%D \module
%D   [       file=char-act,
%D        version=2006.12.05,
%D          title=\CONTEXT\ Character Support,
%D       subtitle=Active,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Character Support / Active}

\unprotect

%D \macros
%D   {processingverbatim}
%D
%D Typesetting a file in most cases results in more than one
%D page. Because we don't want problems with files that are
%D read in during the construction of the page, we set \type
%D {\ifprocessingverbatim}, so the output routine can adapt
%D its behavior. Originally we used \type {\scratchread}, but
%D because we want to support nesting, we decided to use a
%D separate input file.

\newif\ifprocessingverbatim

%D \macros
%D   {obeyedspace, obeyedtab, obeyedline, obeyedpage}
%D
%D We have followed Knuth in naming macros that make \SPACE,
%D \NEWLINE\ and \NEWPAGE\ active and assigning them
%D \type{\obeysomething}, but first we set some default values.

\def\obeyedspace {\ifprocessingverbatim\hbox{ }\else\space\fi}
\def\obeyedtab   {\obeyedspace}
\def\obeyedline  {\par}
\def\obeyedpage  {\vfill\eject}

%D \macros
%D   {controlspace,setcontrolspaces}
%D
%D First we define \type{\obeyspaces}. When we want visible
%D spaces (control spaces) we only have to adapt the definition
%D of \type{\obeyedspace} to:

\def\controlspace{\hbox{\char32}} % rather tex
\def\normalspace { }
\def\normalspaces{\catcode\spaceasciicode\spacecatcode}

\bgroup
\catcode\spaceasciicode\activecatcode
\gdef\obeyspaces{\catcode\spaceasciicode\activecatcode\def {\obeyedspace}}
\gdef\setcontrolspaces{\catcode\spaceasciicode\activecatcode\def {\controlspace}}
\egroup

%D \macros
%D   {obeytabs, obeylines, obeypages,ignoretabs, ignorelines, ignorepages}
%D
%D Next we take care of \NEWLINE\ and \NEWPAGE\ and because we
%D want to be able to typeset listings that contain \TAB, we
%D have to handle those too. Because we have to redefine the
%D \NEWPAGE\ character locally, we redefine the meaning of
%D this (often already) active character.

% \bgroup \permitcircumflexescape

%     \catcode\formfeedasciicode\activecatcode

%     \gdef^^L{\par}

% \egroup

\expandafter\def\activeformfeedtoken{\par}

%D The following indirect definitions enable us to implement
%D all kind of \type{\obeyed} handlers.

% \bgroup \permitcircumflexescape

%     \catcode\tabasciicode      \activecatcode
%     \catcode\endoflineasciicode\activecatcode
%     \catcode\formfeedasciicode \activecatcode

%     \gdef\obeytabs   {\catcode\tabasciicode      \activecatcode\def^^I{\obeyedtab }}
%     \gdef\obeylines  {\catcode\endoflineasciicode\activecatcode\def^^M{\obeyedline}}
%     \gdef\obeypages  {\catcode\formfeedasciicode \activecatcode\def^^L{\obeyedpage}}

%     \gdef\ignoretabs {\catcode\tabasciicode      \activecatcode\def^^I{\obeyedspace}}
%     \gdef\ignorelines{\catcode\endoflineasciicode\activecatcode\def^^M{\obeyedspace}}
%     \gdef\ignorepages{\catcode\formfeedasciicode \ignorecatcode}
%     \gdef\ignoreeofs {\catcode\endoffileasciicode\ignorecatcode}

% \egroup

\def\obeytabs   {\catcode\tabasciicode      \activecatcode\expandafter\def\activetabtoken      {\obeyedtab }}
\def\obeylines  {\catcode\endoflineasciicode\activecatcode\expandafter\def\activeendoflinetoken{\obeyedline}}
\def\obeypages  {\catcode\formfeedasciicode \activecatcode\expandafter\def\activeformfeedtoken {\obeyedpage}}

\def\ignoretabs {\catcode\tabasciicode      \activecatcode\expandafter\def\activetabtoken      {\obeyedspace}}
\def\ignorelines{\catcode\endoflineasciicode\activecatcode\expandafter\def\activeendoflinetoken{\obeyedspace}}
\def\ignorepages{\catcode\formfeedasciicode \ignorecatcode}
\def\ignoreeofs {\catcode\endoffileasciicode\ignorecatcode}

%D \macros
%D   {naturaltextext}
%D
%D When one uses \ETEX, switching to normal \TEX\ is possible
%D too. We also introduce a switch that can be used in the
%D drivers and set in higher level shell macros.

\def\naturaltextext#1\relax
  {\bgroup
   \def\ascii{#1}%
   \setcatcodetable\ctxcatcodes
   \prettynaturalfont{\scantextokens\expandafter{\ascii}\ifhmode\unskip\fi}%
   \egroup}

\endinput \protect

% obsolete (old hack for idris)

% %D This is a hack, and only meant for special situations. We don't
% %D support this in for instance verbatim. The active characters map
% %D onto the \CONTEXT\ names and font handling etc. is up to the user.
%
% \registerctxluafile{char-act}{1.001}
%
% \def\enableactiveutf {\ctxlua{characters.active.enable()}}
% \def\disableactiveutf{\ctxlua{characters.active.disable()}}
% \def\testactiveutf #1{\ctxlua{characters.active.test("#1")}}

%D Usage:
%D
%D \starttyping
%D \enableactiveutf \testactiveutf{eacute}
%D \stoptyping