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diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-contents.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-contents.tex new file mode 100644 index 00000000000..6d06b3ef082 --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-contents.tex @@ -0,0 +1,20 @@ +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-contents + +\starttitle[title=Contents] + +\start + + \definecolor[maincolor][black] + + \placelist + [chapter,section,subsection] + [criterium=text] + +\stop + +\stoptitle + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-enhancements.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-enhancements.tex new file mode 100644 index 00000000000..35c27cfb601 --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-enhancements.tex @@ -0,0 +1,879 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-enhancements + +\startchapter[reference=enhancements,title={Basic \TEX\ enhancements}] + +\section{Introduction} + +From day one, \LUATEX\ has offered extra features compared to the superset of +\PDFTEX\ and \ALEPH. This has not been limited to the possibility to execute +\LUA\ code via \type {\directlua}, but \LUATEX\ also adds functionality via new +\TEX|-|side primitives or extensions to existing ones. + +When \LUATEX\ starts up in \quote {iniluatex} mode (\type {luatex -ini}), it +defines only the primitive commands known by \TEX82 and the one extra command +\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 \quote {Missing number} error), so +it may be needed to put these assignments before the above line: + +\starttyping +\catcode `\{=1 +\catcode `\}=2 +\stoptyping + +More fine|-|grained primitives control is possible and you can look up the +details in \in {section} [luaprimitives]. For simplicity's sake, this manual +assumes that you have executed the \type {\directlua} command as given above. + +The startup behaviour documented above is considered stable in the sense that +there will not be backward|-|incompatible changes any more. We have promoted some +rather generic \PDFTEX\ primitives to core \LUATEX\ ones, and the ones inherited +frome \ALEPH\ (\OMEGA) are also promoted. Effectively this means that we now only +have the \type {tex}, \type {etex} and \type {luatex} sets left. + +In \in {Chapter} [modifications] we discuss several primitives that are derived +from \PDFTEX\ and \ALEPH\ (\OMEGA). Here we stick to real new ones. In the +chapters on fonts and math we discuss a few more new ones. + +\section{Version information} + +\subsection {\type {\luatexbanner}, \type {\luatexversion} and \type {\luatexrevision}} + +There are three new primitives to test the version of \LUATEX: + +\starttabulate[|l|pl|pl|] +\NC \bf primitive \NC \bf explanation \NC \bf value \NC \NR +\NC \type {\luatexbanner} \NC the banner reported on the command line \NC \luatexbanner \NC \NR +\NC \type {\luatexversion} \NC a combination of major and minor number \NC \the\luatexversion \NC \NR +\NC \type {\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 \type {\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 \type {\luatexversion} modulo 100. +\stopitem +\startitem + The revision is the given by \type {\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 + +\subsection{\type {\formatname}} + +The \type {\formatname} syntax is identical to \type {\jobname}. In \INITEX, the +expansion is empty. Otherwise, the expansion is the value that \type {\jobname} had +during the \INITEX\ run that dumped the currently loaded format. You can use this +token list to provide your own version info. + +\section{\UNICODE\ text support} + +\subsection {Extended ranges} + +Text input and output is now considered to be \UNICODE\ text, so input characters +can use the full range of \UNICODE\ ($2^{20}+2^{16}-1 = \hbox{0x10FFFF}$). Later +chapters will talk of characters and glyphs. Although these are not +interchangeable, they are closely related. During typesetting, a character is +always converted to a suitable graphic representation of that character in a +specific font. However, while processing a list of to|-|be|-|typeset nodes, its +contents may still be seen as a character. Inside \LUATEX\ there is no clear +separation between the two concepts. Because the subtype of a glyph node can be +changed in \LUA\ it is up to the user: subtypes larger than 255 indicate that +font processing has happened. + +A few primitives are affected by this, all in a similar fashion: each of them has +to accommodate for a larger range of acceptable numbers. For instance, \type +{\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: \type {\char}, \type +{\lccode}, \type {\uccode}, \type {\catcode}, \type {\sfcode}, \type {\efcode}, +\type {\lpcode}, \type {\rpcode}, \type {\chardef}. + +As far as the core engine is concerned, all input and output to text files is +\UTF-8 encoded. Input files can be pre|-|processed using the \type {reader} +callback. This will be explained in 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. You can disable +escaping with \type {texio.setescape(false)} in which case you get the normal +characters on the console. + +Normalization of the \UNICODE\ input can be handled by a macro package during +callback processing (this will be explained in \in {section} [iocallback]). + +\subsection{\type {\Uchar}} + +The expandable command \type {\Uchar} reads a number between~0 and $1{,}114{,}111$ +and expands to the associated \UNICODE\ character. + +\section{Extended tables} + +All traditional \TEX\ and \ETEX\ registers can be 16-bit numbers. The affected +commands are: + +\startfourcolumns +\starttyping +\count +\dimen +\skip +\muskip +\marks +\toks +\countdef +\dimendef +\skipdef +\muskipdef +\toksdef +\insert +\box +\unhbox +\unvbox +\copy +\unhcopy +\unvcopy +\wd +\ht +\dp +\setbox +\vsplit +\stoptyping +\stopfourcolumns + +Because font memory management has been rewritten, character properties in fonts +are no longer shared among fonts instances that originate from the same metric +file. + +\section{Attributes} + +\subsection{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 +\type {\the} etc.\ just like the normal \type {\count} registers. + +\startsyntax +\attribute <16-bit number> <optional equals> <32-bit number>!crlf +\attributedef <csname> <optional equals> <16-bit number> +\stopsyntax + +Conceptually, an attribute is either \quote {set} or \quote {unset}. Unset +attributes have a special negative value to indicate that they are unset, that +value is the lowest legal value: \type {-"7FFFFFFF} in hexadecimal, a.k.a. +$-2147483647$ in decimal. It follows that the value \type {-"7FFFFFFF} cannot be +used as a legal attribute value, but you {\it can\/} assign \type {-"7FFFFFFF} to +\quote {unset} an attribute. All attributes start out in this \quote {unset} +state in \INITEX. + +Attributes can be used as extra counter values, but their usefulness comes mostly +from the fact that the numbers and values of all \quote {set} attributes are +attached to all nodes created in their scope. These can then be queried from any +\LUA\ code that deals with node processing. Further information about how to use +attributes for node list processing from \LUA\ is given in~\in {chapter}[nodes]. + +Attributes are stored in a sorted (sparse) linked list that are shared when +possible. This permits efficient testing and updating. + +\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 \type {\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} + +\subsection{\type {\directlua}} + +In order to merge \LUA\ code with \TEX\ input, a few new primitives are needed. +The primitive \type {\directlua} is used to execute \LUA\ code immediately. The +syntax is + +\startsyntax +\directlua <general text>!crlf +\directlua <16-bit number> <general text> +\stopsyntax + +The \syntax {<general text>} is expanded fully, and then fed into the \LUA\ +interpreter. After reading and expansion has been applied to the \syntax +{<general text>}, the resulting token list is converted to a string as if it was +displayed using \type {\the\toks}. On the \LUA\ side, each \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. + +Likewise, the \syntax {<16-bit number>} designates a name of a \LUA\ chunk and is +taken from the \type {lua.name} array (see the documentation of the \type {lua} +table further in this manual). When a chunk name starts with a \type {@} it will +be displayed as a file name. This is a side effect of the way \LUA\ implements +error handling. + +The \type {\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 \type {\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 \type {\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 behaviour documented in the above subsection is considered stable in the sense +that there will not be backward-incompatible changes any more. + +\subsection{\type {\latelua}} + +Contrary to \type {\directlua}, \type {\latelua} stores \LUA\ code in a whatsit +that will be processed at the time of shipping out. Its intended use is a cross +between \PDF\ literals (often available as \type {\pdfliteral}) and the +traditional \TEX\ extension \type {\write}. Within the \LUA\ code you can print +\PDF\ statements directly to the \PDF\ file via \type {pdf.print}, or you can +write to other output streams via \type {texio.write} or simply using \LUA\ \IO\ +routines. + +\startsyntax +\latelua <general text>!crlf +\latelua <16-bit number> <general text> +\stopsyntax + +Expansion of macros in the final \type {<general text>} is delayed until just +before the whatsit is executed (like in \type {\write}). With regard to \PDF\ +output stream \type {\latelua} behaves as \PDF\ page literals. The \syntax +{name <general text>} and \syntax {<16-bit number>} behave in the same way as +they do for \type {\directlua} + +\subsection{\type {\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 + +\subsection{\type {\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 of +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 the following example the number \type {8} gets typeset. + +\starttyping +\directlua { + local t = lua.get_functions_table() + t[8] = function(slot) tex.print(slot) end +} +\stoptyping + +\section {Alignments} + +\subsection{\tex {alignmark}} + +This primitive duplicates the functionality of \type {#} inside alignment +preambles. + +\subsection{\tex {aligntab}} + +This primitive duplicates the functionality of \type {&} inside alignments and +preambles. + +\section{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. This subsystem is backward compatible: if you never use the +following commands, your document will not notice any difference in behaviour +compared to traditional \TEX. The contents of each catcode table is independent +from any other catcode tables, and their contents is stored and retrieved from +the format file. + +\subsection{\type {\catcodetable}} + +\startsyntax +\catcodetable <15-bit number> +\stopsyntax + +The primitive \type {\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. + +\subsection{\type {\initcatcodetable}} + +\startsyntax +\initcatcodetable <15-bit number> +\stopsyntax + +The primitive \type {\initcatcodetable} creates a new table with catcodes identical +to those defined by \INITEX: + +\starttabulate[|r|l|l|l|] +\NC 0 \NC \tttf \letterbackslash \NC \NC \type {escape} \NC\NR +\NC 5 \NC \tttf \letterhat\letterhat M \NC return \NC \type {car_ret} \NC\NR +\NC 9 \NC \tttf \letterhat\letterhat @ \NC null \NC \type {ignore} \NC\NR +\NC 10 \NC \tttf <space> \NC space \NC \type {spacer} \NC\NR +\NC 11 \NC {\tttf a} \endash\ {\tttf z} \NC \NC \type {letter} \NC\NR +\NC 11 \NC {\tttf A} \endash\ {\tttf Z} \NC \NC \type {letter} \NC\NR +\NC 12 \NC everything else \NC \NC \type {other} \NC\NR +\NC 14 \NC \tttf \letterpercent \NC \NC \type {comment} \NC\NR +\NC 15 \NC \tttf \letterhat\letterhat ? \NC delete \NC \type {invalid_char} \NC\NR +\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. + +\subsection{\type {\savecatcodetable}} + +\startsyntax +\savecatcodetable <15-bit number> +\stopsyntax + +\type {\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. + +\section{Suppressing errors} + +\subsection{\type {\suppressfontnotfounderror}} + +\startsyntax +\suppressfontnotfounderror = 1 +\stopsyntax + +If this integer parameter is non|-|zero, then \LUATEX\ will not complain about +font metrics that are not found. Instead it will silently skip the font +assignment, making the requested csname for the font \type {\ifx} equal to \type +{\nullfont}, so that it can be tested against that without bothering the user. + +\subsection{\type {\suppresslongerror}} + +\startsyntax +\suppresslongerror = 1 +\stopsyntax + +If this 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{\type {\suppressifcsnameerror}} + +\startsyntax +\suppressifcsnameerror = 1 +\stopsyntax + +If this 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. If the input expansion is unbalanced with respect +to \type {\csname} \ldots \type {\endcsname} pairs, the \LUATEX\ process may hang +indefinitely. + +\subsection{\type {\suppressoutererror}} + +\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. + +\subsection{\type {\suppressmathparerror}} + +The following setting will permit \type {\par} tokens in a math formula: + +\startsyntax +\suppressmathparerror = 1 +\stopsyntax + +So, the next code is valid then: + +\starttyping +$ x + 1 = + +a $ +\stoptyping + +\section {Math} + +\subsection{Extensions} + +We will cover math in its own chapter because not only the font subsystem and +spacing model have been enhanced (thereby introducing many new primitives) but +also because some more control has been added to existing functionality. + +\subsection{\type {\matheqnogapstep}} + +By default \TEX\ will add one quad between the equation and the number. This is +hard coded. A new primitive can control this: + +\startsyntax +\matheqnogapstep = 1000 +\stopsyntax + +Because a math quad from the math text font is used instead of a dimension, we +use a step to control the size. A value of zero will suppress the gap. The step +is divided by 1000 which is the usual way to mimmick floating point factors in +\TEX. + +\section{Fonts} + +\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{\type {\fontid}} + +\startsyntax +\fontid\font +\stopsyntax + +This primitive expands into a number. It is not a register so there is no need to +prefix with \type {\number} (and using \type {\the} gives an error). The currently +used font id is \fontid\font. Here are some more: + +\starttabulate[|l|c|] +\NC \type {\bf} \NC \bf \fontid\font \NC \NR +\NC \type {\it} \NC \it \fontid\font \NC \NR +\NC \type {\bi} \NC \bi \fontid\font \NC \NR +\stoptabulate + +These numbers depend on the macro package used because each one has its own way +of dealing with fonts. They can also differ per run, as they can depend on the +order of loading fonts. For instance, when in \CONTEXT\ virtual math \UNICODE\ +fonts are used, we can easily get over a hundred ids in use. Not all ids have to +be bound to a real font, after all it's just a number. + +\subsection{\type {\setfontid}} + +The primitive \type {\setfontid} can be used to enable a font with the given id +(which of course needs to be a valid one). + +\subsection{\type {\noligs} and \type {\nokerns}} + +These primitives prohibit ligature and kerning insertion at the time when the +initial node list is built by \LUATEX's main control loop. You can enable these +primitives when you want to do node list processing of \quote {characters}, where +\TEX's normal processing would get in the way. + +\startsyntax +\noligs <integer>!crlf +\nokerns <integer> +\stopsyntax + +These primitives can also be implemented by overloading the ligature building and +kerning functions, i.e.\ by assigning dummy functions to their associated +callbacks. Keep in mind that when you define a font (using \LUA) you can also +omit the kern and ligature tables, which has the same effect as the above. + +\subsection{\type{\nospaces}} + +This new primitive can be used to overrule the usual \type {\spaceskip} +related heuristics when a space character is seen in a text flow. The +value~\type{1} triggers no injection while \type{2} results in injection of +a zero skip. Below we see the results for four characters separated by a +space. + +\startlinecorrection +\startcombination[3*2] + {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 10mm}} + {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 10mm}} + {\ruledhbox to 5cm{\vtop{\hsize 10mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 10mm}} + {\ruledhbox to 5cm{\vtop{\hsize 1mm\nospaces=0\relax x x x x \par}\hss}} {\type {0 / hsize 1mm}} + {\ruledhbox to 5cm{\vtop{\hsize 1mm\nospaces=1\relax x x x x \par}\hss}} {\type {1 / hsize 1mm}} + {\ruledhbox to 5cm{\vtop{\hsize 1mm\nospaces=2\relax x x x x \par}\hss}} {\type {2 / hsize 1mm}} +\stopcombination +\stoplinecorrection + +\section{Tokens, commands and strings} + +\subsection{\type {\scantextokens}} + +The syntax of \type {\scantextokens} is identical to \type {\scantokens}. This +primitive is a slightly adapted version of \ETEX's \type {\scantokens}. The +differences are: + +\startitemize +\startitem + The last (and usually only) line does not have a \type {\endlinechar} + appended. +\stopitem +\startitem + \type {\scantextokens} never raises an EOF error, and it does not execute + \type {\everyeof} tokens. +\stopitem +\startitem + There are no \quote {\unknown\ while end of file \unknown} error tests + executed. This allows the expansion to end on a different grouping level or + while a conditional is still incomplete. +\stopitem +\stopitemize + +\subsection{\type {\toksapp}, \type {\tokspre}, \type {\etoksapp} and \type {\etokspre}} + +Instead of: + +\starttyping +\toks0\expandafter{\the\toks0 foo} +\stoptyping + +you can use: + +\starttyping +\etoksapp0{foo} +\stoptyping + +The \type {pre} variants prepend instead of append, and the \type {e} variants +expand the passed general text. + +\subsection{\type {\csstring}, \type {\begincsname} and \type {\lastnamedcs}} + +These are somewhat special. The \type {\csstring} primitive is like +\type {\string} but it omits the leading escape character. This can be +somewhat more efficient that stripping it of afterwards. + +The \type {\begincsname} primitive is like \type {\csname} but doesn't create +a relaxed equivalent when there is no such name. It is equivalent to + +\starttyping +\ifcsname foo\endcsname + \csname foo\endcsname +\fi +\stoptyping + +The advantage is that it saves a lookup (don't expect much speedup) but more +important is that it avoids using the \type {\if}. + +The \type {\lastnamedcs} is one that should be used with care. The above +example could be written as: + +\starttyping +\ifcsname foo\endcsname + \lastnamedcs +\fi +\stoptyping + +This is slightly more efficient than constructing the string twice (deep down in +\LUATEX\ this also involves some \UTF8 juggling), but probably more relevant is +that it saves a few tokens and can make code a bit more more readable. + +\subsection{\type {\clearmarks}} + +This primitive complements the \ETEX\ mark primitives and clears a mark class +completely, resetting all three connected mark texts to empty. It is an +immediate command. + +\startsyntax +\clearmarks <16-bit number> +\stopsyntax + +\subsection{\type{\letcharcode}} + +This primitive is still experimental but can be used to assign a meaning to an active +character, as in: + +\starttyping +\def\foo{bar} \letcharcode123\foo +\stoptyping + +This can be a bit nicer that using the uppercase tricks (using the property of +\type {\uppercase} that it treats active characters special). + +\section{Boxes, rules and leaders} + +\subsection{\type {\outputbox}} + +\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{\type {\vpack}, \type {\hpack} and \type {\tpack}} + +These three primitives are like \type {\vbox}, \type {\hbox} and \type {\vtop} +but don't apply the related callbacks. + +\subsection{Images and Forms} + +These two concepts are now core concepts and no longer whatsits. They are in fact +now implemented as rules with special properties. Normal rules have subtype~0, +saved boxes have subtype~1 and images have subtype~2. This has the positive side +effect that whenever we need to take content with dimensions into account, when we +look at rule nodes, we automatically also deal with these two types. + +The syntax of the \type {\save...resource} is the same as in \PDFTEX\ but you +should consider them to be backend specific. This means that a macro package +should treat them as such and check for the current output mode if applicable. +Here are the equivalents: + +\starttabulate[|l|l|] +\NC \type {\saveboxresource} \EQ \type {\pdfxform} \NC \NR +\NC \type {\saveimageresource} \EQ \type {\pdfximage} \NC \NR +\NC \type {\useboxresource} \EQ \type {\pdfrefxform} \NC \NR +\NC \type {\useimageresource} \EQ \type {\pdfrefximage} \NC \NR +\NC \type {\lastsavedboxresourceindex} \EQ \type {\pdflastxform} \NC \NR +\NC \type {\lastsavedimageresourceindex} \EQ \type {\pdflastximage} \NC \NR +\NC \type {\lastsavedimageresourcepages} \EQ \type {\pdflastximagepages} \NC \NR +\stoptabulate + +\LUATEX\ accepts optional dimension parameters for \type {\use...resource} in the +same format as for rules. With images, these dimensions are then used instead of +the ones given to \type {\useimageresource} but the original dimensions are not +overwritten, so that a \type {\useimageresource} without dimensions still +provides the image with dimensions defined by \type {\saveimageresource}. These +optional parameters are not implemented for \type {\saveboxresource}. + +\starttyping +\useimageresource width 20mm height 10mm depth 5mm \lastsavedimageresourceindex +\useboxresource width 20mm height 10mm depth 5mm \lastsavedboxresourceindex +\stoptyping + +\subsection{\type {\nohrule} and \type {\novrule}} + +Because introducing a new keyword can cause incompatibilities, two new primitives +were introduced: \type {\nohrule} and \type {\novrule}. These can be used to +reserve space. This is often more efficient than creating an empty box with fake +dimensions). + +\subsection{\type {\gleaders}} + +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\/}. The \type {g} stresses this global nature. + +\section {Languages} + +\subsection{\type {\hyphenationmin}} + +This primitive can be used to set the minimal word length, so setting it to a value +of~$5$ means that only words of 6 characters and more will be hyphenated, of course +within the constraints of the \type {\lefthyphenmin} and \type {\righthyphenmin} +values (as stored in the glyph node). This primitive accepts a number and stores +the value with the language. + +\subsection{\type {\boundary}, \type {\noboundary}, \type {\protrusionboundary} and \type +{\wordboundary}} + +The \type {\noboundary} commands used to inject a whatsit node but now injects a normal +node with type \type {boundary} and subtype~0. In addition you can say: + +\starttyping +x\boundary 123\relax y +\stoptyping + +This has the same effect but the subtype is now~1 and the value~123 is stored. +The traditional ligature builder still sees this as a cancel boundary directive +but at the \LUA\ end you can implement different behaviour. The added benefit of +passing this value is a side effect of the generalization. The subtypes~2 and~3 +are used to control protrusion and word boundaries in hyphenation. + +\section{Control and debugging} + +\subsection {Tracing} + +If \type {\tracingonline} is larger than~2, the node list display will also print +the node number of the nodes. + +\subsection{\type {\outputmode} and \type {\draftmode}} + +The \type {\outputmode} variable tells \LUATEX\ what it has to produce: + +\starttabulate[|l|l|] +\NC \type {0} \NC \DVI\ code \NC \NR +\NC \type {1} \NC \PDF\ code \NC \NR +\stoptabulate + +The value of the \type {\draftmode} counter signals the backend if it should +output less. The \PDF\ backend accepts a value of~$1$, while the \DVI\ backend +ignores the value. + +\section {Files} + +\subsection{File syntax} + +\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{Writing to file} + +You can now open upto 127 files with \type {\openout}. When no file is open +writes will go to the console and log. As a consequence a system command is +no longer possible but one can use \type {os.execute} to do the same. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-fonts.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-fonts.tex new file mode 100644 index 00000000000..7384f3b3ecc --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-fonts.tex @@ -0,0 +1,717 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-fonts + +\startchapter[reference=fonts,title={Font structure}] + +\section {The font tables} + +All \TEX\ fonts are represented to \LUA\ code as tables, and internally as +\CCODE~structures. All keys in the table below are saved in the internal font +structure if they are present in the table returned by the \type {define_font} +callback, or if they result from the normal \TFM|/|\VF\ reading routines if there +is no \type {define_font} callback defined. + +The column \quote {\VF} means that this key will be created by the \type +{font.read_vf()} routine, \quote {\TFM} means that the key will be created by the +\type {font.read_tfm()} routine, and \quote{used} means whether or not the +\LUATEX\ engine itself will do something with the key. + +The top|-|level keys in the table are as follows: + +\starttabulate[|Tl|c|c|c|l|p|] +\NC \rmbf key \NC \bf vf \NC \bf 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 indicates usage (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 \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 This is the \POSTSCRIPT\ fontname in the incoming font + source, and it's used as fontname identifier in the \PDF\ + output. \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 \type {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 \type {\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 \type {\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 the name of the font on disk \NC \NR +\NC tounicode \NC no \NC yes \NC yes \NC number \NC When this is set to~1 \LUATEX\ assumes per|-|glyph + tounicode entries are present in the font. \NC \NR +\NC stretch \NC no \NC no \NC yes \NC number \NC the \quote {stretch} value from \type + {\expandglyphsinfont} \NC \NR +\NC shrink \NC no \NC no \NC yes \NC number \NC the \quote {shrink} value from \type + {\expandglyphsinfont} \NC \NR +\NC step \NC no \NC no \NC yes \NC number \NC the \quote {step} value from \type + {\expandglyphsinfont} \NC \NR +\NC auto_expand \NC no \NC no \NC yes \NC boolean\NC the \quote {autoexpand} keyword from \crlf + \type {\expandglyphsinfont} \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 \type {\pdffontattr} \NC \NR +\NC cache \NC no \NC no \NC yes \NC string \NC This key controls caching of the \LUA\ table on the + \TEX\ end where \type {yes} means: use a reference to + the table that is passed to \LUATEX\ (this is the + default), and no \type {no} means: don't store the + table reference, don't cache any \LUA\ data for this + font while \type {renew} means: don't store the table + reference, but save a reference to the table that is + created at the first access to one of its fields in font. + 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. \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 entries for math|-|specific keys. \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. \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. \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 \type +{\expandglyphsinfont} 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 set font attributes in the \PDF\ file. The key +\type {used} is set by the engine when a font is actively in use, this makes sure +that the font's definition is written to the output file (\DVI\ or \PDF). The +\TFM\ reader sets it to false. The \type {direction} is a number signalling the +\quote {normal} direction for this font. There are sixteen possibilities: + +\starttabulate[|Tc|Tc|Tc|Tc|] +\NC \rmbf number \NC \rmbf meaning \NC \rmbf number \NC \rmbf 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. Keep in mind that +\LUATEX\ has a bit different directional model so these values are not used for +anything. + +The \type {parameters} is a hash with mixed key types. There are seven possible +string keys, as well as a number of integer indices (these start from 8 up). The +seven strings are actually used instead of the bottom seven indices, because that +gives a nicer user interface. + +The names and their internal remapping are: + +\starttabulate[|lT|c|] +\NC \rmbf name \NC \rmbf remapping \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 \type {cmr10 at 10pt}: + +\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 \rmbf key \NC \bf vf \NC \bf tfm \NC \bf used \NC \bf 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 \type {\lpcode} \NC\NR +\NC right_protruding \NC no \NC no \NC maybe \NC number \NC character's \type {\rpcode} \NC\NR +\NC expansion_factor \NC no \NC no \NC maybe \NC number \NC character's \type {\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 \type {\protrudechars} is non-zero. + +Whether or not \type {expansion_factor} is used depends on the font's global +expansion settings, as well as on the value of \type {\adjustspacing}. + +The usage of \type {tounicode} is this: if this font specifies a \type +{tounicode=1} at the top level, then \LUATEX\ will construct a \type {/ToUnicode} +entry for the \PDF\ font (or font subset) based on the character|-|level \type +{tounicode} strings, where they are available. If a character does not have a +sensible \UNICODE\ equivalent, do not provide a string either (no empty strings). + +If the font level \type {tounicode} is not set, then \LUATEX\ will build up \type +{/ToUnicode} based on the \TEX\ code points you used, and any character-level +\type {tounicodes} will be ignored. The string format is exactly the format that +is expected by Adobe \CMAP\ files (\UTF-16BE in hexadecimal encoding), minus the +enclosing angle brackets. For instance the \type {tounicode} for a \type {fi} +ligature would be \type {00660069}. When you pass a number the conversion will be +done for you. + +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 \rmbf key \NC \bf type \NC \bf description \NC\NR +\NC top \NC number \NC top character index \NC\NR +\NC mid \NC number \NC middle character index \NC\NR +\NC bot \NC number \NC bottom character index \NC\NR +\NC rep \NC number \NC 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 \rmbf 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 The maximum overlap at the starting side (in scaled points). \NC \NR +\NC end \NC number \NC The maximum overlap at the ending side (in scaled points). \NC \NR +\NC advance \NC number \NC The total advance width of this item. It can be zero or missing, + then the natural size of the glyph for character \type {component} + is used. \NC \NR +\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 \rmbf 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 \type{l + r =: n} \NC 0 \NC \type{=:} \NC \type{|n} \NC\NR +\NC \type{l + r =:| n} \NC 1 \NC \type{=:|} \NC \type{|nr} \NC\NR +\NC \type{l + r |=: n} \NC 2 \NC \type{|=:} \NC \type{|ln} \NC\NR +\NC \type{l + r |=:| n} \NC 3 \NC \type{|=:|} \NC \type{|lnr} \NC\NR +\NC \type{l + r =:|> n} \NC 5 \NC \type{=:|>} \NC \type{n|r} \NC\NR +\NC \type{l + r |=:> n} \NC 6 \NC \type{|=:>} \NC \type{l|n} \NC\NR +\NC \type{l + r |=:|> n} \NC 7 \NC \type{|=:|>} \NC \type{l|nr} \NC\NR +\NC \type{l + r |=:|>> n} \NC 11 \NC \type{|=:|>>} \NC \type{ln|r} \NC\NR +\stoptabulate + +The default value is~0, and can be left out. That signifies a \quote {normal} +ligature where the ligature replaces both original glyphs. In this table the~\type {|} +indicates the final insertion point. + +The \type {commands} array is explained below. + +\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} are: + +\starttabulate[|Tl|p|] +\NC \rmbf value \NC \rmbf 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] +\startitem + Whether the used font fits in an 8-bit encoding scheme or not. +\stopitem +\startitem + The type of the disk font file. +\stopitem +\startitem + The level of embedding requested. +\stopitem +\stopitemize + +A font that uses anything other than an 8-bit encoding vector has to be written +to the \PDF\ in a different way. + +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 behaviour might +silently be removed in the future, in which case the related primitives and \LUA\ +functions will become no|-|ops. + +If a \quote {wide} font is used, the new subsystem kicks in, and some +extra fields have to be present in the font structure. In this case, \LUATEX\ +does not use a map file at all. + +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 \rmbf value \NC \rmbf 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 \rmbf value \NC \rmbf 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 + +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} and use the table +indices as \type {index} fields. + +In order to make sure that cut and paste of the final document works okay you can +best make sure that there is a \type {tounicode} vector enforced. + +\section[virtualfonts]{Virtual fonts} + +\subsection{The structure} + +You have to take the following steps if you want \LUATEX\ to treat the returned +table from \type {define_font} as a virtual font: + +\startitemize[packed] +\startitem + Set the top|-|level key \type {type} to \type {virtual}. +\stopitem +\startitem + Make sure there is at least one valid entry in \type {fonts} (see below). +\stopitem +\startitem + Give a \type {commands} array to every character (see below). +\stopitem +\stopitemize + +The presence of the toplevel \type {type} key with the specific value \type +{virtual} will trigger handling of the rest of the special virtual font fields in +the table, but the mere existence of 'type' is enough to prevent \LUATEX\ from +looking for a virtual font on its own. + +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 \type {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 font id +\quote {38}. + +The array index numbers are used by the character command definitions that are +part of each character. + +The \type {commands} array is a hash where each item is another small array, +with the first entry representing a command and the extra items being the +parameters to that command. The allowed commands and their arguments are: + +\starttabulate[|Tl|l|l|p|] +\NC \rmbf command name \NC \bf arguments \NC \bf type \NC \bf description \NC\NR +\NC font \NC 1 \NC number \NC select a new font from the local \type {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 \type {\special} command\NC\NR +\NC lua \NC 1 \NC string \NC execute a \LUA\ script (at \type {\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 + +When a font id is set to~0 then it will be replaced by the currently assigned +font id. This prevents the need for hackery with future id's (normally one could +use \type {font.nextid} but when more complex fonts are built in the meantime +other instances could have been loaded. + +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 + +\section{The \type {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 \type {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 +\startitem + If it is positive, it specifies an \quote {at size} in scaled points. +\stopitem +\startitem + If it is negative, its absolute value represents a \quote {scaled} + setting relative to the designsize of the font. +\stopitem +\stopitemize + +The 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 \type {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 \type {font.fonts} by calling this function: + +\startfunctioncall +<number> i = + font.define(<table> f) +\stopfunctioncall + +The return value is the internal id number of the defined font (the index into +\type {font.fonts}). If the font creation fails, an error is raised. The table +is a font structure, 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} + +\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. + +\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. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-introduction.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-introduction.tex new file mode 100644 index 00000000000..8ab8b4463df --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-introduction.tex @@ -0,0 +1,121 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-introduction + +\startchapter[title=Introduction] + +This is the reference manual of \LUATEX. We don't claim it is complete and we +assume that the reader knows about \TEX\ as described in \quotation {The \TEX\ +Book}, the \quotation {\ETEX\ manual}, the \quotation {\PDFTEX\ manual}, etc. +Additional reference material is published in journals of user groups and +\CONTEXT\ related documentation. + +It took about a decade to reach stable version 1.0, but for good reason. +Successive versions brought new functionality, more control, some cleanup of +internals and experimental features evolved into stable ones or were dropped. +Already quite early \LUATEX\ could be used for production and it was used on a +daily basis by the authors. Successive versions sometimes demanded a adaption to +the \LUA\ interfacing, but the concepts were unchanged. The current version can +be considered stable in functionality and there will be no fundamental changes. +Of course we then can decide to move towards version 2.00 with different +properties. + +Don't expect \LUATEX\ to behave the same as \PDFTEX ! Although the core +functionality of that 8 bit engine was starting point, it has been combined with +the directional support of \OMEGA\ (\ALEPH). But, \LUATEX\ can behave different +due to its wide (32 bit) characters, many registers and large memory support. +There is native \UTF\ input, support for large (more that 8 bit) fonts, and the +math machinery is tuned for \OPENTYPE\ math. There is support for directional +typesetting too. The log output can differ from other engines and will likely +differ more as we move forward. When you run plain \TEX\ for sure \LUATEX\ runs +slower than \PDFTEX\ but when you run for instance \CONTEXT\ \MKIV\ in many cases +it runs faster, especially when you have a bit more complex documents or input. +Anyway, 32 bit all||over combined with more features has a price, but on a modern +machine this is no real problem. + +Testing is done with \CONTEXT, but \LUATEX\ should work fine with other macro +packages too. For that purpose we provide generic font handlers that are mostly +the same as used in \CONTEXT. Discussing specific implementations is beyond this +manual. Even when we keep \LUATEX\ lean and mean, we already have enough to +discuss here. + +\LUATEX\ consists of a number of interrelated but (still) distinguishable parts. +The organization of the source code is adapted so that it can glue all these +components together. We continue cleaning up side effects of the accumulated +code in \TEX\ engines (especially code that is not needed any longer). + +\startitemize[packed] + \startitem + Most of \PDFTEX\ version 1.40.9, converted to \CCODE. Some experimental + features have been removed and some utility macros are not inherited as + their functionality can be done in \LUA. The number of backend interface + commands has been reduced to a few. The extensions are separated from the + core (which we keep close to the original \TEX\ core). Some mechanisms + like expansion and protrusion can behave different from the original due + to some cleanup and optimization. Some whatsit based functionality (image + support and reusable content) is now core functionality. + \stopitem + \startitem + The direction model and some other bits from \ALEPH\ RC4 (derived from + \OMEGA) is included. The related primitives are part of core \LUATEX\ but + at the node level directional support is no longer based on so called + whatsits but on real nodes. In fact, whatsits are now only used for + backend specific extensions. + \stopitem + \startitem + 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). In a similar fashion all file + \IO\ can be intercepted. + \stopitem + \startitem + We currently use \LUA\ 5.2.*. At some point we might decide to move to + 5.3.* but that is yet to be decided. There are few \LUA\ libraries that + we consider part of the core \LUA\ machinery, for instance \type {lpeg}. + There are additional \LUA\ libraries that interface to the internals of + \TEX. + \stopitem + \startitem + There are various \TEX\ extensions but only those that cannot be done + using the \LUA\ interfaces. The math machinery often has two code paths: + one traditional and the other more suitable for wide \OPENTYPE\ fonts. + \stopitem + \startitem + The fontloader uses parts of \FONTFORGE\ 2008.11.17 combined with + additional code specific for usage in a \TEX\ engine. We try to minimize + specific font support to what \TEX\ needs: character references and + dimensions and delegate everything else to \LUA. That way we keep \TEX\ + open for extensions without touching the core. + \stopitem + \startitem + The \METAPOST\ library is integral part of \LUATEX. This gives \TEX\ some + graphical capabilities using a relative high speed graphical subsystem. + Again \LUA\ is used as glue between the frontend and backend. Further + development of \METAPOST\ is closely related to \LUATEX. + \stopitem +\stopitemize + +The \TEXLIVE\ version is to be considered the current stable version. Any version +between the yearly \TEXLIVE\ releases are to be considered beta. The beta +releases are normally available via the \CONTEXT\ distribution channels (the +garden and so called minimals). + +\blank[1*big] + +Hans Hagen, Harmut Henkel, \crlf +Taco Hoekwater \& Luigi Scarso + +\blank[3*big] + +\starttabulate +\NC Version \EQ \currentdate \NC \NR +\NC \LUATEX \EQ Snapshot \number\luatexversion.\luatexrevision \NC \NR +\NC \CONTEXT \EQ \contextversion \NC \NR +\stoptabulate + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-languages.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-languages.tex new file mode 100644 index 00000000000..19e3f7b1458 --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-languages.tex @@ -0,0 +1,705 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-languages + +\startchapter[reference=languages,title={Languages, 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 by replacing ligatures +with their components and ignoring the kerning. Then it runs the hyphenation +algorithm on this string, and converts the hyphenated result back into a \quote +{horizontal list} that is consecutively spliced back into the paragraph stream. +Keep in mind that the paragraph may contain unboxed horizontal material, which +then already contains ligatures and kerns and the words therein are part of the +hyphenation process. + +Those \type {char_node} records are somewhat misnamed, as they are glyph +positions in specific fonts, and therefore not really \quote {characters} in the +linguistic sense. There is no language information inside the \type {char_node} +records at all. Instead, language information is passed along using \type +{language whatsit} 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 current font and a +reference to a character in that font. + +When it becomes necessary to typeset a paragraph, \LUATEX\ first inserts all +hyphenation points right into the whole node list. Next, it processes all the +font information in the whole list (creating ligatures and adjusting kerning), +and finally it adjusts all the subtype identifiers so that the records are \quote +{glyph nodes} from now on. + +\section[charsandglyphs]{Characters and glyphs} + +\TEX82 (including \PDFTEX) differentiates 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 + +\startitem A subtype, split into four main types: + + \startitemize + \startitem + \type {character}, for characters to be hyphenated: the lowest bit + (bit 0) is set to 1. + \stopitem + \startitem + \type {glyph}, for specific font glyphs: the lowest bit (bit 0) is + not set. + \stopitem + \startitem + \type {ligature}, for ligatures (bit 1 is set) + \stopitem + \startitem + \type {ghost}, for \quote {ghost objects} (bit 2 is set) + \stopitem + \stopitemize + + The latter two make further use of two extra fields (bits 3 and 4): + + \startitemize + \startitem + \type {left}, for ligatures created from a left word boundary and for + ghosts created from \type {\leftghost} + \stopitem + \startitem + \type {right}, for ligatures created from a right word boundary and + for ghosts created from \type {\rightghost} + \stopitem + \stopitemize + + For ligatures, both bits can be set at the same time (in case of a + single|-|glyph word). + +\stopitem + +\startitem + \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 + \type {\setlanguage} (15 bits), \type {\lefthyphenmin} (8 bits), \type + {\righthyphenmin} (8 bits), and \type {\uchyph} (1 bit). +\stopitem + +\stopitemize + +Incidentally, \LUATEX\ allows 16383 separate languages, and words can be 256 +characters long. The language is stored with each character. You can set +\type {\firstvalidlanguage} to for instance~1 and make thereby language~0 +an ignored hyphenation language. + +The new primitive \type {\hyphenationmin} can be used to signal the minimal length +of a word. This value stored with the (current) language. + +Because the \type {\uchyph} value is saved in the actual nodes, its handling is +subtly different from \TEX82: changes to \type {\uchyph} become effective +immediately, not at the end of the current partial paragraph. + +Typeset boxes now always have their language information embedded in the nodes +themselves, so there is no longer a possible dependency on the surrounding +language settings. In \TEX82, a mid-paragraph statement like \type {\unhbox0} would +process the box using the current paragraph language unless there was a +\type {\setlanguage} issued inside the box. In \LUATEX, all language variables are +already frozen. + +In traditional \TEX\ the process of hyphenation is driven by \type {lccode}s. In +\LUATEX\ we made this dependency less strong. There are several strategies +possible. When you do nothing, the currently used \type {lccode}s are used, when +loading patterns, setting exceptions or hyphenating a list. + +When you set \type {\savinghyphcodes} to a value larger than zero the current set +of \type {lccode}s will be saved with the language. In that case changing a \type +{lccode} afterwards has no effect. However, you can adapt the set with: + +\starttyping +\hjcode`a=`a +\stoptyping + +This change is global which makes sense if you keep in mind that the moment that +hyphenation happens is (normally) when the paragraph or a horizontal box is +constructed. When \type {\savinghyphcodes} was zero when the language got +initialized you start out with nothing, otherwise you already have a set. + +Carrying all this information with each glyph would give too much overhead and +also make the process of setting up thee codes more complex. A solution with +\type {hjcode} sets was considered but rejected because in practice the current +approach is sufficient and it would not be compatible anyway. + +Beware: the values are always saved in the format, independent of the setting +of \type {\savinghyphcodes} at the moment the format is dumped. + +A boundary node normally would mark the end of a word which interferes with for +instance discretionary injection. For this you can use the \type {\wordboundary} +as trigger. Here are a few examples of usage: + +\startbuffer + discrete---discrete +\stopbuffer +\typebuffer \start \dontcomplain \hsize 1pt \getbuffer \par \stop +\startbuffer + discrete\discretionary{}{}{---}discrete +\stopbuffer +\typebuffer \start \dontcomplain \hsize 1pt \getbuffer \par \stop +\startbuffer + discrete\wordboundary\discretionary{}{}{---}discrete +\stopbuffer +\typebuffer \start \dontcomplain \hsize 1pt \getbuffer \par \stop +\startbuffer + discrete\wordboundary\discretionary{}{}{---}\wordboundary discrete +\stopbuffer +\typebuffer \start \dontcomplain \hsize 1pt \getbuffer \par \stop +\startbuffer + discrete\wordboundary\discretionary{---}{}{}\wordboundary discrete +\stopbuffer +\typebuffer \start \dontcomplain \hsize 1pt \getbuffer \par \stop + +\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 exceptions. + +First, the \type {\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 \type {\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. \footnote {Of course, modern packages will +not use the \type {\accent} primitive at all but try to map directly on composed +characters.} A secondary reason is that in \TEX82, \type {\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 \type {\char}, that now generates \quote +{glyph} nodes with a character subtype. In traditional \TEX\ there was a strong +relationship between the 8|-|bit input encoding, hyphenation and glyphs taken +from a font. In \LUATEX\ we have \UTF\ input, and in most cases this maps +directly to a character in a font, apart from glyph replacement in the font +engine. If you want to access arbitrary glyphs in a font directly you can always +use \LUA\ to do so, because fonts are available as \LUA\ table. + +Second, all the results of processing in math mode eventually become nodes with +\quote {glyph} subtypes. + +Third, the \ALEPH|-|derived commands \type {\leftghost} and \type {\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 \type +{\hyphenchar} in the current font. This test is wrong in our opinion: whether or +not hyphenation takes place should not depend on the current font, it is a +language property. \footnote {When \TEX\ showed up we didn't have \UNICODE\ yet +and being limited to eight bits meant that one sometimes had to compromise +between supporting character input, glyph rendering, hyphenation.} + +In \LUATEX, it works like this: if \LUATEX\ senses a string of input characters +that matches the value of the new integer parameter \type {\exhyphenchar}, it will +insert an explicit discretionary after that series of nodes. Initex sets the \type +{\exhyphenchar=`\-}. Incidentally, this is a global parameter instead of a +language-specific one because it may be useful to change the value depending on +the document structure instead of the text language. + +The insertion of discretionaries after a sequence of explicit hyphens happens at +the same time as the other hyphenation processing, {\it not\/} inside the main +control loop. + +The only use \LUATEX\ has for \type {\hyphenchar} is at the check whether a word +should be considered for hyphenation at all. If the \type {\hyphenchar} of the +font attached to the first character node in a word is negative, then hyphenation +of that word is abandoned immediately. This behaviour is added for backward +compatibility only, and the use of \type {\hyphenchar=-1} as a means of +preventing hyphenation should not be used in new \LUATEX\ documents. + +Fifth, \type {\setlanguage} no longer creates whatsits. The meaning of \type +{\setlanguage} is changed so that it is now an integer parameter like all others. +That integer parameter is used in \type {\glyph_node} creation to add language +information to the glyph nodes. In conjunction, the \type {\language} primitive is +extended so that it always also updates the value of \type {\setlanguage}. + +Sixth, the \type {\noboundary} command (that prohibits word boundary processing +where that would normally take place) now does create nodes. These nodes are +needed because the exact place of the \type {\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 \type +{\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 \type {\patterns} has to be proper \UTF8 with +individual patterns separated by spaces, no \type {\char} or \type {\chardef}d +commands are allowed. The current implementation quite strict and will reject all +non|-|\UNICODE\ characters. + +Likewise, the expanded argument for \type {\hyphenation} also has to be proper +\UTF8, but here a bit of extra syntax is provided: + +\startitemize[n] +\startitem + Three sets of arguments in curly braces (\type {{}{}{}}) indicates a desired + complex discretionary, with arguments as in \type {\discretionary}'s command in + normal document input. +\stopitem +\startitem + A \type {-} indicates a desired simple discretionary, cf.\ \type {\-} and \type + {\discretionary{-}{}{}} in normal document input. +\stopitem +\startitem + Internal command names are ignored. This rule is provided especially for \type + {\discretionary}, but it also helps to deal with \type {\relax} commands that + may sneak in. +\stopitem +\startitem + An \type {=} indicates a (non|-|discretionary) hyphen in the document input. +\stopitem +\stopitemize + +The expanded argument is first converted back to a space-separated string while +dropping the internal command names. This string is then converted into a +dictionary by a routine that creates key|-|value pairs by converting the other +listed items. It is important to note that the keys in an exception dictionary +can always be generated from the values. Here are a few examples: + +\starttabulate[|l|l|l|] +\NC \bf value \NC \bf implied key (input) \NC \bf 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 \type {\language}. + +In the last line of the table, you see there is no \type {\discretionary} command +in the value: the command is optional in the \TEX-based input syntax. The +underlying reason for that is that it is conceivable that a whole dictionary of +words is stored as a plain text file and loaded into \LUATEX\ using one of the +functions in the \LUA\ \type {lang} library. This loading method is quite a bit +faster than going through the \TEX\ language primitives, but some (most?) of that +speed gain would be lost if it had to interpret command sequences while doing so. + +It is possible to specify extra hyphenation points in compound words by using +\type {{-}{}{-}} for the explicit hyphen character (replace \type {-} by the +actual explicit hyphen character if needed). For example, this matches the word +\quote {multi|-|word|-|boundaries} and allows an extra break inbetween \quote +{boun} and \quote {daries}: + +\starttyping +\hyphenation{multi{-}{}{-}word{-}{}{-}boun-daries} +\stoptyping + +The motivation behind the \ETEX\ extension \type {\savinghyphcodes} was that +hyphenation heavily depended on font encodings. This is no longer true in +\LUATEX, and the corresponding primitive is basically ignored. Because we now +have \type {hjcode}, the case relate codes can be used exclusively for \type +{\uppercase} and \type {\lowercase}. + +\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. + +There are a few differences between \LUATEX\ and \TEX82 that are a direct result +of the implementation: + +\startitemize +\startitem + \LUATEX\ happily hyphenates the full \UNICODE\ character range. +\stopitem +\startitem + Pattern and exception dictionary size is limited by the available memory + only, all allocations are done dynamically. The trie|-|related settings in + \type {texmf.cnf} are ignored. +\stopitem +\startitem + Because there is no \quote {trie preparation} stage, language patterns never + become frozen. This means that the primitive \type {\patterns} (and its \LUA\ + counterpart \type {lang.patterns}) can be used at any time, not only in + ini\TEX. +\stopitem +\startitem + Only the string representation of \type {\patterns} and \type {\hyphenation} is + stored in the format file. At format load time, they are simply + re|-|evaluated. It follows that there is no real reason to preload languages + in the format file. In fact, it is usually not a good idea to do so. It is + much smarter to load patterns no sooner than the first time they are actually + needed. +\stopitem +\startitem + \LUATEX\ uses the language-specific variables \type {\prehyphenchar} and \type + {\posthyphenchar} in the creation of implicit discretionaries, instead of + \TEX82's \type {\hyphenchar}, and the values of the language|-|specific variables + \type {\preexhyphenchar} and \type {\postexhyphenchar} for explicit + discretionaries (instead of \TEX82's empty discretionary). +\stopitem +\startitem + The value of the two counters related to hyphenation, \type {\hyphenpenalty} + and \type {\exhyphenpenalty}, are now stored in the discretionary nodes. This + permits a local overload for explicit \type {\discretionary} commands. The + value current when the hyphenation pass is applied is used. When no callbacks + are used this is compatible with traditional \TEX. When you apply the \LUA\ + \type {lang.hyphenate} function the current values are used. +\stopitem +\stopitemize + +Because we store penalties in the disc node the \type {\discretionary} command has +been extended to accept an optional penalty specification, so you can do the +following: + +\startbuffer +\hsize1mm +1:foo{\hyphenpenalty 10000\discretionary{}{}{}}bar\par +2:foo\discretionary penalty 10000 {}{}{}bar\par +3:foo\discretionary{}{}{}bar\par +\stopbuffer + +\typebuffer + +This results in: + +\blank \start \getbuffer \stop \blank + +Inserted characters and ligatures inherit their attributes from the nearest glyph +node item (usually the preceding one, but the following one for the items +inserted at the left-hand side of a word). + +Word boundaries are no longer implied by font switches, but by language switches. +One word can have two separate fonts and still be hyphenated correctly (but it +can not have two different languages, the \type {\setlanguage} command forces a +word boundary). + +All languages start out with \type {\prehyphenchar=`\-}, \type {\posthyphenchar=0}, +\type {\preexhyphenchar=0} and \type {\postexhyphenchar=0}. When you assign the +values of one of these four parameters, you are actually changing the settings +for the current \type {\language}, this behaviour is compatible with \type {\patterns} +and \type {\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 behaviour cannot be controlled). + +If you are using the \LUA\ function \type {lang.hyphenate}, you should be aware +that this function expects to receive a list of \quote {character} nodes. It will +not operate properly in the presence of \quote {glyph}, \quote {ligature}, or +\quote {ghost} nodes, nor does it know how to deal with kerning. + +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. + +\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. At some point all of the possible inputs will +become supported. \footnote {Not all of this makes sense because we nowadays have +\OPENTYPE\ fonts and ligature building can happen in ,any different ways there.} + +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. + +Of course there is still that relationship with fonts: ligatures can be implemented by +mapping a sequence of glyphs onto one glyph, but also by selective replacement and +kerning. This means that the above examples are just representing the traditional +approach. + +\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. In traditional \TEX\ the discretionary node contains a +counter indicating how many nodes to skip, but in \LUATEX\ we store the pre, post +and replace text in the discretionary node. + +The combined effect of these two differences is that \LUATEX\ does not always use +all of the potential breakpoints in a paragraph, especially when fonts with many +ligatures are used. Of course kerning also complicates matters here. + +\section{The \type {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 \type {lang} +library. These functions can also be used as if they were object methods, using +the colon syntax. + +Without an argument, the next available internal id number will be assigned to +this object. With argument, an object will be created that links to the internal +language with that id number. + +\startfunctioncall +<number> n = lang.id(<language> l) +\stopfunctioncall + +returns the internal \type {\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 (string) for this language. + +\startfunctioncall +<string> n = lang.clean(<language> l, <string> o) +<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. + +The following two commands can be used to set or query hj codes: + +\startfunctioncall +lang.sethjcode(<language> l, <number> char, <number> usedchar) +<number> usedchar = lang.gethjcode(<language> l, <number> char) +\stopfunctioncall + +When you set a hjcode the current sets get initialized unless the set was already +initialized due to \type {\savinghyphcodes} being larger than zero. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-logos.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-logos.tex new file mode 100644 index 00000000000..7406dd60206 --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-logos.tex @@ -0,0 +1,19 @@ +\startenvironment luatex-logos + +\logo[DFONT] {dfont} +\logo[CFF] {cff} +\logo[CMAP] {CMap} +\logo[PATGEN] {patgen} +\logo[MP] {MetaPost} +\logo[METAPOST] {MetaPost} +\logo[MPLIB] {MPlib} +\logo[COCO] {coco} +\logo[SUNOS] {SunOS} +\logo[BSD] {bsd} +\logo[SYSV] {sysv} +\logo[DPI] {dpi} +\logo[DLL] {dll} +\logo[OPENOFFICE]{OpenOffice} +\logo[OCP] {OCP} + +\stopenvironment diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-lua.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-lua.tex new file mode 100644 index 00000000000..79c4e08ed6b --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-lua.tex @@ -0,0 +1,548 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-lua + +\startchapter[reference=lua,title={\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] +\startitem + if a \type {--luaonly} option is given on the commandline, or +\stopitem +\startitem + if the executable is named \type {texlua} or \type {luatexlua}, or +\stopitem +\startitem + if the only non|-|option argument (file) on the commandline has the extension + \type {lua} or \type {luc}. +\stopitem +\stopitemize + +In this mode, it will set \LUA's \type {arg[0]} to the found script name, pushing +preceding options in negative values and the rest of the command line in the +positive values, just like the \LUA\ interpreter. + +\LUATEX\ will exit immediately after executing the specified \LUA\ script and is, +in effect, a somewhat bulky stand alone \LUA\ interpreter with a bunch of extra +preloaded libraries. + +\subsection{\LUATEX\ as a \LUA\ byte compiler} + +There are two situations that make \LUATEX\ behave like the \LUA\ byte compiler: + +\startitemize[packed] +\startitem if a \type {--luaconly} option is given on the command line, or \stopitem +\startitem if the executable is named \type {texluac} \stopitem +\stopitemize + +In this mode, \LUATEX\ is exactly like \type {luac} from the stand alone \LUA\ +distribution, except that it does not have the \type {-l} switch, and that it +accepts (but ignores) the \type {--luaconly} switch. + +\subsection{Other commandline processing} + +When the \LUATEX\ executable starts, it looks for the \type {--lua} command line +option. If there is no \type {--lua} option, the command line is interpreted in a +similar fashion as the other \TEX\ engines. Some options are accepted but have no +consequence. The following command|-|line options are understood: + +\starttabulate[|lT|p|] +\NC --fmt=FORMAT \NC load the format file \type {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 \type {iniluatex}, for dumping formats \NC\NR +\NC --interaction=STRING \NC set interaction mode: \type {batchmode}, \type {nonstopmode}, + \type {scrollmode} or \type {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 \type {NUMBER} \NC \NR +\NC --progname=STRING \NC set the program name to \type {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 --output-comment=STRING \NC use \type {STRING} for \DVI\ file comment + instead of date (no effect for \PDF) \NC \NR +\NC --output-directory=DIR \NC use \type {DIR} as the directory to write + files to \NC \NR +\NC --draftmode \NC switch on draft mode i.e.\ generate no + output in \PDF\ mode \NC \NR +\NC --output-format=FORMAT \NC use \type {FORMAT} for job output; \type + {FORMAT} is \type {dvi} or \type {pdf} \NC + \NR +\NC --[no-]shell-escape \NC disable/enable system calls \NC \NR +\NC --enable-write18 \NC enable system calls \NC \NR +\NC --disable-write18 \NC disable system calls \NC \NR +\NC --shell-restricted \NC restrict system calls to a list of commands + given in \type {texmf.cnf} \NC \NR +\NC --debug-format \NC enable format debugging \NC \NR +\NC --[no-]file-line-error \NC disable/enable \type {file:line:error} style + messages \NC \NR +\NC --[no-]file-line-error-style \NC aliases of \type {--[no-]file-line-error} \NC \NR +\NC --jobname=STRING \NC set the job name to \type {STRING} \NC \NR +\NC --[no-]mktex=FMT \NC disable/enable \type {mktexFMT} generation + with \type {FMT} is \type {tex} or \type + {tfm} \NC \NR +\NC --synctex=NUMBER \NC enable \type {synctex} \NC \NR +\stoptabulate + +Some of the traditional flags are just ignored: \type {--etex}, \type +{--translate-file}, \type {--8bit}. \type {--[no-]parse-first-line}, \type +{--default-translate-file}. Also, we no longer support write18 because \type +{os.execute} can do the same. + +The value to use for \type {\jobname} is decided as follows: + +\startitemize +\startitem + If \type {--jobname} is given on the command line, its argument will be the + value for \type {\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 \type {\jobname} setting. +\stopitem +\startitem + Otherwise, \type {\jobname} will be the name of the first file that is read + from the file system, with any path components and the last extension (the + part following the last \type {.}) stripped off. +\stopitem +\startitem + 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 \type {\jobname} is set to \type {texput} as a + last resort. +\stopitem +\stopitemize + +The file names for output files that are generated automatically are created by +attaching the proper extension (\type {log}, \type {pdf}, etc.) to the found +\type {\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 command line 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 command line as usual, but it will only interpret a small subset of the +options immediately: \type {--safer}, \type {--nosocket}, \type +{--[no-]shell-escape}, \type {--enable-write18}, \type {--disable-write18}, \type +{--shell-restricted}, \type {--help}, \type {--version}, and \type {--credits}. + +Next \LUATEX\ searches for the requested \LUA\ initialization script. If it +cannot be found using the actual name given on the command line, a second attempt +is made by prepending the value of the environment variable \type {LUATEXDIR}, if +that variable is defined in the environment. + +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 \type {os} \NC \type {execute} \type {exec} \type {spawn} \type {setenv} \type {rename} \type {remove} \type {tmpdir} \NC \NR +\NC \type {io} \NC \type {popen} \type {output} \type {tmpfile} \NC \NR +\NC \type {lfs} \NC \type {rmdir} \type {mkdir} \type {chdir} \type {lock} \type {touch} \NC \NR +\stoptabulate + +Furthermore, it disables loading of compiled \LUA\ libraries and it makes \type +{io.open()} fail on files that are opened for anything besides reading. + +When \LUATEX\ starts it set the locale to a neutral value. If for some reason you +use \type {os.locale}, you need to make sure you \type {nil} it afterwards +because otherwise it can interfere with code that for instance generates dates. +You can nil the locale with + +\starttyping +os.setlocale(nil.nil) +\stoptyping + +The \type {--nosocket} option makes the socket library unavailable, so that \LUA\ +cannot use networking. + +The switches \type {--[no-]shell-escape}, \type {--[enable|disable]-write18}, and +\type {--shell-restricted} have the same effects as in \PDFTEX, and additionally +make \type {io.popen()}, \type {os.execute}, \type {os.exec} and \type {os.spawn} +adhere to the requested option. + +Next the initialization script is loaded and executed. From within the script, +the entire command line is available in the \LUA\ table \type {arg}, beginning with +\type {arg[0]}, containing the name of the executable. As consequence warnings +about unrecognized options are suppressed. + +Command line processing happens very early on. So early, in fact, that none of +\TEX's initializations have taken place yet. For that reason, the tables that +deal with typesetting, like \type {tex}, \type {token}, \type {node} and +\type {pdf}, are off|-|limits during the execution of the startup file (they +are \type {nil}'d). Special care is taken that \type {texio.write} and \type +{texio.write_nl} function properly, so that you can at least report your actions +to the log file when (and if) it eventually becomes opened (note that \TEX\ does +not even know its \type {\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 \TEX\ specific libraries like +\type {tex}, \type {token}, \type {node} and \type {pdf} tables. These will be +initialized to their documented state after the execution of the script. You +should not store anything in variables or within tables with these four global +names, as they will be overwritten completely. + +We recommend you use the startup file only for your own \TEX|-|independent +initializations (if you need any), to parse the command line, set values in the +\type {texconfig} table, and register the callbacks you need. + +\LUATEX\ allows some of the command line options to be overridden by reading +values from the \type {texconfig} table at the end of script execution (see the +description of the \type {texconfig} table later on in this document for more +details on which ones exactly). + +Unless the \type {texconfig} table tells \LUATEX\ not to initialize \KPATHSEA\ +at all (set \type {texconfig.kpse_init} to \type {false} for that), \LUATEX\ +acts on some more command line options after the initialization script is +finished: in order to initialize the built|-|in \KPATHSEA\ library properly, +\LUATEX\ needs to know the correct program name to use, and for that it needs to +check \type {--progname}, or \type {--ini} and \type {--fmt}, if \type +{--progname} is missing. + +\section{\LUA\ behaviour} + +\LUA s \type {tostring} function (and \type {string.format} may return values in +scientific notation, thereby confusing the \TEX\ end of things when it is used as +the right|-|hand side of an assignment to a \type {\dimen} or \type {\count}. + +Loading dynamic \LUA\ libraries will fail if there are two \LUA\ libraries loaded +at the same time (which will typically happen on \type {win32}, because there is +one \LUA\ 5.2 inside \LUATEX, and another will likely be linked to the \DLL\ file +of the module itself). + +\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()}. + +\LUATEX\ is able to use dynamically loadable \LUA\ libraries, unless +\type {--safer} was given as an option on the command line. For this purpose, +\type {package.searchers[3]} is replaced by a different loader function, that +decides at runtime whether to use \KPATHSEA\ or the built|-|in core \LUA\ +function. It uses \KPATHSEA\ when that is already initialized at that point in +time, otherwise it reverts to using the normal \type {package.cpath} loader. + +This functionality required an extension to kpathsea: + +\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. +Of course it no big deal to write an alternative loader and use that in a macro +package. + +One level up (a \type {lib} directory parallel to \type {bin}) would have been +nicer, but that is not doable because \TEXLIVE\ uses a \type {bin/<arch>} +structure. +\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 we +mean that it is called as \type {luatex}, as opposed to \type {texlua}, and that +the command line option \type {--luaonly} was not given), it will only run the +four functions above if the matching \type {texmf.cnf} variable(s) or their \type +{texconfig} (see \in {section} [texconfig]) counterparts allow execution of the +requested system command. In \quote {script interpreter} runs of \LUATEX, these +settings have no effect, and all four functions function as normal. + +The \type {f:read("*line")} and \type {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. + +\type {luafilesystem} has been extended: there are two extra boolean functions +(\type {lfs.isdir(filename)} and \type {lfs.isfile(filename)}) and one extra +string field in its attributes table (\type {permissions}). There is an +additional function \type {lfs.shortname()} which takes a file name and returns +its short name on \type {win32} platforms. On other platforms, it just returns +the given argument. The file name is not tested for existence. Finally, for +non|-|\type {win32} platforms only, there is the new function \type +{lfs.readlink()} hat takes an existing symbolic link as argument and returns its +content. It returns an error on \type {win32}. + +The \type {string} library has an extra function: \type {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 \type {string} library also has six extra iterators that return strings +piecemeal: + +\startitemize +\startitem + \type {string.utfvalues(s)}: an integer value in the \UNICODE\ range +\stopitem +\startitem + \type {string.utfcharacters(s)}: a string with a single \UTF-8 token in it +\stopitem +\startitem + \type {string.characters(s)} \NC a string containing one byte +\stopitem +\startitem + \type {string.characterpairs(s)} two strings each containing one byte or an + empty second string if the string length was odd +\stopitem +\startitem + \type {string.bytes(s)} a single byte value +\stopitem +\startitem + \type {string.bytepairs(s)} two byte values or nil instead of a number as + its second return value if the string length was odd +\stopitem +\stopitemize + +The \type {string.characterpairs()} and \type {string.bytepairs()} iterators +are useful especially in the conversion of \UTF16 encoded data into \UTF8. + +There is also a two|-|argument form of \type {string.dump()}. The second argument +is a boolean which, if true, strips the symbols from the dumped data. This +matches an extension made in \type {luajit}. + +The \type {string} library functions \type {len}, \type {lower}, \type {sub} +etc.\ are not \UNICODE|-|aware. For strings in the \UTF8 encoding, i.e., strings +containing characters above code point 127, the corresponding functions from the +\type {slnunicode} library can be used, e.g., \type {unicode.utf8.len}, \type +{unicode.utf8.lower} etc.\ The exceptions are \type {unicode.utf8.find}, that +always returns byte positions in a string, and \type {unicode.utf8.match} and +\type {unicode.utf8.gmatch}. While the latter two functions in general {\it +are} \UNICODE|-|aware, they fall|-|back to non|-|\UNICODE|-|aware behavior when +using the empty capture \type {()} but other captures work as expected. For the +interpretation of character classes in \type {unicode.utf8} functions refer to +the library sources at \hyphenatedurl {http://luaforge.net/projects/sln}. Version +5.3 of \LUA\ will provide some native \UTF8 support. + +\blank + +The \type {os} library has a few extra functions and variables: + +\startitemize + +\startitem + \type {os.selfdir} is a variable that holds the directory path of the + actual executable. For example: \type {\directlua {tex.sprint(os.selfdir)}}. +\stopitem + +\startitem + \type {os.exec(commandline)} is a variation on \type {os.execute}. Here + \type {commandline} can be either a single string or a single table. + + 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 path name. + + 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 \type {\"}, \type {\'} or \type + {\\} within the quoted text are unescaped. 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 \MSWINDOWS, the current process is actually kept in memory until after the + execution of the command has finished. This prevents crashes in situations + where \TEXLUA\ scripts are run inside integrated \TEX\ environments. + + The original reason for this command is that it cleans out the current + process before starting the new one, making it especially useful for use in + \TEXLUA. +\stopitem + +\startitem + \type {os.spawn(commandline)} is a returning version of \type {os.exec}, + with otherwise identical calling conventions. + + If the command ran ok, then the return value is the exit status of the + command. Otherwise, it will return the two values \type {nil} and \type + {error}. +\stopitem + +\startitem + \type {os.setenv(key,value)} sets a variable in the environment. Passing + \type {nil} instead of a value string will remove the variable. +\stopitem + +\startitem + \type {os.env} is a hash table containing a dump of the variables and + values in the process environment at the start of the run. It is writeable, + but the actual environment is {\em not\/} updated automatically. +\stopitem + +\startitem + \type {os.gettimeofday()} returns the current \quote {\UNIX\ time}, but as a + float. This function is not available on the \SUNOS\ platforms, so do not use + this function for portable documents. +\stopitem + +\startitem + \type {os.times()}returns the current process times according to \ the + \UNIX\ C library function \quote {times}. This function is not available on + the \MSWINDOWS\ and \SUNOS\ platforms, so do not use this function for + portable documents. +\stopitem + +\startitem + \type {os.tmpdir()} creates a directory in the \quote {current directory} + with the name \type {luatex.XXXXXX} where the \type {X}-es are replaced by a + unique string. The function also returns this string, so you can \type + {lfs.chdir()} into it, or \type {nil} if it failed to create the directory. + The user is responsible for cleaning up at the end of the run, it does not + happen automatically. +\stopitem + +\startitem + \type {os.type} is a string that gives a global indication of the class of + operating system. The possible values are currently \type {windows}, \type + {unix}, and \type {msdos} (you are unlikely to find this value \quote {in the + wild}). +\stopitem + +\startitem + \type {os.name} is a string that gives a more precise indication of the + operating system. These possible values are not yet fixed, and for \type + {os.type} values \type {windows} and \type {msdos}, the \type {os.name} + values are simply \type {windows} and \type {msdos} + + The list for the type \type {unix} is more precise: \type {linux}, \type + {freebsd}, \type {kfreebsd}, \type {cygwin}, \type {openbsd}, \type + {solaris}, \type {sunos} (pre-solaris), \type {hpux}, \type {irix}, \type + {macosx}, \type {gnu} (hurd), \type {bsd} (unknown, but \BSD|-|like), \type + {sysv} (unknown, but \SYSV|-|like), \type {generic} (unknown). +\stopitem + +\startitem + \type {os.uname()} returns a table with specific operating system + information acquired at runtime. The keys in the returned table are all + string valued, and their names are: \type {sysname}, \type {machine}, \type + {release}, \type {version}, and \type {nodename}. +\stopitem + +\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} + +Some modules that are normally external to \LUA\ are statically linked in with +\LUATEX, because they offer useful functionality: + +\startitemize + +\startitem + \type {slnunicode}, from the \type {selene} libraries, \hyphenatedurl + {http://luaforge.net/projects/sln}. This library has been slightly extended + so that the \type {unicode.utf8.*} functions also accept the first 256 values + of plane~18. This is the range \LUATEX\ uses for raw binary output, as + explained above. +\stopitem + +\startitem + \type {luazip}, from the kepler project, \hyphenatedurl + {http://www.keplerproject.org/luazip/}. +\stopitem + +\startitem + \type {luafilesystem}, also from the kepler project, \hyphenatedurl + {http://www.keplerproject.org/luafilesystem/}. +\stopitem + +\startitem + \type {lpeg}, by Roberto Ierusalimschy, \hyphenatedurl + {http://www.inf.puc-rio.br/~roberto/lpeg/lpeg.html}. This library is not + \UNICODE|-|aware, but interprets strings on a byte|-|per|-|byte basis. This + mainly means that \type {lpeg.S} cannot be used with \UTF8 characters encoded + in more than two bytes, and thus \type {lpeg.S} will look for one of those + two bytes when matching, not the combination of the two. The same is true for + \type {lpeg.R}, although the latter will display an error message if used + with multibyte characters. Therefore \type {lpeg.R('aä')} results in the + message \type {bad argument #1 to 'R' (range must have two characters)}, + since to \type {lpeg}, \type {ä} is two 'characters' (bytes), so \type {aä} + totals three. In practice this is no real issue. +\stopitem + +\startitem + \type {lzlib}, by Tiago Dionizio, \hyphenatedurl + {http://luaforge.net/projects/lzlib/}. +\stopitem + +\startitem + \type {md5}, by Roberto Ierusalimschy \hyphenatedurl + {http://www.inf.puc-rio.br/~roberto/md5/md5-5/md5.html}. +\stopitem + +\startitem + \type {luasocket}, by Diego Nehab \hyphenatedurl + {http://w3.impa.br/~diego/software/luasocket/}. The \type {.lua} support + modules from \type {luasocket} are also preloaded inside the executable, + there are no external file dependencies. +\stopitem + +\stopitemize + +At some point (this also depends on distributions) \LUATEX\ might have these +libraries loaded on demand. For this reason you can best use \type {require} to +make sure they are loaded. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-math.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-math.tex new file mode 100644 index 00000000000..cb8d198b1fc --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-math.tex @@ -0,0 +1,1049 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-math + +\startchapter[reference=math,title={Math}] + +The handling of mathematics in \LUATEX\ differs quite a bit from how \TEX82 (and +therefore \PDFTEX) handles math. First, \LUATEX\ adds primitives and extends some +others so that \UNICODE\ input can be used easily. Second, all of \TEX82's +internal special values (for example for operator spacing) have been made +accessible and changeable via control sequences. Third, there are extensions that +make it easier to use \OPENTYPE\ math fonts. And finally, there are some +extensions that have been proposed or considered in the past that are now added +to the engine. + +\section{The current math style} + +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{\type {\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{\type {\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 (\type {\over}, \type {\atop}, +\type {\overwithdelims}, \type {\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 + +The altered \TEX82 primitives are: + +\starttabulate[|l|l|r|c|l|r|] +\NC \bf primitive \NC \bf min \NC \bf max \NC \kern 2em \NC \bf min \NC \bf max \NC \NR +\NC \type {\mathcode} \NC 0 \NC 10FFFF \NC = \NC 0 \NC 8000 \NC \NR +\NC \type {\delcode} \NC 0 \NC 10FFFF \NC = \NC 0 \NC FFFFFF \NC \NR +\stoptabulate + +The unaltered ones are: + +\starttabulate[|l|l|r|] +\NC \bf primitive \NC \bf min \NC \bf max \NC \NR +\NC \type {\mathchardef} \NC 0 \NC 8000 \NC \NR +\NC \type {\mathchar} \NC 0 \NC 7FFF \NC \NR +\NC \type {\mathaccent} \NC 0 \NC 7FFF \NC \NR +\NC \type {\delimiter} \NC 0 \NC 7FFFFFF \NC \NR +\NC \type {\radical} \NC 0 \NC 7FFFFFF \NC \NR +\stoptabulate + +For practical reasons \type {\mathchardef} will silently accept values larger +that \type {0x8000} and interpret it as \type {\Umathcharnumdef}. This is needed +to satisfy older macro packages. + +The following new primitives are compatible with \XETEX: + +% somewhat fuzzy: + +\starttabulate[|l|l|r|c|l|r|] +\NC \bf primitive \NC \bf min \NC \bf max \NC \kern 2em \NC \bf min \NC \bf max \NC \NR +\NC \type {\Umathchardef} \NC 0+0+0 \NC 7+FF+10FFFF\rlap{\high{1}} \NC \NC \NC \NC \NR +\NC \type {\Umathcharnumdef}\rlap{\high{5}} \NC -80000000 \NC 7FFFFFFF\rlap{\high{3}} \NC \NC \NC \NC \NR +\NC \type {\Umathcode} \NC 0 \NC 10FFFF \NC = \NC 0+0+0 \NC 7+FF+10FFFF\rlap{\high{1}} \NC \NR +\NC \type {\Udelcode} \NC 0 \NC 10FFFF \NC = \NC 0+0 \NC FF+10FFFF\rlap{\high{2}} \NC \NR +\NC \type {\Umathchar} \NC 0+0+0 \NC 7+FF+10FFFF \NC \NC \NC \NC \NR +\NC \type {\Umathaccent} \NC 0+0+0 \NC 7+FF+10FFFF\rlap{\high{2,4}} \NC \NC \NC \NC \NR +\NC \type {\Udelimiter} \NC 0+0+0 \NC 7+FF+10FFFF\rlap{\high{2}} \NC \NC \NC \NC \NR +\NC \type {\Uradical} \NC 0+0 \NC FF+10FFFF\rlap{\high{2}} \NC \NC \NC \NC \NR +\NC \type {\Umathcharnum} \NC -80000000 \NC 7FFFFFFF\rlap{\high{3}} \NC \NC \NC \NC \NR +\NC \type {\Umathcodenum} \NC 0 \NC 10FFFF \NC = \NC -80000000 \NC 7FFFFFFF\rlap{\high{3}} \NC \NR +\NC \type {\Udelcodenum} \NC 0 \NC 10FFFF \NC = \NC -80000000 \NC 7FFFFFFF\rlap{\high{3}} \NC \NR +\stoptabulate + +Specifications typically look like: + +\starttyping +\Umathchardef\xx="1"0"456 +\Umathcode 123="1"0"789 +\stoptyping + +Note 1: 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 \type {\Umathoperatorsize} parameter (more +information can be found in a following section). + +Note 2: For these three primitives, all information is packed into a single +signed integer. For the first two (\type {\Umathcharnum} and \type +{\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 \type {\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 3: The \type {\Umathaccent} command accepts optional keywords to control +various details regarding math accents. See \in {section} [mathacc] below for +details. + +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 \type {\Uroot} \NC 0+0--FF+10FFFF$^2$ \NC \NR +\NC \type {\Uoverdelimiter} \NC 0+0--FF+10FFFF$^2$ \NC \NR +\NC \type {\Uunderdelimiter} \NC 0+0--FF+10FFFF$^2$ \NC \NR +\NC \type {\Udelimiterover} \NC 0+0--FF+10FFFF$^2$ \NC \NR +\NC \type {\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. + +In Eijkhouts \quotation {\TEX\ by Topic} the rules for handling styles in scripts +are described as follows: + +\startitemize +\startitem + In any style superscripts and subscripts are taken from the next smaller style. + Exception: in display style they are taken in script style. +\stopitem +\startitem + Subscripts are always in the cramped variant of the style; superscripts are only + cramped if the original style was cramped. +\stopitem +\startitem + In an \type {..\over..} formula in any style the numerator and denominator are + taken from the next smaller style. +\stopitem +\startitem + The denominator is always in cramped style; the numerator is only in cramped + style if the original style was cramped. +\stopitem +\startitem + Formulas under a \type {\sqrt} or \type {\overline} are in cramped style. +\stopitem +\stopitemize + +In \LUATEX\ one can set the styles in more detail which means that you sometimes +have to set both normal and cramped styles to get the effect you want. If we +force styles in the script using \type {\scriptstyle} and \type {\crampedscriptstyle} +we get this: + +\startbuffer[demo] +\starttabulate +\NC default \NC $b_{x=xx}^{x=xx}$ \NC \NR +\NC script \NC $b_{\scriptstyle x=xx}^{\scriptstyle x=xx}$ \NC \NR +\NC crampedscript \NC $b_{\crampedscriptstyle x=xx}^{\crampedscriptstyle x=xx}$ \NC \NR +\stoptabulate +\stopbuffer + +\getbuffer[demo] + +Now we set the following parameters + +\startbuffer[setup] +\Umathordrelspacing\scriptstyle=30mu +\Umathordordspacing\scriptstyle=30mu +\stopbuffer + +\typebuffer[setup] + +This gives: + +\start\getbuffer[setup,demo]\stop + +But, as this is not what is expected (visually) we should say: + +\startbuffer[setup] +\Umathordrelspacing\scriptstyle=30mu +\Umathordordspacing\scriptstyle=30mu +\Umathordrelspacing\crampedscriptstyle=30mu +\Umathordordspacing\crampedscriptstyle=30mu +\stopbuffer + +\typebuffer[setup] + +Now we get: + +\start\getbuffer[setup,demo]\stop + +\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 18 mu'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{Skips around display math} + +The injection of \type {\abovedisplayskip} and \type {\belowdisplayskip} is not +symmetrical. An above one is always inserted, also when zero, but the below is +only inserted when larger than zero. Especially the later mkes it sometimes hard +to fully control spacing. Therefore \LUATEX\ comes with a new directive: \type +{\mathdisplayskipmode}. The following values apply: + +\starttabulate +\NC 0 \NC normal \TEX\ behaviour: always above, only below when larger than zero \NC \NR +\NC 1 \NC always \NC \NR +\NC 2 \NC only when not zero \NC \NR +\NC 3 \NC never, not even when not zero \NC \NR +\stoptabulate + +\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 \type +{\textfont} set the values for the cramped and uncramped display and text styles, +\type {\scriptfont} sets the script styles, and \type {\scriptscriptfont} sets +the scriptscript styles, so we have eight parameters for three font sizes. In the +\TFM\ case, assignments only happen in family~2 and family~3 (and of course only +for the parameters for which there are font dimensions). + +Besides the parameters below, \LUATEX\ also looks at the \quote {space} font +dimension parameter. For math fonts, this should be set to zero. + +\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 \type {\Umathaxis} \NC -- \NC AxisHeight \NC axis_height \NC \NR +\NC \type {\Umathoperatorsize} \NC D, D' \NC DisplayOperatorMinHeight \NC $^6$ \NC \NR +\NC \type {\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 \type {\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 \type {\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 \type {\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 \type {\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 \type {\Umathfractionrule} \NC -- \NC FractionRuleThickness \NC default_rule_thickness \NC \NR +\NC \type {\Umathskewedfractionhgap} \NC -- \NC SkewedFractionHorizontalGap \NC math_quad/2 \NC \NR +\NC \type {\Umathskewedfractionvgap} \NC -- \NC SkewedFractionVerticalGap \NC math_x_height \NC \NR +\NC \type {\Umathlimitabovebgap} \NC -- \NC UpperLimitBaselineRiseMin \NC big_op_spacing3 \NC \NR +\NC \type {\Umathlimitabovekern} \NC -- \NC 0$^1$ \NC big_op_spacing5 \NC \NR +\NC \type {\Umathlimitabovevgap} \NC -- \NC UpperLimitGapMin \NC big_op_spacing1 \NC \NR +\NC \type {\Umathlimitbelowbgap} \NC -- \NC LowerLimitBaselineDropMin \NC big_op_spacing4 \NC \NR +\NC \type {\Umathlimitbelowkern} \NC -- \NC 0$^1$ \NC big_op_spacing5 \NC \NR +\NC \type {\Umathlimitbelowvgap} \NC -- \NC LowerLimitGapMin \NC big_op_spacing2 \NC \NR +\NC \type {\Umathoverdelimitervgap} \NC -- \NC StretchStackGapBelowMin \NC big_op_spacing1 \NC \NR +\NC \type {\Umathoverdelimiterbgap} \NC -- \NC StretchStackTopShiftUp \NC big_op_spacing3 \NC \NR +\NC \type {\Umathunderdelimitervgap} \NC-- \NC StretchStackGapAboveMin \NC big_op_spacing2 \NC \NR +\NC \type {\Umathunderdelimiterbgap} \NC-- \NC StretchStackBottomShiftDown \NC big_op_spacing4 \NC \NR +\NC \type {\Umathoverbarkern} \NC -- \NC OverbarExtraAscender \NC default_rule_thickness \NC \NR +\NC \type {\Umathoverbarrule} \NC -- \NC OverbarRuleThickness \NC default_rule_thickness \NC \NR +\NC \type {\Umathoverbarvgap} \NC -- \NC OverbarVerticalGap \NC 3*default_rule_thickness \NC \NR +\NC \type {\Umathquad} \NC -- \NC <font_size(f)>$^1$ \NC math_quad \NC \NR +\NC \type {\Umathradicalkern} \NC -- \NC RadicalExtraAscender \NC default_rule_thickness \NC \NR +\NC \type {\Umathradicalrule} \NC -- \NC RadicalRuleThickness \NC <not set>$^2$ \NC \NR +\NC \type {\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 \type {\Umathradicaldegreebefore} \NC -- \NC RadicalKernBeforeDegree \NC <not set>$^2$ \NC \NR +\NC \type {\Umathradicaldegreeafter} \NC -- \NC RadicalKernAfterDegree \NC <not set>$^2$ \NC \NR +\NC \type {\Umathradicaldegreeraise} \NC -- \NC RadicalDegreeBottomRaisePercent \NC <not set>$^{2,7}$ \NC \NR +\NC \type {\Umathspaceafterscript} \NC -- \NC SpaceAfterScript \NC script_space$^4$ \NC \NR +\NC \type {\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 \type {\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 \type {\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 \type {\Umathsubshiftdown} \NC -- \NC SubscriptShiftDown \NC sub1 \NC \NR +\NC \type {\Umathsubshiftdrop} \NC -- \NC SubscriptBaselineDropMin \NC sub_drop \NC \NR +\NC \type {\Umathsubsupshiftdown} \NC -- \NC SubscriptShiftDownWithSuperscript$^8$ \NC \NC \NR +\NC \NC \NC \quad\ or SubscriptShiftDown \NC sub2 \NC \NR +\NC \type {\Umathsubtopmax} \NC -- \NC SubscriptTopMax \NC (abs(math_x_height * 4) / 5) \NC \NR +\NC \type {\Umathsubsupvgap} \NC -- \NC SubSuperscriptGapMin \NC 4*default_rule_thickness \NC \NR +\NC \type {\Umathsupbottommin} \NC -- \NC SuperscriptBottomMin \NC (abs(math_x_height) / 4) \NC \NR +\NC \type {\Umathsupshiftdrop} \NC -- \NC SuperscriptBaselineDropMax \NC sup_drop \NC \NR +\NC \type {\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 \type {\Umathsupsubbottommax} \NC -- \NC SuperscriptBottomMaxWithSubscript \NC (abs(math_x_height * 4) / 5) \NC \NR +\NC \type {\Umathunderbarkern} \NC -- \NC UnderbarExtraDescender \NC default_rule_thickness \NC \NR +\NC \type {\Umathunderbarrule} \NC -- \NC UnderbarRuleThickness \NC default_rule_thickness \NC \NR +\NC \type {\Umathunderbarvgap} \NC -- \NC UnderbarVerticalGap \NC 3*default_rule_thickness \NC \NR +\NC \type {\Umathconnectoroverlapmin} \NC -- \NC MinConnectorOverlap \NC 0$^5$ \NC \NR +\stoptabulate + +\stop + +Note 1: \OPENTYPE\ fonts set \type {\Umathlimitabovekern} and \type +{\Umathlimitbelowkern} to zero and set \type {\Umathquad} to the font size of the +used font, because these are not supported in the \type {MATH} table, + +Note 2: Traditional \TFM\ fonts do not set \type {\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 +\type {\Umathradicaldegreebefore}, \type {\Umathradicaldegreeafter}, and \type +{\Umathradicaldegreeraise}. These are then automatically initialized to +$5/18$quad, $-10/18$quad, and 60. + +Note 3: If \TFM\ fonts are used, then the \type {\Umathradicalvgap} is not set +until the first time \LUATEX\ has to typeset a formula because this needs +parameters from both family~2 and family~3. This provides a partial backward +compatibility with \TEX82, but that compatibility is only partial: once the \type +{\Umathradicalvgap} is set, it will not be recalculated any more. + +Note 4: When \TFM\ fonts are used a similar situation arises with respect to +\type {\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 \type {\Umathspaceafterscript} is set, \type {\scriptspace} will never +be looked at again. + +Note 5: Traditional \TFM\ fonts set \type {\Umathconnectoroverlapmin} to zero +because \TEX82\ always stacks extensibles without any overlap. + +Note 6: The \type {\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 \type {\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. + +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. + +\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: + +\starttwocolumns +\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 +\stoptwocolumns + +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 \type {initex} to the values mentioned in the table +in Chapter~18 of the \TEX book. + +Note 1: for ease of use as well as for backward compatibility, \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 \type {\Umathaccent}. + +The keyword \type {bottom} after \type {\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 \type {MathConstants} table, then \type +{AccentBaseHeight} is used instead. + +The vertical placement of a bottom accent is straight below the accentee, no +correction takes place. + +Possible locations are \type {top}, \type {bottom}, \type {both} and \type +{center}. When no location is given \type {top} is assumed. An additional +parameter \type {fraction} can be specified followed by a number; a value of for +instance 1200 means that the criterium is 1.2 times the width of the nuclues. The +fraction only applies to the stepwise selected shapes and is mostly meant for the +\type {overlay} location. It also works for the other locations but then it +concerns the width. + +\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 items are \OPENTYPE\ fonts (as +opposed to legacy \TEX\ fonts), then \LUATEX\ will use the \OPENTYPE\ math +algorithm for deciding on the horizontal placement of the super- or subscript. + +This works as follows: + +\startitemize + \startitem + The vertical position of the script is calculated. + \stopitem + \startitem + The default horizontal position is flat next to the base character. + \stopitem + \startitem + For superscripts, the italic correction of the base character is added. + \stopitem + \startitem + For a superscript, two vertical values are calculated: the bottom of the + script (after shifting up), and the top of the base. For a subscript, the two + values are the top of the (shifted down) script, and the bottom of the base. + \stopitem + \startitem + For each of these two locations: + \startitemize + \startitem + find the math kern value at this height for the base (for a subscript + placement, this is the bottom_right corner, for a superscript + placement the top_right corner) + \stopitem + \startitem + find the math kern value at this height for the script (for a + subscript placement, this is the top_left corner, for a superscript + placement the bottom_left corner) + \stopitem + \startitem + add the found values together to get a preliminary result. + \stopitem + \stopitemize + \stopitem + \startitem + The horizontal kern to be applied is the smallest of the two results from + previous step. + \stopitem +\stopitemize + +The math kern value at a specific height is the kern value that is specified by the +next higher height and kern pair, or the highest one in the character (if there is no +value high enough in the character), or simply zero (if the character has no math kern +pairs at all). + +\section{Scripts on horizontally extensible items like arrows} + +The primitives \type {\Uunderdelimiter} and \type {\Uoverdelimiter} allow the +placement of a subscript or superscript on an automatically extensible item and +\type {\Udelimiterunder} and \type {\Udelimiterover} allow the placement of an +automatically extensible item as a subscript or superscript on a nucleus. The +input: + +% these produce radical noads .. in fact the code base has the numbers wrong for +% quite a while, so no one seems to use this + +\startbuffer +$\Uoverdelimiter 0 "2194 {\hbox{\strut overdelimiter}}$ +$\Uunderdelimiter 0 "2194 {\hbox{\strut underdelimiter}}$ +$\Udelimiterover 0 "2194 {\hbox{\strut delimiterover}}$ +$\Udelimiterunder 0 "2194 {\hbox{\strut delimiterunder}}$ +\stopbuffer + +\typebuffer will render this: + +\blank \startnarrower \getbuffer \stopnarrower \blank + +The vertical placements are controlled by \type {\Umathunderdelimiterbgap}, \type +{\Umathunderdelimitervgap}, \type {\Umathoverdelimiterbgap}, and \type +{\Umathoverdelimitervgap} in a similar way as limit placements on large operators. +The superscript in \type {\Uoverdelimiter} is typeset in a suitable scripted style, +the subscript in \type {\Uunderdelimiter} is cramped as well. + +These primitives accepts an option \type {width} specification. When used the +also optional keywords \type {left}, \type {middle} and \type {right} will +determine what happens when a requested size can't be met (which can happen when +we step to successive larger variants). + +An extra primitive \type {\Uhextensible} is available that can be used like this: + +\startbuffer +$\Uhextensible width 10cm 0 "2194$ +\stopbuffer + +\typebuffer This will render this: + +\blank \startnarrower \getbuffer \stopnarrower \blank + +Here you can also pass options, like: + +\startbuffer +$\Uhextensible width 1pt middle 0 "2194$ +\stopbuffer + +\typebuffer This gives: + +\blank \startnarrower \getbuffer \stopnarrower \blank + +\LUATEX\ internally uses a structure that supports \OPENTYPE\ \quote +{MathVariants} as well as \TFM\ \quote {extensible recipes}. In most cases where +font metrics are involved we have a different code path for traditional fonts end +\OPENTYPE\ fonts. + +\section {Extracting values} + +You can extract the components of a math character. Say that we have defined: + +\starttyping +\Umathcode 1 2 3 4 +\stoptyping + +then + +\starttyping +[\Umathcharclass1] [\Umathcharfam1] [\Umathcharslot1] +\stoptyping + +will return: + +\starttyping +[2] [3] [4] +\stoptyping + +These commands are provides as convenience. Before they came available you could +do the following: + +\starttyping +\def\Umathcharclass{\directlua{tex.print(tex.getmathcode(token.scan_int())[1])}} +\def\Umathcharfam {\directlua{tex.print(tex.getmathcode(token.scan_int())[2])}} +\def\Umathcharslot {\directlua{tex.print(tex.getmathcode(token.scan_int())[3])}} +\stoptyping + +\section{fractions} + +The \type {\abovewithdelims} command accepts a keyword \type {exact}. When issued +the extra space relative to the rule thickness is not added. One can of course +use the \type {\Umathfraction..gap} commands to influence the spacing. Also the +rule is still positioned around the math axis. + +\starttyping +$$ { {a} \abovewithdelims() exact 4pt {b} }$$ +\stoptyping + +The math parameter table contains some parameters that specify a horizontal and +vertical gap for skewed fractions. Of course some guessing is needed in order to +implement something that uses them. And so we now provide a primitive similar to the +other fraction related ones but with a few options so that one can influence the +rendering. Of course a user can also mess around a bit with the parameters +\type {\Umathskewedfractionhgap} and \type {\Umathskewedfractionvgap}. + +The syntax used here is: + +\starttyping +{ {1} \Uskewed / <options> {2} } +{ {1} \Uskewedwithdelims / () <options> {2} } +\stoptyping + +where the options can be \type {noaxis} and \type {exact}. By default we add half +the axis to the shifts and by default we zero the width of the middle character. +For Latin Modern The result looks as follows: + +\def\ShowA#1#2#3{$x + { {#1} \Uskewed / #3 {#2} } + x$} +\def\ShowB#1#2#3{$x + { {#1} \Uskewedwithdelims / () #3 {#2} } + x$} + +\start + \switchtobodyfont[modern] + \starttabulate[||||||] + \NC \NC + \ShowA{a}{b}{} \NC + \ShowA{1}{2}{} \NC + \ShowB{a}{b}{} \NC + \ShowB{1}{2}{} \NC + \NR + \NC \type{exact} \NC + \ShowA{a}{b}{exact} \NC + \ShowA{1}{2}{exact} \NC + \ShowB{a}{b}{exact} \NC + \ShowB{1}{2}{exact} \NC + \NR + \NC \type{noaxis} \NC + \ShowA{a}{b}{noaxis} \NC + \ShowA{1}{2}{noaxis} \NC + \ShowB{a}{b}{noaxis} \NC + \ShowB{1}{2}{noaxis} \NC + \NR + \NC \type{exact noaxis} \NC + \ShowA{a}{b}{exact noaxis} \NC + \ShowA{1}{2}{exact noaxis} \NC + \ShowB{a}{b}{exact noaxis} \NC + \ShowB{1}{2}{exact noaxis} \NC + \NR + \stoptabulate +\stop + +\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 {$$}: %$ + +\starttabulate[|l|l|l|l|] +\NC \bf primitive \NC \bf explanation \NC \NR +\NC \type {\Usuperscript} \NC Duplicates the functionality of \type {^} \NC \NR +\NC \type {\Usubscript} \NC Duplicates the functionality of \type {_} \NC \NR +\NC \type {\Ustartmath} \NC Duplicates the functionality of \type {$}, % $ + when used in non-math mode. \NC \NR +\NC \type {\Ustopmath} \NC Duplicates the functionality of \type {$}, % $ + when used in inline math mode. \NC \NR +\NC \type {\Ustartdisplaymath} \NC Duplicates the functionality of \type {$$}, % $$ + when used in non-math mode. \NC \NR +\NC \type {\Ustopdisplaymath} \NC Duplicates the functionality of \type {$$}, % $$ + when used in display math mode. \NC \NR +\stoptabulate + +The \type {\Ustopmath} and \type {\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 surrounding skips} + +Inline math is surrounded by (optional) \type {\mathsurround} spacing but that is fixed +dimension. There is now an additional parameter \type {\mathsurroundskip}. When set to a +non|-|zero value (or zero with some stretch or shrink) this parameter will replace +\type {\mathsurround}. By using an additional parameter instead of changing the nature +of \type {\mathsurround}, we can remain compatible. + +% \section{Math todo} +% +% The following items are still todo. +% +% \startitemize +% \startitem +% Pre-scripts. +% \stopitem +% \startitem +% Multi-story stacks. +% \stopitem +% \startitem +% Flattened accents for high characters (maybe). +% \stopitem +% \startitem +% Better control over the spacing around displays and handling of equation numbers. +% \stopitem +% \startitem +% Support for multi|-|line displays using \MATHML\ style alignment points. +% \stopitem +% \stopitemize + +\subsection {Delimiters: \type{\Uleft}, \type {\Umiddle} and \type {\Uright}} + +Normally you will force delimiters to certain sizes by putting an empty box or +rule next to it. The resulting delimiter will either be a character from the +stepwise size range or an extensible. The latter can be quite differently +positioned that the characters as it depends on the fit as well as the fact if +the used characters in the font have depth or height. Commands like (plain \TEX +s) \type {\big} need use this feature. In \LUATEX\ we provide a bit more control +by three variants that supporting optional parameters \type {height}, \type +{depth} and \type {axis}. The following example uses this: + +\startbuffer +\Uleft height 30pt depth 10pt \Udelimiter "0 "0 "000028 +\quad x\quad +\Umiddle height 40pt depth 15pt \Udelimiter "0 "0 "002016 +\quad x\quad +\Uright height 30pt depth 10pt \Udelimiter "0 "0 "000029 +\quad \quad \quad +\Uleft height 30pt depth 10pt axis \Udelimiter "0 "0 "000028 +\quad x\quad +\Umiddle height 40pt depth 15pt axis \Udelimiter "0 "0 "002016 +\quad x\quad +\Uright height 30pt depth 10pt axis \Udelimiter "0 "0 "000029 +\stopbuffer + +\typebuffer + +\startlinecorrection +\ruledhbox{\mathematics{\getbuffer}} +\stoplinecorrection + +The keyword \type {exact} can be used as directive that the real dimensions +should be applied when the criteria can't be met which can happen when we're +still stepping through the successively larger variants. When no dimensions are +given the \type {noaxis} command can be used to prevent shifting over the axis. + +You can influence the final class with the keyword \type {class} which will +influence the spacing. + +\subsection{Fixed scripts} + +We have three parameters that are used for this fixed anchoring: + +\starttabulate[|l|l|] +\NC $d$ \NC \type {\Umathsubshiftdown} \NC \NR +\NC $u$ \NC \type {\Umathsupshiftup} \NC \NR +\NC $s$ \NC \type {\Umathsubsupshiftdown} \NC \NR +\stoptabulate + +When we set \type {\mathscriptsmode} to a value other than zero these are used +for calculating fixed positions. This is something that is needed for instance +for chemistry. You can manipulate the mentioned variables to achive different +effects. + +\def\SampleMath#1% + {$\mathscriptsmode#1\mathupright CH_2 + CH^+_2 + CH^2_2$} + +\starttabulate[|c|c|c|l|] +\NC \bf mode \NC \bf down \NC \bf up \NC \NC \NR +\NC 0 \NC dynamic \NC dynamic \NC \SampleMath{0} \NC \NR +\NC 1 \NC $d$ \NC $u$ \NC \SampleMath{1} \NC \NR +\NC 2 \NC $s$ \NC $u$ \NC \SampleMath{2} \NC \NR +\NC 3 \NC $s$ \NC $u + s - d$ \NC \SampleMath{3} \NC \NR +\NC 4 \NC $d + (s-d)/2$ \NC $u + (s-d)/2$ \NC \SampleMath{4} \NC \NR +\NC 5 \NC $d$ \NC $u + s - d$ \NC \SampleMath{5} \NC \NR +\stoptabulate + +The value of this parameter obeys grouping but applies to the whole current +formula. + +% if needed we can put the value in stylenodes but maybe more should go there + +\subsection {Tracing} + +Because there are quite some math related parameters and values, it is possible +to limit tracing. Only when \type {tracingassigns} and|/|or \type +{tracingrestores} are set to~2 or more they will be traced. + +\subsection {Math options} + +The logic in the math engine is rather complex and there are often no universal +solutions (read: what works out well for one font, fails for another). Therefore +some variations in the implementation will be driven by options for which a new +primitive \type {\mathoption} has been introduced (so that we don't end up with +many new commands). The approach of options also permits us to see what effect a +specific solution has. + +\subsubsection {\type {\mathoption noitaliccompensation}} + +This option compensates placement for characters with a built|-|in italic +correction. + +\startbuffer +{\showboxes\int}\quad +{\showboxes\int_{|}^{|}}\quad +{\showboxes\int\limits_{|}^{|}} +\stopbuffer + +\typebuffer + +Gives (with computer modern that has such italics): + +\startlinecorrection[blank] + \switchtobodyfont[modern] + \startcombination[nx=2,ny=2,distance=5em] + {\mathoption noitaliccompensation 0\relax \mathematics{\getbuffer}} + {\nohyphens\type{0:inline}} + {\mathoption noitaliccompensation 0\relax \mathematics{\displaymath\getbuffer}} + {\nohyphens\type{0:display}} + {\mathoption noitaliccompensation 1\relax \mathematics{\getbuffer}} + {\nohyphens\type{1:inline}} + {\mathoption noitaliccompensation 1\relax \mathematics{\displaymath\getbuffer}} + {\nohyphens\type{1:display}} + \stopcombination +\stoplinecorrection + +\subsubsection {\type {\mathoption nocharitalic}} + +When two characters follow each other italic correction can interfere. The +following example shows what this option does: + +\startbuffer +\catcode"1D443=11 +\catcode"1D444=11 +\catcode"1D445=11 +P( PP PQR +\stopbuffer + +\typebuffer + +Gives (with computer modern that has such italics): + +\startlinecorrection[blank] + \switchtobodyfont[modern] + \startcombination[nx=2,ny=2,distance=5em] + {\mathoption nocharitalic 0\relax \mathematics{\getbuffer}} + {\nohyphens\type{0:inline}} + {\mathoption nocharitalic 0\relax \mathematics{\displaymath\getbuffer}} + {\nohyphens\type{0:display}} + {\mathoption nocharitalic 1\relax \mathematics{\getbuffer}} + {\nohyphens\type{1:inline}} + {\mathoption nocharitalic 1\relax \mathematics{\displaymath\getbuffer}} + {\nohyphens\type{1:display}} + \stopcombination +\stoplinecorrection + +\subsubsection {\type {\mathoption useoldfractionscaling}} + +This option has been introduced as solution for tracker item 604 for fuzzy cases +around either or not present fraction related settings for new fonts. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-modifications.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-modifications.tex new file mode 100644 index 00000000000..0507a56e0fa --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-modifications.tex @@ -0,0 +1,867 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-modifications + +\startchapter[reference=modifications,title={Modifications}] + +\startsection[title=The merged engines] + +\startsubsection[title=The need for change] + +The first version of \LUATEX\ only had a few extra primitives and it was largely +the same as \PDFTEX. Then we merged substantial parts of \ALEPH\ into the code +and got more primitives. When we got more stable the decision was made to clean +up the rather hybrid nature of the program. This means that some primitives have +been promoted to core primitives, often with a different name, and that others +were removed. This made it possible to start cleaning up the code base. In \in +{chapter} [enhancements] we discussed some new primitives, here we will cover +most of the adapted ones. + +Besides the expected changes caused by new functionality, there are a number of +not|-|so|-|expected changes. These are sometimes a side|-|effect of a new +(conflicting) feature, or, more often than not, a change neccessary to clean up +the internal interfaces. These will also be mentioned. + +\stopsubsection + +\startsubsection[title=Changes from \TEX\ 3.1415926] + +Of course it all starts with traditional \TEX. Even if we started with \PDFTEX, +most still comes from the original. But we divert a bit. + +\startitemize + +\startitem + The current code base is written in \CCODE, not \PASCAL. We use \CWEB\ when + possible. As a consequence instead of one large file plus change files, we + now have multiple files organized in categories like \type {tex}, \type + {pdf}, \type {lang}, \type {font}, \type {lua}, etc. There are some artefacts + of the conversion to \CCODE, but in due time we will clean up the source code + and make sure that the documentation is done right. Many files are in the + \CWEB\ format, but others, like those interfacing to \LUA, are \CCODE\ files. + Of course we want to stay as close as possible to the original so that the + documentation of the fundamentals behind \TEX\ by Don Knuth still applies. +\stopitem + +\startitem + See \in {chapter} [languages] for many small changes related to paragraph + building, language handling and hyphenation. The most important change is + that adding a brace group in the middle of a word (like in \type {of{}fice}) + does not prevent ligature creation. +\stopitem + +\startitem + There is no pool file, all strings are embedded during compilation. +\stopitem + +\startitem + The specifier \type {plus 1 fillll} does not generate an error. The extra + \quote{l} is simply typeset. +\stopitem + +\startitem + The upper limit to \type {\endlinechar} and \type {\newlinechar} is 127. +\stopitem + +\startitem + Magnification (\type {\mag}) is only supported in \DVI\ output mode. +\stopitemize + +\stopsubsection + +\startsubsection[title=Changes from \ETEX\ 2.2] + +Being the de factor standard extension of course we provide the \ETEX\ +functionality, but with a few small adaptations. + +\startitemize + +\startitem + The \ETEX\ functionality is always present and enabled so the prepended + asterisk or \type {-etex} switch for \INITEX\ is not needed. +\stopitem + +\startitem + The \TEXXET\ extension is not present, so the primitives \type + {\TeXXeTstate}, \type {\beginR}, \type {\beginL}, \type {\endR} and \type + {\endL} are missing. Instead we use the \OMEGA\ approach to directionality. +\stopitem + +\startitem + Some of the tracing information that is output by \ETEX's \type + {\tracingassigns} and \type {\tracingrestores} is not there. +\stopitem + +\startitem + 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. +\stopitem + +\startitem + When kpathsea is used to find files, \LUATEX\ uses the \type {ofm} file + format to search for font metrics. In turn, this means that \LUATEX\ looks at + the \type {OFMFONTS} configuration variable (like \OMEGA\ and \ALEPH) instead + of \type {TFMFONTS} (like \TEX\ and \PDFTEX). Likewise for virtual fonts + (\LUATEX\ uses the variable \type {OVFFONTS} instead of \type {VFFONTS}). +\stopitem + +\stopitemize + +\stopsubsection + +\startsubsection[title=Changes from \PDFTEX\ 1.40] + +Because we want to produce \PDF\ the most natural starting point was the popular +\PDFTEX\ program. We inherit the stable features, dropped most of the +experimental code and promoted some functionality to core \LUATEX\ functionality +which in turn triggered renaming primitives. + +For compatibility reasons we still refer to \type {\pdf...} commands but \LUATEX\ +has a different backend interface. Instead of these primitives there are three +interfacing primitives: \type {\pdfextension}, \type {\pdfvariable} and +\type {\pdffeedback} that take keywords and optional further arguments. This way +we can extend the features when needed but don't need to adapt the core engine. +The front- and backend are decoupled as much as possible. + +\startitemize + +\startitem + The (experimental) support for snap nodes has been removed, because it is + much more natural to build this functionality on top of node processing and + attributes. The associated primitives that are now gone are: \type + {\pdfsnaprefpoint}, \type {\pdfsnapy}, and \type {\pdfsnapycomp}. +\stopitem + +\startitem + The (experimental) support for specialized spacing around nodes has also been + removed. The associated primitives that are now gone are: \type + {\pdfadjustinterwordglue}, \type {\pdfprependkern}, and \type + {\pdfappendkern}, as well as the five supporting primitives \type + {\knbscode}, \type {\stbscode}, \type {\shbscode}, \type {\knbccode}, and + \type {\knaccode}. +\stopitem + +\startitem + A number of \quote {\PDFTEX\ primitives} have been removed as they can be + implemented using \LUA: + + \start \raggedright + \type {\pdfelapsedtime}, \type {\pdfescapehex}, \type {\pdfescapename}, \type + {\pdfescapestring}, \type {\pdffiledump}, \type {\pdffilemoddate}, \type + {\pdffilesize}, \type {\pdfforcepagebox}, \type {\pdflastmatch}, \type + {\pdfmatch}, \type {\pdfmdfivesum}, \type {\pdfmovechars}, \type + {\pdfoptionalwaysusepdfpagebox}, \type {\pdfoptionpdfinclusionerrorlevel}, + \type {\pdfresettimer}, \type {\pdfshellescape}, \type {\pdfstrcmp} and \type + {\pdfunescapehex} + \par \stop +\stopitem + +\startitem + The version related primitives \type {\pdftexbanner}, \type {\pdftexversion} + and \type {\pdftexrevision} are no longer present as there is no longer a + relationship with \PDFTEX\ development. +\stopitem + +\startitem + The experimental snapper mechanism has been removed and therefore also the + primitives: + + \start \raggedright + \type {\pdfignoreddimen}, \type {\pdffirstlineheight}, \type + {\pdfeachlineheight}, \type {\pdfeachlinedepth} and \type + {\pdflastlinedepth} + \par \stop +\stopitem + +\startitem + The experimental primitives \type {\primitive}, \type {\ifprimitive}, \type + {\ifabsnum} and \type {\ifabsdim} are promoted to core primitives. The \type + {\pdf*} prefixed originals are not available. +\stopitem + +\startitem + The \PNG\ transparency fix from 1.40.6 is not applied as high|-|level support + is pending. Because \LUATEX\ has a different subsystem for managing images, + more diversion from its ancestor happened in the meantime. +\stopitem + +\startitem + Two extra token lists are provides, \type {\pdfxformresources} and \type + {\pdfxformattr}, as an alternative to \type {\pdfxform} keywords. +\stopitem + +\startitem + The current version of \LUATEX\ no longer replaces and|/|or merges fonts in + embedded \PDF\ files with fonts of the enveloping \PDF\ document. This + regression may be temporary, depending on how the rewritten font backend will + look like. +\stopitem + +\startitem + The primitives \type {\pdfpagewidth} and \type {\pdfpageheight} have been removed + because \type {\pagewidth} and \type {\pageheight} have that purpose. +\stopitem + +\startitem + The primitives \type {\pdfnormaldeviate}, \type {\pdfuniformdeviate}, \type + {\pdfsetrandomseed} and \type {\pdfrandomseed} have been promoted to core + primitives without \type {pdf} prefix so the original commands are no longer + recognized. +\stopitem + +\startitem + The primitives \type {\ifincsname}, \type {\expanded} and \type {\quitvmode} + are now core primitives. +\stopitem + +\startitem + As the hz and protrusion mechanism are part of the core the related + primitives \type {\lpcode}, \type {\rpcode}, \type {\efcode}, \type + {\leftmarginkern}, \type {\rightmarginkern} are promoted to core primitives. The + two commands \type {\protrudechars} and \type {\adjustspacing} replace their + prefixed with \type {\pdf} originals. +\stopitem + +\startitem + The hz optimization code has been partially redone so that we no longer need + to create extra font instances. The front- and backend have been decoupled + and more efficient (\PDF) code is generated. +\stopitem + +\startitem + When \type {\adjustspacing} has value~2, hz optimization will be applied to + glyphs and kerns. When the value is~3, only glyphs will be treated. A value + smaller than~2 disables this feature. +\stopitem + +\startitem + The \type {\tagcode} primitive is promoted to core primitive. +\stopitem + +\startitem + The \type {\letterspacefont} feature is now part of the core but will not be + changed (improved). We just provide it for legacy use. +\stopitem + +\startitem + The \type {\pdfnoligatures} primitive is now \type {\ignoreligaturesinfont}. +\stopitem + +\startitem + The \type {\pdfcopyfont} primitive is now \type {\copyfont}. +\stopitem + +\startitem + The \type {\pdffontexpand} primitive is now \type {\expandglyphsinfont}. +\stopitem + +\startitem + Because position tracking is also available in \DVI\ mode the \type + {\savepos}, \type {\lastxpos} and \type {\lastypos} commands now replace + their \type {pdf} prefixed originals. +\stopitem + +\startitem + The introspective primitives \type {\pdflastximagecolordepth} and \type + {\pdfximagebbox} have been removed. One can use external applications to + determine these properties or use the built|-|in \type {img} library. +\stopitem + +\startitem + The initializers \type {\pdfoutput} has been replaced by \type {\outputmode} and + \type {\pdfdraftmode} is now \type {\draftmode}. +\stopitem + +\startitem + The pixel multiplier dimension \type {\pdfpxdimen} lots its prefix and is now calles + \type {\pxdimen}. +\stopitem + +\startitem + An extra \type {\pdfimageaddfilename} option has been added that can be used to block + writing the filename to the \PDF\ file. +\stopitem + +\startitem + The primitive \type {\pdftracingfonts} is now \type {\tracingfonts} as it + doesn't relate to the backend. +\stopitem + +\startitem + The experimental primitive \type {\pdfinsertht} is kept as \type {\insertht}. +\stopitem + +\startitem + The promotion of primitives to core primitives as well as the separation of + font- and backend means that the initialization namespace \type {pdftex} is + gone. +\stopitem + +\stopitemize + +One change involves the so called xforms and ximages. In \PDFTEX\ these are +implemented as so called whatsits. But contrary to other whatsits they have +dimensions that need to be taken into account when for instance calculating +optimal line breaks. In \LUATEX\ these are now promoted to normal nodes, which +simplifies code that needs those dimensions. + +Another reason for promotion is that these are useful concepts. Backends can +provide the ability to use content that has been rendered in several places, +and images are also common. For that reason we also changed the names: + +\starttabulate[|l|l|] +\NC \bf new name \NC \bf old name \NC \NR +\NC \type {\saveboxresource} \NC \type {\pdfxform} \NC \NR +\NC \type {\saveimageresource} \NC \type {\pdfximage} \NC \NR +\NC \type {\useboxresource} \NC \type {\pdfrefxform} \NC \NR +\NC \type {\useimageresource} \NC \type {\pdfrefximage} \NC \NR +\NC \type {\lastsavedboxresourceindex} \NC \type {\pdflastxform} \NC \NR +\NC \type {\lastsavedimageresourceindex} \NC \type {\pdflastximage} \NC \NR +\NC \type {\lastsavedimageresourcepages} \NC \type {\pdflastximagepages} \NC \NR +\stoptabulate + +There are a few \type {\pdffeedback} features that relate to this but these are +typical backend specific ones. The index that gets returned is to be considered +as \quote {just a number} and although it still has the same meaning (object +related) as before, you should not depend on that. + +The protrusion detection mechanism is enhanced a bit to enable a bit more complex +situations. When protrusion characters are identified some nodes are skipped: + +\startitemize[packed] +\startitem zero glue \stopitem +\startitem penalties \stopitem +\startitem empty discretionaries \stopitem +\startitem normal zero kerns \stopitem +\startitem rules with zero dimensions \stopitem +\startitem math nodes with a surround of zero \stopitem +\startitem dir nodes \stopitem +\startitem empty horizontal lists \stopitem +\startitem local par nodes \stopitem +\startitem inserts, marks and adjusts \stopitem +\startitem boundaries \stopitem +\startitem whatsits \stopitem +\stopitemize + +Because this can not be enough, you can also use a protrusion boundary node to +make the next node being ignored. When the value is~1 or~3, the next node will be +ignored in the test when locating a left boundary condition. When the value is~2 +or~3, the previous node will be ignored when locating a right boundary condition +(the search goes from right to left). This permits protrusion combined with for +instance content moved into the margin: + +\starttyping +\protrusionboundary1\llap{!\quad}«Who needs protrusion?» +\stoptyping + +\stopsubsection + +\startsubsection[title=Changes from \ALEPH\ RC4] + +Because we wanted proper directional typesetting the \ALEPH\ mechanisms looked +most attractive. These are rather close to the ones provided by \OMEGA, so what +we say next applies to both these programs. + +\startitemize + +\startitem + The extended 16-bit math primitives (\type {\omathcode} etc.) have been + removed. +\stopitem + +\startitem + The \OCP\ processing has been removed completely and as a consequence, the + following primitives have been removed: + + \start \raggedright + \type {\ocp}, \type {\externalocp}, \type {\ocplist}, \type {\pushocplist}, + \type {\popocplist}, \type {\clearocplists}, \type {\addbeforeocplist}, \type + {\addafterocplist}, \type {\removebeforeocplist}, \type {\removeafterocplist} + and \type {\ocptracelevel} + \par \stop +\stopitem + +\startitem + \LUATEX\ only understands 4~of the 16~direction specifiers of \ALEPH: \type + {TLT} (latin), \type {TRT} (arabic), \type {RTT} (cjk), \type {LTL} + (mongolian). All other direction specifiers generate an error. +\stopitem + +\startitem + The input translations from \ALEPH\ are not implemented, the related + primitives are not available: + + \start \raggedright + \type {\DefaultInputMode}, \type {\noDefaultInputMode}, \type {\noInputMode}, + \type {\InputMode}, \type {\DefaultOutputMode}, \type {\noDefaultOutputMode}, + \type {\noOutputMode}, \type {\OutputMode}, \type {\DefaultInputTranslation}, + \type {\noDefaultInputTranslation}, \type {\noInputTranslation}, \type + {\InputTranslation}, \type {\DefaultOutputTranslation}, \type + {\noDefaultOutputTranslation}, \type {\noOutputTranslation} and \type + {\OutputTranslation} + \par \stop +\stopitem + +\startitem + Several bugs have been fixed an confusing implementation details have been sorted + out. +\stopitem + +\startitem + The scanner for direction specifications now allows an optional space after + the direction is completely parsed. +\stopitem + +\startitem + The \type {^^} notation has been extended: after \type {^^^^} four hexadecimal + characters are expected and after \type {^^^^^^} six hexadecimal characters + have to be given. The original \TEX\ interpretation is still valid for the + \type {^^} case but the four and six variants do no backtracking, i.e.\ when + they are not followed by the right number of hexadecimal digits they issue an + error message. Because \type{^^^} is a normal \TEX\ case, we don't support the + odd number of \type {^^^^^} either. +\stopitem + +\startitem + Glues {\it immediately after} direction change commands are not legal + breakpoints. +\stopitem + +\startitem + Several mechanisms that need to be right|-|to|-|left aware have been + improved. For instance placement of formula numbers. +\stopitem + +\startitem + The page dimension related primitives \type {\pagewidth} and \type + {\pageheight} have been promoted to core primitives. The \type {\hoffset} and + \type {\voffset} primitives have been fixed. +\stopitem + +\startitem + The primitives \type {\charwd}, \type {\charht}, \type {\chardp} and \type + {\charit} have been removed as we have the \ETEX\ variants \type + {\fontchar*}. +\stopitem + +\startitem + The two dimension registers \type {\pagerightoffset} and \type + {\pagebottomoffset} are now core primitives. +\stopitem + +\startitem + The direction related primitives \type {\pagedir}, \type {\bodydir}, \type + {\pardir}, \type {\textdir}, \type {\mathdir} and \type {\boxdir} are now + core primitives. +\stopitem + +\startitem + The promotion of primitives to core primitives as well as the removed of all + others means that the initialization namespace \type {aleph} is gone. +\stopitem + +\stopitemize + +The above let's itself summarize as: we took the 32 bit aspects and much of the +directional mechanisms. + +\stopsubsection + +\startsubsection[title=Changes from standard \WEBC] + +The compilation framework is \WEBC\ and we keep using that but without the +\PASCAL\ to \CCODE\ step. This framework also provides some common features that +deal with reading bytes from files and locating files in \TDS. This is what we do +different: + +\startitemize + +\startitem + There is no mltex support. +\stopitem + +\startitem + There is no enctex support. +\stopitem + +\startitem + The following encoding related command line switches are silently ignored, + even in non|-|\LUA\ mode: \type {-8bit}, \type {-translate-file}, \type + {-mltex}, \type {-enc} and \type {-etex}. +\stopitem + +\startitem + The \type {\openout} whatsits are not written to the log file. +\stopitem + +\startitem + Some of the so|-|called \WEBC\ extensions are hard to set up in non|-|\KPSE\ + mode because \type {texmf.cnf} is not read: \type {shell-escape} is off (but + that is not a problem because of \LUA's \type {os.execute}), and the paranoia + checks on \type {openin} and \type {openout} do not happen. However, it is + easy for a \LUA\ script to do this itself by overloading \type {io.open}. +\stopitem + +\startitem + The \quote{E} option does not do anything useful. +\stopitem + +\stopitemize + +\stopsubsection + +\startsubsection[reference=backendprimitives,title=The backend primitives \type {\pdf*}] + +In a previous section we mentioned that some \PDFTEX\ primitives were removed and +others promoted to core \LUATEX\ primitives. That is only part of the story. In +order to separate the backend specific primitives in de code these commands are +now replaced by only a few. In traditional \TEX\ we only had the \DVI\ backend +but now we have two: \DVI\ and \PDF. Additional functionality is implemented as +\quote {extensions} in \TEX speak. By separating more strickly we are able to +keep the core (fontend) clean and stable. If for some reason an extra backend +option is needed, it can be implemented without touching the core. The three +\PDF\ backend related primitives are + +\starttyping +\pdfextension command [specification] +\pdfvariable name +\pdffeedback name +\stoptyping + +An extension triggers further parsing, depending on the command given. A variable is +a (kind of) register and can be read and written, while a feedback is reporting +something (as it comes from the backend it's normally a sequence of tokens). + +In order for \LUATEX\ to be more than just \TEX\ you need to enable primitives. That +has already be the case right from the start. If you want the traditional \PDFTEX\ +primitives (for as far their functionality is still around) you now can do this: + +\starttyping +\protected\def\pdfliteral {\pdfextension literal} +\protected\def\pdfcolorstack {\pdfextension colorstack} +\protected\def\pdfsetmatrix {\pdfextension setmatrix} +\protected\def\pdfsave {\pdfextension save\relax} +\protected\def\pdfrestore {\pdfextension restore\relax} +\protected\def\pdfobj {\pdfextension obj } +\protected\def\pdfrefobj {\pdfextension refobj } +\protected\def\pdfannot {\pdfextension annot } +\protected\def\pdfstartlink {\pdfextension startlink } +\protected\def\pdfendlink {\pdfextension endlink\relax} +\protected\def\pdfoutline {\pdfextension outline } +\protected\def\pdfdest {\pdfextension dest } +\protected\def\pdfthread {\pdfextension thread } +\protected\def\pdfstartthread {\pdfextension startthread } +\protected\def\pdfendthread {\pdfextension endthread\relax} +\protected\def\pdfinfo {\pdfextension info } +\protected\def\pdfcatalog {\pdfextension catalog } +\protected\def\pdfnames {\pdfextension names } +\protected\def\pdfincludechars {\pdfextension includechars } +\protected\def\pdffontattr {\pdfextension fontattr } +\protected\def\pdfmapfile {\pdfextension mapfile } +\protected\def\pdfmapline {\pdfextension mapline } +\protected\def\pdftrailer {\pdfextension trailer } +\protected\def\pdfglyphtounicode {\pdfextension glyphtounicode } +\stoptyping + +The introspective primitives can be defined as: + +\starttyping +\def\pdftexversion {\numexpr\pdffeedback version\relax} +\def\pdftexrevision {\pdffeedback revision} +\def\pdflastlink {\numexpr\pdffeedback lastlink\relax} +\def\pdfretval {\numexpr\pdffeedback retval\relax} +\def\pdflastobj {\numexpr\pdffeedback lastobj\relax} +\def\pdflastannot {\numexpr\pdffeedback lastannot\relax} +\def\pdfxformname {\numexpr\pdffeedback xformname\relax} +\def\pdfcreationdate {\pdffeedback creationdate} +\def\pdffontname {\numexpr\pdffeedback fontname\relax} +\def\pdffontobjnum {\numexpr\pdffeedback fontobjnum\relax} +\def\pdffontsize {\dimexpr\pdffeedback fontsize\relax} +\def\pdfpageref {\numexpr\pdffeedback pageref\relax} +\def\pdfcolorstackinit {\pdffeedback colorstackinit} +\stoptyping + +The configuration related registers have become: + +\starttyping +\edef\pdfcompresslevel {\pdfvariable compresslevel} +\edef\pdfobjcompresslevel {\pdfvariable objcompresslevel} +\edef\pdfdecimaldigits {\pdfvariable decimaldigits} +\edef\pdfgamma {\pdfvariable gamma} +\edef\pdfimageresolution {\pdfvariable imageresolution} +\edef\pdfimageapplygamma {\pdfvariable imageapplygamma} +\edef\pdfimagegamma {\pdfvariable imagegamma} +\edef\pdfimagehicolor {\pdfvariable imagehicolor} +\edef\pdfimageaddfilename {\pdfvariable imageaddfilename} +\edef\pdfpkresolution {\pdfvariable pkresolution} +\edef\pdfpkfixeddpi {\pdfvariable pkfixeddpi} +\edef\pdfinclusioncopyfonts {\pdfvariable inclusioncopyfonts} +\edef\pdfinclusionerrorlevel {\pdfvariable inclusionerrorlevel} +\edef\pdfignoreunknownimages {\pdfvariable ignoreunknownimages} +\edef\pdfgentounicode {\pdfvariable gentounicode} +\edef\pdfpagebox {\pdfvariable pagebox} +\edef\pdfminorversion {\pdfvariable minorversion} +\edef\pdfuniqueresname {\pdfvariable uniqueresname} + +\edef\pdfhorigin {\pdfvariable horigin} +\edef\pdfvorigin {\pdfvariable vorigin} +\edef\pdflinkmargin {\pdfvariable linkmargin} +\edef\pdfdestmargin {\pdfvariable destmargin} +\edef\pdfthreadmargin {\pdfvariable threadmargin} +\edef\pdfxformmargin {\pdfvariable xformmargin} + +\edef\pdfpagesattr {\pdfvariable pagesattr} +\edef\pdfpageattr {\pdfvariable pageattr} +\edef\pdfpageresources {\pdfvariable pageresources} +\edef\pdfxformattr {\pdfvariable xformattr} +\edef\pdfxformresources {\pdfvariable xformresources} +\edef\pdfpkmode {\pdfvariable pkmode} + +\edef\pdfsuppressoptionalinfo {\pdfvariable suppressoptionalinfo } +\edef\pdftrailerid {\pdfvariable trailerid } +\stoptyping + +The variables are internal ones, so they are anonymous. When you ask for the +meaning of a few previously defined ones: + +\starttyping +\meaning\pdfhorigin +\meaning\pdfcompresslevel +\meaning\pdfpageattr +\stoptyping + +you will get: + +\starttyping +macro:->[internal backend dimension] +macro:->[internal backend integer] +macro:->[internal backend tokenlist] +\stoptyping + +The \type {\edef} can also be an \type {\def} but it's a bit more efficient +to expand the lookup related register beforehand. After that you can adapt +the defaults; these are: + +\starttyping +\pdfcompresslevel 9 +\pdfobjcompresslevel 1 % used: (0,9) +\pdfdecimaldigits 4 % used: (3,6) +\pdfgamma 1000 +\pdfimageresolution 71 +\pdfimageapplygamma 0 +\pdfimagegamma 2200 +\pdfimagehicolor 1 +\pdfimageaddfilename 1 +\pdfpkresolution 72 +\pdfpkfixeddpi 0 +\pdfinclusioncopyfonts 0 +\pdfinclusionerrorlevel 0 +\pdfignoreunknownimages 0 +\pdfgentounicode 0 +\pdfpagebox 0 +\pdfminorversion 4 +\pdfuniqueresname 0 + +\pdfhorigin 1in +\pdfvorigin 1in +\pdflinkmargin 0pt +\pdfdestmargin 0pt +\pdfthreadmargin 0pt +\pdfxformmargin 0pt +\stoptyping + +If you also want some backward compatibility, you can add: + +\starttyping +\let\pdfpagewidth \pagewidth +\let\pdfpageheight \pageheight + +\let\pdfadjustspacing \adjustspacing +\let\pdfprotrudechars \protrudechars +\let\pdfnoligatures \ignoreligaturesinfont +\let\pdffontexpand \expandglyphsinfont +\let\pdfcopyfont \copyfont + +\let\pdfxform \saveboxresource +\let\pdflastxform \lastsavedboxresourceindex +\let\pdfrefxform \useboxresource + +\let\pdfximage \saveimageresource +\let\pdflastximage \lastsavedimageresourceindex +\let\pdflastximagepages\lastsavedimageresourcepages +\let\pdfrefximage \useimageresource + +\let\pdfsavepos \savepos +\let\pdflastxpos \lastxpos +\let\pdflastypos \lastypos + +\let\pdfoutput \outputmode +\let\pdfdraftmode \draftmode + +\let\pdfpxdimen \pxdimen + +\let\pdfinsertht \insertht + +\let\pdfnormaldeviate \normaldeviate +\let\pdfuniformdeviate \uniformdeviate +\let\pdfsetrandomseed \setrandomseed +\let\pdfrandomseed \randomseed + +\let\pdfprimitive \primitive +\let\ifpdfprimitive \ifprimitive + +\let\ifpdfabsnum \ifabsnum +\let\ifpdfabsdim \ifabsdim +\stoptyping + +And even: + +\starttyping +\newdimen\pdfeachlineheight +\newdimen\pdfeachlinedepth +\newdimen\pdflastlinedepth +\newdimen\pdffirstlineheight +\newdimen\pdfignoreddimen +\stoptyping + +The backend is derived from \PDFTEX\ so the same syntax applies. However, the +\type {outline} command accepts a \type {objnum} followed by a number. No +checking takes place so when this is used it had better be a valid (flushed) +object. + +In order to be (more or less) compatible with \PDFTEX\ we also support the +option to suppress some info: + +\starttyping +\pdfvariable suppressoptionalinfo \numexpr + 0 + + 1 % PTEX.FullBanner + + 2 % PTEX.FileName + + 4 % PTEX.PageNumber + + 8 % PTEX.InfoDict + + 16 % Creator + + 32 % CreationDate + + 64 % ModDate + + 128 % Producer + + 256 % Trapped + + 512 % ID +\relax +\stoptyping + +In addition you can overload the trailer id, but we don't do any checking on +validity, so you have to pass a valid array. The following is like the ones +normally generated by the engine: + +\starttyping +\pdfvariable trailerid {[ + <FA052949448907805BA83C1E78896398> + <FA052949448907805BA83C1E78896398> +]} +\stoptyping + +So, you even need to include the brackets! + +\stopsubsection + +\stopsection + +\startsection[title=Implementation notes] + +\startsubsection[title=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}. We mention this because using the \TEX book as +reference is still quite valid but not for memory related details. Another +significate detail is that we have double linked node lists and that some nodes +carry more data. + +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. Details like this are +of no concern to users. + +The input line buffer and pool size are now also reallocated when needed, and the +\type {texmf.cnf} settings \type {buf_size} and \type {pool_size} are silently +ignored. + +\stopsubsection + +\startsubsection[title=Sparse arrays] + +The \type {\mathcode}, \type {\delcode}, \type {\catcode}, \type {\sfcode}, \type +{\lccode} and \type {\uccode} (and the new \type {\hjcode}) tables are now sparse +arrays that are implemented in~\CCODE. They are no longer part of the \TEX\ +\quote {equivalence table} and because each had 1.1 million entries with a few +memory words each, this makes a major difference in memory usage. + +The \type {\catcode}, \type {\sfcode}, \type {\lccode}, \type {\uccode} and \type +{\hjcode} assignments do not yet show up when using the \ETEX\ tracing routines +\type {\tracingassigns} and \type {\tracingrestores}. + +A side|-|effect of the current implementation is that \type {\global} is now more +expensive in terms of processing than non|-|global assignments. + +The glyph ids within a font are also managed by means of a sparse array as glyph +ids can go up to index $2^{21}-1$. + +\stopsubsection + +\startsubsection[title=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. + +\stopsubsection + +\startsubsection[title=Compressed format] + +The format is passed through \type {zlib}, allowing it to shrink to roughly half +of the size it would have had in uncompressed form. This takes a bit more \CPU\ +cycles but much less disk \IO, so it should still be faster. + +\stopsubsection + +\startsubsection[title=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 \CCODE\ function +using basically the same convention as the callback: a single read into a buffer +big enough to hold the entire file contents. While this uses more memory than the +previous code (that mostly used \type {getc} calls), it can be quite a bit faster +(depending on your \IO\ subsystem). + +\stopsubsection + +\stopsection + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-nodes.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-nodes.tex new file mode 100644 index 00000000000..372aca1e58b --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-nodes.tex @@ -0,0 +1,1804 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-nodes + +\startchapter[reference=nodes,title={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 \type {node.types()} is: +\startluacode + for id, name in table.sortedhash(node.types()) do + context.type(name) + context(" (%s), ",id) + end + context.removeunwantedspaces() + context.removepunctuation() +\stopluacode +. % period + +The \type {\lastnodetype} primitive is \ETEX\ compliant. The valid range is still +$[-1,15]$ and glyph nodes (formerly known as char nodes) have number~0 while +ligature nodes are mapped to~7. That way macro packages can use the same symbolic +names as in traditional \ETEX. Keep in mind that these \ETEX\ node numbers are +different from the real internal ones and that there are more \ETEX\ node types +than~15. + +You can ask for a list of fields with the \type {node.fields} (which takes an id) +and for valid subtypes with \type {node.subtypes} (which takes a string because +eventually we might support more used enumerations). + +\subsection{Attributes} + +The newly introduced attribute registers are non|-|trivial, because the value +that is attached to a node is essentially a sparse array of key|-|value pairs. It +is generally easiest to deal with attribute lists and attributes by using the +dedicated functions in the \type {node} library, but for completeness, here is +the low|-|level interface. + +\subsubsection{attribute_list nodes} + +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 \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC next \NC node \NC pointer to the first attribute \NC \NR +\stoptabulate + +\subsubsection{attribute nodes} + +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. + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC next \NC 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. + +\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 \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC next \NC 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. By now most of \TEX's node processing makes sure that the +\type {prev} nodes are valid but there can be exceptions, especially when the +internal magic uses a leading \type {temp} nodes to temporarily store a state. + +\subsubsection{hlist nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{list} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width of the box \NC \NR +\NC height \NC number \NC the height of the box \NC \NR +\NC depth \NC number \NC the depth of the box \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 = \type {normal}, 1 = \type {stretching}, 2 = \type {shrinking} \NC \NR +\NC head/list \NC 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 field name \type {head} and \type {list} are both valid. Sometimes it +makes more sense to refer to a list by \type {head}, sometimes \type {list} makes +more sense. + +\subsubsection{vlist nodes} + +This node is similar to \type {hlist}, except that \quote {shift} is a displacement +perpendicular to the line progression direction, and \quote {subtype} only has +the values 0, 4, and~5. + +\subsubsection{rule nodes} + +Contrary to traditional \TEX, \LUATEX\ has more subtypes because we also use +rules to store reuseable objects and images. User nodes are invisible and can be +intercepted by a callback. + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{rule} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width of the rule where 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 +\NC index \NC number \NC an optional index that can be referred to \NC \NR +\stoptabulate + +\subsubsection{ins nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC the insertion class \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC cost \NC number \NC the penalty associated with this insert \NC \NR +\NC height \NC number \NC height of the insert \NC \NR +\NC depth \NC number \NC depth of the insert \NC \NR +\NC head/list \NC node \NC the first node of the body of this insert \NC \NR +\stoptabulate + +There is a set of extra fields that concern the associated glue: \type {width}, +\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}. +These are all numbers. + +A warning: never assign a node list to the \type {head} field unless you are sure +its internal link structure is correct, otherwise an error may be result. You can use +\type {list} instead (often in functions you want to use local variable swith similar +names and both names are equally sensible). + +\subsubsection{mark nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC unused \NC \NR +\NC attr \NC node \NC list of attributes \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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{adjust} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC head/list \NC 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. + +\subsubsection{disc nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{disc} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC pre \NC node \NC pointer to the pre|-|break text \NC \NR +\NC post \NC node \NC pointer to the post|-|break text \NC \NR +\NC replace \NC node \NC pointer to the no|-|break text \NC \NR +\NC penalty \NC number \NC the penalty associated with the break, normally \type {\hyphenpenalty} or \type {\exhyphenpenalty} \NC \NR +\stoptabulate + +The subtype numbers~4 and~5 belong to the \quote {of-f-ice} explanation given +elsewhere. + +\subsubsection{math nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{math} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC surround \NC number \NC width of the \type {\mathsurround} kern \NC \NR +\stoptabulate + +There is a set of extra fields that concern the associated glue: \type {width}, +\type {stretch}, \type {stretch_order}, \type {shrink} and \type {shrink_order}. +These are all numbers. + +\subsubsection{glue nodes} + +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 \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC width \NC number \NC the horizontal or vertical displacement \NC \NR +\NC stretch \NC number \NC extra (positive) displacement or stretch amount \NC \NR +\NC stretch_order \NC number \NC factor applied to stretch amount \NC \NR +\NC shrink \NC number \NC extra (negative) displacement or shrink amount\NC \NR +\NC shrink_order \NC number \NC factor applied to shrink amount \NC \NR +\stoptabulate + +The effective width of some glue subtypes depends on the stretch or shrink needed +to make the encapsulating box fit its dimensions. For instance, in a paragraph +lines normally have glue representing spaces and these stretch of shrink to make +the content fit in the available space. The \type {effective_glue} function that +takes a glue node and a parent (hlist or vlist) returns the effective width of +that glue item. + +A gluespec node is a special kind of node that is used for storing a set of glue +values in registers. Originally they were also used to store properties of glue +nodes (using a system of reference counts) but we now keep these properties in +the glue nodes themselves, which gives a cleaner interface to \LUA. + +The indirect spec approach was in fact an optimization in the original \TEX\ +code. First of all it can save quite some memory because all these spaces that +become glue now share the same specification (only the reference count is +incremented), and zero testing is also a bit faster because only the pointer has +to be checked (this is no longer true for engines that implement for instance +protrusion where we really need to ensure that zero is zero when we test for +bounds). Another side effect is that glue specifications are read|-|only, so in +the end copies need to be made when they are used from \LUA\ (each assignment to +a field can result in a new copy). So in the end the advantages of sharing are +not that high (and nowadays memory is less an issue, also given that a glue node +is only a few memory words larger than a spec). + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{glue} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC leader \NC node \NC pointer to a box or rule for leaders \NC \NR +\stoptabulate + +In addition there are the \type {width}, \type {stretch} \type {stretch_order}, +\type {shrink}, and \type {shrink_order} fields. Note that we use the key \type +{width} in both horizontal and vertical glue. This suits the \TEX\ internals well +so we decided to stick to that naming. + +A regular word space also results in a \type {spaceskip} subtype (this used to be +a \type {userskip} with subtype zero). + +\subsubsection{kern nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{kern} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC kern \NC number \NC fixed horizontal or vertical advance \NC \NR +\stoptabulate + +\subsubsection{penalty nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC not used \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC penalty \NC number \NC the penalty value \NC \NR +\stoptabulate + +\subsubsection[glyphnodes]{glyph nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \rmbf type \NC \rmbf explanation \NC \NR +\NC subtype \NC number \NC bitfield \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC char \NC number \NC the chatacter index in the font \NC \NR +\NC font \NC number \NC the font identifier \NC \NR +\NC lang \NC number \NC the language identifier \NC \NR +\NC left \NC number \NC the frozen \type {\lefthyphenmnin} value \NC \NR +\NC right \NC number \NC the frozen \type {\righthyphenmnin} value \NC \NR +\NC uchyph \NC boolean \NC the frozen \type {\uchyph} value \NC \NR +\NC components \NC node \NC pointer to ligature components \NC \NR +\NC xoffset \NC number \NC a virtual displacement in horizontal direction \NC \NR +\NC yoffset \NC number \NC a virtual displacement in vertical direction \NC \NR +\NC xadvance \NC number \NC an additional advance after the glyph (experimental) \NC \NR +\NC width \NC number \NC the (original) width of the character \NC \NR +\NC height \NC number \NC the (original) height of the character\NC \NR +\NC depth \NC number \NC the (original) depth of the character\NC \NR +\NC expansion_factor \NC number \NC the to be applied expansion_factor \NC \NR +\stoptabulate + +The \type {width}, \type {height} and \type {depth} values are read|-|only. The +\type {expansion_factor} is assigned in the parbuilder and used in the backend. + +A warning: never assign a node list to the components field unless you are sure +its internal link structure is correct, otherwise an error may be result. Valid +bits for the \type {subtype} field are: + +\starttabulate[|c|l|] +\NC \rmbf 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} has been introduced as part of the separation +between font- and backend. It is the result of extensive experiments with a more +efficient implementation of expansion. Early versions of \LUATEX\ already +replaced multiple instances of fonts in the backend by scaling but contrary to +\PDFTEX\ in \LUATEX\ we now also got rid of font copies in the frontend and +replaced them by expansion factors that travel with glyph nodes. Apart from a +cleaner approach this is also a step towards a better separation between front- +and backend. + +The \type {is_char} function checks if a node is a glyph node with a subtype still +less than 256. This function can be used to determine if applying font logic to a +glyph node makes sense. The value \type {nil} gets returned when the node is not +a glyph, a character number is returned if the node is still tagged as character +and \type {false} gets returned otherwise. When nil is returned, the id is also +returned. The \type {is_glyph} variant doesn't check for a subtype being less +than 256, so it returns either the character value or nil plus the id. These +helpers are not always faster than separate calls but they sometimes permit +making more readable tests. + +\subsubsection{boundary nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{boundary} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC value \NC number \NC values 0--255 are reserved \NC \NR +\stoptabulate + +This node relates to the \type {\noboundary}, \type {\boundary}, \type +{\protrusionboundary} and \type {\wordboundary} primitives. + +\subsubsection{local_par nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC pen_inter \NC number \NC local interline penalty (from \type {\localinterlinepenalty}) \NC \NR +\NC pen_broken \NC number \NC local broken penalty (from \type {\localbrokenpenalty}) \NC \NR +\NC dir \NC string \NC the direction of this par. see~\in [dirnodes] \NC \NR +\NC box_left \NC node \NC the \type {\localleftbox} \NC \NR +\NC box_left_width \NC number \NC width of the \type {\localleftbox} \NC \NR +\NC box_right \NC node \NC the \type {\localrightbox} \NC \NR +\NC box_right_width \NC number \NC width of the \type {\localrightbox} \NC \NR +\stoptabulate + +A warning: never assign a node list to the \type {box_left} or \type {box_right} +field unless you are sure its internal link structure is correct, otherwise an +error may be result. + +\subsubsection[dirnodes]{dir nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \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 +\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[packed] +\startitem + the first is the direction of the \quote{top} of paragraphs. +\stopitem +\startitem + the second is the direction of the \quote{start} of lines. +\stopitem +\startitem + the third is the direction of the \quote{top} of glyphs. +\stopitem +\stopitemize + +However, only four combinations are accepted: \type {TLT}, \type {TRT}, \type +{RTT}, and \type {LTL}. + +Inside actual \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{margin_kern nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{margin_kern} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the advance of the kern \NC \NR +\NC glyph \NC node \NC the glyph to be used \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 subnodes 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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC char \NC number \NC the character index \NC \NR +\NC fam \NC number \NC the family number \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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC head/list \NC node \NC list of nodes \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. + +\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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC small_char \NC number \NC character index of base character \NC \NR +\NC small_fam \NC number \NC family number of base character \NC \NR +\NC large_char \NC number \NC character index of next larger character \NC \NR +\NC large_fam \NC number \NC family number of next larger character \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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{noad} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC nucleus \NC kernel node \NC base \NC \NR +\NC sub \NC kernel node \NC subscript \NC \NR +\NC sup \NC kernel node \NC superscript \NC \NR +\stoptabulate + +\subsubsubsection{accent nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{accent} \NC \NR +\NC nucleus \NC kernel node \NC base \NC \NR +\NC sub \NC kernel node \NC subscript \NC \NR +\NC sup \NC kernel node \NC superscript \NC \NR +\NC accent \NC kernel node \NC top accent \NC \NR +\NC bot_accent \NC kernel node \NC bottom accent \NC \NR +\stoptabulate + +\subsubsubsection{style nodes} + +\starttabulate[|lT|l|p|] +\NC \rmbf 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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC display \NC node \NC list of display size alternatives \NC \NR +\NC text \NC node \NC list of text size alternatives \NC \NR +\NC script \NC node \NC list of scriptsize alternatives \NC \NR +\NC scriptscript \NC node \NC list of scriptscriptsize alternatives \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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{radical} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC nucleus \NC kernel node \NC base \NC \NR +\NC sub \NC kernel node \NC subscript \NC \NR +\NC sup \NC kernel node \NC superscript \NC \NR +\NC left \NC delimiter node \NC \NC \NR +\NC degree \NC kernel node \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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC (optional) width of the fraction \NC \NR +\NC num \NC kernel node \NC numerator \NC \NR +\NC denom \NC kernel node \NC denominator \NC \NR +\NC left \NC delimiter node \NC left side symbol \NC \NR +\NC right \NC delimiter node \NC right side symbol\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} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC subtype \NC number \NC \showsubtypes{fence} \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC delim \NC delimiter node \NC delimiter specification \NC \NR +\stoptabulate + +\subsection{whatsit nodes} + +Whatsit nodes come in many subtypes that you can ask for by running +\type {node.whatsits()}: +\startluacode + for id, name in table.sortedpairs(node.whatsits()) do + context.type(name) + context(" (%s), ",id) + end + context.removeunwantedspaces() + context.removepunctuation() +\stopluacode +. % period + +\subsubsection{front|-|end whatits} + +\subsubsubsection{open whatsits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \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 + +\subsubsubsection{write whatsits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \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 + +\subsubsubsection{close whatsits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC stream \NC number \NC \TEX's stream id number \NC \NR +\stoptabulate + +\subsubsubsection{user_defined whatits} + +User|-|defined whatsit nodes can only be created and handled from \LUA\ code. In +effect, they are an extension to the extension mechanism. The \LUATEX\ engine +will simply step over such whatsits without ever looking at the contents. + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \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 a \LUA\ number \NC \NR +\NC \NC node \NC a node list \NC \NR +\NC \NC string \NC a \LUA\ string \NC \NR +\NC \NC table \NC a \LUA\ table \NC \NR +\stoptabulate + +The \type {type} can have one of five distinct values: + +\starttabulate[|lT|p|] +\NC \rmbf value \NC \bf explanation \NC \NR +\NC 97 \NC list of attributes \NC \NR +\NC 100 \NC a \LUA\ number \NC \NR +\NC 110 \NC a node list \NC \NR +\NC 115 \NC a \LUA\ string \NC \NR +\NC 116 \NC a \LUA\ token list in \LUA\ table form \NC \NR +\stoptabulate + +\subsubsubsection{save_pos whatsits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\stoptabulate + +\subsubsubsection{late_lua whatsits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC data \NC string \NC data to execute \NC \NR +\NC string \NC string \NC data to execute \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 \type {\latelua}. The +\type {string} version is treated as a literal string. + +\subsubsection{\DVI\ backend whatits} + +\subsubsection{special whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC data \NC string \NC the \type {\special} information \NC \NR +\stoptabulate + +\subsubsection{\PDF\ backend whatits} + +\subsubsubsection{pdf_literal whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC mode \NC number \NC the \quote {mode} setting of this literal \NC \NR +\NC data \NC string \NC the \type {\pdfliteral} information \NC \NR +\stoptabulate + +Possible mode values are: + +\starttabulate[|lT|p|] +\NC \rmbf value \NC \rmbf \PDFTEX\ keyword \NC \NR +\NC 0 \NC setorigin \NC \NR +\NC 1 \NC page \NC \NR +\NC 2 \NC direct \NC \NR +\stoptabulate + +\subsubsubsection{pdf_refobj whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC objnum \NC number \NC the referenced \PDF\ object number \NC \NR +\stoptabulate + +\subsubsubsection{pdf_annot whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width (not used in calculations) \NC \NR +\NC height \NC number \NC the height (not used in calculations) \NC \NR +\NC depth \NC number \NC the depth (not used in calculations) \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 + +\subsubsubsection{pdf_start_link whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width (not used in calculations) \NC \NR +\NC height \NC number \NC the height (not used in calculations) \NC \NR +\NC depth \NC number \NC the depth (not used in calculations) \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 node \NC the action to perform \NC \NR +\stoptabulate + +\subsubsubsection{pdf_end_link whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC \NC \NR +\stoptabulate + +\subsubsubsection{pdf_dest whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width (not used in calculations) \NC \NR +\NC height \NC number \NC the height (not used in calculations) \NC \NR +\NC depth \NC number \NC the depth (not used in calculations) \NC \NR +\NC named_id \NC number \NC is the \type {dest_id} a string value? \NC \NR +\NC dest_id \NC number \NC the destination id \NC \NR +\NC \NC string \NC the destination name \NC \NR +\NC dest_type \NC number \NC type of destination \NC \NR +\NC xyz_zoom \NC number \NC the zoom factor (times 1000) \NC \NR +\NC objnum \NC number \NC the \PDF\ object number \NC \NR +\stoptabulate + +\subsubsubsection{pdf_action whatits} + +These are a special kind of item that only appears inside \PDF\ start link +objects. + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC action_type \NC number \NC the kind of action involved \NC \NR +\NC action_id \NC number or string \NC token list reference or string \NC \NR +\NC named_id \NC number \NC the index of the destination \NC \NR +\NC file \NC string \NC the target filename \NC \NR +\NC new_window \NC number \NC the window state of the target \NC \NR +\NC data \NC string \NC the name of the destination \NC \NR +\stoptabulate + +Valid action types are: + +\starttabulate[|lT|lT|] +\NC 0 \NC page \NC \NR +\NC 1 \NC goto \NC \NR +\NC 2 \NC thread \NC \NR +\NC 3 \NC user \NC \NR +\stoptabulate + +Valid window types are: + +\starttabulate[|lT|lT|] +\NC 0 \NC notset \NC \NR +\NC 1 \NC new \NC \NR +\NC 2 \NC nonew \NC \NR +\stoptabulate + +\subsubsubsection{pdf_thread whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width (not used in calculations) \NC \NR +\NC height \NC number \NC the height (not used in calculations) \NC \NR +\NC depth \NC number \NC the depth (not used in calculations) \NC \NR +\NC named_id \NC number \NC is \type {tread_id} a string value? \NC \NR +\NC tread_id \NC number \NC the thread id \NC \NR +\NC \NC string \NC the thread name \NC \NR +\NC thread_attr \NC number \NC extra thread information \NC \NR +\stoptabulate + +\subsubsubsection{pdf_start_thread whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC width \NC number \NC the width (not used in calculations) \NC \NR +\NC height \NC number \NC the height (not used in calculations) \NC \NR +\NC depth \NC number \NC the depth (not used in calculations) \NC \NR +\NC named_id \NC number \NC is \type {tread_id} a string value? \NC \NR +\NC tread_id \NC number \NC the thread id \NC \NR +\NC \NC string \NC the thread name \NC \NR +\NC thread_attr \NC number \NC extra thread information \NC \NR +\stoptabulate + +\subsubsubsection{pdf_end_thread whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC \NC \NR +\stoptabulate + +\subsubsubsection{pdf_colorstack whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC stack \NC number \NC colorstack id number \NC \NR +\NC command \NC number \NC command to execute \NC \NR +\NC data \NC string \NC data \NC \NR +\stoptabulate + +\subsubsubsection{pdf_setmatrix whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\NC data \NC string \NC data \NC \NR +\stoptabulate + +\subsubsubsection{pdf_save whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\stoptabulate + +\subsubsubsection{pdf_restore whatits} + +\starttabulate[|lT|l|p|] +\NC \rmbf field \NC \bf type \NC \bf explanation \NC \NR +\NC attr \NC node \NC list of attributes \NC \NR +\stoptabulate + +\section{Two access models} + +Deep down in \TEX\ a node has a number which is an numeric entry in a memory +table. In fact, this model, where \TEX\ manages memory is real fast and one of +the reasons why plugging in callbacks that operate on nodes is quite fast too. +Each node gets a number that is in fact an index in the memory table and that +number often gets reported when you print node related information. + +There are two access models, a robust one using a so called user data object that +provides a virtual interface to the internal nodes, and a more direct access which +uses the node numbers directly. The first model provide key based access while +the second always accesses fields via functions: + +\starttyping +nodeobject.char +getfield(nodenumber,"char") +\stoptyping + +If you use the direct model, even if you know that you deal with numbers, you +should not depend on that property but treat it an abstraction just like +traditional nodes. In fact, the fact that we use a simple basic datatype has the +penalty that less checking can be done, but less checking is also the reason why +it's somewhat faster. An important aspect is that one cannot mix both methods, +but you can cast both models. So, multiplying a node number makes no sense. + +So our advice is: use the indexed (table) approach when possible and investigate +the direct one when speed might be an real 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 + +If performance matters you can use an function instead: + +\starttabulate[|T|p|] +\NC getnext \NC parsing nodelist always involves this one \NC \NR +\NC getprev \NC used less but is logical companion to \type {getnext} \NC \NR +\NC getboth \NC returns the next and prev pointer of a node \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 \OPENTYPE\ handling (glyph nodes are consulted a lot) \NC \NR +\NC getchar \NC idem and also in other places \NC \NR +\NC getdisc \NC returns the \type {pre}, \type {post} and \type {replace} fields and + optionally when true is passed also the tail fields. \NC \NR +\NC 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 + +The direct variants also have setters, where the discretionary setter takes three +(optional) arguments plus an optional fourth indicating the subtype. + +It doesn't make sense to add getters for all fields, also because some are not +unique to one node type. 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: + +% \startcolumns[balance=yes] + +\def\yes{$+$} \def\nop{$-$} + +\starttabulate[|T|c|c|] +\HL +\NC \bf function \NC \bf node \NC \bf direct \NC \NR +\HL +\NC \type {copy_list} \NC \yes \NC \yes \NC \NR +\NC \type {copy} \NC \yes \NC \yes \NC \NR +\NC \type {count} \NC \yes \NC \yes \NC \NR +\NC \type {current_attr} \NC \yes \NC \yes \NC \NR +\NC \type {dimensions} \NC \yes \NC \yes \NC \NR +\NC \type {do_ligature_n} \NC \yes \NC \yes \NC \NR +\NC \type {effective_glue} \NC \yes \NC \yes \NC \NR +\NC \type {end_of_math} \NC \yes \NC \yes \NC \NR +\NC \type {family_font} \NC \yes \NC \nop \NC \NR +\NC \type {fields} \NC \yes \NC \nop \NC \NR +\NC \type {first_character} \NC \yes \NC \nop \NC \NR +\NC \type {first_glyph} \NC \yes \NC \yes \NC \NR +\NC \type {flush_list} \NC \yes \NC \yes \NC \NR +\NC \type {flush_node} \NC \yes \NC \yes \NC \NR +\NC \type {free} \NC \yes \NC \yes \NC \NR +\NC \type {getboth} \NC \yes \NC \yes \NC \NR +\NC \type {getbox} \NC \nop \NC \yes \NC \NR +\NC \type {getchar} \NC \yes \NC \yes \NC \NR +\NC \type {getdisc} \NC \yes \NC \yes \NC \NR +\NC \type {getfield} \NC \yes \NC \yes \NC \NR +\NC \type {getfont} \NC \yes \NC \yes \NC \NR +\NC \type {getid} \NC \yes \NC \yes \NC \NR +\NC \type {getleader} \NC \yes \NC \yes \NC \NR +\NC \type {getlist} \NC \yes \NC \yes \NC \NR +\NC \type {getnext} \NC \yes \NC \yes \NC \NR +\NC \type {getprev} \NC \yes \NC \yes \NC \NR +\NC \type {getsubtype} \NC \yes \NC \yes \NC \NR +\NC \type {has_attribute} \NC \yes \NC \yes \NC \NR +\NC \type {has_field} \NC \yes \NC \yes \NC \NR +\NC \type {has_glyph} \NC \yes \NC \yes \NC \NR +\NC \type {hpack} \NC \yes \NC \yes \NC \NR +\NC \type {id} \NC \yes \NC \nop \NC \NR +\NC \type {insert_after} \NC \yes \NC \yes \NC \NR +\NC \type {insert_before} \NC \yes \NC \yes \NC \NR +\NC \type {is_char} \NC \yes \NC \yes \NC \NR +\NC \type {is_glyph} \NC \yes \NC \yes \NC \NR +\NC \type {is_direct} \NC \nop \NC \yes \NC \NR +\NC \type {is_node} \NC \yes \NC \yes \NC \NR +\NC \type {kerning} \NC \yes \NC \yes \NC \NR +\NC \type {last_node} \NC \yes \NC \yes \NC \NR +\NC \type {length} \NC \yes \NC \yes \NC \NR +\NC \type {ligaturing} \NC \yes \NC \yes \NC \NR +\NC \type {mlist_to_hlist} \NC \yes \NC \nop \NC \NR +\NC \type {new} \NC \yes \NC \yes \NC \NR +\NC \type {next} \NC \yes \NC \nop \NC \NR +\NC \type {prev} \NC \yes \NC \nop \NC \NR +\NC \type {protect_glyph} \NC \yes \NC \yes \NC \NR +\NC \type {protect_glyphs} \NC \yes \NC \yes \NC \NR +\NC \type {protrusion_skippable} \NC \yes \NC \yes \NC \NR +\NC \type {remove} \NC \yes \NC \yes \NC \NR +\NC \type {set_attribute} \NC \yes \NC \yes \NC \NR +\NC \type {setboth} \NC \yes \NC \yes \NC \NR +\NC \type {setbox} \NC \yes \NC \yes \NC \NR +\NC \type {setchar} \NC \yes \NC \yes \NC \NR +\NC \type {setdisc} \NC \yes \NC \yes \NC \NR +\NC \type {setfield} \NC \yes \NC \yes \NC \NR +\NC \type {setlink} \NC \yes \NC \yes \NC \NR +\NC \type {setnext} \NC \yes \NC \yes \NC \NR +\NC \type {setprev} \NC \yes \NC \yes \NC \NR +\NC \type {slide} \NC \yes \NC \yes \NC \NR +\NC \type {subtype} \NC \yes \NC \nop \NC \NR +\NC \type {subtypes} \NC \yes \NC \nop \NC \NR +\NC \type {tail} \NC \yes \NC \yes \NC \NR +\NC \type {todirect} \NC \yes \NC \yes \NC \NR +\NC \type {tonode} \NC \yes \NC \yes \NC \NR +\NC \type {tostring} \NC \yes \NC \yes \NC \NR +\NC \type {traverse_id} \NC \yes \NC \yes \NC \NR +\NC \type {traverse_char} \NC \yes \NC \yes \NC \NR +\NC \type {traverse} \NC \yes \NC \yes \NC \NR +\NC \type {types} \NC \yes \NC \nop \NC \NR +\NC \type {type} \NC \yes \NC \nop \NC \NR +\NC \type {unprotect_glyphs} \NC \yes \NC \yes \NC \NR +\NC \type {unset_attribute} \NC \yes \NC \yes \NC \NR +\NC \type {usedlist} \NC \yes \NC \yes \NC \NR +\NC \type {vpack} \NC \yes \NC \yes \NC \NR +\NC \type {whatsits} \NC \yes \NC \nop \NC \NR +\NC \type {whatsitsubtypes} \NC \yes \NC \nop \NC \NR +\NC \type {write} \NC \yes \NC \yes \NC \NR +\NC \type {setglue} \NC \yes \NC \yes \NC \NR +\NC \type {getglue} \NC \yes \NC \yes \NC \NR +\NC \type {glue_is_zero} \NC \yes \NC \yes \NC \NR +\stoptabulate + +% \stopcolumns + +The \type {node.next} and \type {node.prev} functions will stay but for +consistency there are variants called \type {getnext} and \type {getprev}. We had +to use \type {get} because \type {node.id} and \type {node.subtype} are already +taken for providing meta information about nodes. Note: The getters do only basic +checking for valid keys. You should just stick to the keys mentioned in the +sections that describe node properties. + +Some nodes have indirect references. For instance a math character refers to a +family instead of a font. In that case we provide a virtual font field as +accessor. So, \type {getfont} and \type {.font} can be used on them. The same is +true for the \type {width}, \type {height} and \type {depth} of glue nodes. These +actually access the spec node properties, and here we can set as well as get the +values. + +\section{The \type {node} library} + +The \type {node} library contains functions that facilitate dealing with (lists +of) nodes and their values. They allow you to create, alter, copy, delete, and +insert \LUATEX\ node objects, the core objects within the typesetter. + +\LUATEX\ nodes are represented in \LUA\ as userdata with the metadata type +\type {luatex.node}. The various parts within a node can be accessed using +named fields. + +Each node has at least the three fields \type {next}, \type {id}, and \type +{subtype}: + +\startitemize[intro] + +\startitem + The \type {next} field returns the userdata object for the next node in a + linked list of nodes, or \type {nil}, if there is no next node. +\stopitem + +\startitem + The \type {id} indicates \TEX's \quote{node type}. The field \type {id} has a + numeric value for efficiency reasons, but some of the library functions also + accept a string value instead of \type {id}. +\stopitem + +\startitem + The \type {subtype} is another number. It often gives further information + about a node of a particular \type {id}, but it is most important when + dealing with \quote {whatsits}, because they are differentiated solely based + on their \type {subtype}. +\stopitem + +\stopitemize + +The other available fields depend on the \type {id} (and for \quote {whatsits}, +the \type {subtype}) of the node. 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{\type {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{\type {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{\type {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 \type +{node.types}, except that it provides an array of \type {subtype} mappings. + +\subsubsection{\type {node.id}} + +\startfunctioncall +<number> id = + node.id(<string> type) +\stopfunctioncall + +This converts a single type name to its internal numeric representation. + +\subsubsection{\type {node.subtype}} + +\startfunctioncall +<number> subtype = + node.subtype(<string> type) +\stopfunctioncall + +This converts a single whatsit name to its internal numeric representation (\type +{subtype}). + +\subsubsection{\type {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, and \type {nil} +otherwise. + +\subsubsection{\type {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{\type {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{\type {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{\type {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{\type {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{\type {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{\type {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{\type {node.next}} + +\startfunctioncall +<node> m = + node.next(<node> n) +\stopfunctioncall + +Returns the node following this node, or \type {nil} if there is no such node. + +\subsubsection{\type {node.prev}} + +\startfunctioncall +<node> m = + node.prev(<node> n) +\stopfunctioncall + +Returns the node preceding this node, or \type {nil} if there is no such node. + +\subsubsection{\type {node.current_attr}} + +\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{\type {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 (\type {\hbox spread}) or exact (\type {\hbox to}) width to be used. The +second return value is the badness of the generated box. + +Caveat: at this moment, there can be unexpected side|-|effects to this function, +like updating some of the \type {\marks} and \type {\inserts}. Also note that the +content of \type {h} is the original node list \type {n}: if you call \type +{node.free(h)} you will also free the node list itself, unless you explicitly set +the \type {list} field to \type {nil} beforehand. And in a similar way, calling +\type {node.free(n)} will invalidate \type {h} as well! + +\subsubsection{\type {node.vpack}} + +\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 (\type {\vbox spread}) or exact (\type {\vbox to}) height to be used. + +The second return value is the badness of the generated box. + +See the description of \type {node.hpack()} for a few memory allocation caveats. + +\subsubsection{\type {node.dimensions}} + +\startfunctioncall +<number> w, <number> h, <number> d = + node.dimensions(<node> n) +<number> w, <number> h, <number> d = + node.dimensions(<node> n, <string> dir) +<number> w, <number> h, <number> d = + node.dimensions(<node> n, <node> t) +<number> w, <number> h, <number> d = + node.dimensions(<node> n, <node> t, <string> dir) +\stopfunctioncall + +This function calculates the natural in|-|line dimensions of the node list starting +at node \type {n} and terminating just before node \type {t} (or the end of the +list, if there is no second argument). The return values are scaled points. An +alternative format that starts with glue parameters as the first three arguments +is also possible: + +\startfunctioncall +<number> w, <number> h, <number> d = + node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order, + <node> n) +<number> w, <number> h, <number> d = + node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order, + <node> n, <string> dir) +<number> w, <number> h, <number> d = + node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order, + <node> n, <node> t) +<number> w, <number> h, <number> d = + node.dimensions(<number> glue_set, <number> glue_sign, <number> glue_order, + <node> n, <node> t, <string> dir) +\stopfunctioncall + +This calling method takes glue settings into account and is especially useful for +finding the actual width of a sublist of nodes that are already boxed, for +example in code like this, which prints the width of the space in between the +\type {a} and \type {b} as it would be if \type {\box0} was used as-is: + +\starttyping +\setbox0 = \hbox to 20pt {a b} + +\directlua{print (node.dimensions( + tex.box[0].glue_set, + tex.box[0].glue_sign, + tex.box[0].glue_order, + tex.box[0].head.next, + node.tail(tex.box[0].head) +)) } +\stoptyping + +You need to keep in mind that this is one of the few places in \TEX\ where floats +are used, which means that you can get small differences in rounding when you +compare the width repported by \type {hpack} with \type {dimensions}. + +\subsubsection{\type {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{\type {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{\type {node.tail}} + +\startfunctioncall +<node> m = + node.tail(<node> n) +\stopfunctioncall + +Returns the last node of the node list that starts at \type {n}. + +\subsubsection{\type {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{\type {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{\type {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}. +Typically code looks like this: + +\starttyping +for n in node.traverse(head) do + ... +end +\stoptyping + +is functionally equivalent to: + +\starttyping +do + local n + local function f (head,var) + local t + if var == nil then + t = head + else + t = var.next + end + return t + end + while true do + n = f (head, n) + if n == nil then break end + ... + end +end +\stoptyping + +It should be clear from the definition of the function \type {f} that even though +it is possible to add or remove nodes from the node list while traversing, you +have to take great care to make sure all the \type {next} (and \type {prev}) +pointers remain valid. + +If the above is unclear to you, see the section \quote {For Statement} in the +\LUA\ Reference Manual. + +\subsubsection{\type {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{\type {node.end_of_math}} + +\startfunctioncall +<node> t = + node.end_of_math(<node> start) +\stopfunctioncall + +Looks for and returns the next \type {math_node} following the \type {start}. If +the given node is a math 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{\type {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{\type {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{\type {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{\type {node.first_glyph}} + +\startfunctioncall +<node> n = + node.first_glyph(<node> n) +<node> n = + node.first_glyph(<node> n, <node> m) +\stopfunctioncall + +Returns the first node in the list starting at \type {n} that is a glyph node +with a subtype indicating it is a glyph, or \type {nil}. If \type {m} is given, +processing stops at (but including) that node, otherwise processing stops at the +end of the list. + +\subsubsection{\type {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{\type {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 node list. The tail node \type {m} is +optional. The two returned nodes \type {h} and \type {t} are the head and tail +(either one of these can be an inserted kern node, because special kernings with +word boundaries are possible). + +\subsubsection{\type {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{\type {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{\type {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{\type {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! There is no error checking +either! + +\subsubsection{\type {node.protrusion_skippable}} + +\startfunctioncall +<boolean> skippable = + node.protrusion_skippable(<node> n) +\stopfunctioncall + +Returns \type {true} if, for the purpose of line boundary discovery when +character protrusion is active, this node can be skipped. + +\subsection{Glue handling} + +\subsubsection{\type {node.setglue}} + +You can set the properties of a glue in one go. If you pass no values, the glue +will become a zero glue. + +\startfunctioncall +node.setglue(<node> n) +node.setglue(<node> n,width,stretch,shrink,stretch_order,shrink_order) +\stopfunctioncall + +When you pass values, only arguments that are numbers +are assigned so + +\starttyping +node.setglue(n,655360,false,65536) +\stoptyping + +will only adapt the width and shrink. + +\subsubsection{\type {node.getglue}} + +The next call will return 5 values (or northing when no glue is passed). + +\startfunctioncall +<integer> width, <integer> stretch, <integer> shrink, <integer> stretch_order, + <integer> shrink_order = node.getglue(<node> n) +\stopfunctioncall + +\subsubsection{\type {node.is_zero_glue}} + +This function returns \type {true} when the width, stretch and shrink properties +are zero. + +\startfunctioncall +<boolean> isglue = + node.is_zero_glue(<node> n) +\stopfunctioncall + +\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{\type {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{\type {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{\type {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}. + +\stopchapter + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-style.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-style.tex new file mode 100644 index 00000000000..feca120eddb --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-style.tex @@ -0,0 +1,355 @@ +\startenvironment luatex-style + +\usemodule[abr-02] + +\setuplayout + [height=middle, + width=middle, + backspace=2cm, + topspace=10mm, + bottomspace=10mm, + header=10mm, + footer=10mm, + footerdistance=10mm, + headerdistance=10mm] + +\setuppagenumbering + [alternative=doublesided] + +\setuptolerance + [stretch,tolerant] + +\setuptype + [lines=hyphenated] + +\setuptyping + [lines=hyphenated] + +\setupitemize + [each] + [packed] + +\setupwhitespace + [medium] + +\startluacode + local skipped = table.tohash { 'id', 'subtype', 'next', 'prev' } + + function document.functions.showfields(s) + local t = string.split(s,',') + local f = node.fields(t[1],t[2]) + if f then + local d = false + for i=1,#f do + local fi = f[i] + if skipped[fi] then + -- okay + elseif d then + context(', {\tttf %s}', fi) + else + context('{\tttf %s}', fi) + d = true + end + end + end + end + + function document.functions.showid(s) + local t = string.split(s,',') + context('{tttf %s}',node.id(t[1])) + if t[2] then + context(', {tttf %s}',node.subtype(t[2])) + end + end + + function document.functions.showsubtypes(s) + local s = node.subtypes(s) + local d = false + for k, v in table.sortedhash(s) do + if d then + context(', %s = {\\tttf %s}',k,v) + else + context('%s = {\\tttf %s}',k,v) + d = true + end + end + end +\stopluacode + +\unexpanded\def\showfields #1{\ctxlua{document.functions.showfields("#1")}} +\unexpanded\def\showid #1{\ctxlua{document.functions.showid("#1")}} +\unexpanded\def\showsubtypes#1{\ctxlua{document.functions.showsubtypes("#1")}} + +\definecolor[blue] [b=.5] +\definecolor[red] [r=.5] +\definecolor[green] [g=.5] +\definecolor[maincolor] [b=.5] +\definecolor[keptcolor] [b=.5] +\definecolor[othercolor][r=.5,g=.5] + +\setupbodyfont[modern] % we need this in examples so we predefine + +% \doifmodeelse {atpragma} { +% +% % \setupbodyfont +% % [lucidaot,10pt] +% +% \setupbodyfont +% [dejavu,10pt] +% +% \setuphead [chapter] [style=\bfd] +% \setuphead [section] [style=\bfb] +% \setuphead [subsection] [style=\bfa] +% \setuphead [subsubsection][style=\bf] +% +% } { +% +% \definetypeface[mainfacenormal] [ss][sans] [iwona] [default] +% \definetypeface[mainfacenormal] [rm][serif][palatino] [default] +% \definetypeface[mainfacenormal] [tt][mono] [modern] [default][rscale=1.1] +% \definetypeface[mainfacenormal] [mm][math] [iwona] [default] +% +% \definetypeface[mainfacemedium] [ss][sans] [iwona-medium][default] +% \definetypeface[mainfacemedium] [rm][serif][palatino] [default] +% \definetypeface[mainfacemedium] [tt][mono] [modern] [default][rscale=1.1] +% \definetypeface[mainfacemedium] [mm][math] [iwona-medium][default] +% +% \setupbodyfont +% [mainfacenormal,10pt] +% +% \setuphead [chapter] [style=\mainfacemedium\bfd] +% \setuphead [section] [style=\mainfacemedium\bfb] +% \setuphead [subsection] [style=\mainfacemedium\bfa] +% \setuphead [subsubsection][style=\mainfacemedium\bf] +% +% } + +\writestatus{luatex manual}{we assume that dejavu math is available} + +\setupbodyfont % assumes dejavu-math + [dejavu,10pt] + +\setuphead [chapter] [align={flushleft,broad},style=\bfd] +\setuphead [section] [align={flushleft,broad},style=\bfb] +\setuphead [subsection] [align={flushleft,broad},style=\bfa] +\setuphead [subsubsection][align={flushleft,broad},style=\bf] + +\setuphead [chapter] [color=maincolor] +\setuphead [section] [color=maincolor] +\setuphead [subsection] [color=maincolor] +\setuphead [subsubsection][color=maincolor] + +\definehead + [remark] + [subsubsubject] + +\setupheadertexts + [] + +\definemixedcolumns + [twocolumns] + [n=2, + balance=yes, + before=\blank, + after=\blank] + +\definemixedcolumns + [threecolumns] + [twocolumns] + [n=3] + +\definemixedcolumns + [fourcolumns] + [threecolumns] + [n=4] + +% if we do this we also need to do it in table cells +% +% \setuptyping +% [color=maincolor] +% +% \setuptype +% [color=maincolor] + +\definetyping + [functioncall] + +\startMPdefinitions + + color luaplanetcolor ; luaplanetcolor := \MPcolor{maincolor} ; + color luaholecolor ; luaholecolor := white ; + numeric luaextraangle ; luaextraangle := 0 ; + numeric luaorbitfactor ; luaorbitfactor := .25 ; + + vardef lualogo = image ( + + % Graphic design by A. Nakonechnyj. Copyright (c) 1998, All rights reserved. + + save d, r, p ; numeric d, r, p ; + + d := sqrt(2)/4 ; r := 1/4 ; p := r/8 ; + + fill fullcircle scaled 1 + withcolor luaplanetcolor ; + draw fullcircle rotated 40.5 scaled (1+r) + dashed evenly scaled p + withpen pencircle scaled (p/2) + withcolor (luaorbitfactor * luaholecolor) ; + fill fullcircle scaled r shifted (d+1/8,d+1/8) + rotated luaextraangle + withcolor luaplanetcolor ; + fill fullcircle scaled r shifted (d-1/8,d-1/8) + withcolor luaholecolor ; + luaorbitfactor := .25 ; + ) enddef ; + +\stopMPdefinitions + +\startuseMPgraphic{luapage} + StartPage ; + + fill Page withcolor \MPcolor{othercolor} ; + + luaorbitfactor := 1 ; + picture p ; p := lualogo xsized (3PaperWidth/5) ; + draw p shifted center Page shifted (0,-.5ypart center ulcorner p) ; + + StopPage ; +\stopuseMPgraphic + +\starttexdefinition luaextraangle + % we can also just access the last page and so in mp directly + \ctxlua { + context(\lastpage == 0 and 0 or \realfolio*360/\lastpage) + } +\stoptexdefinition + +\startuseMPgraphic{luanumber} + luaextraangle := \luaextraangle; + luaorbitfactor := 0.25 ; + picture p ; p := lualogo ; + setbounds p to boundingbox fullcircle ; + draw p ysized 1cm ; +\stopuseMPgraphic + +\definelayer + [page] + [width=\paperwidth, + height=\paperheight] + +\setupbackgrounds + [leftpage] + [background=page] + +\setupbackgrounds + [rightpage] + [background=page] + +\startsetups pagenumber:right + \setlayerframed + [page] + [preset=rightbottom,offset=1cm] + [frame=off,height=1cm,offset=overlay] + {\useMPgraphic{luanumber}} + \setlayerframed + [page] + [preset=rightbottom,offset=1cm,x=1.5cm] + [frame=off,height=1cm,width=1cm,offset=overlay] + {\pagenumber} + \setlayerframed + [page] + [preset=rightbottom,offset=1cm,x=2.5cm] + [frame=off,height=1cm,offset=overlay] + {\getmarking[chapter]} +\stopsetups + +\startsetups pagenumber:left + \setlayerframed + [page] + [preset=leftbottom,offset=1cm,x=2.5cm] + [frame=off,height=1cm,offset=overlay] + {\getmarking[chapter]} + \setlayerframed + [page] + [preset=leftbottom,offset=1cm,x=1.5cm] + [frame=off,height=1cm,width=1cm,offset=overlay] + {\pagenumber} + \setlayerframed + [page] + [preset=leftbottom,offset=1cm] + [frame=off,height=1cm,offset=overlay] + {\useMPgraphic{luanumber}} +\stopsetups + +\unexpanded\def\nonterminal#1>{\mathematics{\langle\hbox{\rm #1}\rangle}} + +% taco's brainwave -) + +\newcatcodetable\syntaxcodetable + +\unexpanded\def\makesyntaxcodetable + {\begingroup + \catcode`\<=13 \catcode`\|=12 + \catcode`\!= 0 \catcode`\\=12 + \savecatcodetable\syntaxcodetable + \endgroup} + +\makesyntaxcodetable + +\unexpanded\def\startsyntax {\begingroup\catcodetable\syntaxcodetable \dostartsyntax} +\unexpanded\def\syntax {\begingroup\catcodetable\syntaxcodetable \dosyntax} + \let\stopsyntax \relax + +\unexpanded\def\syntaxenvbody#1% + {\par + \tt + \startnarrower + \maincolor #1 + \stopnarrower + \par} + +\unexpanded\def\syntaxbody#1% + {\begingroup + \maincolor \tt #1% + \endgroup} + +\bgroup \catcodetable\syntaxcodetable + +!gdef!dostartsyntax#1\stopsyntax{!let<!nonterminal!syntaxenvbody{#1}!endgroup} +!gdef!dosyntax #1{!let<!nonterminal!syntaxbody{#1}!endgroup} + +!egroup + +% end of wave + +\setupinteraction + [state=start, + focus=standard, + style=, + color=, + contrastcolor=] + +\placebookmarks + [chapter,section,subsection] + +\setuplist + [chapter,section,subsection,subsubsection] + [interaction=all, + width=3em] + +\setuplist + [chapter] + [style=bold, + color=keptcolor] + +\setuplist + [subsection,subsubsection] + [margin=3em, + width=5em] + +% Hans doesn't like the bookmarks opening by default so we comment this: +% +% \setupinteractionscreen +% [option=bookmark] + +\stopenvironment diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-titlepage.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-titlepage.tex new file mode 100644 index 00000000000..8ab56f85dd2 --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex-titlepage.tex @@ -0,0 +1,70 @@ +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-titlepage + +\startstandardmakeup + + \switchtobodyfont + [mainfacemedium] + + \definedfont[Bold*default at \the\dimexpr.08\paperheight\relax] \setupinterlinespace + + \setlayer + [page] + {\useMPgraphic{luapage}} + + \setlayerframed + [page] + [preset=middletop, + voffset=.05\paperheight] + [align=middle, + foregroundcolor=blue, + frame=off] + {Lua\TeX\\Reference} + + \definedfont[Bold*default at 18pt] \setupinterlinespace + + \setlayerframed + [page] + [preset=rightbottom, + offset=.01\paperheight] + [align=flushright, + foregroundcolor=blue, + frame=off] + {\doifsomething{\documentvariable{status}}{\documentvariable{status}\par} + \currentdate[month,space,year]\par + Version \documentvariable{version}} + +\stopstandardmakeup + +\startstandardmakeup + + \start + \raggedleft + \definedfont[Bold*default at 48pt] + \setupinterlinespace + \blue Lua\TeX \endgraf Reference \endgraf Manual \endgraf + \stop + + \vfill + + \definedfont[Bold*default at 12pt] + + \starttabulate[|l|l|] + \NC copyright \EQ Lua\TeX\ development team \NC \NR + \NC more info \EQ www.luatex.org \NC \NR + \NC version \EQ \currentdate \doifsomething{\documentvariable{snapshot}}{(snapshot \documentvariable{snapshot})} \NC \NR + \stoptabulate + +\stopstandardmakeup + +\setupbackgrounds + [leftpage] + [setups=pagenumber:left] + +\setupbackgrounds + [rightpage] + [setups=pagenumber:right] + +\stopcomponent diff --git a/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex.tex b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex.tex new file mode 100644 index 00000000000..a9524246b9c --- /dev/null +++ b/Master/texmf-dist/doc/context/sources/general/manuals/luatex/luatex.tex @@ -0,0 +1,37 @@ +% macros=mkvi + +% \tex vs \type vs \syntax vs. \luatex +% \em \it \/ + +\environment luatex-style +\environment luatex-logos + +\dontcomplain + +\startdocument + [version=0.95.0, + status=Pre-release] + +\component luatex-titlepage + +\startfrontmatter + \component luatex-contents + \component luatex-introduction +\stopfrontmatter + +\startbodymatter + \component luatex-enhancements + \component luatex-modifications + \component luatex-lua + \component luatex-languages + \component luatex-fonts + \component luatex-math + \component luatex-nodes + \component luatex-callbacks + \component luatex-tex + \component luatex-graphics + \component luatex-fontloader + \component luatex-backend +\stopbodymatter + +\stopdocument |