKernBeforeDegree \NC <not set>$^2$ \NC\NR
-\NC \tex{Umathradicaldegreeafter}\NC -- \NC RadicalKernAfterDegree \NC <not set>$^2$ \NC\NR
-\NC \tex{Umathradicaldegreeraise}\NC -- \NC RadicalDegreeBottomRaisePercent \NC <not set>$^{2,7}$ \NC\NR
-\NC \tex{Umathspaceafterscript} \NC -- \NC SpaceAfterScript \NC script_space$^4$ \NC\NR
-\NC \tex{Umathstackdenomdown} \NC D, D' \NC StackBottomDisplayStyleShiftDown \NC denom1 \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC StackBottomShiftDown \NC denom2 \NC\NR
-\NC \tex{Umathstacknumup} \NC D, D' \NC StackTopDisplayStyleShiftUp \NC num1 \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC StackTopShiftUp \NC num3 \NC\NR
-\NC \tex{Umathstackvgap} \NC D, D' \NC StackDisplayStyleGapMin \NC 7*default_rule_thickness \NC\NR
-\NC " \NC T, T', S, S', SS, SS' \NC StackGapMin \NC 3*default_rule_thickness \NC\NR
-\NC \tex{Umathsubshiftdown} \NC -- \NC SubscriptShiftDown \NC sub1 \NC\NR
-\NC \tex{Umathsubshiftdrop} \NC -- \NC SubscriptBaselineDropMin \NC sub_drop \NC\NR
-\NC \tex{Umathsubsupshiftdown} \NC -- \NC SubscriptShiftDownWithSuperscript$^8$ \NC \NC\NR
-\NC \NC \NC \quad\ or SubscriptShiftDown \NC sub2 \NC\NR
-\NC \tex{Umathsubtopmax} \NC -- \NC SubscriptTopMax \NC (abs(math_x_height * 4) / 5) \NC\NR
-\NC \tex{Umathsubsupvgap} \NC -- \NC SubSuperscriptGapMin \NC 4*default_rule_thickness \NC\NR
-\NC \tex{Umathsupbottommin} \NC -- \NC SuperscriptBottomMin \NC (abs(math_x_height) / 4) \NC\NR
-\NC \tex{Umathsupshiftdrop} \NC -- \NC SuperscriptBaselineDropMax \NC sup_drop \NC\NR
-\NC \tex{Umathsupshiftup} \NC D \NC SuperscriptShiftUp \NC sup1 \NC\NR
-\NC " \NC T, S, SS, \NC SuperscriptShiftUp \NC sup2 \NC\NR
-\NC " \NC D', T', S', SS' \NC SuperscriptShiftUpCramped \NC sup3 \NC\NR
-\NC \tex{Umathsupsubbottommax} \NC -- \NC SuperscriptBottomMaxWithSubscript \NC (abs(math_x_height * 4) / 5) \NC\NR
-\NC \tex{Umathunderbarkern} \NC -- \NC UnderbarExtraDescender \NC default_rule_thickness \NC\NR
-\NC \tex{Umathunderbarrule} \NC -- \NC UnderbarRuleThickness \NC default_rule_thickness \NC\NR
-\NC \tex{Umathunderbarvgap} \NC -- \NC UnderbarVerticalGap \NC 3*default_rule_thickness \NC\NR
-\NC \tex{Umathconnectoroverlapmin}\NC -- \NC MinConnectorOverlap \NC 0$^5$ \NC\NR
-\stoptabulate
-
-\stop
-
-Note 1: \OPENTYPE\ fonts set \tex{Umathlimitabovekern} and
-\tex{Umathlimitbelowkern} to zero and set \tex{Umathquad} to the font size of the used font,
-because these are not supported in the MATH table,
-
-Note 2: \TFM\ fonts do not set \tex{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 \tex{Umathradicaldegreebefore}, \tex{Umathradicaldegreeafter}, and
-\tex{Umathradicaldegreeraise}. These are then automatically initialized to $5/18$quad, $-10/18$quad, and 60.
-
-Note 3: If tfm fonts are used, then the \tex{Umathradicalvgap} is not set until the first time
-\LUATEX\ has to typeset a formula because this needs parameters from both family2 and family3.
-This provides a partial backward compatibility with \TEX82, but that compatibility is only partial:
-once the \tex{Umathradicalvgap} is set, it will not be recalculated any more.
-
-Note 4: (also if tfm fonts are used) A similar situation arises wrt. \tex{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 \tex{Umathspaceafterscript} is set, \tex{scriptspace} will never be looked at again.
-
-Note 5: Tfm fonts set \tex{Umathconnectoroverlapmin} to zero because
-\TeX82\ always stacks extensibles without any overlap.
-
-Note 6: The \tex{Umathoperatorsize} is only used in \type{\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 \tex{Umathradicaldegreeraise} is a special case because it is the only parameter that is
-expressed in a percentage instead of as 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. New in version 0.38.
-
-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. New in version 0.47.
-
-
-\section{Math spacing setting}
-
-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:
-
-\startcolumns[n=2]
-\starttyping
-\Umathordordspacing
-\Umathordopspacing
-\Umathordbinspacing
-\Umathordrelspacing
-\Umathordopenspacing
-\Umathordclosespacing
-\Umathordpunctspacing
-\Umathordinnerspacing
-\Umathopordspacing
-\Umathopopspacing
-\Umathopbinspacing
-\Umathoprelspacing
-\Umathopopenspacing
-\Umathopclosespacing
-\Umathoppunctspacing
-\Umathopinnerspacing
-\Umathbinordspacing
-\Umathbinopspacing
-\Umathbinbinspacing
-\Umathbinrelspacing
-\Umathbinopenspacing
-\Umathbinclosespacing
-\Umathbinpunctspacing
-\Umathbininnerspacing
-\Umathrelordspacing
-\Umathrelopspacing
-\Umathrelbinspacing
-\Umathrelrelspacing
-\Umathrelopenspacing
-\Umathrelclosespacing
-\Umathrelpunctspacing
-\Umathrelinnerspacing
-\Umathopenordspacing
-\Umathopenopspacing
-\Umathopenbinspacing
-\Umathopenrelspacing
-\Umathopenopenspacing
-\Umathopenclosespacing
-\Umathopenpunctspacing
-\Umathopeninnerspacing
-\Umathcloseordspacing
-\Umathcloseopspacing
-\Umathclosebinspacing
-\Umathcloserelspacing
-\Umathcloseopenspacing
-\Umathcloseclosespacing
-\Umathclosepunctspacing
-\Umathcloseinnerspacing
-\Umathpunctordspacing
-\Umathpunctopspacing
-\Umathpunctbinspacing
-\Umathpunctrelspacing
-\Umathpunctopenspacing
-\Umathpunctclosespacing
-\Umathpunctpunctspacing
-\Umathpunctinnerspacing
-\Umathinnerordspacing
-\Umathinneropspacing
-\Umathinnerbinspacing
-\Umathinnerrelspacing
-\Umathinneropenspacing
-\Umathinnerclosespacing
-\Umathinnerpunctspacing
-\Umathinnerinnerspacing
-\stoptyping
-\stopcolumns
-
-These parameters are of type \type{\muskip}, so setting a parameter
-can be done like this:
-
-\starttyping
-\Umathopordspacing\displaystyle=4mu plus 2mu
-\stoptyping
-
-They are all initialized by 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, \type{\thinmuskip},
-\type{\medmuskip} and \type{\thickmuskip} are treated especially. In their case a pointer to
-the corresponding internal parameter is saved, not the actual \type{\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.
-
-
-\section[mathacc]{Math accent handling}
-
-\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 \tex{Umathaccent}.
-
-The keyword \type{bottom} after \tex{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 \type{\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 value that turns out to be zero and the
-font had a MathConstants table, then \type{AccentBaseHeight} is used instead.
-
-If a math bottom accent has to be placed, the \type{bot_accent} value is checked instead
-of \type{top_accent}. Because bottom accents do not exist in \TEX82, the \type{\skewchar}
-kern is ignored.
-
-The vertical placement of a bottom accent is straight below the accentee, no correction
-takes place.
-
-\section{Math root extension}
-
-The new primitive \type{\Uroot} allows the construction of a radical
-noad including a degree field. Its syntax is an extension of \type{\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
-\type{\Umathradicaldegreebefore}, \type{\Umathradicaldegreeafter}, and
-\type{\Umathradicaldegreeraise}. The degree will be typeset in \type{\scriptscriptstyle}.
-
-
-\section{Math kerning in 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 imtes 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
-\item The vertical position of the script is calculated.
-\item The default horizontal position is flat next to the base character.
-\item For superscripts, the italic correction of the base character is added.
-\item 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.
-\item For each of these two locations:
- \startitemize
- \item find the mathkern 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)
- \item find the mathkern 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)
- \item add the found values together to get a preliminary result.
- \stopitemize
-\item The horizontal kern to be applied is the smallest of the two results from
- previous step.
-\stopitemize
-
-The mathkern 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 mathkern
-pairs at all).
-
-\section{Scripts on horizontally extensible items like arrows}
-
-The new primitives \tex{Uunderdelimiter} and \tex{Uoverdelimiter}
-(both from 0.35) allow the placement of a subscript or superscript on
-an automatically extensible item and \tex{Udelimiterunder} and
-\tex{Udelimiterover} (both from 0.37) allow the placement of
-an automatically extensible item as a subscript or superscript on a
-nucleus.
-
-The vertical placements are controlled by
-\tex{Umathunderdelimiterbgap}, \tex{Umathunderdelimitervgap},
-\tex{Umathoverdelimiterbgap}, and \tex{Umathoverdelimitervgap} in a similar way as limit
-placements on large operators. The superscript in \tex{Uoverdelimiter} is typeset in
-a suitable scripted style, the subscript in \tex{Uunderdelimiter} is cramped as well.
-
-\section {Extensible delimiters}
-
-\LUATEX\ internally uses a structure that supports \OPENTYPE\ \quote{MathVariants} as well
-as \TFM\ \quote{extensible recipes}.
-
-
-\section{Other Math changes}
-
-\subsection {Verbose versions of single-character math commands}
-
-\LUATEX\ defines six new primitives that have the same function as
-\type{^}, \type{_}, \type{$}, and \type{$$}. %$
-
-\starttabulate[|l|l|l|l|]
-\NC \bf primitive \NC \bf explanation \NC\NR
-\NC \tex{Usuperscript} \NC Duplicates the functionality of \type{^} \NC\NR
-\NC \tex{Usubscript} \NC Duplicates the functionality of \type{_} \NC\NR
-\NC \tex{Ustartmath} \NC Duplicates the functionality of \type{$}, % $
- when used in non-math mode. \NC\NR
-\NC \tex{Ustopmath} \NC Duplicates the functionality of \type{$}, % $
- when used in inline math mode. \NC\NR
-\NC \tex{Ustartdisplaymath}\NC Duplicates the functionality of \type{$$}, % $$
- when used in non-math mode. \NC\NR
-\NC \tex{Ustopdisplaymath} \NC Duplicates the functionality of \type{$$}, % $$
- when used in display math mode. \NC\NR
-\stoptabulate
-
-All are new in version 0.38. The \tex{Ustopmath} and \tex{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{Allowed math commands in non-math modes}
-
-The commands \type{\mathchar}, and \type{\Umathchar} and control
-sequences that are the result of \type{\mathchardef} or
-\type{\Umathchardef} are also acceptable in the horizontal and vertical modes.
-In those cases, the \type{\textfont} from the requested math family is used.
-
-\section{Math todo}
-
-The following items are still todo.
-
-\startitemize
-\item Pre-scripts.
-\item Multi-story stacks.
-\item Flattened accents for high characters (?).
-\item Better control over the spacing around displays and handling of equation numbers.
-\item Support for multi-line displays using \MATHML\ style alignment points.
-\stopitemize
-
-\chapter[languages]{Languages and characters, fonts and glyphs}
-
-\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 array 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.
-
-The \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. Instead, language information is passed along
-using \type{language whatsit} records inside the horizontal list.
-
-In \LUATEX, the situation is quite different. The characters you
-type are always converted into \type{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 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.
-
-That was the broad overview. The rest of this chapter will deal with the
-minutiae of the new process.
-
-\section[charsandglyphs]{Characters and glyphs}
-
-\TEX82 (including \PDFTEX) differentiated between \type{char_node}s
-and \type{lig_node}s. 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 \type{glyph_node}. Besides having the old
-character, font, and component fields, and the new special fields like
-\quote{attr} (see~\in{section}[glyphnodes]), these nodes also contain:
-
-\startitemize
-
-\item A subtype, split into four main types:
-
- \startitemize
- \item \type{character}, for characters to be hyphenated: the lowest
- bit (bit 0) is set to 1.
- \item \type{glyph}, for specific font glyphs: the lowest bit
- (bit 0) is not set.
- \item \type{ligature}, for ligatures (bit 1 is set)
- \item \type{ghost}, for \quote{ghost objects} (bit 2 is set)
- \stopitemize
-
- The latter two make further use of two extra fields (bits 3 and 4):
-
- \startitemize
- \item \type{left}, for ligatures created from a left word boundary and
- for ghosts created from \tex{leftghost}
- \item \type{right}, for ligatures created from a right word boundary and
- for ghosts created from \tex{rightghost}
- \stopitemize
-
- For ligatures, both bits can be set at the same time (in case of a single|-|glyph word).
-
-\item \type{glyph_node}s of type \quote{character} also contain language data,
- split into four items that were current when the node was created:
- the \tex{setlanguage} (15 bits), \tex{lefthyphenmin} (8 bits),
- \tex{righthyphenmin} (8 bits), and \tex{uchyph} (1 bit).
-
-\stopitemize
-
-Incidentally, \LUATEX\ allows 16383 separate languages, and words can
-be 256 characters long.
-
-Because the \tex{uchyph} value is saved in the actual nodes, its
-handling is subtly different from \TEX82: changes to \tex{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 \tex{unhbox0} would process the box using the current
-paragraph language unless there was a \tex{setlanguage} issued inside
-the box. In \LUATEX, all language variables are already frozen.
-
-
-\section{The main control loop}
-
-In \LUATEX's main loop, almost all input characters that are to be
-typeset are converted into \type{glyph_node} records with subtype
-\quote{character}, but there are a few small exceptions.
-
-First, the \tex{accent} primitives 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 \tex{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, \tex{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.
-
-This change of meaning did happen with \tex{char}, that now generates
-\quote{character} nodes, consistent with its changed meaning in \XETEX.
-The changed status of \tex{char} is not yet finalized, but if it stays
-as it is now, a new primitive \tex{glyph} should be added to directly
-insert a font glyph id.
-
-Second, all the results of processing in math mode eventually become
-nodes with \quote{glyph} subtypes.
-
-Third, the \ALEPH-derived commands \tex{leftghost} and
-\tex{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.
-
-Fourth, automatic discretionaries are handled differently. \TEX82
-inserts an empty discretionary after sensing an input character that
-matches the \tex{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.
-
-In \LUATEX, it works like this: if \LUATEX\ senses a string of input
-characters that matches the value of the new integer parameter
-\tex{exhyphenchar}, it will insert an explicit discretionary after that
-series of nodes. Initex sets the \tex{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.
-
-Note: as of \LUATEX\ 0.63.0, 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 \tex{hyphenchar} is at the check
-whether a word should be considered for hyphenation at all. If the
-\tex{hyphenchar} of the font attached to the first character node in a
-word is negative, then hyphenation of that word is abandoned
-immediately. {\bf This behavior 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.}
-
-Fifth, \tex{setlanguage} no longer creates whatsits. The meaning of
-\tex{setlanguage} is changed so that it is now an integer parameter
-like all others. That integer parameter is used in \tex{glyph_node}
-creation to add language information to the glyph nodes. In
-conjunction, the \tex{language} primitive is extended so that it
-always also updates the value of \tex{setlanguage}.
-
-Sixth, the \tex{noboundary} command (this command prohibits word
-boundary processing where that would normally take place) now does
-create whatsits. These whatsits are needed because the exact place of
-the \tex{noboundary} command in the input stream has to be retained
-until after the ligature and font processing stages.
-
-Finally, 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 \tex{tracingcommands} is on, this is
-visible because the full word is reported, instead of just the initial
-character.
-
-
-\section[patternsexceptions]{Loading patterns and exceptions}
-
-The hyphenation algorithm in \LUATEX\ is quite different from the one
-in \TEX82, although it uses essentially the same user input.
-
-After expansion, the argument for \tex{patterns} has to be proper
-UTF-8 with individual patterns separated by spaces, no \tex{char} or
-\tex{chardef-ed} commands are allowed. (The current implementation is
-even more strict, and will reject all non|-|\UNICODE\ characters, but
-that will be changed in the future. For now, the generated errors are
-a valuable tool in discovering font-encoding specific pattern files)
-
-Likewise, the expanded argument for \tex{hyphenation} also has to be
-proper UTF-8, but here a tiny little bit of extra syntax is provided:
-
-\startitemize[n]
-\item three sets of arguments in curly braces (\type{{}{}{}})
- indicates a desired complex discretionary, with arguments
- as in \tex{discretionary}'s command in normal document input.
-\item \type{-} indicates a desired simple discretionary, cf. \tex{-} and
- \type{\discretionary{-}{}{}} in normal document input.
-\item Internal command names are ignored. This rule is provided
- especially for \tex{discretionary}, but it also helps to deal with
- \tex{relax} commands that may sneak in.
-\item \type{=} indicates a (non-discretionary) hyphen in the document input.
-\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|]
-\NC \ssbf value \NC \ssbf implied key (input) \NC \ssbf effect\NC\NR
-\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
-\stoptabulate
-
-The resultant patterns and exception dictionary will be stored under
-the language code that is the present value of \tex{language}.
-
-In the last line of the table, you see there is no \tex{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\ \luatex{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.
-
-Starting with \LUATEX\ 0.63.0, 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 inbetweem \quote{boun} and \quote{daries}:
-
-\starttyping
-\hyphenation{multi{-}{}{-}word{-}{}{-}boun-daries}
-\stoptyping
-
-The motivation behind the \ETEX\ extension \tex{savinghyphcodes} was
-that hyphenation heavily depended on font encodings. This is no longer
-true in \LUATEX, and the corresponding primitive is ignored pending
-complete removal. The future semantics of \tex{uppercase} and
-\tex{lowercase} are still under consideration, no changes have taken
-place yet.
-
-
-\section{Applying hyphenation}
-
-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 \PATGEN-generated pattern
-files, 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.
-The memory allocation for this new implementation is completely
-dynamic, so the \WEBC\ setting for \type{trie_size} is ignored.
-
-Differences between \LUATEX\ and \TEX82 that are a direct result of that:
-
-\startitemize
-\item \LUATEX\ happily hyphenates the full \UNICODE\ character range.
-\item 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.
-\item Because there is no \quote{trie preparation} stage, language patterns
- never become frozen. This means that the primitive \tex{patterns}
- (and its \LUA\ counterpart \luatex{lang.patterns}) can be used at any
- time, not only in initex.
-\item Only the string representation of \tex{patterns} and
- \tex{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.
-\item \LUATEX\ uses the language-specific variables
-\tex{prehyphenchar} and \tex{posthyphenchar} in the creation of
-implicit discretionaries, instead of \TEX82's \tex{hyphenchar}, and
-the values of the language-specific variables \tex{preexhyphenchar} and
-\tex{postexhyphenchar} for explicit discretionaries (instead of
-\TEX82's empty discretionary).
-\stopitemize
-
-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 \tex{setlanguage} command forces a word boundary).
-
-All languages start out with \tex{prehyphenchar=`\-},
-\tex{posthyphenchar=0}, \tex{preexhyphenchar=0} and
-\tex{postexhyphenchar=0}.
-When you assign the values of one of these four parameters, you are
-actually changing the settings for the current \tex{language}, this
-behavior is compatible with \tex{patterns} and \tex{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 generate an error 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 behavior 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. In the near future, it will be able to skip over \quote{ghost}
-nodes, and we may add a less fuzzy function you can call as well.
-
-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.
-
-A technical paper detailing the new algorithm will be released as a
-separate document.
-
-\section{Applying ligatures and 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
-\type{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 work 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.
-
-Work in this area is not yet complete, but most of the possible cases
-are handled by our rewritten ligaturing engine. We are working hard to
-make sure all of the possible inputs will become supported soon.
-
-For 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:
-
-\starttabulate[|l|l|l|l|]
-\NC \NC pre \NC post \NC replace \NC \NR
-\NC topdisc \NC \type{f-}$^1$ \NC sub1 \NC sub2 \NC \NR
-\NC sub1 \NC \type{f-}$^2$ \NC \type{i}$^3$ \NC \type{<fi>}$^4$ \NC \NR
-\NC sub2 \NC \type{<ff>-}$^5$\NC \type{i}$^6$ \NC \type{<ffi>}$^7$\NC \NR
-\stoptabulate
-
-When line breaking is choosing its breakpoints, the following fields will eventually
-be selected:
-
-\starttabulate[|l|l|l|]
-\NC \type{of-f-ice} \NC \type{f-}$^1$ \NC \NR
-\NC \NC \type{f-}$^2$ \NC \NR
-\NC \NC \type{i}$^3$ \NC \NR
-\NC \type{of-fice} \NC \type{f-}$^1$ \NC \NR
-\NC \NC \type{<fi>}$^4$ \NC \NR
-\NC \type{off-ice} \NC \type{<ff>-}$^5$ \NC \NR
-\NC \NC \type{i}$^6$ \NC \NR
-\NC \type{office} \NC \type{<ffi>}$^7$ \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 that \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|p|]
-\NC \bf field \NC \bf description \NC \NR
-\NC \type{disc1.pre} \NC \type{f-}$^1$ \NC \NR
-\NC \type{disc1.post} \NC \type{<fi>}$^4$ \NC \NR
-\NC \type{disc1.replace} \NC \type{<ffi>}$^7$ \NC \NR
-\NC \type{disc2.pre} \NC \type{f-}$^2$ \NC \NR
-\NC \type{disc2.post} \NC \type{i}$^{3{,}6}$\NC \NR
-\NC \type{disc2.replace} \NC \type{<ff>-}$^5$\NC \NR
-\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.
-
-
-\section{Breaking paragraphs into lines}
-
-This code is still 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 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 (the
-discretionary node contained a counter indicating how many nodes to
-skip).
-
-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.
-
-% TODO:
-% Check \sfcode handling
-% Implement \glyph
-%
-% Remove \savinghyphcodes
-% Allow non-UCS characters in \patterns
-
-\chapter[fonts]{Font structure}
-
-All \TEX\ fonts are represented to \LUA\ code as tables, and
-internally as C~structures. All keys in the table below are saved in
-the internal font structure if they are present in the table returned
-by the
-\luatex{define_font} callback, or if they result from the normal \TFM|/|\VF\
-reading routines if there is no \luatex{define_font} callback defined.
-
-The column \quote{from \VF} means that this key will be created by the
-\luatex{font.read_vf()} routine, \quote{from \TFM} means that the key will be created
-by the \luatex{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[|Tl|l|l|l|l|p|]
-\NC \ssbf key \NC \bf from vf \NC \bf from tfm \NC \bf used\NC \bf value type \NC \bf description \NC\NR
-\NC name \NC yes \NC yes \NC yes \NC string \NC metric (file) name\NC\NR
-\NC area \NC no \NC yes \NC yes \NC string \NC (directory) location, typically empty\NC\NR
-\NC used \NC no \NC yes \NC yes \NC boolean\NC used already? (initial: false)\NC \NR
-\NC characters \NC yes \NC yes \NC yes \NC table \NC the defined glyphs of this font \NC \NR
-\NC checksum \NC yes \NC yes \NC no \NC number \NC default: 0 \NC \NR
-\NC designsize \NC no \NC yes \NC yes \NC number \NC expected size (default: 655360 == 10pt) \NC \NR
-\NC direction \NC no \NC yes \NC yes \NC number \NC default: 0 (TLT) \NC \NR
-\NC encodingbytes \NC no \NC no \NC yes \NC number \NC default: depends on \type {format}\NC\NR
-\NC encodingname \NC no \NC no \NC yes \NC string \NC encoding name\NC\NR
-\NC fonts \NC yes \NC no \NC yes \NC table \NC locally used fonts\NC \NR
-\NC psname \NC no \NC no \NC yes \NC string
-\NC actual (\POSTSCRIPT) name (this is the PS fontname in the
-incoming font source, also used as fontname identifier in the \PDF\ output, new in 0.43)\NC\NR
-\NC fullname \NC no \NC no \NC yes \NC string \NC output font name, used as a fallback in the \PDF\ output if the psname is not set\NC\NR
-\NC header \NC yes \NC no \NC no \NC string \NC header comments, if any\NC \NR
-\NC hyphenchar \NC no \NC no \NC yes \NC number \NC default: TeX's \tex{hyphenchar} \NC \NR
-\NC parameters \NC no \NC yes \NC yes \NC hash \NC default: 7 parameters, all zero \NC \NR
-\NC size \NC no \NC yes \NC yes \NC number \NC loaded (at) size. (default: same as designsize) \NC \NR
-\NC skewchar \NC no \NC no \NC yes \NC number \NC default: TeX's \tex{skewchar} \NC \NR
-\NC type \NC yes \NC no \NC yes \NC string \NC basic type of this font\NC \NR
-\NC format \NC no \NC no \NC yes \NC string \NC disk format type\NC \NR
-\NC embedding \NC no \NC no \NC yes \NC string \NC \PDF\ inclusion\NC \NR
-\NC filename \NC no \NC no \NC yes \NC string \NC disk file name\NC\NR
-\NC tounicode \NC no \NC yes \NC yes \NC number \NC if 1, \LUATEX\ assumes per-glyph tounicode entries are
- present in the font\NC\NR
-\NC stretch \NC no \NC no \NC yes \NC number \NC the \quote {stretch} value from \tex{pdffontexpand}\NC\NR
-\NC shrink \NC no \NC no \NC yes \NC number \NC the \quote {shrink} value from \tex{pdffontexpand}\NC\NR
-\NC step \NC no \NC no \NC yes \NC number \NC the \quote {step} value from \tex{pdffontexpand}\NC\NR
-\NC auto_expand \NC no \NC no \NC yes \NC boolean\NC the \quote {autoexpand} keyword from\crlf \tex{pdffontexpand}\NC\NR
-\NC expansion_factor \NC no \NC no \NC no \NC number \NC the actual expansion factor of an expanded font\NC\NR
-\NC attributes \NC no \NC no \NC yes \NC string \NC the \tex{pdffontattr}\NC\NR
-\NC cache \NC no \NC no \NC yes \NC string \NC this key controls caching of the lua table on the \type{tex}
- end. \type{yes}: use a reference to the table that is
- passed to \LUATEX\ (this is the default). \type{no}: don't store the table
- reference, don't cache any lua data for this font.
- \type{renew}: 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 font.fonts.
- (new in 0.40.0, before that caching was always \type{yes}).
-Note: the saved reference 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 ($\approx$ coroutine)\NC\NR
-\NC 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 enties for math-specific keys. (0.42.0)\NC\NR
-\NC slant \NC no \NC no \NC yes \NC number \NC This has the same semantics as the \type{SlantFont} operator
- in font map files. (0.47.0)\NC\NR
-\NC extent \NC no \NC no \NC yes \NC number \NC This has the same semantics as the \type{ExtendFont} operator
- in font map files. (0.50.0)\NC\NR
-\stoptabulate
-
-The key \type{name} is always required. The keys \type{stretch},
-\type{shrink}, \type{step} and optionally \type{auto_expand} only
-have meaning when used together: they can be used to replace a
-post-loading \tex{pdffontexpand} command. 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. The key \type{attributes} can be used to replace
-\tex{pdffontattr}. 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|c|c|]
-\NC \ssbf number \NC \bf meaning \NC \bf number \NC \bf meaning \NC\NR
-\NC 0 \NC LT \NC 8 \NC TT \NC\NR
-\NC 1 \NC LL \NC 9 \NC TL \NC\NR
-\NC 2 \NC LB \NC 10 \NC TB \NC\NR
-\NC 3 \NC LR \NC 11 \NC TR \NC\NR
-\NC 4 \NC RT \NC 12 \NC BT \NC\NR
-\NC 5 \NC RL \NC 13 \NC BL \NC\NR
-\NC 6 \NC RB \NC 14 \NC BB \NC\NR
-\NC 7 \NC RR \NC 15 \NC BR \NC\NR
-\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.
-
-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[|lT|c|]
-\NC \ssbf name \NC \bf internal remapped number \NC\NR
-\NC slant \NC 1 \NC\NR
-\NC space \NC 2 \NC\NR
-\NC space_stretch \NC 3 \NC\NR
-\NC space_shrink \NC 4 \NC\NR
-\NC x_height \NC 5 \NC\NR
-\NC quad \NC 6 \NC\NR
-\NC extra_space \NC 7 \NC\LR
-\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!).
-
-Other index keys are ignored.
-
-Each character hash itself is a hash. For example, here is the
-character \quote{f} (decimal 102) in the font cmr10 at 10 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[|lT|c|c|c|l|p|]
-\NC \ssbf key \NC \bf from vf \NC \bf from tfm \NC \bf used \NC \bf value type \NC \bf description \NC\NR
-\NC width \NC yes \NC yes \NC yes \NC number \NC character's width, in sp (default 0) \NC\NR
-\NC height \NC no \NC yes \NC yes \NC number \NC character's height, in sp (default 0) \NC\NR
-\NC depth \NC no \NC yes \NC yes \NC number \NC character's depth, in sp (default 0) \NC\NR
-\NC italic \NC no \NC yes \NC yes \NC number \NC character's italic correction, in sp (default zero) \NC\NR
-\NC top_accent \NC no \NC no \NC maybe \NC number \NC character's top accent alignment place, in sp (default zero) \NC\NR
-\NC bot_accent \NC no \NC no \NC maybe \NC number \NC character's bottom accent alignment place, in sp (default zero) \NC\NR
-\NC left_protruding \NC no \NC no \NC maybe \NC number \NC character's \tex{lpcode}\NC\NR
-\NC right_protruding \NC no \NC no \NC maybe \NC number \NC character's \tex{rpcode}\NC\NR
-\NC expansion_factor \NC no \NC no \NC maybe \NC number \NC character's \tex{efcode}\NC\NR
-\NC tounicode \NC no \NC no \NC maybe \NC string \NC character's Unicode equivalent(s), in UTF-16BE hexadecimal format\NC\NR
-\NC next \NC no \NC yes \NC yes \NC number \NC the \quote{next larger} character index \NC\NR
-\NC extensible \NC no \NC yes \NC yes \NC table \NC the constituent parts of an extensible recipe \NC\NR
-\NC vert_variants \NC no \NC no \NC yes \NC table \NC constituent parts of a vertical variant set\NC \NR
-\NC horiz_variants\NC no \NC no \NC yes \NC table \NC constituent parts of a horizontal variant set\NC \NR
-\NC kerns \NC no \NC yes \NC yes \NC table \NC kerning information \NC\NR
-\NC ligatures \NC no \NC yes \NC yes \NC table \NC ligaturing information \NC\NR
-\NC commands \NC yes \NC no \NC yes \NC array \NC virtual font commands \NC\NR
-\NC name \NC no \NC no \NC no \NC string \NC the character (\POSTSCRIPT) name \NC\NR
-\NC index \NC no \NC no \NC yes \NC number \NC the (\OPENTYPE\ or \TRUETYPE) font glyph index \NC\NR
-\NC used \NC no \NC yes \NC yes \NC boolean \NC typeset already (default: false)? \NC\NR
-\NC mathkern \NC no \NC no \NC yes \NC table \NC math cut-in specifications \NC\NR
-\stoptabulate
-
-The values of \type{top_accent}, \type{bot_accent} and \type{mathkern} are used only for math
-accent and superscript placement, see the \at{math chapter}[math] in this manual for details.
-
-The values of \type{left_protruding} and \type{right_protruding} are used only when
-\tex{pdfprotrudechars} 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 \tex{pdfadjustspacing}.
-
-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. {\it At the moment, the string format is exactly the
-format that is expected by Adobe \CMAP\ files (\UTF-16BE in hexadecimal encoding), minus
-the enclosing angle brackets. This may change in the future.} Small example: the
-\type{tounicode} for a \type{fi} ligature would be \type{00660069}.
-
-The presence of \type{extensible} will overrule \type{next}, if that is also present.
-It in in turn can be overruled by \type{vert_variants}.
-
-The \type{extensible} table is very simple:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf description \NC\NR
-\NC top \NC number \NC \quote{top} character index \NC\NR
-\NC mid \NC number \NC \quote{middle} character index \NC\NR
-\NC bot \NC number \NC \quote{bottom} character index \NC\NR
-\NC rep \NC number \NC \quote{repeatable} character index \NC\NR
-\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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC glyph \NC number \NC The character index (note that this is an encoding number, not a name).\NC \NR
-\NC extender \NC number \NC One (1) if this part is repeatable, zero (0) otherwise.\NC \NR
-\NC start \NC number \NC Maximum overlap at the starting side (in scaled points).\NC \NR
-\NC end \NC number \NC Maximum overlap at the ending side (in scaled points).\NC \NR
-\NC advance \NC number \NC Total advance width of this item (can be zero or missing,
- then the natural size of the glyph for character \type{component}
- is used).\NC \NR
-\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 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[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf description \NC\NR
-\NC type \NC number \NC the type of this ligature command, default 0 \NC\NR
-\NC char \NC number \NC the character index of the resultant ligature \NC\NR
-\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|]
-\NC \bf textual (Knuth) \NC \bf number \NC \bf string \NC result \NC\NR
-\NC l + r =: n \NC 0 \NC \type{=:} \NC \|n \NC\NR
-\NC l + r =:\| n \NC 1 \NC \type{=:|} \NC \|nr \NC\NR
-\NC l + r \|=: n \NC 2 \NC \type{|=:} \NC \|ln \NC\NR
-\NC l + r \|=:\| n \NC 3 \NC \type{|=:|} \NC \|lnr \NC\NR
-\NC l + r =:\|\> n \NC 5 \NC \type{=:|>} \NC n\|r \NC\NR
-\NC l + r \|=:\> n \NC 6 \NC \type{|=:>} \NC l\|n \NC\NR
-\NC l + r \|=:\|\> n \NC 7 \NC \type{|=:|>} \NC l\|nr \NC\NR
-\NC l + r \|=:\|\>\> n \NC 11 \NC \type{|=:|>>} \NC ln\|r \NC\NR
-\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~\| indicates the final insertion point.
-
-The \type{commands} array is explained below.
-
-\section {Real fonts}
-
-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}:
-
-\starttabulate[|Tl|p|]
-\NC \ssbf value \NC \bf description \NC\NR
-\NC real \NC this is a base font \NC\NR
-\NC virtual \NC this is a virtual font \NC\NR
-\stoptabulate
-
-The actions to be taken depend on a number of different variables:
-
-\startitemize[packed]
-\item Whether the used font fits in an 8-bit encoding scheme or not
-\item The type of the disk font file
-\item The level of embedding requested
-\stopitemize
-
-A font that uses anything other than an 8-bit encoding vector has to
-be written to the \PDF\ in a different way.
-
-The rule is: if the font table has \type {encodingbytes} set to~2,
-then this 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\ currently falls back to the
-mapfile|-|based solution used by \PDFTEX\ and \DVIPS. This behavior
-will be removed in the future, when the existing code becomes
-integrated in the new subsystem.
-
-But if this is a \quote{wide} font, then 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.
-
-The 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.
-
-Values for \type{format} are:
-
-\starttabulate[|Tl|p|]
-\NC \ssbf value \NC \bf description \NC\NR
-\NC type1 \NC this is a \POSTSCRIPT\ \TYPEONE\ font \NC\NR
-\NC type3 \NC this is a bitmapped (\PK) font \NC\NR
-\NC truetype \NC this is a \TRUETYPE\ or \TRUETYPE|-|based \OPENTYPE\ font \NC\NR
-\NC opentype \NC this is a \POSTSCRIPT|-|based \OPENTYPE\ font \NC\NR
-\stoptabulate
-
-(\type{type3} fonts are provided for backward compatibility only, and do not
-support the new wide encoding options.)
-
-Values for \type{embedding} are:
-
-\starttabulate[|Tl|p|]
-\NC \ssbf value \NC \bf description \NC\NR
-\NC no \NC don't embed the font at all \NC\NR
-\NC subset \NC include and atttempt to subset the font \NC\NR
-\NC full \NC include this font in its entirety \NC\NR
-\stoptabulate
-
-It is not possible to artificially modify the transformation matrix
-for the font at the moment.
-
-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_xxx_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.
-
-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. The way
-to get the correct \type{index} numbers for \TYPEONE\ fonts is by
-loading the font via \type{fontloader.open}; use the table indices as
-\type{index} fields.
-
-This type of reencoding means that there is no longer a clear
-connection between the text in your input file and the strings in the
-output \PDF\ file. Dealing with this is high on the agenda.
-
-\section[virtualfonts]{Virtual fonts}
-
-You have to take the following steps if you want \LUATEX\ to treat the
-returned table from \luatex{define_font} as a virtual font:
-
-\startitemize[packed]
-\item Set the top|-|level key \type {type} to \type {virtual}.
-\item Make sure there is at least one valid entry in \luatex{fonts} (see below).
-\item Give a \type {commands} array to every character (see below).
-\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.
-
-Therefore, this also works \quote{in reverse}: if you are absolutely certain
-that a font is not a virtual font, assigning the value \type{base} or
-\type{real} to \type{type} will inhibit \LUATEX\ from looking for a virtual font
-file, thereby saving you a disk search.
-
-The \luatex{fonts} is another \LUA\ array. 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.
-
-An example makes this easy to understand
-
-\starttyping
-fonts = {
- { name = 'ptmr8a', size = 655360 },
- { name = 'psyr', size = 600000 },
- { id = 38 }
-}
-\stoptyping
-
-says that the first referenced font (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 previously defined font that
-is known to \LUATEX\ as fontid \quote{38}.
-
-The array index numbers are used by the character command definitions
-that are part of each character.
-
-The \luatex{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[|Tl|l|l|p|]
-\NC \ssbf command name \NC \bf arguments \NC \bf arg type \NC \bf description \NC\NR
-\NC font \NC 1 \NC number \NC select a new font from the local \luatex{fonts} table\NC\NR
-\NC 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 node \NC 1 \NC node \NC output this node (list), and move right
- by the width of this list\NC\NR
-\NC slot \NC 2 \NC number \NC a shortcut for the combination of a font and char command\NC\NR
-\NC push \NC 0 \NC \NC save current position\NC\NR
-\NC nop \NC 0 \NC \NC do nothing \NC\NR
-\NC pop \NC 0 \NC \NC pop position \NC\NR
-\NC rule \NC 2 \NC 2 numbers \NC output a rule $ht*wd$, and move right.\NC\NR
-\NC down \NC 1 \NC number \NC move down on the page\NC\NR
-\NC right \NC 1 \NC number \NC move right on the page\NC\NR
-\NC special \NC 1 \NC string \NC output a \tex{special} command\NC\NR
-\NC lua \NC 1 \NC string \NC execute a \LUA\ script (at \tex{latelua} time)\NC\NR
-\NC 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 comment \NC any \NC any \NC the arguments of this command are ignored\NC\NR
-\stoptabulate
-
-Here is a rather elaborate glyph commands example:
-\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')
- {'pop'}, -- go all the way back
- {'down', -200000}, -- move upwards by about 3pt
- {'special', 'pdf: 1 0 0 rg'} -- switch to red color
- {'rule', 500000, 20000} -- draw a bar
- {'special','pdf: 0 g'} -- back to black
-}
-...
-\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 create 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.
-
-\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}
-
-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
- 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'},
- }
- else
- v.commands = {{'char',i}}
- end
- end
- else
- f = font.read_tfm(name,size)
- end
- return f
- 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
-
-%\getbuffer
-
-\chapter[nodes]{Nodes}
-
-\section{\LUA\ node representation}
-
-\TEX's nodes are represented in \LUA\ as userdata object with a variable
-set of fields. In the following syntax tables, such the type of such a
-userdata object is represented as \syntax{<node>}.
-
-
-The current return value of \luatex{node.types()} is:
-\ctxlua {
- local d = node.types()
- tex.print('\\type{' .. d[0] .. '} (' .. 0 .. '), ')
- for _,v in pairs(d) do
- if _ > 0 then
- tex.print('\\type{' .. v .. '} (' .. _ .. '), ')
- end
- end
-}.
-
-NOTE: The \type {\lastnodetype} primitive is \ETEX\ compliant. The valid
-range is still -1 .. 15 and glyph nodes have number 0 (used to be
-char node) and ligature nodes are mapped to 7. That way macro
-packages can use the same symbolic names as in traditional \ETEX.
-Keep in mind that the internal node numbers are different and that
-there are more node types than 15.
-
-\subsection{Auxiliary items}
-
-A few node|-|typed userdata objects do not occur in the \quote{normal}
-list of nodes, but can be pointed to from within that list. They are
-not quite the same as regular nodes, but it is easier for the library
-routines to treat them as if they were.
-
-\subsubsection{glue_spec items}
-
-Skips are about the only type of data objects in traditional \TEX\
-that are not a simple value. The structure that represents the glue
-components of a skip is called a \type {glue_spec}, and it has the following
-accessible fields:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf key \NC \bf type \NC \bf explanation \NC\NR
-\NC width \NC number \NC \NC\NR
-\NC stretch \NC number \NC \NC\NR
-\NC stretch_order \NC number \NC \NC\NR
-\NC shrink \NC number \NC \NC\NR
-\NC shrink_order \NC number \NC \NC\NR
-\NC writable \NC boolean \NC If this is true, you can't assign to this \type{glue_spec}
- because it is one of the preallocated special cases. New in 0.52\NC\NR
-\stoptabulate
-
-These objects are reference counted, so there is actually an extra
-read-only field named \type {ref_count} as well. This item type will likely
-disappear in the future, and the glue fields themselves will
-become part of the nodes referencing glue items.
-
-\subsubsection{attribute{\_}list and attribute items}
-
-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 \luatex{node} library, but
-for completeness, here is the low|-|level interface.
-
-An \type{attribute_list} item is used as a head pointer for a list
-of attribute items. It has only one user-visible field:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC next \NC \syntax{<node>} \NC pointer to the first attribute\NC\NR
-\stoptabulate
-
-A normal node's attribute field will point to an item of type
-\type{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.
-
-Valid fields in \type{attribute} items:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC next \NC \syntax{<node>} \NC pointer to the next attribute\NC\NR
-\NC number \NC number \NC the attribute type id\NC\NR
-\NC value \NC number \NC the attribute value\NC\NR
-\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.
-
-
-
-\subsubsection{action item}
-
-Valid fields: \showfields{action}\crlf
-Id: \showid{action}
-
-These are a special kind of item that only appears inside
-pdf start link objects.
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC action_type \NC number \NC \NC\NR
-\NC action_id \NC number or string \NC \NC\NR
-\NC named_id \NC number \NC \NC\NR
-\NC file \NC string \NC \NC\NR
-\NC new_window \NC number \NC \NC\NR
-\NC data \NC string \NC \NC\NR
-\NC ref_count \NC number \NC (read-only)\NC\NR
-\stoptabulate
-
-\subsection{Main text nodes}
-
-These are the nodes that comprise actual typesetting commands.
-
-A few fields are present in all nodes regardless of their type, these are:
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC next \NC \syntax{<node>} \NC The next node in a list, or nil\NC\NR
-\NC id \NC number \NC The node's type (\type{id}) number \NC\NR
-\NC subtype \NC number \NC The node \type{subtype} identifier\NC\NR
-\stoptabulate
-
-The \type{subtype} is sometimes just a stub entry. 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.
-
-
-\subsubsection{hlist nodes}
-
-Valid fields: \showfields{hlist}\crlf
-Id: \showid{hlist}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = unknown origin, 1 = created by
-linebreaking, 2 = explicit box command. (0.46.0),
-3 = paragraph indentation box, 4 = alignment column or row, 5 = alignment cell (0.62.0)\NC\NR
-\NC attr \NC \syntax{<node>} \NC The head of the associated attribute list \NC\NR
-\NC width \NC number \NC \NC\NR
-\NC height \NC number \NC \NC\NR
-\NC depth \NC number \NC \NC\NR
-\NC shift \NC number \NC a displacement perpendicular to the
- character progression direction \NC\NR
-\NC glue_order \NC number \NC a number in the range 0--4, indicating
- the glue order\NC\NR
-\NC glue_set \NC number \NC the calculated glue ratio\NC\NR
-\NC glue_sign \NC number \NC 0 = normal,1 = stretching,2 = shrinking \NC\NR
-\NC head \NC \syntax{<node>} \NC the first node of the body of this list\NC\NR
-\NC dir \NC string \NC the direction of this box. see~\in{}[dirnodes]\NC\NR
-\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 result.
-
-Note: the new field name \type{head} was introduced in 0.65 to replace
-the old name \type{list}. Use of the name \type{list} is now
-deprecated, but it will stay available until at least version 0.80.
-
-\subsubsection{vlist nodes}
-
-Valid fields: As for hlist, except that \quote{shift} is a displacement
-perpendicular to the line progression direction, and \quote{subtype} only
-has subtypes 0, 4, and 5.
-
-\subsubsection{rule nodes}
-
-Valid fields: \showfields{rule}\crlf
-Id: \showid{rule}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC unused\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC the width of the rule; the special value $-1073741824$
- is used for \quote{running} glue dimensions\NC\NR
-\NC height \NC number \NC the height of the rule (can be negative)\NC\NR
-\NC depth \NC number \NC the depth of the rule (can be negative)\NC\NR
-\NC dir \NC string \NC the direction of this rule. see~\in{}[dirnodes]\NC\NR
-\stoptabulate
-
-\subsubsection{ins nodes}
-
-Valid fields: \showfields{ins}\crlf
-Id: \showid{ins}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC the insertion class\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC cost \NC number \NC the penalty associated with this insert\NC\NR
-\NC height \NC number \NC \NC\NR
-\NC depth \NC number \NC \NC\NR
-\NC head \NC \syntax{<node>} \NC the first node of the body of this insert\NC\NR
-\NC spec \NC \syntax{<node>} \NC a pointer to the \tex{splittopskip} glue spec\NC\NR
-\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 result.
-
-Note: the new field name \type{head} was introduced in 0.65 to replace
-the old name \type{list}. Use of the name \type{list} is now
-deprecated, but it will stay available until at least version 0.80.
-
-
-\subsubsection{mark nodes}
-
-Valid fields: \showfields{mark}\crlf
-Id: \showid{mark}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC unused\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC class \NC number \NC the mark class\NC\NR
-\NC mark \NC table \NC a table representing a token list\NC\NR
-\stoptabulate
-
-\subsubsection{adjust nodes}
-
-Valid fields: \showfields{adjust}\crlf
-Id: \showid{adjust}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = normal, 1 = \quote{pre}\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC head \NC \syntax{<node>} \NC adjusted material\NC\NR
-\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 result.
-
-Note: the new field name \type{head} was introduced in 0.65 to replace
-the old name \type{list}. Use of the name \type{list} is now
-deprecated, but it will stay available until at least version 0.80.
-
-
-\subsubsection{disc nodes}
-
-Valid fields: \showfields{disc}\crlf
-Id: \showid{disc}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC indicates the source of a discretionary.
- 0 = the \tex{discretionary} command,
- 1 = the \tex{-} command,
- 2 = added automatically following a \type{-},
- 3 = added by the hyphenation algorithm (simple),
- 4 = added by the hyphenation algorithm (hard, first item),
- 5 = added by the hyphenation algorithm (hard, second item)\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC pre \NC \syntax{<node>} \NC pointer to the pre|-|break text\NC\NR
-\NC post \NC \syntax{<node>} \NC pointer to the post|-|break text\NC\NR
-\NC replace \NC \syntax{<node>} \NC pointer to the no|-|break text\NC\NR
-\stoptabulate
-
-The subtype numbers~4 and~5 belong to the \quote{of-f-ice} explanation given elsewhere.
-
-A warning: never assign a node list to the pre, post or replace field
-unless you are sure its internal link structure is correct, otherwise
-an error may be result.
-
-\subsubsection{math nodes}
-
-Valid fields: \showfields{math}\crlf
-Id: \showid{math}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = \quote{on}, 1 = \quote{off}\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC surround \NC number \NC width of the \tex{mathsurround} kern\NC\NR
-\stoptabulate
-
-\subsubsection{glue nodes}
-
-Valid fields: \showfields{glue}\crlf
-Id: \showid{glue}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = \tex{skip},
- 1--18 = internal glue parameters,
- 100-103 = \quote{leader} subtypes \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC spec \NC \syntax{<node>} \NC pointer to a glue{\_}spec item \NC\NR
-\NC leader \NC \syntax{<node>} \NC pointer to a box or rule for leaders\NC\NR
-\stoptabulate
-
-The exact meanings of the subtypes are as follows:
-
-\starttabulate[|rT|l|]
-\NC 1 \NC \tex{lineskip} \NC \NR
-\NC 2 \NC \tex{baselineskip} \NC \NR
-\NC 3 \NC \tex{parskip} \NC \NR
-\NC 4 \NC \tex{abovedisplayskip} \NC \NR
-\NC 5 \NC \tex{belowdisplayskip} \NC \NR
-\NC 6 \NC \tex{abovedisplayshortskip} \NC \NR
-\NC 7 \NC \tex{belowdisplayshortskip} \NC \NR
-\NC 8 \NC \tex{leftskip} \NC \NR
-\NC 9 \NC \tex{rightskip} \NC \NR
-\NC 10 \NC \tex{topskip} \NC \NR
-\NC 11 \NC \tex{splittopskip} \NC \NR
-\NC 12 \NC \tex{tabskip} \NC \NR
-\NC 13 \NC \tex{spaceskip} \NC \NR
-\NC 14 \NC \tex{xspaceskip} \NC \NR
-\NC 15 \NC \tex{parfillskip} \NC \NR
-\NC 16 \NC \tex{thinmuskip} \NC \NR
-\NC 17 \NC \tex{medmuskip} \NC \NR
-\NC 18 \NC \tex{thickmuskip} \NC \NR
-\NC 100 \NC \tex{leaders} \NC \NR
-\NC 101 \NC \tex{cleaders} \NC \NR
-\NC 102 \NC \tex{xleaders} \NC \NR
-\NC 103 \NC \tex{gleaders} \NC \NR
-\stoptabulate
-
-\subsubsection{kern nodes}
-
-Valid fields: \showfields{kern}\crlf
-Id: \showid{kern}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = from font,
- 1 = from \tex{kern} or \tex{/},
- 2 = from \tex{accent}\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC kern \NC number \NC \NC\NR
-\stoptabulate
-
-
-\subsubsection{penalty nodes}
-
-Valid fields: \showfields{penalty}\crlf
-Id: \showid{penalty}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC not used\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC penalty \NC number \NC \NC\NR
-\stoptabulate
-
-\subsubsection[glyphnodes]{glyph nodes}
-
-Valid fields: \showfields{glyph}\crlf
-Id: \showid{glyph}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \ssbf type \NC \ssbf explanation \NC \NR
-\NC subtype \NC number \NC bitfield \NC \NR
-\NC attr \NC \syntax{<node>} \NC \NC \NR
-\NC char \NC number \NC \NC \NR
-\NC font \NC number \NC \NC \NR
-\NC lang \NC number \NC \NC \NR
-\NC left \NC number \NC \NC \NR
-\NC right \NC number \NC \NC \NR
-\NC uchyph \NC boolean \NC \NC \NR
-\NC components \NC \syntax{<node>} \NC pointer to ligature components \NC \NR
-\NC xoffset \NC number \NC \NC \NR
-\NC yoffset \NC number \NC \NC \NR
-\NC width \NC number \NC (new in 0.53) \NC \NR
-\NC height \NC number \NC (new in 0.53) \NC \NR
-\NC depth \NC number \NC (new in 0.53) \NC \NR
-\NC expansion_factor \NC number \NC (new in 0.78) \NC \NR
-\stoptabulate
-
-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|]
-\NC \ssbf bit \NC \bf meaning \NC\NR
-\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
-\stoptabulate
-
-See \in{section}[charsandglyphs] for a detailed description of the
-\type{subtype} field.
-
-The \type {expansion_factor} is relatively new and 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.
-
-\subsubsection{margin{\_}kern nodes}
-
-Valid fields: \showfields{margin_kern}\crlf
-Id: \showid{margin_kern}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 0 = left side,
- 1 = right side\NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC\NR
-\NC glyph \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsection{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 sub-nodes so
-that the list of possible fields is actually quite small. First, the subnodes:
-
-\subsubsection{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.
-
-\subsubsubsection{math{\_}char and math{\_}text{\_}char subnodes}
-
-Valid fields: \showfields{math_char}\crlf
-Id: \showid{math_char}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC char \NC number \NC \NC \NR
-\NC fam \NC number \NC \NC\NR
-\stoptabulate
-
-The \type{math_char} is the simplest subnode field, it contains
-the character and family for a single glyph object. The
-\type{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).
-
-\subsubsubsection{sub{\_}box and sub{\_}mlist subnodes}
-
-Valid fields: \showfields{sub_box}\crlf
-Id: \showid{sub_box}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC head \NC \syntax{<node>}\NC \NC \NR
-\stoptabulate
-
-These two subnode types are used for subsidiary list items. For
-\type{sub_box}, the \type{head} points to a \quote{normal} vbox or
-hbox. For \type{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 may be result.
-
-Note: the new field name \type{head} was introduced in 0.65 to replace
-the old name \type{list}. Use of the name \type{list} is now
-deprecated, but it will stay available until at least version 0.80.
-
-\subsubsection{Math delimiter subnode}
-
-There is a fifth subnode type that is used exclusively for delimiter
-fields. As before, the \type{next} and \type{prev} fields are unused.
-
-\subsubsubsection{delim subnodes}
-
-Valid fields: \showfields{delim}\crlf
-Id: \showid{delim}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC small_char \NC number \NC \NC \NR
-\NC small_fam \NC number \NC \NC\NR
-\NC large_char \NC number \NC \NC \NR
-\NC large_fam \NC number \NC \NC\NR
-\stoptabulate
-
-The fields \type{large_char} and \type{large_fam} can be zero, in that
-case the font that is sed for the \type{small_fam} is expected to
-provide the large version as an extension to the \type{small_char}.
-
-\subsubsection{Math core nodes}
-
-First, there are the objects (the \TEX book calls then \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.
-
-\subsubsubsection{simple nodes}
-
-Valid fields: \showfields{noad}\crlf
-Id: \showid{noad}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC see below \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC nucleus \NC \syntax{<kernel>}\NC \NC\NR
-\NC sub \NC \syntax{<kernel>}\NC \NC\NR
-\NC sup \NC \syntax{<kernel>}\NC \NC\NR
-\stoptabulate
-
-Operators are a bit special because they occupy three subtypes.
-\type{subtype}.
-
-\starttabulate[|lT|p|]
-\NC \ssbf number \NC \bf node sub type \NC\NR
-\NC 0 \NC Ord \NC\NR
-\NC 1 \NC Op, \type{\displaylimits} \NC\NR
-\NC 2 \NC Op, \type{\limits} \NC\NR
-\NC 3 \NC Op, \type{\nolimits} \NC\NR
-\NC 4 \NC Bin \NC\NR
-\NC 5 \NC Rel \NC\NR
-\NC 6 \NC Open \NC\NR
-\NC 7 \NC Close \NC\NR
-\NC 8 \NC Punct \NC\NR
-\NC 9 \NC Inner \NC\NR
-\NC 10 \NC Under \NC\NR
-\NC 11 \NC Over \NC\NR
-\NC 12 \NC Vcent \NC\NR
-\stoptabulate
-
-\subsubsubsection{accent nodes}
-
-Valid fields: \showfields{accent}\crlf
-Id: \showid{accent}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC the first bit is used for a fixed top accent flag (if the \type{accent} field is present),
- the second bit for a fixed bottom accent flag (if the \type{bot_accent} field is present).
- Example: the actual value \type{3} means: do not stretch either accent\NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC nucleus \NC \syntax{<kernel>}\NC \NC \NR
-\NC sub \NC \syntax{<kernel>}\NC \NC\NR
-\NC sup \NC \syntax{<kernel>}\NC \NC \NR
-\NC accent \NC \syntax{<kernel>}\NC \NC\NR
-\NC bot_accent \NC \syntax{<kernel>}\NC \NC\NR
-\stoptabulate
-
-\subsubsubsection{style nodes}
-
-Valid fields: \showfields{style}\crlf
-Id: \showid{style}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC style \NC string \NC contains the style \NC\NR
-\stoptabulate
-
-There are eight possibilities for the string value: one of
-\quote{display}, \quote{text}, \quote{script}, or \quote{scriptscript}.
-Each of these can have a trailing \type{'} to signify
-\quote{cramped} styles.
-
-\subsubsubsection{choice nodes}
-
-Valid fields: \showfields{choice}\crlf
-Id: \showid{choice}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC display \NC \syntax{<node>}\NC \NC\NR
-\NC text \NC \syntax{<node>}\NC \NC\NR
-\NC script \NC \syntax{<node>}\NC \NC\NR
-\NC scriptscript \NC \syntax{<node>}\NC \NC\NR
-\stoptabulate
-
-A warning: never assign a node list to the display, text, script, or
-scriptscript field unless you are sure its internal link structure is
-correct, otherwise an error may be result.
-
-\subsubsubsection{radical nodes}
-
-Valid fields: \showfields{radical}\crlf
-Id: \showid{radical}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC nucleus \NC \syntax{<kernel>}\NC \NC \NR
-\NC sub \NC \syntax{<kernel>}\NC \NC\NR
-\NC sup \NC \syntax{<kernel>}\NC \NC \NR
-\NC left \NC \syntax{<delim>}\NC \NC \NR
-\NC degree \NC \syntax{<kernel>}\NC Only set by \type{\Uroot} \NC \NR
-\stoptabulate
-
-A warning: never assign a node list to the nucleus, sub, sup, left, or
-degree field
-unless you are sure its internal link structure is correct, otherwise
-an error may be result.
-
-\subsubsubsection{fraction nodes}
-
-Valid fields: \showfields{fraction}\crlf
-Id: \showid{fraction}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC num \NC \syntax{<kernel>}\NC \NC\NR
-\NC denom \NC \syntax{<kernel>}\NC \NC \NR
-\NC left \NC \syntax{<delim>}\NC \NC \NR
-\NC right \NC \syntax{<delim>}\NC \NC \NR
-\stoptabulate
-
-A warning: never assign a node list to the num, or denom field
-unless you are sure its internal link structure is correct, otherwise
-an error may be result.
-
-\subsubsubsection{fence nodes}
-
-Valid fields: \showfields{fence}\crlf
-Id: \showid{fence}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC subtype \NC number \NC 1 = \type{\left},
- 2 = \type{\middle},
- 3 = \type{\right} \NC\NR
-\NC attr \NC \syntax{<node>}\NC \NC\NR
-\NC delim \NC \syntax{<delim>}\NC \NC \NR
-\stoptabulate
-
-\subsection{whatsit nodes}
-
-Whatsit nodes come in many subtypes that you can ask for by running
-\luatex{node.whatsits()}:
-\ctxlua {for n,name in table.sortedpairs(node.whatsits()) do
- if (n<100) then
- if (n>0) then tex.sprint (', ') end
- tex.sprint('\\type{' .. name .. '} (' .. n .. ')') end
-end }
-
-\subsubsection{open nodes}
-
-Valid fields: \showfields{whatsit,open}\crlf
-Id: \showid{whatsit,open}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC stream \NC number \NC \TEX's stream id number\NC\NR
-\NC name \NC string \NC file name \NC\NR
-\NC ext \NC string \NC file extension \NC\NR
-\NC area \NC string \NC file area (this may become obsolete) \NC\NR
-\stoptabulate
-
-\subsubsection{write nodes}
-
-Valid fields: \showfields{whatsit,write}\crlf
-Id: \showid{whatsit,write}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC stream \NC number \NC \TEX's stream id number\NC\NR
-\NC data \NC table \NC a table representing the token list to be written\NC\NR
-\stoptabulate
-
-\subsubsection{close nodes}
-
-Valid fields: \showfields{whatsit,close}\crlf
-Id: \showid{whatsit,close}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC stream \NC number \NC \TEX's stream id number\NC\NR
-\stoptabulate
-
-\subsubsection{special nodes}
-
-Valid fields: \showfields{whatsit,special}\crlf
-Id: \showid{whatsit,special}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC data \NC string \NC the \tex{special} information\NC\NR
-\stoptabulate
-
-\subsubsection{language nodes}
-
-
-\LUATEX\ does not have language whatsits any more. All language
-information is already present inside the glyph nodes themselves.
-This whatsit subtype will be removed in the next release.
-
-
-\subsubsection{local_par nodes}
-
-Valid fields: \showfields{whatsit,local_par}\crlf
-Id: \showid{whatsit,local_par}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC pen_inter \NC number \NC local interline penalty (from \tex{localinterlinepenalty})\NC\NR
-\NC pen_broken\NC number \NC local broken penalty (from \tex{localbrokenpenalty})\NC\NR
-\NC dir \NC string \NC the direction of this par. see~\in{}[dirnodes]\NC\NR
-\NC box_left \NC \syntax{<node>} \NC the \tex{localleftbox}\NC\NR
-\NC box_left_width\NC number\NC width of the \tex{localleftbox}\NC\NR
-\NC box_right \NC \syntax{<node>} \NC the \tex{localrightbox}\NC\NR
-\NC box_right_width\NC number\NC width of the \tex{localrightbox}\NC\NR
-\stoptabulate
-
-A warning: never assign a node list to the box_left or box_right field
-unless you are sure its internal link structure is correct, otherwise
-an error may be result.
-
-
-
-
-\subsubsection[dirnodes]{dir nodes}
-
-Valid fields: \showfields{whatsit,dir}\crlf
-Id: \showid{whatsit,dir}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC dir \NC string \NC the direction (but see below)\NC\NR
-\NC level \NC number \NC nesting level of this direction whatsit\NC\NR
-\NC dvi_ptr \NC number \NC a saved dvi buffer byte offset\NC\NR
-\NC dir_h \NC number \NC a saved dvi position\NC\NR
-\stoptabulate
-
-A note on \type{dir} strings. 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
-\item the first is the direction of the \quote{top} of paragraphs.
-\item the second is the direction of the \quote{start} of lines.
-\item the third is the direction of the \quote{top} of glyphs.
-\stopitemize
-
-However, only four combinations are accepted: \type{TLT}, \type{TRT},
-\type{RTT}, and \type{LTL}.
-
-Inside actual \type{dir} whatsit nodes, the representation of
-\type{dir} is not a three-letter but a four-letter combination. The
-first character in this case is always either \type{+} or \type{-},
-indicating whether the value is pushed or popped from the direction
-stack.
-
-\subsubsection{pdf_literal nodes}
-
-Valid fields: \showfields{whatsit,pdf_literal}\crlf
-Id: \showid{whatsit,pdf_literal}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC mode \NC number \NC the \quote{mode} setting of this literal\NC\NR
-\NC data \NC string \NC the \tex{pdfliteral} information\NC\NR
-\stoptabulate
-
-Mode values:
-
-\starttabulate[|lT|p|]
-\NC \ssbf value \NC \ssbf corresponding \tex{pdftex} keyword \NC \NR
-\NC 0 \NC setorigin \NC \NR
-\NC 1 \NC page \NC \NR
-\NC 2 \NC direct \NC \NR
-\stoptabulate
-
-\subsubsection{pdf_refobj nodes}
-
-Valid fields: \showfields{whatsit,pdf_refobj}\crlf
-Id: \showid{whatsit,pdf_refobj}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC objnum \NC number \NC the referenced \PDF\ object number\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_refxform nodes}
-
-Valid fields: \showfields{whatsit,pdf_refxform}\crlf
-Id: \showid{whatsit,pdf_refxform}.
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC objnum \NC number \NC the referenced \PDF\ object number\NC\NR
-\stoptabulate
-
-Be aware that \type{pdf_refxform} nodes have dimensions that are used by \LUATEX.
-
-\subsubsection{pdf_refximage nodes}
-
-Valid fields: \showfields{whatsit,pdf_refximage}\crlf
-Id: \showid{whatsit,pdf_refximage}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC objnum \NC number \NC the referenced \PDF\ object number\NC\NR
-\stoptabulate
-
-Be aware that \type{pdf_refximage} nodes have dimensions that are used by \LUATEX.
-
-\subsubsection{pdf_annot nodes}
-
-Valid fields: \showfields{whatsit,pdf_annot}\crlf
-Id: \showid{whatsit,pdf_annot}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC objnum \NC number \NC the referenced \PDF\ object number\NC\NR
-\NC data \NC string \NC the annotation data\NC\NR
-\stoptabulate
-
-
-\subsubsection{pdf_start_link nodes}
-
-Valid fields: \showfields{whatsit,pdf_start_link}\crlf
-Id: \showid{whatsit,pdf_start_link}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC objnum \NC number \NC the referenced \PDF\ object number\NC\NR
-\NC link_attr \NC table \NC the link attribute token list\NC\NR
-\NC action \NC \syntax{<node>} \NC the action to perform\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_end_link nodes}
-
-Valid fields: \showfields{whatsit,pdf_end_link}\crlf
-Id: \showid{whatsit,pdf_end_link}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsubsection{pdf_dest nodes}
-
-Valid fields: \showfields{whatsit,pdf_dest}\crlf
-Id: \showid{whatsit,pdf_dest}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC named_id \NC number \NC is the dest_id a string value?\NC\NR
-\NC dest_id \NC number or string \NC the destination id\NC\NR
-\NC dest_type \NC number\NC type of destination\NC\NR
-\NC xyz_zoom \NC number\NC \NC\NR
-\NC objnum \NC number \NC the \PDF\ object number\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_thread nodes}
-
-Valid fields: \showfields{whatsit,pdf_thread}\crlf
-Id: \showid{whatsit,pdf_thread}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC named_id \NC number \NC is the tread_id a string value?\NC\NR
-\NC tread_id \NC number or string \NC the thread id\NC\NR
-\NC thread_attr\NC number \NC extra thread information\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_start_thread nodes}
-
-Valid fields: \showfields{whatsit,pdf_start_thread}\crlf
-Id: \showid{whatsit,pdf_start_thread}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC width \NC number \NC \NC \NR
-\NC height \NC number \NC \NC \NR
-\NC depth \NC number \NC \NC \NR
-\NC named_id \NC number \NC is the tread_id a string value?\NC\NR
-\NC tread_id \NC number or string \NC the thread id\NC\NR
-\NC thread_attr\NC number \NC extra thread information\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_end_thread nodes}
-
-Valid fields: \showfields{whatsit,pdf_end_thread}\crlf
-Id: \showid{whatsit,pdf_end_thread}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsubsection{pdf_save_pos nodes}
-
-Valid fields: \showfields{whatsit,pdf_save_pos}\crlf
-Id: \showid{whatsit,pdf_save_pos}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsubsection{late_lua nodes}
-
-Valid fields: \showfields{whatsit,late_lua}\crlf
-Id: \showid{whatsit,late_lua}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC data \NC string \NC data to execute\NC\NR
-\NC string \NC string \NC data to execute (0.63)\NC\NR
-\NC name \NC string \NC the name to use for lua error reporting\NC\NR
-\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
-\tex{latelua}. The \type{string} version is treated as a literal string.
-
-\subsubsection{pdf_colorstack nodes}
-
-Valid fields: \showfields{whatsit,pdf_colorstack}\crlf
-Id: \showid{whatsit,pdf_colorstack}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC stack \NC number \NC colorstack id number\NC\NR
-\NC cmd \NC number \NC command to execute\NC\NR
-\NC data \NC string \NC data\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_setmatrix nodes}
-
-Valid fields: \showfields{whatsit,pdf_setmatrix}\crlf
-Id: \showid{whatsit,pdf_setmatrix}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC data \NC string \NC data\NC\NR
-\stoptabulate
-
-\subsubsection{pdf_save nodes}
-
-Valid fields: \showfields{whatsit,pdf_save}\crlf
-Id: \showid{whatsit,pdf_save}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsubsection{pdf_restore nodes}
-
-Valid fields: \showfields{whatsit,pdf_restore}\crlf
-Id: \showid{whatsit,pdf_restore}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\stoptabulate
-
-\subsubsection{user_defined nodes}
-
-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.
-
-Valid fields: \showfields{whatsit,user_defined}\crlf
-Id: \showid{whatsit,user_defined}
-
-\starttabulate[|lT|l|p|]
-\NC \ssbf field \NC \bf type \NC \bf explanation \NC\NR
-\NC attr \NC \syntax{<node>} \NC \NC\NR
-\NC user_id \NC number \NC id number\NC\NR
-\NC type \NC number \NC type of the value\NC\NR
-\NC value \NC number \NC \NC\NR
-\NC \NC string \NC \NC\NR
-\NC \NC \syntax{<node>} \NC \NC\NR
-\NC \NC table \NC \NC\NR
-\stoptabulate
-
-The \type{type} can have one of five distinct values:
-
-\starttabulate[|lT|p|]
-\NC \ssbf value \NC \bf explanation \NC\NR
-\NC 97 \NC the value is an attribute node list \NC\NR
-\NC 100 \NC the value is a number \NC\NR
-\NC 110 \NC the value is a node list \NC\NR
-\NC 115 \NC the value is a string\NC\NR
-\NC 116 \NC the value is a token list in \LUA\ table form\NC\NR
-\stoptabulate
-
-\section{Two access models}
-
-After doing lots of tests with \LUATEX\ and \LUAJITTEX\, with and without just in
-time compilation enabled, and with and without using ffi, we came to the
-conclusion that userdata prevents a speedup. We also found that the checking of
-metatables as well as assignment comes with overhead that can't be neglected.
-This is normally not really a problem but when processing fonts for more complex
-scripts it could have quite some overhead.
-
-Because the userdata approach has some benefits, this remains the recommended way
-to access nodes. We did several experiments with faster access using this model,
-but eventually settled for the \quote {direct} approach. For code that is proven
-to be okay, one can use this access model that operates on nodes more directly.
-
-Deep down in \TEX\ a node has a number which is an 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. No matter what
-future memory model \LUATEX\ has, an internal reference will always be a simple data
-type (like a number or light userdata in \LUA\ speak). So, if you use the direct
-model, even if you know that you currently deal with numbers, you should not depend
-on that property but treat it 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 our advice is: use the indexed approach when possible and investigate the
-direct one when speed might be an issue. For that reason we 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
-we're accessing nodes 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
-
-There are several such function based accessors now:
-
-\starttabulate[|T|p|]
-\NC getnext \NC parsing nodelist always involves this one \NC \NR
-\NC getprev \NC used less but is logical companion to getnext \NC \NR
-\NC getid \NC consulted a lot \NC \NR
-\NC getsubtype \NC consulted less but also a topper \NC \NR
-\NC getfont \NC used a lot in otf handling (glyph nodes are consulted a lot) \NC \NR
-\NC getchar \NC idem and also in other places \NC \NR
-\NC getlist \NC we often parse nested lists so this is a convenient one too
- (only works for hlist and vlist!) \NC \NR
-\NC 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 getfield \NC generic getter, sufficient for the rest (other field names are
- often shared so a specific getter makes no sense then) \NC \NR
-\stoptabulate
-
-It doesn't make sense to add more. Profiling demonstrated that these fields can
-get accesses way more times than other fields. Even in complex documents, many
-node and fields types never get seen, or seen only a few times. Most functions in the
-\type {node} namespace have a companion in \type {node.direct}, but of course not the
-ones that don't deal with nodes themselves. The following table summarized this:
-
-\start \def\yes{$+$} \def\nop{$-$}
-
-\starttabulate[|T|c|c|]
-\HL
-\NC \bf function \NC \bf node \NC \bf direct \NC \NR
-\HL
-\NC copy \NC \yes \NC \yes \NC \NR
-\NC copy_list \NC \yes \NC \yes \NC \NR
-\NC count \NC \yes \NC \yes \NC \NR
-\NC current_attr \NC \yes \NC \yes \NC \NR
-\NC dimensions \NC \yes \NC \yes \NC \NR
-\NC do_ligature_n \NC \yes \NC \yes \NC \NR
-\NC end_of_math \NC \yes \NC \yes \NC \NR
-\NC family_font \NC \yes \NC \nop \NC \NR
-\NC fields \NC \yes \NC \nop \NC \NR
-\NC first_character \NC \yes \NC \nop \NC \NR
-\NC first_glyph \NC \yes \NC \yes \NC \NR
-\NC flush_list \NC \yes \NC \yes \NC \NR
-\NC flush_node \NC \yes \NC \yes \NC \NR
-\NC free \NC \yes \NC \yes \NC \NR
-\NC getbox \NC \nop \NC \yes \NC \NR
-\NC getchar \NC \yes \NC \yes \NC \NR
-\NC getfield \NC \yes \NC \yes \NC \NR
-\NC getfont \NC \yes \NC \yes \NC \NR
-\NC getid \NC \yes \NC \yes \NC \NR
-\NC getnext \NC \yes \NC \yes \NC \NR
-\NC getprev \NC \yes \NC \yes \NC \NR
-\NC getlist \NC \yes \NC \yes \NC \NR
-\NC getleader \NC \yes \NC \yes \NC \NR
-\NC getsubtype \NC \yes \NC \yes \NC \NR
-\NC has_glyph \NC \yes \NC \yes \NC \NR
-\NC has_attribute \NC \yes \NC \yes \NC \NR
-\NC has_field \NC \yes \NC \yes \NC \NR
-\NC hpack \NC \yes \NC \yes \NC \NR
-\NC id \NC \yes \NC \nop \NC \NR
-\NC insert_after \NC \yes \NC \yes \NC \NR
-\NC insert_before \NC \yes \NC \yes \NC \NR
-\NC is_direct \NC \nop \NC \yes \NC \NR
-\NC is_node \NC \yes \NC \yes \NC \NR
-\NC kerning \NC \yes \NC \nop \NC \NR
-\NC last_node \NC \yes \NC \yes \NC \NR
-\NC length \NC \yes \NC \yes \NC \NR
-\NC ligaturing \NC \yes \NC \nop \NC \NR
-\NC mlist_to_hlist \NC \yes \NC \nop \NC \NR
-\NC new \NC \yes \NC \yes \NC \NR
-\NC next \NC \yes \NC \nop \NC \NR
-\NC prev \NC \yes \NC \nop \NC \NR
-\NC tostring \NC \yes \NC \yes \NC \NR
-\NC protect_glyphs \NC \yes \NC \yes \NC \NR
-\NC protrusion_skippable \NC \yes \NC \yes \NC \NR
-\NC remove \NC \yes \NC \yes \NC \NR
-\NC set_attribute \NC \yes \NC \yes \NC \NR
-\NC setbox \NC \yes \NC \yes \NC \NR
-\NC setfield \NC \yes \NC \yes \NC \NR
-\NC slide \NC \yes \NC \yes \NC \NR
-\NC subtype \NC \yes \NC \nop \NC \NR
-\NC tail \NC \yes \NC \yes \NC \NR
-\NC todirect \NC \yes \NC \yes \NC \NR
-\NC tonode \NC \yes \NC \yes \NC \NR
-\NC traverse \NC \yes \NC \yes \NC \NR
-\NC traverse_id \NC \yes \NC \yes \NC \NR
-\NC type \NC \yes \NC \nop \NC \NR
-\NC types \NC \yes \NC \nop \NC \NR
-\NC unprotect_glyphs \NC \yes \NC \yes \NC \NR
-\NC unset_attribute \NC \yes \NC \yes \NC \NR
-\NC usedlist \NC \yes \NC \yes \NC \NR
-\NC vpack \NC \yes \NC \yes \NC \NR
-\NC whatsits \NC \yes \NC \nop \NC \NR
-\NC write \NC \yes \NC \yes \NC \NR
-\stoptabulate
-
-\stop
-
-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.
-
-\chapter{Modifications}
-
-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.
-
-\section{Changes from \TEX\ 3.1415926}
-
-\startitemize
-
-\item The current code base is written in C, not Pascal web (as of \LUATEX~0.42.0).
-
-\item See~\in{chapter}[languages] for many small changes related to paragraph
- building, language handling, and hyphenation. Most important change:
- adding a brace group in the middle of a word (like in \type{of{}fice})
- does not prevent ligature creation.
-
-\item There is no pool file, all strings are embedded during compilation.
-
-\item \type {plus 1 fillll} does not generate an error. The extra \quote{l} is
-simply typeset.
-
-\item The upper limit to \tex{endlinechar} and \tex{newlinechar} is 127.
-
-\stopitemize
-
-\section{Changes from \ETEX\ 2.2}
-
-\startitemize
-
-\item The \ETEX\ functionality is always present and enabled
- (but see below about \TEXXET), so the prepended asterisk or
- \type{-etex} switch for \INITEX\ is not needed.
-
-\item \TEXXET\ is not present, so the primitives
-
-\starttyping
-\TeXXeTstate
-\beginR
-\beginL
-\endR
-\endL
-\stoptyping
-
-are missing.
-
-\item Some of the tracing information that is output by \ETEX's \tex{tracingassigns} and
- \tex{tracingrestores} is not there.
-
-\item Register management in \LUATEX\ uses the \ALEPH\ model, so the maximum value is 65535
- and the implementation uses a flat array instead of the mixed
- flat|\&|sparse model from \ETEX.
-
-\item \type{savinghyphcodes} is a no-op.
-See~\in{chapter}[languages] for details.
-
-\item 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}).
-
-
-\stopitemize
-
-\section{Changes from \PDFTEX\ 1.40}
-
-\startitemize
-
-\item 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 now gone
-are: \tex{pdfsnaprefpoint}, \tex{pdfsnapy}, and \tex{pdfsnapycomp}.
-
-\item The (experimental) support for specialized spacing around nodes
-has also been removed. The associated primitives that are now gone are:
-\tex{pdfadjustinterwordglue}, \tex{pdfprependkern}, and \tex{pdfappendkern},
-as well as the five supporting primitives \tex{knbscode}, \tex{stbscode},
-\tex{shbscode}, \tex{knbccode}, and \tex{knaccode}.
-
-\item A number of \quote{utility functions} is removed:
-
-\startcolumns[n=3]
-\starttyping
-\pdfelapsedtime
-\pdfescapehex
-\pdfescapename
-\pdfescapestring
-\pdffiledump
-\pdffilemoddate
-\pdffilesize
-\pdflastmatch
-\pdfmatch
-\pdfmdfivesum
-\pdfresettimer
-\pdfshellescape
-\pdfstrcmp
-\pdfunescapehex
-\stoptyping
-\stopcolumns
-
-\item The four primitives that were already marked obsolete in \PDFTEX~1.40
-have been removed since \LUATEX~0.42:
-
-\startcolumns[n=2]
-\starttyping
-\pdfoptionalwaysusepdfpagebox
-\pdfoptionpdfinclusionerrorlevel
-\pdfforcepagebox
-\pdfmovechars
-\stoptyping
-\stopcolumns
-
-
-\item A few other experimental primitives are also provided without the
- extra \luatex {pdf} prefix, so they can also be called like this:
-
-\startcolumns[n=3]
-\starttyping
-\primitive
-\ifprimitive
-\ifabsnum
-\ifabsdim
-\stoptyping
-\stopcolumns
-
-\item The \tex{pdftexversion} is set to 200.
-
-\item The PNG transparency fix from 1.40.6 is not applied
-(high-level support is pending)
-
-\item LFS (\PDF\ Files larger than 2GiB) support is not working yet.
-
-\item \LUATEX~0.45.0 introduces two extra token lists, \tex{pdfxformresources}
-and \tex{pdfxformattr}, as an alternative to \tex{pdfxform} keywords.
-
-\item As of \LUATEX~0.50.0 is no longer possible for fonts from embedded pdf files
- to be replaced by / merged with the document fonts of the enveloping
- pdf document. This regression may be temporary, depending on how the
- rewritten font backend will look after beta 0.60.
-
-
-\stopitemize
-
-\section{Changes from \ALEPH\ RC4}
-
-\startitemize
-
-\item Starting with \LUATEX\ 0.75.0, the extended 16-bit math primitives
- (\tex{omathcode} etc.~) have been removed.
-
-\item Starting with \LUATEX\ 0.63.0, OCP processing is no longer
- supported at all. As a consequence, the following primitives have
- been removed:
-
-\startcolumns[n=2]
-\starttyping
-\ocp
-\externalocp
-\ocplist
-\pushocplist
-\popocplist
-\clearocplists
-\addbeforeocplist
-\addafterocplist
-\removebeforeocplist
-\removeafterocplist
-\ocptracelevel
-\stoptyping
-\stopcolumns
-
-\item \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 (\LUATEX\ 0.45).
-
-\item The input translations from \ALEPH\ are not implemented, the
- related primitives are not available:
-
-\startcolumns[n=2]
-\starttyping
-\DefaultInputMode
-\noDefaultInputMode
-\noInputMode
-\InputMode
-\DefaultOutputMode
-\noDefaultOutputMode
-\noOutputMode
-\OutputMode
-\DefaultInputTranslation
-\noDefaultInputTranslation
-\noInputTranslation
-\InputTranslation
-\DefaultOutputTranslation
-\noDefaultOutputTranslation
-\noOutputTranslation
-\OutputTranslation
-\stoptyping
-\stopcolumns
-
-\item The \tex{hoffset} bug when \tex{pagedir TRT} is fixed,
-removing the need for an explicit fix to \tex{hoffset}
-
-\item A bug causing \tex{fam} to fail for family numbers above
- 15 is fixed.
-
-\item A fair amount of other minor bugs are fixed as well, most of these
-related to \tex{tracingcommands} output.
-
-\item The internal function \type{scan_dir()} has been renamed to
-\type{scan_direction()} to prevent a naming clash, and it now allows
-an optional space after the direction is completely parsed.
-
-\item The \type{^^} notation can come in five and six item repetitions also, to
-insert characters that do not fit in the BMP.
-
-\item Glues {\it immediately after} direction change commands are not
-legal breakpoints.
-
-\stopitemize
-
-\section{Changes from standard \WEBC}
-
-\startitemize
-
-\item There is no mltex
-
-\item There is no enctex
-
-\item The following commandline switches are silently ignored, even
-in non|-|\LUA\ mode:
-
-\starttyping
--8bit
--translate-file=TCXNAME
--mltex
--enc
--etex
-\stoptyping
-
-\item \tex{openout} whatsits are not written to the log file.
-
-\item Some of the so|-|called web2c extensions are hard to set up
- in non|-|\KPSE\ mode because texmf.cnf is not read: \type{shell-escape}
- is off (but that is not a problem because of \LUA's
- \lua{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 \lua{io.open}).
-
-\item The \quote{E} option does not do anything useful.
-
-\stopitemize
-
-\chapter{Implementation notes}
-
-\section{Primitives overlap}
-
-The primitives
-
-\starttabulate[|l|l|]
-\NC \tex{pdfpagewidth} \NC \tex{pagewidth} \NC \NR
-\NC \tex{pdfpageheight}\NC \tex{pageheight} \NC \NR
-\NC \tex{fontcharwd} \NC \tex{charwd} \NC \NR
-\NC \tex{fontcharht} \NC \tex{charht} \NC \NR
-\NC \tex{fontchardp} \NC \tex{chardp} \NC \NR
-\NC \tex{fontcharic} \NC \tex{charit} \NC \NR
-\stoptabulate
-
-are all aliases of each other.
-
-\section{Memory allocation}
-
-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}.
-
-The implementation of the growth of two arrays (via reallocation)
-introduces a potential pitfall: the memory arrays should never be used
-as the left hand side of a statement that can modify the array in
-question.
-
-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.
-
-\section{Sparse arrays}
-
-The \tex{mathcode}, \tex{delcode}, \tex{catcode},
-\tex{sfcode}, \tex{lccode} and \tex{uccode} tables are now
-sparse arrays that are implemented in~C. 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.
-
-The \tex{catcode}, \tex{sfcode}, \tex{lccode} and \tex{uccode} assignments
-do not yet show up when using the etex tracing routines \tex{tracingassigns}
-and \tex{tracingrestores} (code simply not written yet).
-
-A side|-|effect of the current implementation is that \tex{global} is
-now more expensive in terms of processing than non|-|global assignments.
-
-See \type{mathcodes.c} and \type{textcodes.c} if you are interested in
-the details.
-
-Also, the glyph ids within a font are now managed by means
-of a sparse array and glyph ids can go up to index $2^{21}-1$.
-
-\section{Simple single-character 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.
-
-\section{Compressed format}
-
-The format is passed through 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 I/O, so it should still be
-faster.
-
-\section{Binary file reading}
-
-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 C 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 I/O subsystem).
-
-\chapter{Known bugs and limitations, TODO}
-
-There used to be a lists of bugs and planned features below here, but that did not
-work out too well. There are lists of open bugs and feature requests in the tracker at
-\hyphenatedurl{http://tracker.luatex.org}.
-
-\stoptext