%D \module
%D   [       file=back-exp,
%D        version=2010.08.22,
%D          title=\CONTEXT\ Backend Macros,
%D       subtitle=XML export,
%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.

% see t:/export/todo-fonts.tex for (future) experiment

\writestatus{loading}{ConTeXt Backend Macros / XML export}

\registerctxluafile{back-exp}        {autosuffix}
\registerctxluafile{back-exp-imp-tag}{autosuffix}
\registerctxluafile{back-exp-imp-mth}{autosuffix}
\registerctxluafile{back-exp-imp-ref}{autosuffix}

%D This is an experimental exporter and a logical follow up on tagging. The
%D exporter assumes a properly tagged document. Some elements get a couple
%D of attributes because otherwise rendering information would get lost. In
%D general we assume that when the \XML\ is converted to \HTML\ some stylesheet
%D is applied anyway.

\unprotect

% we can replace this by a more generic attributeset mechanism where we bind
% to any element (needed anyway, see userdata thingies)

\definesystemattribute[taggedpar][public]

\permanent\tolerant\protected\def\setelementexporttag[#1]#*[#2]#*[#3]%
  {\ifarguments\or\or
     \clf_settagproperty{#1}{export}{#2}%
   \or
     \clf_settagproperty{#1}{#2}{#3}%
   \fi}

% todo: no need for calls when trialtypesetting

\permanent\def\taggedctxcommand
  {\iftrialtypesetting
     \expandafter\gobbleoneargument
   \else
     \expandafter\ctxcommand
   \fi}

\newcount\tagparcounter

\permanent\protected\lettonothing\dotagsetparcounter
\permanent\protected\lettonothing\doresetparcounter

\appendtoks
    \doresetparcounter
\to \everyflushatnextpar

% \appendtoks
%     \dotagsetparcounter
% \to \everypar

\prependtoks
    \dotagsetparcounter
\to \everypar

% \appendtoks
%     \dotagsetparcounter
% \to \neverypar

\prependtoks
    \dotagsetparcounter
\to \neverypar

\appendtoks
    \dotagsetparcounter
\to \everytabulatepar % tricky, maybe this should be neverypar

\appendtoks
    \enforced\permanent\protected\def\dotagTABLEcell
      {\iftrialtypesetting\else
         \clf_settagtablecell
           \numexpr\tablecellrows\relax
           \numexpr\tablecellcolumns\relax
           \numexpr\raggedstatus\relax
       \fi}%
    % brrr, we need to tag empty cells (unless we start numbering)
    \enforced\permanent\protected\def\dotagTABLEsignal
      {\signalcharacter}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagtabulatecell
      {\iftrialtypesetting\else
         \clf_settagtabulatecell\c_tabl_tabulate_align\c_tabl_tabulate_kind
       \fi}%
    \enforced\permanent\protected\def\dotagtabulatesignal
      {\dontleavehmode\signalcharacter\ignorespaces}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsynonym
      {\iftrialtypesetting\else\clf_settagsynonym{\currentsynonymtag}\fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsorting
      {\iftrialtypesetting\else\clf_settagsorting{\currentsortingtag}\fi}%
\to \everyenableelements

\appendtoks % frozen and assumed global per highlight class
    \enforced\permanent\protected\def\dotagconstruct
      {\iftrialtypesetting\else
         \clf_settagconstruct
           {\currentstartstop}%
           {\startstopparameter\c!style}%
           \c_attr_color
           \ifvmode\plusone\else\zerocount\fi
           \relax
       \fi}%
\to \everyenableelements

\appendtoks % frozen and assumed global per highlight class
    \enforced\permanent\protected\def\dotaghighlight
      {\iftrialtypesetting\else
         \clf_settaghighlight
           {\currenthighlight}%
           {\highlightparameter\c!style}
           \c_attr_color
           \ifvmode\plusone\else\zerocount\fi
           \relax
       \fi}%
\to \everyenableelements

\appendtoks % we can have differently scaled images
    \enforced\permanent\protected\def\dotagfigure
      {\iftrialtypesetting\else
         \clf_settagfigure
           {\figurefileoriginal}%
           {\figurefullname}%
           {\figurefilepage}%
           \dimexpr\figurewidth\relax
           \dimexpr\figureheight\relax
           {\figurelabel}%
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagcombination
      {\iftrialtypesetting\else
         \clf_settagcombination
            \numexpr\combinationparameter\c!nx\relax
            \numexpr\combinationparameter\c!ny\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetparcounter
      {\global\advance\tagparcounter\plusone\c_attr_taggedpar\tagparcounter}%
    \enforced\permanent\protected\def\doresetparcounter
      {\c_attr_taggedpar\attributeunsetvalue}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetitemgroup
      {\iftrialtypesetting\else
         \clf_settagitemgroup
           \ifconditional\c_strc_itemgroups_pack true\else false\fi\space
           \numexpr\currentitemlevel\relax
           {\currentitemgroupsymbol}%
       \fi}%
    \enforced\permanent\protected\def\dotagsetitem#1%
      {\iftrialtypesetting\else
         \clf_settagitem{#1}%
       \fi}%
\to \everyenableelements

%     \appendtoks
%         \enforced\permanent\protected\def\dotagsetdescription
%           {\iftrialtypesetting\else
%              \clf_settagdescription{\currentdescription}\currentdescriptionnumberentry\relax
%            \fi}%
%     \to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetnotation
      {\iftrialtypesetting\else
        \clf_settagnotation{\currentnote}\currentnotenumber\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetnotesymbol
      {\iftrialtypesetting\else
         \clf_settagnotationsymbol{\currentnote}\currentnotenumber\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagregisterlocation
      {\iftrialtypesetting\else
         \clf_settagregister{\currentregister}\currentregisternumber\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotaglistlocation
      {\iftrialtypesetting\else
         \clf_settaglist\currentlistindex\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetdelimitedsymbol#1%
      {\iftrialtypesetting\else
         \clf_settagdelimitedsymbol{#1}\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagsetsubsentencesymbol#1%
      {\iftrialtypesetting\else
         \clf_settagsubsentencesymbol{#1}\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagregisterfloat#1#2%
      {\iftrialtypesetting\else
         \clf_settagfloat{#1}{#2}\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\let\specialfixedspace    \explicitfixedspace
    \enforced\let\specialobeyedspace   \explicitobeyedspace
    \enforced\let\specialstretchedspace\explicitstretchedspace
    \enforced\let\specialcontrolspace  \explicitcontrolspace
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagregisterformula#1%
      {\iftrialtypesetting\else
         \clf_settagformulacontent#1\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagmarginanchor#1%
      {\iftrialtypesetting\else\clf_settagmarginanchor#1\relax\fi}%
    \enforced\permanent\protected\def\dotagmargintext#1%
      {\iftrialtypesetting\else\clf_settagmargintext#1\relax\fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagpublication#1#2%
      {\iftrialtypesetting\else
         \clf_settagpublication{#1}{#2}\relax
       \fi}%
\to \everyenableelements

\appendtoks
    \enforced\permanent\protected\def\dotagparagraph#1%
      {\iftrialtypesetting\else
         \clf_settagparagraph{#1}\relax
       \fi}%
\to \everyenableelements

% The action: \setupbackend[export=yes] % or filename

% maybe xhtml css settings will move to setupexport

% maybe some day a definer

\installcorenamespace{export}

\installparameterhandler \??export {export}
\installsetuphandler     \??export {export}

\setupexport
  [\c!align=\number\raggedstatus,
   \c!bodyfont=\bodyfontsize,
   \c!width=\textwidth,
   \c!title={\directinteractionparameter\c!title},
   \c!subtitle={\directinteractionparameter\c!subtitle},
   \c!author={\directinteractionparameter\c!author},
 % \c!firstpage=, % imagename
 % \c!lastpage=,  % imagename
   \c!properties=\v!no, % no: ignore, yes: as attribute, otherwise: use as prefix
   \c!hyphen=\v!no,
   \c!svgstyle=,
   \c!cssfile=,
   \c!file=]

\resetsystemmode\v!export

\permanent\protected\def\doinitializeexport
  {\edef\p_export{\backendparameter\c!export}%
   \ifempty\p_export \else
      % yes | xml
      \setuptagging[\c!state=\v!start]%
      \clf_initializeexport
      \setsystemmode\v!export
      \exportingtrue
      \writestatus\m!backend\empty % so messages will stand out a bit
      \the\everyinitializeexport
      \writestatus\m!backend\empty % so messages will stand out a bit
      \enforced\glet\doinitializeexport\relax
   \fi}

\permanent\protected\def\dostartexport
  {%\glet\dostartexport\relax
   \lettonothing\currentexport
   \clf_setupexport
       align      {\exportparameter\c!align}%
       bodyfont   \dimexpr\exportparameter\c!bodyfont\relax
       width      \dimexpr\exportparameter\c!width\relax
       properties {\exportparameter\c!properties}%
       hyphen     {\exportparameter\c!hyphen}%
       title      {\exportparameter\c!title}%
       subtitle   {\exportparameter\c!subtitle}%
       author     {\exportparameter\c!author}%
       firstpage  {\exportparameter\c!firstpage}%
       lastpage   {\exportparameter\c!lastpage}%
       svgstyle   {\exportparameter\c!svgstyle}%
       cssfile    {\exportparameter\c!cssfile}%
       file       {\exportparameter\c!file}%
       export     {\backendparameter\c!export}%
   \relax}

\permanent\protected\def\dostopexport
  {\enforced\glet\dostopexport\relax
   \clf_finishexport}

\appendtoks
    \doinitializeexport
\to \everysetupbackend

\appendtoks
    \ifexporting
        \dostartexport
    \fi
\to \everystarttext

% better (before pdf gets closed, so we can embed), but it needs testing:

\appendtoks
    \ifexporting
        \dostopexport
    \fi
\to \everystoptext

\appendtoks
    \ifexporting
        \dostartexport % in case it is done inside \starttext
    \fi
\to \everystartdocument

%D This can replace the older (rather unknown) attachment feature because it
%D is more immediate (same run). I can also use this then for manuals.
%D
%D \setuptagging[state=start] % mandate here
%D
%D \starttyping
%D \startmathexport % [buffer=yes]
%D     test $ x = 1 + a $ test
%D \stopmathexport
%D
%D \typebuffer
%D
%D \startmathexport[buffer=math]
%D     test $ x = 1 + a^2 $ test
%D     test $ x = 1 + a $ test
%D     test $ x = z + \sqrt{a} $ test
%D \stopmathexport
%D
%D \typebuffer[math]
%D
%D \startmathexport[filename=foo.xml]
%D     test $ x = z + \sqrt{a} $ test
%D \stopmathexport
%D
%D \dorecurse{\collectedmath} {\page \collectedmath #1 \page}
%D \stoptyping
%D
%D This one also does buffers and files:
%D
%D \starttyping
%D \startboxexport
%D     \startparagraph
%D         \input tufte
%D     \stopparagraph
%D     \startitemize
%D         \startitem item one \stopitem
%D         \startitem item two \stopitem
%D     \stopitemize
%D     \startparagraph
%D         \input tufte
%D     \stopparagraph
%D \stopboxexport
%D
%D \typebuffer
%D \stoptyping

\installcorenamespace {boxexport}
\installcorenamespace {mathexport}

\installsetuponlycommandhandler \??boxexport  {boxexport}
\installsetuponlycommandhandler \??mathexport {mathexport}

% \permanent\tolerant\protected\def\startboxexport[#1]%
%   {\dowithnextbox{\strc_export_box{#1}}\vbox\bgroup}
%
% \permanent\protected\def\stopboxexport
%   {\egroup}
%
% \def\strc_export_box#1%
%   {\ctxlua{buffers.assign("#1",structures.tags.exportbox(\number\nextbox))}}

\permanent\tolerant\protected\def\startboxexport[#1]%
  {\begingroup
   \iftok{#1}\emptytoks
      \letboxexportparameter\c!buffer\v!yes
   \orelse\ifhastok={#1}\relax
      \setupmathexport[#1]%
   \else
      \setboxexportparameter\c!buffer{#1}%
   \fi
   \setbox\nextbox\vbox\bgroup}

\permanent\protected\def\stopboxexport
  {\egroup
   \clf_exportbox \nextbox
     {\boxexportparameter\c!file}%
     {\boxexportparameter\c!buffer}%
   \endgroup}

\permanent\tolerant\protected\def\startmathexport[#1]%
  {\begingroup
   \iftok{#1}\emptytoks
      \letboxexportparameter\c!buffer\v!yes
   \orelse\ifhastok={#1}\relax
      \setupmathexport[#1]%
   \else
      \setboxexportparameter\c!buffer{#1}%
   \fi
   \clf_startcollectingmath}

\permanent\protected\def\stopmathexport
  {\clf_stopcollectingmath
   \clf_processcollectedmath
     {\boxexportparameter\c!file}
     {\boxexportparameter\c!buffer}%
   \endgroup}

% Defined at the \LUA\ end:
%
% \the\collectedmath : number of snippets
% \collectedmath n   : specific snippet

\protect \endinput