%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]
%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`\ =\@@space}

\bgroup
\catcode`\ =\@@active
\gdef\obeyspaces{\catcode`\ =\@@active\def {\obeyedspace}}
\gdef\setcontrolspaces{\catcode`\ =\@@active\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.

\catcode`\^^L=\@@active \def^^L{\par}

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

\bgroup

\catcode`\^^I=\@@active
\catcode`\^^M=\@@active
\catcode`\^^L=\@@active

\gdef\obeytabs    {\catcode`\^^I=\@@active\def^^I{\obeyedtab}}
\gdef\obeylines   {\catcode`\^^M=\@@active\def^^M{\obeyedline}}
\gdef\obeypages   {\catcode`\^^L=\@@active\def^^L{\obeyedpage}}

\gdef\ignoretabs  {\catcode`\^^I=\@@active\def^^I{\obeyedspace}}
\gdef\ignorelines {\catcode`\^^M=\@@active\def^^M{\obeyedspace}}
\gdef\ignorepages {\catcode`\^^L=\@@ignore}  % \@@active\def^^L{\obeyedline}}
\gdef\ignoreeofs  {\catcode`\^^Z=\@@ignore}

\egroup

%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}

%D What-a-mess:

% \def\normalspacecodes
%   {\catcode`\^^I = 10
%    \catcode`\^^M =  5
%    \catcode`\^^L =  5
%    \catcode`\    = 10
%    \catcode`\^^Z =  9 }

% \appendtoks
%     \normalspacecodes
% \to \everybeforeoutput

\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.

%D This feature is obsolete.

\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