%D \module
%D   [       file=catc-ini,
%D        version=2006.09.18,
%D          title=\CONTEXT\ System Macros,
%D       subtitle=Catcode Handling,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D We've split the functionality of syst-cat.* over more files
%D now so that we can load more selectively.

\registerctxluafile{catc-ini} {1.001}

%D A long standing wish has been the availability of catcode
%D arrays. Because traditional \TEX\ does not provide this we
%D implement a fake method in the \MKII\ file. There is some
%D overlap in code with \MKII\ but we take that for granted.

\ifx\zerocount\undefined \chardef           \zerocount= 0 \fi
\ifx\plusone  \undefined \chardef           \plusone  = 1 \fi
\ifx\minusone \undefined \newcount\minusone \minusone =-1 \fi

\chardef\escapecatcode      =  0
\chardef\begingroupcatcode  =  1
\chardef\endgroupcatcode    =  2
\chardef\mathshiftcatcode   =  3
\chardef\alignmentcatcode   =  4
\chardef\endoflinecatcode   =  5
\chardef\parametercatcode   =  6
\chardef\superscriptcatcode =  7
\chardef\subscriptcatcode   =  8
\chardef\ignorecatcode      =  9
\chardef\spacecatcode       = 10
\chardef\lettercatcode      = 11
\chardef\othercatcode       = 12   \chardef\other  = 12
\chardef\activecatcode      = 13   \chardef\active = 13
\chardef\commentcatcode     = 14

\ifx\gobbleoneargument\undefined \long\def\gobbleoneargument#1{} \fi

\newif \ifrecatcodeuppercharacters % only used in good old tex

\newcount\cctdefcounter \cctdefcounter\zerocount % 0 = signal, so advance before allocate

\newcount\cctcountera
\newcount\cctcounterb
\newcount\cctcounterc

\def\newcatcodetable#1%
  {\global\advance\cctdefcounter\plusone
   \expandafter\xdef\csname @@ccn:\number\cctdefcounter\endcsname{\string#1}% logging
   \global\chardef#1\cctdefcounter
   \ctxlua{catcodes.register("\expandafter\gobbleoneargument\string#1",\number#1)}%
   % we have two ways to access catcodetable numbers
   \startruntimectxluacode tex.\expandafter\gobbleoneargument\string#1 = \number#1 ;\stopruntimectxluacode}

\newcatcodetable \scratchcatcodes \initcatcodetable\scratchcatcodes

\newtoks \setdefaultcatcodes

\setdefaultcatcodes
  {\catcode`\\   \othercatcode
   \catcode`\^^M \othercatcode
   \catcode`\    \othercatcode
   \catcode`\%   \othercatcode
   \catcode127   \othercatcode}

\long\normalprotected\def\startcatcodetable#1#2\stopcatcodetable
  {\bgroup
   \catcodetable\scratchcatcodes
   \the\setdefaultcatcodes
   #2%
   \savecatcodetable#1\relax
   \egroup}

\newcatcodetable\dummycatcodes

\long\normalprotected\def\startextendcatcodetable#1#2\stopextendcatcodetable
  {\bgroup
   \catcodetable#1\relax
   \globaldefs\plusone
   #2%
   \globaldefs\zerocount
   \egroup}

% ==
%
% \long\normalprotected\def\startextendcatcodetable#1#2\stopextendcatcodetable
%   {\bgroup
%    \scratchcounter\the\catcodetable
%    \catcodetable #1 #2
%    \catcodetable\scratchcounter
%    \egroup}

\def\letcatcodecommand
  {\afterassignment\letcatcodecommanda\cctcountera}

\def\letcatcodecommanda
  {\afterassignment\letcatcodecommandb\cctcounterb}

\let\currentcatcodetable\catcodetable

%D The next command can be defined in a cleaner way in the
%D Mk IV file but we want to have a fast one with a minimal
%D chance for interference. Do we still need this complex
%D mechanism? Future versions of \MKIV\ might only use
%D active characters for very special cases.

\chardef\activehackcode=`\~

%D Once a catcode is assigned, the next assignments will happen faster.

% (expandable) let

\def\letcatcodecommand {\afterassignment\letcatcodecommanda\cctcountera}
\def\letcatcodecommanda{\afterassignment\letcatcodecommandb\cctcounterb}

\def\letcatcodecommandb % each time
  {\ifcsname CCL:\number\cctcountera:\number\cctcounterb\endcsname
     \csname CCL:\number\cctcountera:\number\cctcounterb\expandafter\endcsname
   \else
     \expandafter\letcatcodecommandc
   \fi}

\def\letcatcodecommandc % only first time
  {\expandafter\gdef\csname CCL:\number\cctcountera:\number\cctcounterb\expandafter\endcsname\expandafter
     {\expandafter\let\csname CCC:\number\cctcountera:\number\cctcounterb\endcsname}%
   \reinstatecatcodecommandua % unexpanded
   \csname CCL:\number\cctcountera:\number\cctcounterb\endcsname}

% expandable def

\def\defcatcodecommand {\afterassignment\defcatcodecommanda\cctcountera}
\def\defcatcodecommanda{\afterassignment\defcatcodecommandb\cctcounterb}

\def\defcatcodecommandb % each time
  {\ifcsname CCD:\number\cctcountera:\number\cctcounterb\endcsname
     \csname CCD:\number\cctcountera:\number\cctcounterb\expandafter\endcsname
   \else
     \expandafter\defcatcodecommandc
   \fi}

\def\defcatcodecommandc % only first time (we could use \normalexpanded here)
  {\expandafter\gdef\csname CCD:\number\cctcountera:\number\cctcounterb\expandafter\endcsname
     \expandafter##\expandafter1\expandafter
       {\expandafter\def\csname CCC:\number\cctcountera:\number\cctcounterb\endcsname{##1}}%
   \reinstatecatcodecommanda
   \csname CCD:\number\cctcountera:\number\cctcounterb\endcsname}

% unexpandable def (e.g. used for discretionaries)

\def\uedcatcodecommand {\afterassignment\uedcatcodecommanda\cctcountera}
\def\uedcatcodecommanda{\afterassignment\uedcatcodecommandb\cctcounterb}

\def\uedcatcodecommandb % each time
  {\ifcsname CCU:\number\cctcountera:\number\cctcounterb\endcsname
     \csname CCU:\number\cctcountera:\number\cctcounterb\expandafter\endcsname
   \else
     \expandafter\uedcatcodecommandc
   \fi}

\def\uedcatcodecommandc % only first time
  {\expandafter\gdef\csname CCU:\number\cctcountera:\number\cctcounterb\expandafter\endcsname
     \expandafter##\expandafter1\expandafter
       {\expandafter\normalprotected\expandafter\def\csname CCC:\number\cctcountera:\number\cctcounterb\endcsname{##1}}%
   \reinstatecatcodecommandua % unexpanded
   \csname CCU:\number\cctcountera:\number\cctcounterb\endcsname}

\def\reinstatecatcodecommand{\afterassignment\reinstatecatcodecommanda\cctcounterb}

\def\reinstatecatcodecommanda % can be used when a direct definition has been done
  {\bgroup                    % and the selector has been lost
   \uccode\activehackcode\cctcounterb
   \catcode\uccode\activehackcode\activecatcode
   \uppercase{\xdef~{\noexpand\catcodecommand{\number\cctcounterb}}}%
   \egroup}

\def\reinstatecatcodecommandua % can be used when a direct definition has been done
  {\bgroup                     % and the selector has been lost
   \uccode\activehackcode\cctcounterb
   \catcode\uccode\activehackcode\activecatcode
   \uppercase{\normalprotected\xdef~{\noexpand\catcodecommand{\number\cctcounterb}}}%
   \egroup}

\chardef\defaultcatcodetable\zerocount

\def\catcodecommand#1%
  {\csname CCC:\number
     \ifcsname CCC:\number\currentcatcodetable:\number#1\endcsname
       \currentcatcodetable \else \defaultcatcodetable
     \fi
   :\number#1\endcsname}

%D \macros
%D   {restorecatcodes,
%D    beginrestorecatcodes,endrestorecatcodes}
%D
%D We're not finished dealing \CATCODES\ yet. In \CONTEXT\ we
%D use only one auxiliary file, which deals with tables of
%D contents, registers, two pass tracking, references etc. This
%D file, as well as files concerning graphics, is processed when
%D needed, which can be in the mid of typesetting verbatim.
%D However, when reading in data in verbatim mode, we should
%D temporary restore the normal \CATCODES, and that's exactly
%D what the next macros do. Saving the catcodes can be
%D disabled by saying \type{\localcatcodestrue}.

\let\savedcatcodetable\relax

\newcount\catcoderestorelevel

\def\pushcatcodetable
  {\advance\catcoderestorelevel\plusone
   \tracepushcatcodetable
   \expandafter\chardef\csname scct:\number\catcoderestorelevel\endcsname\currentcatcodetable}

\def\popcatcodetable
  {\ifcase\catcoderestorelevel
     \showcatcodenestingerror
   \else
     \expandafter\catcodetable\csname scct:\number\catcoderestorelevel\endcsname
     \tracepopcatcodetable
     \advance\catcoderestorelevel\minusone
   \fi}

\def\showcatcodenestingerror % can be overloaded
  {\immediate\write16{}%
   \immediate\write16{Fatal error: catcode push/pop mismatch. Fix this!}\wait\end
   \immediate\write16{}}

\def\restorecatcodes % takes previous level
  {\ifnum\catcoderestorelevel>\plusone
     \expandafter\catcodetable\csname scct:\number\numexpr\catcoderestorelevel-1\relax\endcsname
   \fi}

\newtoks\everycatcodetable

\def\setcatcodetable#1%
   {\catcodetable#1%
    \the\everycatcodetable
    \tracesetcatcodetable}

\def\dotracecatcodetable#1{\immediate\write16{[#1]}}

\def\tracecatcodetables
  {\def\tracesetcatcodetable {\dotracecatcodetable{set  \catcodetablename\space                              at \number\catcoderestorelevel}}%
   \def\tracepushcatcodetable{\dotracecatcodetable{push \catcodetablename\space from \catcodetableprev\space at \number\catcoderestorelevel}}%
   \def\tracepopcatcodetable {\dotracecatcodetable{pop  \catcodetablename\space to   \catcodetableprev\space at \number\catcoderestorelevel}}}

\def\catcodetableprev
  {\ifnum\numexpr\catcoderestorelevel-1\relax>\zerocount
     \csname @@ccn:\number\csname scct:\number\numexpr\catcoderestorelevel-1\relax\endcsname\endcsname
   \else
     -%
   \fi}

\def\catcodetablename
  {\ifnum\currentcatcodetable>\zerocount
     \csname @@ccn:\number\currentcatcodetable\endcsname
   \else
     -%
   \fi}

\ifx\empty\undefined \def\empty{} \fi

\let\tracesetcatcodetable \empty
\let\tracepushcatcodetable\empty
\let\tracepopcatcodetable \empty

\def\beginrestorecatcodes{\pushcatcodetable}
\def\endrestorecatcodes  {\popcatcodetable}

%D Handy for debugging:

% \tracecatcodetables

%D Only in \MKIV\ (to be used when crossing pages with changed catcodes
%D in the current vector):
%D
%D \starttyping
%D \normalprotected\def\startcrap
%D   {\bgroup
%D    \pushcatcodes
%D    \whitespace
%D    \obeylines
%D    \activatespacehandler\v!yes
%D    \strut}
%D
%D \normalprotected\def\stopcrap
%D   {\popcatcodes
%D   \egroup}
%D \stoptyping

\newcount\catcodetablelevel

\def\pushcatcodes
  {\bgroup
   \global\advance\catcodetablelevel\plusone
   \ifcsname @@ccf:\number\catcodetablelevel\endcsname \else
     \global\advance\cctdefcounter\plusone
     \expandafter\global\expandafter\chardef\csname @@ccf:\number\catcodetablelevel\endcsname\cctdefcounter
   \fi
   \catcodetable\ctxcatcodes
   \expandafter\savecatcodetable\csname @@ccf:\number\catcodetablelevel\endcsname
   \egroup
   \expandafter\catcodetable\csname @@ccf:\number\catcodetablelevel\endcsname}

\def\popcatcodes
  {\global\advance\catcodetablelevel\minusone}

\endinput