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+% \iffalse meta-comment
+%
+% Copyright 2015
+% The LaTeX3 Project and any individual authors listed elsewhere
+% in this file.
+%
+% It may be distributed and/or modified under the conditions of
+% the LaTeX Project Public License (LPPL), either version 1.3c of
+% this license or (at your option) any later version. The latest
+% version of this license is in the file:
+%
+% http://www.latex-project.org/lppl.txt
+%
+%
+%
+%<2ekernel>%%% From File: ltluatex.dtx
+%<plain>\ifx\newluafunction\undefined\else\expandafter\endinput\fi
+%<tex>\ifx
+%<tex> \ProvidesFile\undefined\begingroup\def\ProvidesFile
+%<tex> #1#2[#3]{\endgroup\immediate\write-1{File: #1 #3}}
+%<tex>\fi
+%<plain>\ProvidesFile{ltluatex.tex}
+%<*driver>
+\ProvidesFile{ltluatex.dtx}
+%</driver>
+%<*tex>
+[2015/09/24 v1.0a
+%</tex>
+%<plain> LuaTeX support for plain TeX (core)
+%<*tex>
+]
+\edef\etatcatcode{\the\catcode`\@}
+\catcode`\@=11
+%</tex>
+%<*driver>
+\documentclass{ltxdoc}
+\GetFileInfo{ltluatex.dtx}
+\begin{document}
+\title{\filename\\(Lua\TeX{}-specific support)}
+\author{David Carlisle and Joseph Wright\footnote{Significant portions
+ of the code here are adapted/simplified from the packages \textsf{luatex} and
+ \textsf{luatexbase} written by Heiko Oberdiek, \'{E}lie Roux,
+ Manuel P\'{e}gouri\'{e}-Gonnar and Philipp Gesang.}}
+\date{\filedate}
+\maketitle
+\setcounter{tocdepth}{2}
+\tableofcontents
+\DocInput{\filename}
+\end{document}
+%</driver>
+% \fi
+%
+%
+% \section{Overview}
+%
+% Lua\TeX{} adds a number of engine-specific functions to \TeX{}. Several of
+% these require set up that is best done in the kernel or need related support
+% functions. This file provides \emph{basic} support for Lua\TeX{} at the
+% \LaTeXe{} kernel level plus as a loadable file which can be used with
+% plain \TeX{} and \LaTeX{}.
+%
+% This file contains code for both \TeX{} (to be stored as part of the format)
+% and Lua (to be loaded at the start of each job). In the Lua code, the kernel
+% uses the namespace |luatexbase|.
+%
+% The following |\count| registers are used here for register allocation:
+% \begin{itemize}
+% \item[\texttt{\string\e@alloc@attribute@count}] Attributes (default~258)
+% \item[\texttt{\string\e@alloc@ccodetable@count}] Category code tables
+% (default~259)
+% \item[\texttt{\string\e@alloc@luafunction@count}] Lua functions
+% (default~260)
+% \item[\texttt{\string\e@alloc@whatsit@count}] User whatsits (default~261)
+% \item[\texttt{\string\e@alloc@bytecode@count}] Lua bytecodes (default~262)
+% \item[\texttt{\string\e@alloc@luachunk@count}] Lua chunks (default~263)
+% \end{itemize}
+% (|\count 256| is used for |\newmarks| allocation and |\count 257|
+% is used for\linebreak
+% |\newXeTeXintercharclass| with Xe\TeX{}, with code defined in
+% \texttt{ltfinal.dtx}).
+% With any \LaTeXe{} kernel from 2015 onward these registers are part of
+% the block in the extended area reserved by the kernel (prior to 2015 the
+% \LaTeXe{} kernel did not provide any functionality for the extended
+% allocation area).
+%
+% \section{Core \TeX{} functionality}
+%
+% The commands defined here are defined for
+% possible inclusion in a future \LaTeX{} format, however also extracted
+% to the file |ltluatex.tex| which may be used with older \LaTeX\
+% formats, and with plain \TeX.
+%
+% \noindent
+% \DescribeMacro{\newattribute}
+% |\newattribute{|\meta{attribute}|}|\\
+% Defines a named \cs{attribute}, indexed from~$1$
+% (\emph{i.e.}~|\attribute0| is never defined). Attributes initially
+% have the marker value |-"7FFFFFFF| (`unset') set by the engine.
+%
+% \noindent
+% \DescribeMacro{\newcatcodetable}
+% |\newcatcodetable{|\meta{catcodetable}|}|\\
+% Defines a named \cs{catcodetable}, indexed from~$1$
+% (|\catcodetable0| is never assigned). A new catcode table will be
+% populated with exactly those values assigned by Ini\TeX{} (as described
+% in the Lua\TeX{} manual).
+%
+% \noindent
+% \DescribeMacro{\newluafunction}
+% |\newluafunction{|\meta{function}|}|\\
+% Defines a named \cs{luafunction}, indexed from~$1$. (Lua indexes
+% tables from $1$ so |\luafunction0| is not available).
+%
+% \noindent
+% \DescribeMacro{\newwhatsit}
+% |\newwhatsit{|\meta{whatsit}|}|\\
+% Defines a custom \cs{whatsit}, indexed from~$1$.
+%
+% \noindent
+% \DescribeMacro{\newluabytecode}
+% |\newluabytecode{|\meta{bytecode}|}|\\
+% Allocates a number for lua bytecode register, indexed from~$1$.
+%
+% \noindent
+% \DescribeMacro{\newluachunkname}
+% |newluachunkname{|\meta{chunkname}|}|\\
+% Allocates a number for lua chunk register, indexed from~$1$.
+% Also enters the name of the regiser (without backslash) into the
+% \verb|lua.name| table to be used in stack traces.
+%
+% \noindent
+% \DescribeMacro{\catcodetable@initex}
+% \DescribeMacro{\catcodetable@string}
+% \DescribeMacro{\catcodetable@latex}
+% \DescribeMacro{\catcodetable@atletter}
+% Predefined category code tables with the obvious assignments. Note
+% that the |latex| and |atletter| tables set the full Unicode range
+% to the codes predefined by the kernel.
+%
+% \noindent
+% \DescribeMacro{\setattribute}
+% \DescribeMacro{\unsetattribute}
+% |\setattribute{|\meta{attribute}|}{|\meta{value}|}|\\
+% |\unsetattribute{|\meta{attribute}|}|\\
+% Set and unset attributes in a manner analogous to |\setlength|. Note that
+% attributes take a marker value when unset so this operation is distinct
+% from setting the value to zero.
+%
+% \section{Plain \TeX\ interface}
+%
+% The \textsf{ltluatex} interface may be used with plain \TeX\ using
+% |\input{ltluatex}| this inputs |ltluatex.tex| which inputs
+% |etex.src| (or |etex.sty| if used with \LaTeX)
+% if it is not already input, and then defines some internal commands to
+% allow the \textsf{ltluatex} interface to be defined.
+%
+% The \textsf{luatexbase} package interface may also be used in plain \TeX,
+% as before, by inputting the package |\input luatexbase.sty|. The new
+% version of \textsf{luatexbase} is based on this \textsf{ltluatex}
+% code but implements a compatibility layer providing the interface
+% of the original package.
+%
+% \section{Lua functionality}
+%
+% \begingroup
+%
+% \begingroup\lccode`~=`_
+% \lowercase{\endgroup\let~}_
+% \catcode`_=12
+%
+% \subsection{Allocators in Lua}
+%
+% \DescribeMacro{new_attribute}
+% |luatexbase.new_attribute(|\meta{attribute}|)|\\
+% Returns an allocation number for the \meta{attribute}, indexed from~$1$.
+% The attribute will be initialised with the marker value |-"7FFFFFFF|
+% (`unset'). The attribute allocation sequence is shared with the \TeX{}
+% code but this function does \emph{not} define a token using
+% |\attributedef|.
+% The attribute name is recorded in the |attributes| table. A
+% metatable is provided so that the table syntax can be used
+% consistently for attributes declared in \TeX\ or lua.
+%
+% \noindent
+% \DescribeMacro{new_whatsit}
+% |luatexbase.new_whatsit(|\meta{whatsit}|)|\\
+% Returns an allocation number for the custom \meta{whatsit}, indexed from~$1$.
+%
+% \noindent
+% \DescribeMacro{new_bytecode}
+% |luatexbase.new_bytecode(|\meta{bytecode}|)|\\
+% Returns an allocation number for a bytecode register, indexed from~$1$.
+% The optional \meta{name} argument is just used for logging.
+%
+% \noindent
+% \DescribeMacro{new_chunkname}
+% |luatexbase.new_chunkname(|\meta{chunkname}|)|\\
+% Returns an allocation number for a lua chunk name for use with
+% |\directlua| and |\latelua|, indexed from~$1$.
+% The number is returned and also \meta{name} argument is added to the
+% |lua.name| array at that index.
+%
+%
+% \subsection{Lua access to \TeX{} register numbers}
+%
+% \DescribeMacro{registernumber}
+% |luatexbase.registernumer(|\meta{name}|)|\\
+% Sometimes (notably in the case of Lua attributes) it is necessary to
+% access a register \emph{by number} that has been allocated by \TeX{}.
+% This package provides a function to look up the relevant number
+% using Lua\TeX{}'s internal tables. After for example
+% |\newattribute\myattrib|, |\myattrib| would be defined by (say)
+% |\myattrib=\attribute15|. |luatexbase.registernumer("myattrib")|
+% would then return the register number, $15$ in this case. If the string passed
+% as argument does not correspond to a token defined by |\attributedef|,
+% |\countdef| or similar commands, the Lua value |false| is returned.
+%
+% As an example, consider the input:
+%\begin{verbatim}
+% \newcommand\test[1]{%
+% \typeout{#1: \expandafter\meaning\csname#1\endcsname^^J
+% \space\space\space\space
+% \directlua{tex.write(luatexbase.registernumber("#1") or "bad input")}%
+% }}
+%
+% \test{undefinedrubbish}
+%
+% \test{space}
+%
+% \test{hbox}
+%
+% \test{@MM}
+%
+% \test{@tempdima}
+% \test{@tempdimb}
+%
+% \test{strutbox}
+%
+% \test{sixt@@n}
+%
+% \attrbutedef\myattr=12
+% \myattr=200
+% \test{myattr}
+%
+%\end{verbatim}
+%
+% If the demonstration code is processed with Lua\LaTeX{} then the following
+% would be produced in the log and terminal output.
+%\begin{verbatim}
+% undefinedrubbish: \relax
+% bad input
+% space: macro:->
+% bad input
+% hbox: \hbox
+% bad input
+% @MM: \mathchar"4E20
+% 20000
+% @tempdima: \dimen14
+% 14
+% @tempdimb: \dimen15
+% 15
+% strutbox: \char"B
+% 11
+% sixt@@n: \char"10
+% 16
+% myattr: \attribute12
+% 12
+%\end{verbatim}
+%
+% Notice how undefined commands, or commands unrelated to registers
+% do not produce an error, just return |false| and so print
+% |bad input| here. Note also that commands defined by |\newbox| work and
+% return the number of the box register even though the actual command
+% holding this number is a |\chardef| defined token (there is no
+% |\boxdef|).
+%
+% \subsection{Module utilities}
+%
+% \DescribeMacro{provides_module}
+% |luatexbase.provides_module(|\meta{info}|)|\\
+% This function is used by modules to identify themselves; the |info| should be
+% a table containing information about the module. The required field
+% |name| must contain the name of the module. It is recommended to provide a
+% field |date| in the usual \LaTeX{} format |yyyy/mm/dd|. Optional fields
+% |version| (a string) and |description| may be used if present. This
+% information will be recorded in the log. Other fields are ignored.
+%
+% \noindent
+% \DescribeMacro{module_info}
+% \DescribeMacro{module_warning}
+% \DescribeMacro{module_error}
+% |luatexbase.module_info(|\meta{module}, \meta{text}|)|\\
+% |luatexbase.module_warning(|\meta{module}, \meta{text}|)|\\
+% |luatexbase.module_error(|\meta{module}, \meta{text}|)|\\
+% These functions are similar to \LaTeX{}'s |\PackageError|, |\PackageWarning|
+% and |\PackageInfo| in the way they format the output. No automatic line
+% breaking is done, you may still use |\n| as usual for that, and the name of
+% the package will be prepended to each output line.
+%
+% Note that |luatexbase.module_error| raises an actual Lua error with |error()|,
+% which currently means a call stack will be dumped. While this may not
+% look pretty, at least it provides useful information for tracking the
+% error down.
+%
+% \subsection{Callback management}
+%
+% \noindent
+% \DescribeMacro{add_to_callback}
+% |luatexbase.add_to_callback(|^^A
+% \meta{callback}, \meta{function}, \meta{description}|)|
+% Registers the \meta{function} into the \meta{callback} with a textual
+% \meta{description} of the function. Functions are inserted into the callback
+% in the order loaded.
+%
+% \noindent
+% \DescribeMacro{remove_from_callback}
+% |luatexbase.remove_from_callback(|\meta{callback}, \meta{description}|)|
+% Removes the callback function with \meta{description} from the \meta{callback}.
+% The removed function and its description
+% are returned as the results of this function.
+%
+% \noindent
+% \DescribeMacro{in_callback}
+% |luatexbase.in_callback(|\meta{callback}, \meta{description}|)|
+% Checks if the \meta{description} matches one of the functions added
+% to the list for the \meta{callback}, returning a boolean value.
+%
+% \noindent
+% \DescribeMacro{disable_callback}
+% |luatexbase.disable_callback(|\meta{callback}|)|
+% Sets the \meta{callback} to \texttt{false} as described in the Lua\TeX{}
+% manual for the underlying \texttt{callback.register} built-in. Callbacks
+% will only be set to false (and thus be skipped entirely) if there are
+% no functions registered using the callback.
+%
+% \noindent
+% \DescribeMacro{callback_descriptions}
+% A list of the descriptions of functions registered to the specified
+% callback is returned. |{}| is returned if there are no functions registered.
+%
+% \noindent
+% \DescribeMacro{create_callback}
+% |luatexbase.create_callback(|\meta{name},meta{type},\meta{default}|)|
+% Defines a user defined callback. The last argument is a default
+% functtion of |false|.
+%
+% \noindent
+% \DescribeMacro{call_callback}
+% |luatexbase.call_callback(|\meta{name},\ldots|)|
+% Calls a user defined callback with the supplied arguments.
+%
+% \endgroup
+%
+% \CheckSum{484}
+% \StopEventually{}
+%
+% \section{Implementation}
+%
+% \begin{macrocode}
+%<*2ekernel|tex|latexrelease>
+%<2ekernel|latexrelease>\ifx\directlua\@undefined\else
+% \end{macrocode}
+%
+%
+% \subsection{Minimum Lua\TeX{} version}
+%
+% Lua\TeX{} has changed a lot over time. In the kernel support for ancient
+% versions is not provided: trying to build a format with a very old binary
+% therefore gives some information in the log and loading stops. The cut-off
+% selected here relates to the tree-searching behaviour of |require()|:
+% from version~0.60, Lua\TeX{} will correctly find Lua files in the |texmf|
+% tree without `help'.
+% \begin{macrocode}
+%<latexrelease>\IncludeInRelease{2015/10/01}
+%<latexrelease> {\newluafunction}{LuaTeX}%
+\ifnum\luatexversion<60 %
+ \wlog{***************************************************}
+ \wlog{* LuaTeX version too old for ltluatex support *}
+ \wlog{***************************************************}
+ \expandafter\endinput
+\fi
+% \end{macrocode}
+%
+% \subsection{Older \LaTeX{}/Plain \TeX\ setup}
+%
+% \begin{macrocode}
+%<*tex>
+% \end{macrocode}
+%
+% Older \LaTeX{} formats don't have the primitives with `native' names:
+% sort that out. If they already exist this will still be safe.
+% \begin{macrocode}
+\directlua{tex.enableprimitives("",tex.extraprimitives("luatex"))}
+% \end{macrocode}
+%
+% \begin{macrocode}
+\ifx\e@alloc\@undefined
+% \end{macrocode}
+%
+% In pre-2014 \LaTeX{}, or plain \TeX{}, load |etex.{sty,src}|.
+% \begin{macrocode}
+ \ifx\documentclass\@undefined
+ \ifx\loccount\@undefined
+ \input{etex.src}%
+ \fi
+ \catcode`\@=11 %
+ \outer\expandafter\def\csname newfam\endcsname
+ {\alloc@8\fam\chardef\et@xmaxfam}
+ \else
+ \RequirePackage{etex}
+ \expandafter\def\csname newfam\endcsname
+ {\alloc@8\fam\chardef\et@xmaxfam}
+ \expandafter\let\expandafter\new@mathgroup\csname newfam\endcsname
+ \fi
+% \end{macrocode}
+%
+% \subsubsection{Fixes to \texttt{etex.src}/\texttt{etex.sty}}
+%
+% These could and probably should be made directly in an
+% update to etex.src which already has some luatex-specific
+% code, but does not define the correct range for luatex.
+%
+% \begin{macrocode}
+% 2015-07-13 higher range in luatex
+\edef \et@xmaxregs {\ifx\directlua\@undefined 32768\else 65536\fi}
+% luatex/xetex also allow more math fam
+\edef \et@xmaxfam {\ifx\Umathchar\@undefined\sixt@@n\else\@cclvi\fi}
+% \end{macrocode}
+%
+% \begin{macrocode}
+\count 270=\et@xmaxregs % locally allocates \count registers
+\count 271=\et@xmaxregs % ditto for \dimen registers
+\count 272=\et@xmaxregs % ditto for \skip registers
+\count 273=\et@xmaxregs % ditto for \muskip registers
+\count 274=\et@xmaxregs % ditto for \box registers
+\count 275=\et@xmaxregs % ditto for \toks registers
+\count 276=\et@xmaxregs % ditto for \marks classes
+% \end{macrocode}
+%
+% and 256 or 16 fam. (Done above due to plain/\LaTeX\ differences in
+% \textsf{ltluatex}.)
+% \begin{macrocode}
+% \outer\def\newfam{\alloc@8\fam\chardef\et@xmaxfam}
+% \end{macrocode}
+%
+% End of proposed changes to \texttt{etex.src}
+%
+% \subsubsection{luatex specific settings}
+%
+% Switch to global cf |luatex.sty| to leave room for inserts
+% not really needed for luatex but possibly most compatible
+% with existing use.
+% \begin{macrocode}
+\expandafter\let\csname newcount\expandafter\expandafter\endcsname
+ \csname globcount\endcsname
+\expandafter\let\csname newdimen\expandafter\expandafter\endcsname
+ \csname globdimen\endcsname
+\expandafter\let\csname newskip\expandafter\expandafter\endcsname
+ \csname globskip\endcsname
+\expandafter\let\csname newbox\expandafter\expandafter\endcsname
+ \csname globbox\endcsname
+% \end{macrocode}
+%
+% Define|\e@alloc| as in latex (the existing macros in |etex.src|
+% hard to extend to further register types as they assume specific
+% 26x and 27x count range. For compatibility the existing register
+% allocation is not changed.
+%
+% \begin{macrocode}
+\chardef\e@alloc@top=65535
+\let\e@alloc@chardef\chardef
+% \end{macrocode}
+%
+% \begin{macrocode}
+\def\e@alloc#1#2#3#4#5#6{%
+ \global\advance#3\@ne
+ \e@ch@ck{#3}{#4}{#5}#1%
+ \allocationnumber#3\relax
+ \global#2#6\allocationnumber
+ \wlog{\string#6=\string#1\the\allocationnumber}}%
+% \end{macrocode}
+%
+% \begin{macrocode}
+\gdef\e@ch@ck#1#2#3#4{%
+ \ifnum#1<#2\else
+ \ifnum#1=#2\relax
+ #1\@cclvi
+ \ifx\count#4\advance#1 10 \fi
+ \fi
+ \ifnum#1<#3\relax
+ \else
+ \errmessage{No room for a new \string#4}%
+ \fi
+ \fi}%
+% \end{macrocode}
+%
+% Two simple \LaTeX\ macros used in |ltlatex.sty|.
+% \begin{macrocode}
+\long\def\@gobble#1{}
+\long\def\@firstofone#1{#1}
+% \end{macrocode}
+%
+% \begin{macrocode}
+% Fix up allocations not to clash with |etex.src|.
+% \end{macrocode}
+%
+% \begin{macrocode}
+\expandafter\csname newcount\endcsname\e@alloc@attribute@count
+\expandafter\csname newcount\endcsname\e@alloc@ccodetable@count
+\expandafter\csname newcount\endcsname\e@alloc@luafunction@count
+\expandafter\csname newcount\endcsname\e@alloc@whatsit@count
+\expandafter\csname newcount\endcsname\e@alloc@bytecode@count
+\expandafter\csname newcount\endcsname\e@alloc@luachunk@count
+% \end{macrocode}
+%
+% End of conditional setup for plain \TeX\ / old \LaTeX.
+% \begin{macrocode}
+\fi
+%</tex>
+% \end{macrocode}
+%
+%
+% \subsection{Attributes}
+%
+% \begin{macro}{\newattribute}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% As is generally the case for the Lua\TeX{} registers we start here
+% from~$1$. Notably, some code assumes that |\attribute0| is never used so
+% this is important in this case.
+% \begin{macrocode}
+\ifx\e@alloc@attribute@count\@undefined
+ \countdef\e@alloc@attribute@count=258
+\fi
+\def\newattribute#1{%
+ \e@alloc\attribute\attributedef
+ \e@alloc@attribute@count\m@ne\e@alloc@top#1%
+}
+\e@alloc@attribute@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\setattribute}
+% \begin{macro}{\unsetattribute}
+% Handy utilities.
+% \begin{macrocode}
+\def\setattribute#1#2{#1=\numexpr#2\relax}
+\def\unsetattribute#1{#1=-"7FFFFFFF\relax}
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Category code tables}
+%
+% \begin{macro}{\newcatcodetable}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% Category code tables are allocated with a limit half of that used by Lua\TeX{}
+% for everything else. At the end of allocation there needs to be an
+% initialisation step. Table~$0$ is already taken (it's the global one for
+% current use) so the allocation starts at~$1$.
+% \begin{macrocode}
+\ifx\e@alloc@ccodetable@count\@undefined
+ \countdef\e@alloc@ccodetable@count=259
+\fi
+\def\newcatcodetable#1{%
+ \e@alloc\catcodetable\chardef
+ \e@alloc@ccodetable@count\m@ne{"8000}#1%
+ \initcatcodetable\allocationnumber
+}
+\e@alloc@ccodetable@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\catcodetable@initex}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% \begin{macro}{\catcodetable@string}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% \begin{macro}{\catcodetable@latex}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% \begin{macro}{\catcodetable@atletter}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% Save a small set of standard tables. The Unicode data is read
+% here in a group avoiding any global definitions: that needs a bit
+% of effort so that in package/plain mode there is no effect on any
+% settings already in force.
+% \begin{macrocode}
+\newcatcodetable\catcodetable@initex
+\newcatcodetable\catcodetable@string
+\begingroup
+ \def\setrangecatcode#1#2#3{%
+ \ifnum#1>#2 %
+ \expandafter\@gobble
+ \else
+ \expandafter\@firstofone
+ \fi
+ {%
+ \catcode#1=#3 %
+ \expandafter\setrangecatcode\expandafter
+ {\number\numexpr#1 + 1\relax}{#2}{#3}
+ }%
+ }
+ \@firstofone{%
+ \catcodetable\catcodetable@initex
+ \catcode0=12 %
+ \catcode13=12 %
+ \catcode37=12 %
+ \setrangecatcode{65}{90}{12}%
+ \setrangecatcode{97}{122}{12}%
+ \catcode92=12 %
+ \catcode127=12 %
+ \savecatcodetable\catcodetable@string
+ \endgroup
+ }%
+\newcatcodetable\catcodetable@latex
+\newcatcodetable\catcodetable@atletter
+\begingroup
+ \let\ENDGROUP\endgroup
+ \let\begingroup\relax
+ \let\endgroup\relax
+ \let\global\relax
+ \let\gdef\def
+ \input{unicode-letters.def}%
+ \let\endgroup\ENDGROUP
+ \@firstofone{%
+ \catcode64=12 %
+ \savecatcodetable\catcodetable@latex
+ \catcode64=11 %
+ \savecatcodetable\catcodetable@atletter
+ }
+\endgroup
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Named Lua functions}
+%
+% \begin{macro}{\newluafunction}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% Much the same story for allocating Lua\TeX{} functions except here they are
+% just numbers so are allocated in the same way as boxes. Lua index from~$1$
+% so once again slot~$0$ is skipped.
+% \begin{macrocode}
+\ifx\e@alloc@luafunction@count\@undefined
+ \countdef\e@alloc@luafunction@count=260
+\fi
+\def\newluafunction{%
+ \e@alloc\luafunction\e@alloc@chardef
+ \e@alloc@luafunction@count\m@ne\e@alloc@top
+}
+\e@alloc@luafunction@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Custom whatsits}
+%
+% \begin{macro}{\newwhatsit}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% These are only settable from Lua but for consistency are definable
+% here.
+% \begin{macrocode}
+\ifx\e@alloc@whatsit@count\@undefined
+ \countdef\e@alloc@whatsit@count=261
+\fi
+\def\newwhatsit#1{%
+ \e@alloc\whatsit\e@alloc@chardef
+ \e@alloc@whatsit@count\m@ne\e@alloc@top#1%
+}
+\e@alloc@whatsit@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Lua bytecode registers}
+%
+% \begin{macro}{\newluabytecode}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% These are only settable from Lua but for consistency are definable
+% here.
+% \begin{macrocode}
+\ifx\e@alloc@bytecode@count\@undefined
+ \countdef\e@alloc@bytecode@count=262
+\fi
+\def\newluabytecode#1{%
+ \e@alloc\luabytecode\e@alloc@chardef
+ \e@alloc@bytecode@count\m@ne\e@alloc@top#1%
+}
+\e@alloc@bytecode@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Lua chunk registers}
+
+% \begin{macro}{\newluachunkname}
+% \changes{v1.0a}{2015/09/24}{Macro added}
+% As for bytecode registers, but in addition we need to add a string
+% to the \verb|lua.name| table to use in stack tracing. We use the
+% name of the command passed to the allocator, with no backslash.
+% \begin{macrocode}
+\ifx\e@alloc@luachunk@count\@undefined
+ \countdef\e@alloc@luachunk@count=263
+\fi
+\def\newluachunkname#1{%
+ \e@alloc\luachunk\e@alloc@chardef
+ \e@alloc@luachunk@count\m@ne\e@alloc@top#1%
+ {\escapechar\m@ne
+ \directlua{lua.name[\the\allocationnumber]="\string#1"}}%
+}
+\e@alloc@luachunk@count=\z@
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Lua loader}
+%
+% Load the Lua code at the start of every job.
+% For the conversion of \TeX{} into numbers at the Lua side we need some
+% known registers: for convenience we use a set of systematic names, which
+% means using a group around the Lua loader.
+% \begin{macrocode}
+%<2ekernel>\everyjob\expandafter{%
+%<2ekernel> \the\everyjob
+ \begingroup
+ \attributedef\attributezero=0 %
+ \chardef \charzero =0 %
+% \end{macrocode}
+% Note name change required on older luatex, for hash table access.
+% \begin{macrocode}
+ \countdef \CountZero =0 %
+ \dimendef \dimenzero =0 %
+ \mathchardef \mathcharzero =0 %
+ \muskipdef \muskipzero =0 %
+ \skipdef \skipzero =0 %
+ \toksdef \tokszero =0 %
+ \directlua{require("ltluatex")}
+ \endgroup
+%<2ekernel>}
+%<latexrelease>\EndIncludeInRelease
+% \end{macrocode}
+%
+% \begin{macrocode}
+%<latexrelease>\IncludeInRelease{2015/09/24}
+%<latexrelease> {\newluafunction}{LuaTeX}%
+%<latexrelease>\let\e@alloc@attribute@count\@undefined
+%<latexrelease>\let\newattribute\@undefined
+%<latexrelease>\let\setattribute\@undefined
+%<latexrelease>\let\unsetattribute\@undefined
+%<latexrelease>\let\e@alloc@ccodetable@count\@undefined
+%<latexrelease>\let\newcatcodetable\@undefined
+%<latexrelease>\let\catcodetable@initex\@undefined
+%<latexrelease>\let\catcodetable@string\@undefined
+%<latexrelease>\let\catcodetable@latex\@undefined
+%<latexrelease>\let\catcodetable@atletter\@undefined
+%<latexrelease>\let\e@alloc@luafunction@count\@undefined
+%<latexrelease>\let\newluafunction\@undefined
+%<latexrelease>\let\e@alloc@luafunction@count\@undefined
+%<latexrelease>\let\newwhatsit\@undefined
+%<latexrelease>\let\e@alloc@whatsit@count\@undefined
+%<latexrelease>\let\newluabytecode\@undefined
+%<latexrelease>\let\e@alloc@bytecode@count\@undefined
+%<latexrelease>\let\newluachunkname\@undefined
+%<latexrelease>\let\e@alloc@luachunk@count\@undefined
+%<latexrelease>\EndIncludeInRelease
+% \end{macrocode}
+%
+% \begin{macrocode}
+%<2ekernel|latexrelease>\fi
+%</2ekernel|tex|latexrelease>
+% \end{macrocode}
+%
+% \subsection{Lua module preliminaries}
+%
+% \begingroup
+%
+% \begingroup\lccode`~=`_
+% \lowercase{\endgroup\let~}_
+% \catcode`_=12
+%
+% \begin{macrocode}
+%<*lua>
+% \end{macrocode}
+%
+% Some set up for the Lua module which is needed for all of the Lua
+% functionality added here.
+%
+% \begin{macro}{luatexbase}
+% \changes{v1.0a}{2015/09/24}{Table added}
+% Set up the table for the returned functions. This is used to expose
+% all of the public functions.
+% \begin{macrocode}
+luatexbase = luatexbase or { }
+local luatexbase = luatexbase
+% \end{macrocode}
+% \end{macro}
+%
+% Some Lua best practice: use local versions of functions where possible.
+% \begin{macrocode}
+local string_gsub = string.gsub
+local tex_count = tex.count
+local tex_setattribute = tex.setattribute
+local tex_setcount = tex.setcount
+local texio_write_nl = texio.write_nl
+% \end{macrocode}
+%
+% \subsection{Lua module utilities}
+%
+% \subsubsection{Module tracking}
+%
+% \begin{macro}{modules}
+% \changes{v1.0a}{2015/09/24}{Function modified}
+% To allow tracking of module usage, a structure is provided to store
+% information and to return it.
+% \begin{macrocode}
+local modules = modules or { }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{provides_module}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Modelled on |\ProvidesPackage|, we store much the same information but
+% with a little more structure.
+% \begin{macrocode}
+local function provides_module(info)
+ if not (info and info.name) then
+ luatexbase_error("Missing module name for provides_modules")
+ return
+ end
+ local function spaced(text)
+ return text and (" " .. text) or ""
+ end
+ texio_write_nl(
+ "log",
+ "Lua module: " .. info.name
+ .. spaced(info.date)
+ .. spaced(info.version)
+ .. spaced(info.description)
+ )
+ modules[info.name] = info
+end
+luatexbase.provides_module = provides_module
+% \end{macrocode}
+% \end{macro}
+%
+% \subsubsection{Module messages}
+%
+% There are various warnings and errors that need to be given. For warnings
+% we can get exactly the same formatting as from \TeX{}. For errors we have to
+% make some changes. Here we give the text of the error in the \LaTeX{} format
+% then force an error from Lua to halt the run. Splitting the message text is
+% done using |\n| which takes the place of |\MessageBreak|.
+%
+% First an auxiliary for the formatting: this measures up the message
+% leader so we always get the correct indent.
+% \begin{macrocode}
+local function msg_format(mod, msg_type, text)
+ local leader = ""
+ local cont
+ if mod == "LaTeX" then
+ cont = string_gsub(leader, ".", " ")
+ leader = leader .. "LaTeX: "
+ else
+ first_head = leader .. "Module " .. msg_type
+ cont = "(" .. mod .. ")"
+ .. string_gsub(first_head, ".", " ")
+ first_head = leader .. "Module " .. mod .. " " .. msg_type .. ":"
+ end
+ if msg_type == "Error" then
+ first_head = "\n" .. first_head
+ end
+ if string.sub(text,-1) ~= "\n" then
+ text = text .. " "
+ end
+ return first_head .. " "
+ .. string_gsub(
+ text
+ .. "on input line "
+ .. tex.inputlineno, "\n", "\n" .. cont .. " "
+ )
+ .. "\n"
+end
+% \end{macrocode}
+%
+% \begin{macro}{module_info}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% \begin{macro}{module_warning}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% \begin{macro}{module_error}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Write messages.
+% \begin{macrocode}
+local function module_info(mod, text)
+ texio_write_nl("log", msg_format(mod, "Info", text))
+end
+luatexbase.module_info = module_info
+local function module_warning(mod, text)
+ texio_write_nl("term and log",msg_format(mod, "Warning", text))
+end
+luatexbase.module_warning = module_warning
+local function module_error(mod, text)
+ error(msg_format(mod, "Error", text))
+end
+luatexbase.module_error = module_error
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% Dedicated versions for the rest of the code here.
+% \begin{macrocode}
+local function luatexbase_warning(text)
+ module_warning("luatexbase", text)
+end
+local function luatexbase_error(text)
+ module_error("luatexbase", text)
+end
+% \end{macrocode}
+%
+%
+% \subsection{Accessing register numbers from Lua}
+%
+% Collect up the data from the \TeX{} level into a Lua table: from
+% version~0.80, Lua\TeX{} makes that easy.
+% \begin{macrocode}
+local luaregisterbasetable = { }
+local registermap = {
+ attributezero = "assign_attr" ,
+ charzero = "char_given" ,
+ CountZero = "assign_int" ,
+ dimenzero = "assign_dimen" ,
+ mathcharzero = "math_given" ,
+ muskipzero = "assign_mu_skip" ,
+ skipzero = "assign_skip" ,
+ tokszero = "assign_toks" ,
+}
+local i, j
+local createtoken
+if tex.luatexversion >79 then
+ createtoken = newtoken.create
+end
+local hashtokens = tex.hashtokens
+local luatexversion = tex.luatexversion
+for i,j in pairs (registermap) do
+ if luatexversion < 80 then
+ luaregisterbasetable[hashtokens()[i][1]] =
+ hashtokens()[i][2]
+ else
+ luaregisterbasetable[j] = createtoken(i).mode
+ end
+end
+% \end{macrocode}
+%
+% \begin{macro}{registernumber}
+% Working out the correct return value can be done in two ways. For older
+% Lua\TeX{} releases it has to be extracted from the |hashtokens|. On the
+% other hand, newer Lua\TeX{}'s have |newtoken|, and whilst |.mode| isn't
+% currently documented, Hans Hagen pointed to this approach so we should be
+% OK.
+% \begin{macrocode}
+local registernumber
+if luatexversion < 80 then
+ function registernumber(name)
+ local nt = hashtokens()[name]
+ if(nt and luaregisterbasetable[nt[1]]) then
+ return nt[2] - luaregisterbasetable[nt[1]]
+ else
+ return false
+ end
+ end
+else
+ function registernumber(name)
+ local nt = createtoken(name)
+ if(luaregisterbasetable[nt.cmdname]) then
+ return nt.mode - luaregisterbasetable[nt.cmdname]
+ else
+ return false
+ end
+ end
+end
+luatexbase.registernumber = registernumber
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Attribute allocation}
+%
+% \begin{macro}{new_attribute}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% As attributes are used for Lua manipulations its useful to be able
+% to assign from this end.
+% \begin{macrocode}
+local attributes=setmetatable(
+{},
+{
+__index = function(t,key)
+return registernumber(key) or nil
+end}
+)
+luatexbase.attributes=attributes
+% \end{macrocode}
+%
+% \begin{macrocode}
+local function new_attribute(name)
+ tex_setcount("global", "e@alloc@attribute@count",
+ tex_count["e@alloc@attribute@count"] + 1)
+ if tex_count["e@alloc@attribute@count"] > 65534 then
+ luatexbase_error("No room for a new \\attribute")
+ return -1
+ end
+ attributes[name]= tex_count["e@alloc@attribute@count"]
+ texio_write_nl("Lua-only attribute " .. name .. " = " ..
+ tex_count["e@alloc@attribute@count"])
+ return tex_count["e@alloc@attribute@count"]
+end
+luatexbase.new_attribute = new_attribute
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Custom whatsit allocation}
+%
+% \begin{macro}{new_whatsit}
+% Much the same as for attribute allocation in Lua
+% \begin{macrocode}
+local function new_whatsit(name)
+ tex_setcount("global", "e@alloc@whatsit@count",
+ tex_count["e@alloc@whatsit@count"] + 1)
+ if tex_count["e@alloc@whatsit@count"] > 65534 then
+ luatexbase_error("No room for a new custom whatsit")
+ return -1
+ end
+ texio_write_nl("Custom whatsit " .. (name or "") .. " = " ..
+ tex_count["e@alloc@whatsit@count"])
+ return tex_count["e@alloc@whatsit@count"]
+end
+luatexbase.new_whatsit = new_whatsit
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Bytecode register allocation}
+%
+% \begin{macro}{new_bytecode}
+% Much the same as for attribute allocation in Lua.
+% The optional \meta{name} argument is used in the log if given.
+% \begin{macrocode}
+local function new_bytecode(name)
+ tex_setcount("global", "e@alloc@bytecode@count",
+ tex_count["e@alloc@bytecode@count"] + 1)
+ if tex_count["e@alloc@bytecode@count"] > 65534 then
+ luatexbase_error("No room for a new bytecode register")
+ return -1
+ end
+ texio_write_nl("Lua bytecode " .. (name or "") .. " = " ..
+ tex_count["e@alloc@bytecode@count"])
+ return tex_count["e@alloc@bytecode@count"]
+end
+luatexbase.new_bytecode = new_bytecode
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Lua chunk name allocation}
+%
+% \begin{macro}{new_chunkname}
+% As for bytecode registers but also store the name in the
+% |lua.name| table.
+% \begin{macrocode}
+local function new_chunkname(name)
+ tex_setcount("global", "e@alloc@luachunk@count",
+ tex_count["e@alloc@luachunk@count"] + 1)
+ local chunkname_count = tex_count["e@alloc@luachunk@count"]
+ chunkname_count = chunkname_count + 1
+ if chunkname_count > 65534 then
+ luatexbase_error("No room for a new chunkname")
+ return -1
+ end
+ lua.name[chunkname_count]=name
+ texio_write_nl("Lua chunkname " .. (name or "") .. " = " ..
+ chunkname_count .. "\n")
+ return chunkname_count
+end
+luatexbase.new_chunkname = new_chunkname
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Lua callback management}
+%
+% The native mechanism for callbacks in Lua allows only one per function.
+% That is extremely restrictive and so a mechanism is needed to add and
+% remove callbacks from the appropriate hooks.
+%
+% \subsubsection{Housekeeping}
+%
+% The main table: keys are callback names, and values are the associated lists
+% of functions. More precisely, the entries in the list are tables holding the
+% actual function as |func| and the identifying description as |description|.
+% Only callbacks with a non-empty list of functions have an entry in this
+% list.
+% \begin{macrocode}
+local callbacklist = callbacklist or { }
+% \end{macrocode}
+%
+% Numerical codes for callback types, and name-to-value association (the
+% table keys are strings, the values are numbers).
+% \begin{macrocode}
+local list, data, exclusive, simple = 1, 2, 3, 4
+local types = {
+ list = list,
+ data = data,
+ exclusive = exclusive,
+ simple = simple,
+}
+% \end{macrocode}
+%
+% Now, list all predefined callbacks with their current type, based on the
+% Lua\TeX{} manual version~0.80. A full list of the currently-available
+% callbacks can be obtained using
+% \begin{verbatim}
+% \directlua{
+% for i,_ in pairs(callback.list()) do
+% texio.write_nl("- " .. i)
+% end
+% }
+% \bye
+% \end{verbatim}
+% in plain Lua\TeX{}. (Some undocumented callbacks are omitted as they are
+% to be removed.)
+% \begin{macrocode}
+local callbacktypes = callbacktypes or {
+% \end{macrocode}
+% Section 4.1.1: file discovery callbacks.
+% \begin{macrocode}
+ find_read_file = exclusive,
+ find_write_file = exclusive,
+ find_font_file = data,
+ find_output_file = data,
+ find_format_file = data,
+ find_vf_file = data,
+ find_map_file = data,
+ find_enc_file = data,
+ find_sfd_file = data,
+ find_pk_file = data,
+ find_data_file = data,
+ find_opentype_file = data,
+ find_truetype_file = data,
+ find_type1_file = data,
+ find_image_file = data,
+% \end{macrocode}
+% Section 4.1.2: file reading callbacks.
+% \begin{macrocode}
+ open_read_file = exclusive,
+ read_font_file = exclusive,
+ read_vf_file = exclusive,
+ read_map_file = exclusive,
+ read_enc_file = exclusive,
+ read_sfd_file = exclusive,
+ read_pk_file = exclusive,
+ read_data_file = exclusive,
+ read_truetype_file = exclusive,
+ read_type1_file = exclusive,
+ read_opentype_file = exclusive,
+% \end{macrocode}
+% Section 4.1.3: data processing callbacks.
+% \begin{macrocode}
+ process_input_buffer = data,
+ process_output_buffer = data,
+ process_jobname = data,
+ token_filter = exclusive,
+% \end{macrocode}
+% Section 4.1.4: node list processing callbacks.
+% \begin{macrocode}
+ buildpage_filter = simple,
+ pre_linebreak_filter = list,
+ linebreak_filter = list,
+ post_linebreak_filter = list,
+ hpack_filter = list,
+ vpack_filter = list,
+ pre_output_filter = list,
+ hyphenate = simple,
+ ligaturing = simple,
+ kerning = simple,
+ mlist_to_hlist = list,
+% \end{macrocode}
+% Section 4.1.5: information reporting callbacks.
+% \begin{macrocode}
+ pre_dump = simple,
+ start_run = simple,
+ stop_run = simple,
+ start_page_number = simple,
+ stop_page_number = simple,
+ show_error_hook = simple,
+ show_error_message = simple,
+ show_lua_error_hook = simple,
+ start_file = simple,
+ stop_file = simple,
+% \end{macrocode}
+% Section 4.1.6: PDF-related callbacks.
+% \begin{macrocode}
+ finish_pdffile = data,
+ finish_pdfpage = data,
+% \end{macrocode}
+% Section 4.1.7: font-related callbacks.
+% \begin{macrocode}
+ define_font = exclusive,
+% \end{macrocode}
+% Undocumented callbacks which are likely to get documented.
+% \begin{macrocode}
+ find_cidmap_file = data,
+ pdf_stream_filter_callback = data,
+}
+luatexbase.callbacktypes=callbacktypes
+% \end{macrocode}
+%
+% \begin{macro}{callback.register}
+% \changes{v1.0a}{2015/09/24}{Function modified}
+% Save the original function for registering callbacks and prevent the
+% original being used. The original is saved in a place that remains
+% available so other more sophisticated code can override the approach
+% taken by the kernel if desired.
+% \begin{macrocode}
+local callback_register = callback_register or callback.register
+function callback.register()
+ luatexbase_error("Attempt to use callback.register() directly\n")
+end
+% \end{macrocode}
+% \end{macro}
+%
+% \subsubsection{Handlers}
+%
+% The handler function is registered into the callback when the
+% first function is added to this callback's list. Then, when the callback
+% is called, then handler takes care of running all functions in the list.
+% When the last function is removed from the callback's list, the handler
+% is unregistered.
+%
+% More precisely, the functions below are used to generate a specialized
+% function (closure) for a given callback, which is the actual handler.
+%
+% Handler for |data| callbacks.
+% \begin{macrocode}
+local function data_handler(name)
+ return function(data, ...)
+ local i
+ for _,i in ipairs(callbacklist[name]) do
+ data = i.func(data,...)
+ end
+ return data
+ end
+end
+% \end{macrocode}
+% Handler for |exclusive| callbacks. We can assume |callbacklist[name]| is not
+% empty: otherwise, the function wouldn't be registered in the callback any
+% more.
+% \begin{macrocode}
+local function exclusive_handler(name)
+ return function(...)
+ return callbacklist[name][1].func(...)
+ end
+end
+% \end{macrocode}
+% Handler for |list| callbacks.
+% \begin{macrocode}
+local function list_handler(name)
+ return function(head, ...)
+ local ret
+ local alltrue = true
+ local i
+ for _,i in ipairs(callbacklist[name]) do
+ ret = i.func(head, ...)
+ if ret == false then
+ luatexbase_warning(
+ "Function `i.description' returned false\n"
+ .. "in callback `name'"
+ )
+ break
+ end
+ if ret ~= true then
+ alltrue = false
+ head = ret
+ end
+ end
+ return alltrue and true or head
+ end
+end
+% \end{macrocode}
+% Handler for |simple| callbacks.
+% \begin{macrocode}
+local function simple_handler(name)
+ return function(...)
+ local i
+ for _,i in ipairs(callbacklist[name]) do
+ i.func(...)
+ end
+ end
+end
+% \end{macrocode}
+%
+% Keep a handlers table for indexed access.
+% \begin{macrocode}
+local handlers = {
+ [data] = data_handler,
+ [exclusive] = exclusive_handler,
+ [list] = list_handler,
+ [simple] = simple_handler,
+}
+% \end{macrocode}
+%
+% \subsubsection{Public functions for callback management}
+%
+% Defining user callbacks perhaps should be in package code,
+% but impacts on |add_to_callback|.
+% If a default function is not required, may may be declared as |false|.
+% First we need a list of user callbacks.
+% \begin{macrocode}
+local user_callbacks_defaults = { }
+% \end{macrocode}
+%
+% \begin{macro}{create_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% The allocator itself.
+% \begin{macrocode}
+local function create_callback(name, ctype, default)
+ if not name or
+ name == "" or
+ callbacktypes[name] or
+ not(default == false or type(default) == "function")
+ then
+ luatexbase_error("Unable to create callback " .. name)
+ end
+ user_callbacks_defaults[name] = default
+ callbacktypes[name] = types[ctype]
+end
+luatexbase.create_callback = create_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{call_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Call a user defined callback. First check arguments.
+% \begin{macrocode}
+local function call_callback(name,...)
+ if not name or
+ name == "" or
+ user_callbacks_defaults[name] == nil
+ then
+ luatexbase_error("Unable to call callback " .. name)
+ end
+ local l = callbacklist[name]
+ local f
+ if not l then
+ f = user_callbacks_defaults[name]
+ if l == false then
+ return nil
+ end
+ else
+ f = handlers[callbacktypes[name]](name)
+ end
+ return f(...)
+end
+luatexbase.call_callback=call_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{add_to_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Add a function to a callback. First check arguments.
+% \begin{macrocode}
+local function add_to_callback(name, func, description)
+ if
+ not name or
+ name == "" or
+ not callbacktypes[name] or
+ type(func) ~= "function" or
+ not description or
+ description == "" then
+ luatexbase_error(
+ "Unable to register callback.\n\n"
+ .. "Correct usage:\n"
+ .. "add_to_callback(<callback>, <function>, <description>)"
+ )
+ return
+ end
+% \end{macrocode}
+% Then test if this callback is already in use. If not, initialise its list
+% and register the proper handler.
+% \begin{macrocode}
+ local l = callbacklist[name]
+ if l == nil then
+ l = { }
+ callbacklist[name] = l
+% \end{macrocode}
+% If it is not a user defined callback use the primitive callback register.
+% \begin{macrocode}
+ if user_callbacks_defaults[name] == nil then
+ callback_register(name, handlers[callbacktypes[name]](name))
+ end
+ end
+% \end{macrocode}
+% Actually register the function and give an error if more than one
+% |exclusive| one is registered.
+% \begin{macrocode}
+ local f = {
+ func = func,
+ description = description,
+ }
+ local priority = #l + 1
+ if callbacktypes[name] == exclusive then
+ if #l == 1 then
+ luatexbase_error(
+ "Cannot add second callback to exclusive function\n`" ..
+ name .. "'")
+ end
+ end
+ table.insert(l, priority, f)
+% \end{macrocode}
+% Keep user informed.
+% \begin{macrocode}
+ texio_write_nl(
+ "Inserting `" .. description .. "' at position "
+ .. priority .. " in `" .. name .. "'."
+ )
+end
+luatexbase.add_to_callback = add_to_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{remove_from_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Remove a function from a callback. First check arguments.
+% \begin{macrocode}
+local function remove_from_callback(name, description)
+ if
+ not name or
+ name == "" or
+ not callbacktypes[name] or
+ not description or
+ description == "" then
+ luatexbase_error(
+ "Unable to remove function from callback.\n\n"
+ .. "Correct usage:\n"
+ .. "remove_from_callback(<callback>, <description>)"
+ )
+ return
+ end
+ local l = callbacklist[name]
+ if not l then
+ luatexbase_error(
+ "No callback list for `" .. name .. "'\n")
+ end
+% \end{macrocode}
+% Loop over the callback's function list until we find a matching entry.
+% Remove it and check if the list is empty: if so, unregister the
+% callback handler.
+% \begin{macrocode}
+ local index = false
+ local i,j
+ local cb = {}
+ for i,j in ipairs(l) do
+ if j.description == description then
+ index = i
+ break
+ end
+ end
+ if not index then
+ luatexbase_error(
+ "No callback `" .. description .. "' registered for `" ..
+ name .. "'\n")
+ return
+ end
+ cb = l[index]
+ table.remove(l, index)
+ texio_write_nl(
+ "Removing `" .. description .. "' from `" .. name .. "'."
+ )
+ if #l == 0 then
+ callbacklist[name] = nil
+ callback_register(name, nil)
+ end
+ return cb.func,cb.description
+end
+luatexbase.remove_from_callback = remove_from_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{in_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% Look for a function description in a callback.
+% \begin{macrocode}
+local function in_callback(name, description)
+ if not name
+ or name == ""
+ or not callbacktypes[name]
+ or not description then
+ return false
+ end
+ local i
+ for _, i in pairs(callbacklist[name]) do
+ if i.description == description then
+ return true
+ end
+ end
+ return false
+end
+luatexbase.in_callback = in_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{disable_callback}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% As we subvert the engine interface we need to provide a way to access
+% this functionality.
+% \begin{macrocode}
+local function disable_callback(name)
+ if(callbacklist[name] == nil) then
+ callback_register(name, false)
+ else
+ luatexbase_error("Callback list for " .. name .. " not empty")
+ end
+end
+luatexbase.disable_callback = disable_callback
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{callback_descriptions}
+% \changes{v1.0a}{2015/09/24}{Function added}
+% List the descriptions of functions registered for the given callback.
+% \begin{macrocode}
+local function callback_descriptions (name)
+ local d = {}
+ if not name
+ or name == ""
+ or not callbacktypes[name]
+ then
+ return d
+ else
+ local i
+ for k, i in pairs(callbacklist[name] or {}) do
+ d[k]= i.description
+ end
+ end
+ return d
+end
+luatexbase.callback_descriptions =callback_descriptions
+% \end{macrocode}
+% \end{macro}
+% \endgroup
+%
+% \begin{macrocode}
+%</lua>
+% \end{macrocode}
+%
+% Reset the catcode of |@|.
+% \begin{macrocode}
+%<tex>\catcode`\@=\etatcatcode\relax
+% \end{macrocode}
+%
+%
+% \Finale