%D \module
%D   [       file=strc-mar,
%D        version=2008.10.20,
%D          title=\CONTEXT\ Structure Macros,
%D       subtitle=Markings,
%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 Structure Macros / Markings}

\registerctxluafile{strc-mar}{autosuffix}

\unprotect

%D Synchronizing marks is a rather tricky and messy business. When setting a mark, a
%D node is added to the list in order for to \TEX\ be able to figure out the 3
%D current marks when a page is made (last mark on previous page, first on current
%D page, last on current page; in \LUATEX\ we might at one point have the first on
%D the next page as well).
%D
%D Resetting a mark is not easy. An empty one will not erase the last one on the
%D previous page for instance. In \LUATEX\ we can clear a marks state register with
%D \type {\clearmarks} but since this is an immediate operation it might have
%D unwanted side effects when \TEX\ has collected several pages of text and
%D finishing off these pages uses marks.
%D
%D In \MKIV\ we provide an alternative model that permits some more control over the
%D way marks are used. It is not entirely compatible with \MKII\ or previous \MKIV\
%D implementations but in practice this is not a real problem. It's also easier now
%D to extend this mechanism.

%D In \LUAMETATEX\ we have extended the marks mechanism with a few handy options.
%D First of all we have automigration built in for inserts and marks (so we no
%D longer need to do that in \LUA) and marks can be properly flushed.

% \ifdefined\automigrationmode \automigrationmode0 \fi
% \starttext
% \dorecurse{10}{
%     \dontleavehmode\setbox0\hbox{SAMPLE #1}\box0
%     \marks\foomark{sample #1}%
%     \samplefile{tufte}\par
% }%
% \stoptext

% current

% column:n | n | column | etc ... now only column:n

% default page all keep

%definesystemattribute [marks] [global]

\installcorenamespace{marking}
\installcorenamespace{markingclass}
\installcorenamespace{markingsyncs}
\installcorenamespace{markingfilter}

\installcommandhandler \??marking {marking} \??marking

\newconditional\inhibitgetmarking % will become private
\newconditional\inhibitsetmarking % will become private

\newtoks       \everymarking

% \clf_definemarking{\currentmarking}{\currentmarkingparent}%

\appendtoks
    \ifcsname\??markingclass\currentmarking\endcsname\else
        \ifempty\currentmarkingparent
            \expandafter\newmarks\csname\??markingclass\currentmarking\endcsname
            \expandafter\newtoks \csname\??markingsyncs\currentmarking\endcsname
        \else
            \expandafter\letcsname\??markingclass\currentmarking\expandafter\endcsname\csname\??markingclass\currentmarkingparent\endcsname
            \expandafter\letcsname\??markingsyncs\currentmarking\expandafter\endcsname\csname\??markingsyncs\currentmarkingparent\endcsname
        \fi
    \fi
\to \everydefinemarking

\permanent\protected\tolerant\def\relatemarking[#1]#*[#2]%
  {\ifarguments\or\else
     \xtoksapp\csname\??markingsyncs#2\endcsname{%
       \flushmarks\csname\??markingclass#1\endcsname
       \noexpand\the\begincsname\??markingsyncs#1\endcsname
     }%
   \fi}

\permanent\protected\tolerant\def\clearmarking[#1]%
  {\ifarguments\else
     \begingroup
     \clearmarks\csname\??markingclass#1\endcsname
     \enforced\let\flushmarks\clearmarks
     \the\csname\??markingsyncs#1\endcsname
     \endgroup
   \fi}

\permanent\protected\tolerant\def\resetmarking[#1]%
  {\ifarguments\else
     % probably best: \dontleavehmode
     \the\csname\??markingsyncs#1\endcsname
   \fi}

\permanent\protected\tolerant\def\resetsynchronizemarking[#1]%
  {\clf_resetsynchronizemarking{#1}}

\tolerant\def\synchronizemarking[#1]#*[#2]#*[#3]% #3: options
  {\clf_synchronizemarking{#1}\plusone\numexpr#2\relax}

\def\strc_markings_synchronize#1#2#3% category n box
  {\ifvoid#3\orelse\ifcstok{#1}\v!page\else
     \clf_synchronizemarking{#1}\numexpr#2\relax\numexpr#3\relax
   \fi}

\permanent\def\doifelsemarking#1%
  {\ifcondition\ifcommandhandler\??marking{#1}%
     \expandafter\firstoftwoarguments
   \else
     \expandafter\secondoftwoarguments
   \fi}

\permanent\protected\tolerant\def\setmarking[#1]#:#2%
  {\ifarguments\orelse\ifconditional\inhibitsetmarking\else
     % so no: \dontleavehmode
     \the\csname\??markingsyncs#1\endcsname
     \ifcstok{\namedmarkingparameter{#1}\c!expansion}\v!yes
       \normalexpanded{%
          \ifvmode\expandafter\flushatnextpar\else\expandafter\firstofoneargument\fi
            {\marks\csname\??markingclass#1\endcsname{#2}}%
       }%
     \else
       \ifvmode\expandafter\flushatnextpar\else\expandafter\firstofoneargument\fi
          {\marks\csname\??markingclass#1\endcsname{#2}}%
     \fi
   \fi}

\aliased\let\marking        \setmarking
\aliased\let\doifmarkingelse\doifelsemarking

% defaults

\setupmarking
  [\c!expansion=\v!no,
   \c!separator=\space\emdash\space,
   \c!filtercommand=\firstofoneargument,
   \c!state=\v!start]

% fetching, regular interface

\permanent\protected\def\getmarking
  {\ifconditional\inhibitgetmarking
     \expandafter\strc_markings_get_nop
   \else
     \expandafter\strc_markings_get_yes
   \fi}

\tolerant\def\strc_markings_get_nop[#-]#*[#-]#*[#-]%
  {}

\tolerant\def\strc_markings_get_yes[#1]#*[#2]#*[#3]%
  {\ifarguments\orelse\ifcstok{\namedmarkingparameter{#1}\c!state}\v!start
     \begingroup
     \setsystemmode\v!marking
     \the\everymarking
     \ifparameter#3\or
       \ifcstok{#2}\v!page
         \markingcommand{#1}{\csname\??markingfilter#3\endcsname{#1}}%
       \else
         \markingcommand{#1}{\clf_getsynchronizemarking\begincsname\??markingclass#1\endcsname{#2}{#3}}%
       \fi
     \orelse\ifparameter#2\or
       \markingcommand{#1}{\csname\??markingfilter#2\endcsname{#1}}%
     \else
       \markingcommand{#1}{\csname\??markingfilter\v!default\endcsname{#1}}%
     \fi
     \endgroup
  \fi}

% previous      : last before sync        next   : first after sync
% top           : first in sync           bottom : last in sync
% first|default : first not top in sync   last   : last not bottom in sync

% current

\defcsname\??markingfilter\v!previous\endcsname#1{\topmarks    \csname\??markingclass#1\endcsname}
\defcsname\??markingfilter\v!next    \endcsname#1{\botmarks    \csname\??markingclass#1\endcsname}

%defcsname\??markingfilter\v!top     \endcsname#1{\topmarks    \csname\??markingclass#1\endcsname}
\defcsname\??markingfilter\v!top     \endcsname#1{\firstmarks  \csname\??markingclass#1\endcsname}
\defcsname\??markingfilter\v!bottom  \endcsname#1{\botmarks    \csname\??markingclass#1\endcsname}

\defcsname\??markingfilter\v!first   \endcsname#1{\firstmarks  \csname\??markingclass#1\endcsname}
\defcsname\??markingfilter\v!last    \endcsname#1{\botmarks    \csname\??markingclass#1\endcsname}

\defcsname\??markingfilter\v!current \endcsname#1{\currentmarks\csname\??markingclass#1\endcsname}

\letcsname\??markingfilter\v!default\expandafter\endcsname
   \csname\??markingfilter\v!first              \endcsname

% the fetchers are fully expandable: [name][method]

\def\strc_markings_fetch_one#1#2#3%
  {\ifparameter#1\or
     \ifconditional\inhibitgetmarking\else
       \ifcstok{#2}\v!page
         \markingcommand{#1}{\begincsname\??markingfilter#3\endcsname{#1}}%
       \else
         \markingcommand{#1}{\clf_getsynchronizemarking{#1}{#2}}%
       \fi
     \fi
   \fi}

\def\strc_markings_fetch_two#1#2%
  {\ifparameter#1\or
     \ifconditional\inhibitgetmarking\else
       \ifcstok{#2}\v!page
         \markingcommand{#1}{\begincsname\??markingfilter\v!first\endcsname{#1}}%
         \markingseparator{#1}%
         \markingcommand{#1}{\begincsname\??markingfilter\v!last\endcsname{#1}}%
       \else
         \markingcommand{#1}{\clf_getsynchronizemarking{#1}\v!first}%
         \markingseparator{#1}%
         \markingcommand{#1}{\clf_getsynchronizemarking{#1}\v!last}%
       \fi
     \fi
   \fi}

\def\strc_markings_fetch_all#1#2%
  {\ifparameter#1\or
     \ifconditional\inhibitgetmarking\else
       \ifcstok{#2}\v!page
         \markingcommand{#1}{\begincsname\??markingfilter\v!previous\endcsname{#1}}%
         \markingseparator{#1}%
         \markingcommand{#1}{\begincsname\??markingfilter\v!first\endcsname{#1}}%
         \markingseparator{#1}%
         \markingcommand{#1}{\begincsname\??markingfilter\v!last\endcsname{#1}}%
       \else
        %\markingcommand{#1}{\begincsname\??markclass:\v!previous\endcsname{#1}}%
        %\markingseparator{#1}%
         \markingcommand{#1}{\clf_getsynchronizemarking{#1}\v!first}%
         \markingseparator{#1}%
         \markingcommand{#1}{\clf_getsynchronizemarking{#1}\v!last}%
       \fi
     \fi
  \fi}

\permanent\tolerant\def\fetchonemark [#1]#*[#2]{\strc_markings_fetch_one{#1}\v!page{#2}}
\permanent\tolerant\def\fetchtwomarks      [#1]{\strc_markings_fetch_two{#1}\v!page}
\permanent\tolerant\def\fetchallmarks      [#1]{\strc_markings_fetch_all{#1}\v!page}

\aliased\let\fetchmark\fetchonemark

% also fully expandable but here we have: [name][range][method]

\permanent\tolerant\def\fetchonemarking [#1]#*[#2]#*[#3]{\strc_markings_fetch_one{#1}{#2}{#3}}
\permanent\tolerant\def\fetchtwomarkings      [#1]#*[#2]{\strc_markings_fetch_two{#1}{#2}}
\permanent\tolerant\def\fetchallmarkings      [#1]#*[#2]{\strc_markings_fetch_all{#1}{#2}}

\aliased\let\fetchmarking\fetchonemarking

\permanent\def\markingseparator#1{\namedmarkingparameter{#1}\c!separator}
\permanent\def\markingcommand  #1{\namedmarkingparameter{#1}\c!filtercommand}

%D Experimental:
%D
%D \starttyping
%D \definemarking[boxmark]
%D
%D \setbox0\ruledvbox{
%D     \marking[boxmark]{tufte} \input tufte \par
%D     \marking[boxmark]{ward}  \input ward  \par
%D }
%D
%D \synchronizemarking[zerobox][0] \box0
%D
%D marks: (\getmarking[boxmark][zerobox][first],\getmarking[boxmark][zerobox][last])
%D \stoptyping

\protect \endinput