%D \module
%D   [       file=strc-lab, % was part of strc-des,
%D        version=2008.10.20,
%D          title=\CONTEXT\ Structure Macros,
%D       subtitle=Labels,
%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 / Labels}

\unprotect

% todo: reset and increment will go

%D Labels are implemented somewhat inefficient but have the advantage that they
%D can be controlled like other constructions. Who knows when that comes in
%D handy?

\installcorenamespace{labels}

\installcommandhandler \??labels {label} \??labels % plural hash, else clash with label (or rename that one)

\installcounterassociation{label}

\let\setuplabels\setuplabel

\setuplabel
  [\c!alternative=\v!intext,
   \c!headstyle=\v!bold,
   \c!titlestyle=\v!bold,
   \c!distance=\zeropoint,
   \c!width=\v!fit,
   \c!titledistance=.5\emwidth,
   \c!margin=\v!no,
   \c!titleleft=(,
   \c!titleright=),
   \c!display=\v!no,
   \c!titlecommand=,
   \c!expansion=\v!no,
   \c!way=\v!by\v!text,
   \c!prefix=\v!no,
   \c!prefixconnector=.,
   \c!text=\currentlabel,
   \c!number=\v!yes, % else description
   \c!start=0,
   \c!state=\v!start,
   \c!levels=3]

\unexpanded\def\strc_define_commands_label#1#2#3% current level parent
  {\doifelsenothing{#3}
     {\normalexpanded{\defineconstruction[#1][\s!handler=\v!label,\c!level=#2]}%
      \setevalue{\??label#1:\s!parent}{\??label}}%
     {\normalexpanded{\defineconstruction[#1][#3][\s!handler=\v!label,\c!level=#2]}%
      \setevalue{\??label#1:\s!parent}{\??label#3}}%
   \ifconditional\c_strc_constructions_define_commands
     \setuevalue{\e!next   #1}{\strc_labels_next   {#1}{\number#2}}% obsolete
     \setuevalue{\v!reset  #1}{\strc_labels_reset  {#1}{\number#2}}% obsolete % should be \e!reset anyway
     %setuevalue{\c!set    #1}{\strc_labels_set    {#1}{\number#2}}% obsolete
   \ifcsname\v!current#1\endcsname
     % we play safe
   \else
     \setuevalue{\v!current#1}{\strc_labels_current{#1}}%          % obsolete % should be \e!current anyway
   \fi
     \setuevalue          {#1}{\strc_labels_command{#1}}%
   \fi}

% todo: \strc_labels_command for user

\appendtoks
    \ifx\currentlabelparent\empty
       % clone => parent | subclone => clone | subsubclone => subclone
       \let\currentlabelsub\empty
       \strc_define_commands_label
         {\currentlabelsub\currentlabel}%
         \plusone
         \empty
       \edef\p_levels{\labelparameter\c!levels}%
       \dostepwiserecurse\plustwo\p_levels\plusone
         {\strc_define_commands_label
            {\v!sub\currentlabelsub\currentlabel}%
            \recurselevel
            {\currentlabelsub\currentlabel}%
          \edef\currentlabelsub{\v!sub\currentlabelsub}}%
   \else
       % clone => parent | subclone => subparent | subsubclone => subsubparent
       \let\currentlabelsub\empty
       \edef\p_levels{\labelparameter\c!levels}%
       \dorecurse\p_levels
         {\strc_define_commands_label
            {\currentlabelsub\currentlabel}%
            \recurselevel
            {\currentlabelsub\currentlabelparent}%
          \edef\currentlabelsub{\v!sub\currentlabelsub}}%
   \fi
   \edef\p_counter{\labelparameter\s!counter}% can inherit from parent
   \ifx\p_counter\empty %
       \let\p_counter\currentlabel
   \fi
   \doifelsecounter\p_counter\donothing{\strc_labels_define_counter\p_counter}%
   \letlabelparameter\s!counter\p_counter
\to \everydefinelabel

\let\p_strc_constructions_title \empty
\let\p_strc_constructions_number\empty

\newconditional\c_strc_constructions_number_keep

\setvalue{\??constructioninitializer\v!label}%
  {\let\currentlabel                    \currentconstruction
   \let\constructionparameter           \labelparameter
   \let\constructionnamespace           \??label
   \let\detokenizedconstructionparameter\detokenizedlabelparameter
   \let\letconstructionparameter        \letlabelparameter
   \let\useconstructionstyleandcolor    \uselabelstyleandcolor
   \let\setupcurrentconstruction        \setupcurrentlabel
   % shared with enumerations
   \edef\p_strc_constructions_number{\constructionparameter\c!number}%
   \ifx\p_strc_constructions_number\v!yes
     \settrue\c_strc_constructions_number_state
     \iftrialtypesetting
       \strc_counters_save\currentconstructionnumber
     \fi
     \ifconditional\c_strc_constructions_number_keep \else
       \strc_counters_increment_sub\currentconstructionnumber\currentconstructionlevel
     \fi
   \else
     \setfalse\c_strc_constructions_number_state
   \fi
   \edef\p_strc_constructions_title{\constructionparameter\c!title}%
   \ifx\p_strc_constructions_title\v!yes
     \settrue\c_strc_constructions_title_state
   \else
     \setfalse\c_strc_constructions_title_state
   \fi}

\setvalue{\??constructionfinalizer\v!label}%
  {\ifconditional\c_strc_constructions_number_state
     \iftrialtypesetting
       \strc_counters_restore\currentconstructionnumber
     \fi
   \fi}

%D Interfaces:

\unexpanded\def\strc_labels_command{\setfalse\c_strc_constructions_number_keep\strc_descriptions_command}
\unexpanded\def\strc_labels_current{\settrue \c_strc_constructions_number_keep\strc_descriptions_command}

\unexpanded\def\strc_labels_next   {\strc_constructions_next_indeed \namedlabelparameter} % #1#2
\unexpanded\def\strc_labels_reset  {\strc_constructions_reset_indeed\namedlabelparameter} % #1#2
%unexpanded\def\strc_labels_set    {\strc_constructions_set_indeed  \namedlabelparameter} % #1#2

% similar to enumerations

\def\strc_labels_define_counter#1%
  {\definecounter[#1]%
   \registerlabelcounter{#1}}

\appendtoks
    \synchronizelabelcounters
\to \everysetuplabel

\appendtoks
    \synchronizelabelcounters
\to \everydefinelabel

% no start stop here

\expandafter\let\csname\??constructionmainhandler\v!label\expandafter\endcsname\csname\??constructionmainhandler\v!description\endcsname

\unexpanded\setevalue{\??constructioncommandhandler\v!label}%
  {\csname\??constructionstarthandler\v!construction\endcsname
   \csname\??constructionstophandler \v!construction\endcsname
   \endgroup}

\unexpanded\setvalue{\??constructiontexthandler\v!label}%
  {\begingroup
   \useconstructionstyleandcolor\c!headstyle\c!headcolor
   \strc_labels_text
   \endgroup}

\let\strc_labels_text\strc_enumerations_text

% inline variant

\defineconstructionalternative
  [\v!intext]
  [\c!renderingsetup=\??constructionrenderings:\v!intext]

\startsetups[\??constructionrenderings:\v!intext]
    \dontleavehmode\box\constructionheadbox
\stopsetups

\protect \endinput