%D \module
%D   [       file=strc-enu, % moved from strc-des
%D        version=2008.10.20,
%D          title=\CONTEXT\ Structure Macros,
%D       subtitle=Enumerations,
%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 / Enumerations}

\unprotect

% command -> headcommand

%D Enumerations are just super descriptions. Therefore we implement
%D them as an extension. After all, the keys don't clash. In order
%D to be able to differentiate between specific settings we use
%D some flags. Unfortunately we have some historic differences
%D in default values. Therefore we push an extra step in the
%D parent chain (we might do the same for regular descriptions).

%D In order to be more flexible with theorems Aditya Mahajan added
%D support for titles and endsymbols. At the same time we added more
%D flexible support for inheriting numbers.
%D
%D \startbuffer
%D \defineenumeration[one]
%D \defineenumeration[two]   [one] % clone one
%D \defineenumeration[three] [counter=one,style=slanted] % only use counter of one
%D \defineenumeration[four]  [three] % clone three
%D \defineenumeration[five]  [three] [counter=five] % clone three and use own counter
%D \defineenumeration[six]   [three] [counter=four] % clone tree and use counter four (undefined)
%D
%D \startone   test test  6 \stopone
%D \starttwo   test test  7 \stoptwo
%D \startthree test test  8 \stopthree
%D \startfour  test test  9 \stopfour
%D \startfive  test test  2 \stopfive
%D \startsix   test test 10 \stopsix
%D \stopbuffer
%D
%D \typebuffer \start \getbuffer \stop
%D
%D \starttyping
%D \setupenumerations[one]  [prefix=yes,prefixsegments=section]
%D \setupenumerations[two]  [prefix=yes,prefixsegments=section]
%D \setupenumerations[three][prefix=yes,prefixsegments=section]
%D \setupenumerations[four] [prefix=yes,prefixsegments=chapter:section]
%D \setupenumerations[five] [prefix=yes,prefixsegments=chapter:section]
%D \setupenumerations[six]  [prefix=yes,prefixsegments=chapter:section]
%D \stoptyping

% list and titles are experimental
%
% \definedescription[test] [location=left,hang=4,headalign={right},distance=1em,list=test]
% \defineenumeration[lemma][title=yes,right=:,textdistance=1em, location=top, titlestyle=\bs,list=lemma]
% \defineenumeration[ammel][title=yes,right=:,textdistance=.5em,location=left,titlestyle=\it,width=9em]
%
% \placelist[enumeration:lemma]
% \placelist[description:test][width=0pt]
%
% \starttest  {something something something}    \input zapf  \stoptest
% \startlemma {with a title of a certain length} \input tufte \stoplemma
% \startammel {with a title}                     \input zapf  \stopammel
%
% \defineenumeration[lemma][...]
% \defineenumeration[titledlemma][lemma][title=yes,right=:,text=lemma,list=lemma]

\installcorenamespace{enumeration}

\installcommandhandler \??enumeration {enumeration} \??enumeration

\installcounterassociation{enumeration}

\let\setupenumerations\setupenumeration

\setupenumeration % check with old
  [\c!alternative=\v!top,
   \c!headstyle=\v!bold,
   \c!titlestyle=\v!bold,
  %\c!style=,
  %\c!color=,
  %\c!headcolor=,
  %\c!titlecolor=,
   \c!width=8\emwidth,
  %\c!distance=\zeropoint,
   \c!distance=\emwidth,
   \c!titledistance=.5\emwidth,
  %\c!hang=,
  %\c!sample=,
  %\c!align=,
  %\c!headalign=,
   \c!margin=\v!no,
   \c!before=\blank,
   \c!inbetween=\blank,
   \c!after=\blank,
   \c!indentnext=\v!yes,
   \c!indenting=\v!never,
   \c!titleleft=(,
   \c!titleright=),
  %\c!closesymbol=,
   \c!closecommand=\wordright,
   \c!display=\v!yes,
  %\c!command=,
   \c!titlecommand=,
   \c!expansion=\v!no,
  %\c!xmlsetup=,
  %\s!catcodes=,
   \c!way=\v!by\v!text,
   \c!prefix=\v!no,
   \c!prefixconnector=.,
  %\c!starter=,
  %\c!stopper=,
   \c!text=\currentenumeration,
   \c!number=\v!yes, % else description
   \c!start=0,
   \c!state=\v!start,
   \c!levels=4,
   \c!define=\v!yes]

% to be considered:
%
% \let\??construction\??enumeration
%
% with push/pop (also at definition time)

\protected\def\strc_define_commands_enumeration#tag#level#parent%
  {\iftok{#parent}\emptytoks
     \normalexpanded{\defineconstruction[#tag][\s!handler=\v!enumeration,\c!level=#level]}%
     \edefcsname\??enumeration#tag:\s!parent\endcsname{\??enumeration}%
   \else
     \normalexpanded{\defineconstruction[#tag][#parent][\s!handler=\v!enumeration,\c!level=#level]}%
     \edefcsname\??enumeration#tag:\s!parent\endcsname{\??enumeration#parent}%
   \fi
   \ifcstok{\enumerationparameter\c!define}\v!yes
     \frozen\protected\instance\edefcsname\e!next #tag\endcsname{\strc_enumerations_next{#tag}{\number#level}}%  obsolete
     \frozen\protected\instance\edefcsname\c!reset#tag\endcsname{\strc_enumerations_reset{#tag}{\number#level}}% obsolete
     %frozen\protected\instance\edefcsname\c!set  #tag\endcsname{\strc_enumerations_set{#tag}{\number#level}}%   obsolete
     \frozen\protected\instance\edefcsname        #tag\endcsname{\namedenumeration[#tag]}%
     \frozen\protected\instance\edefcsname\e!start#tag\endcsname{\startnamedenumeration[#tag]}%
     \frozen\protected\instance \defcsname\e!stop #tag\endcsname{\stopnamedenumeration}%
   \fi}

\lettonothing\m_strc_enumeration_sub

\appendtoks
    \lettonothing\m_strc_enumeration_sub
    \ifempty\currentenumerationparent
       % clone => parent | subclone => clone | subsubclone => subclone
       \strc_define_commands_enumeration
         {\m_strc_enumeration_sub\currentenumeration}%
         \plusone
         \empty
       \edef\p_levels{\enumerationparameter\c!levels}%
       \dostepwiserecurse\plustwo\p_levels\plusone
         {\strc_define_commands_enumeration
            {\v!sub\m_strc_enumeration_sub\currentenumeration}%
            \recurselevel
            {\m_strc_enumeration_sub\currentenumeration}%
          \edef\m_strc_enumeration_sub{\v!sub\m_strc_enumeration_sub}}%
   \else
       % clone => parent | subclone => subparent | subsubclone => subsubparent
       \edef\p_levels{\enumerationparameter\c!levels}%
       \dorecurse\p_levels
         {\strc_define_commands_enumeration
            {\m_strc_enumeration_sub\currentenumeration}%
            \recurselevel
            {\m_strc_enumeration_sub\currentenumerationparent}%
          \edef\m_strc_enumeration_sub{\v!sub\m_strc_enumeration_sub}}%
   \fi
   \edef\p_counter{\enumerationparameter\s!counter}% can inherit from parent
   \ifempty\p_counter %
       \let\p_counter\currentenumeration
   \fi
   \doifelsecounter\p_counter\donothing{\strc_enumerations_define_counter\p_counter}%
   \letenumerationparameter\s!counter\p_counter
  %\strc_enumerations_setup_counter\currentenumeration
\to \everydefineenumeration

\lettonothing\p_strc_constructions_title
\lettonothing\p_strc_constructions_number

\protected\defcsname\??constructioninitializer\v!enumeration\endcsname
  {\let         \currentenumeration              \currentconstruction
   \enforced\let\constructionparameter           \enumerationparameter
   \enforced\let\constructionnamespace           \??enumeration
   \enforced\let\detokenizedconstructionparameter\detokenizedenumerationparameter
   \enforced\let\letconstructionparameter        \letenumerationparameter
   \enforced\let\useconstructionstyleandcolor    \useenumerationstyleandcolor
   \enforced\let\setupcurrentconstruction        \setupcurrentenumeration
   \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
     \strc_counters_increment_sub\currentconstructionnumber\currentconstructionlevel
   \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}

\protected\defcsname\??constructionfinalizer\v!enumeration\endcsname
  {\ifconditional\c_strc_constructions_number_state
     \iftrialtypesetting
       \strc_counters_restore\currentconstructionnumber
     \fi
   \fi}

%D Interfaces:

\let\namedenumeration     \nameddescription
\let\startnamedenumeration\startnameddescription
\let\stopnamedenumeration \stopnameddescription

\protected\def\strc_enumerations_next {\strc_constructions_next_indeed \namedenumerationparameter} % #1#2
\protected\def\strc_enumerations_reset{\strc_constructions_reset_indeed\namedenumerationparameter} % #1#2
%protected\def\strc_enumerations_set  {\strc_constructions_set_indeed  \namedenumerationparameter} % #1#2

%D Counters (maybe we can share this code): (not ok yet, messy with notes)

% Maybe we should move counters to the construction level as more derived mechanisms
% use it \unknown\ so don't depend on names here!

\def\strc_enumerations_define_counter#tag% todo: move inline
  {\definecounter[#tag]%
   \registerenumerationcounter{#tag}}

\appendtoks
    \synchronizeenumerationcounters
\to \everysetupenumeration

\appendtoks
    \synchronizeenumerationcounters
\to \everydefineenumeration

%D Initializer:

%D The handlers.

\newtoks\everyenumeration

\letcsname\??constructionmainhandler   \v!enumeration\expandafter\endcsname\csname\??constructionmainhandler   \v!description\endcsname
\letcsname\??constructioncommandhandler\v!enumeration\expandafter\endcsname\csname\??constructioncommandhandler\v!description\endcsname
\letcsname\??constructionstarthandler  \v!enumeration\expandafter\endcsname\csname\??constructionstarthandler  \v!description\endcsname
\letcsname\??constructionstophandler   \v!enumeration\expandafter\endcsname\csname\??constructionstophandler   \v!description\endcsname

\protected\defcsname\??constructiontexthandler\v!enumeration\endcsname
  {\begingroup
   \useconstructionstyleandcolor\c!headstyle\c!headcolor
   \strc_enumerations_text
   \endgroup}

\protected\def\strc_enumerations_text
  {\the\everyenumeration % will become obsolete
   \ifconditional\c_strc_constructions_number_state
     \ifx\currentconstructionreference\!!plustoken
       \strc_enumerations_full_number_symbol
     \orelse\ifx\currentconstructionreference\!!minustoken
       \strc_enumerations_full_number_nop
     \else
       \strc_enumerations_full_number_coupling
     \fi
   \else
     \strc_enumerations_full_number_nop
   \fi}

\protected\def\strc_enumerations_inject_text_with_space
  {\edef\p_text{\constructionparameter\c!text}%
   \ifempty\p_text \else
      \p_text
      \removeunwantedspaces
      \nobreakspace
   \fi}

\protected\def\strc_enumerations_inject_extra_text
  {\ifconditional\c_strc_constructions_title_state
     \clf_doifelselisthastitle{\currentconstructionmain}\numexpr\currentconstructionlistentry\relax
       \strc_enumerations_inject_extra_text_indeed
       \donothing
   \fi}

\protected\def\strc_enumerations_inject_text
  {\constructionparameter\c!numbercommand
    {\constructionparameter\c!text}}

% head ( number title )

\protected\def\strc_enumerations_inject_extra_text_indeed
  {\begingroup
   \hskip\constructionparameter\c!titledistance % we listen to the headstyle
   \useconstructionstyleandcolor\c!titlestyle\c!titlecolor
   \constructionparameter\c!titlecommand
     {\constructionparameter\c!titleleft
      \clf_savedlisttitle{\currentconstructionmain}\currentconstructionlistentry\relax
      \constructionparameter\c!titleright}%
   \endgroup}

\protected\def\strc_enumerations_inject_symbol % todo check
  {\begingroup
   \useconstructionstyleandcolor\c!numberstyle\c!numbercolor
   \constructionparameter\c!left
   \constructionparameter\c!symbol
   \constructionparameter\c!right
   \endgroup}

\protected\def\strc_enumerations_inject_number
  {\begingroup
   \useconstructionstyleandcolor\c!numberstyle\c!numbercolor
   \constructionparameter\c!left
   \constructionparameter\c!starter
   \clf_savedlistprefixednumber{\currentconstructionmain}\currentconstructionlistentry\relax
   \constructionparameter\c!stopper
   \constructionparameter\c!right
   \endgroup}

\protected\def\strc_enumerations_inject_text_and_number
  {\constructionparameter\c!numbercommand
     {\strc_enumerations_inject_text_with_space
      \strc_enumerations_inject_number}}

\protected\def\strc_enumerations_inject_text_and_symbol
  {\constructionparameter\c!numbercommand
     {\strc_enumerations_inject_text_with_space
      \strc_enumerations_inject_symbol}}

\protected\def\strc_enumerations_full_number_yes
  {\constructionparameter\c!headcommand
     {\begstrut
      \strc_enumerations_inject_text_and_number
      \strc_enumerations_inject_extra_text
      \endstrut}}

\protected\def\strc_enumerations_full_number_nop
  {\constructionparameter\c!headcommand
     {\begstrut
      \strc_enumerations_inject_text
      \strc_enumerations_inject_extra_text
      \endstrut}}

\protected\def\strc_enumerations_full_number_symbol
  {\constructionparameter\c!headcommand
     {\begstrut
      \strc_enumerations_inject_text_and_symbol
      \strc_enumerations_inject_extra_text
      \endstrut}}

% to be used in for instance:
%
% coupling=questions .... coupling=answers
%
% we will provide some more control, like skipping etc or reference relates

% to do / to be checked

\protected\def\strc_enumerations_full_number_coupling
  {\iflocation
     \strc_enumerations_full_number_yes
   \else
     \iftrialtypesetting \else
       % \doenumerationregistercoupling
     \fi
     \strc_enumerations_full_number_yes
     \edef\p_coupling{\constructionparameter\c!coupling}%
     \ifempty\p_coupling \else
       \symbolreference[order(construction:\p_coupling:\the\locationorder)]%
     \fi
   \fi}

\protected\def\strc_enumerations_skip_number_coupling[#tag]% e.g. for questions with no answer
  {\clf_setnextreferenceorder{construction}{#tag}}

\protect \endinput