%D \module
%D   [       file=strc-reg,
%D        version=2008.10.20,
%D          title=\CONTEXT\ Structure Macros,
%D       subtitle=Registers,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=PRAGMA-ADE / Hans Hagen]
%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 / Registers}

\registerctxluafile{strc-reg}{1.001}

\unprotect

\def\c!keys   {keys}
\def\c!entries{entries}

% todo: tag:: becomes rendering
% todo: language, character, linked, location

%D Helper:

% \def\doflushatpar{\ifvmode\expandafter\dogotopar\else\expandafter\firstofoneargument\fi}

\def\doflushatpar{\ifvmode\expandafter\flushatnextpar\else\expandafter\firstofoneargument\fi}

% \starttext
% \placeregister[index]
% \chapter{a} \index{93} \index{456} \index{***} \index{*} \index{@}
% test \index{aa} test \startregister[index][x]{bb} test \page test \page test \page test \stopregister[index][x]
% test \index{aa} test \setregisterentry[index][label=x,entries=bb] test \page test \page test \page test \finishregisterentry[index][label=x]
% test \index{aa} test \setregisterentry[index][label=y] test \page test \page test \page test \finishregisterentry[index][label=y,entries=yy]
% \stoptext

%  In plaats van + kan een & worden gebruikt. Ook kan als
%  eerste karakter worden opgegeven wat de scheider is.
%
%  \index                {entry}
%  \index[key]           {entry}
%  \index[pageclass::]   {entry}
%  \index[pageclass::key]{entry}
%  \index                {textclass::entry}
%  \index[key]           {textclass::entry}
%  \index[pageclass::]   {textclass::entry}
%  \index[pageclass::key]{textclass::entry}

%D Parameters:

\let\currentregister\empty

% \def\registerparameter#1{\csname\??id\currentregister#1\endcsname}

\def\detokenizedregisterparameter#1{\detokenize\expandafter\expandafter\expandafter{\csname\??id#1\endcsname}} % always root

\def\registerparameter    #1{\csname\doregisterparameter{\??id\currentregister}{#1}\endcsname}
\def\registerparameterhash#1{\doregisterparameterhash   {\??id\currentregister}#1}

\def\doregisterparameter    #1#2{\ifcsname#1#2\endcsname#1#2\else\expandafter\doregisterparentparameter    \csname#1\s!parent\endcsname{#2}\fi}
\def\doregisterparameterhash#1#2{\ifcsname#1#2\endcsname  #1\else\expandafter\doregisterparentparameterhash\csname#1\s!parent\endcsname{#2}\fi}

\def\doregisterparentparameter    #1#2{\ifx#1\relax\s!empty\else\doregisterparameter    #1{#2}\fi}
\def\doregisterparentparameterhash#1#2{\ifx#1\relax        \else\doregisterparameterhash#1{#2}\fi}

\def\dosetregisterattributes#1#2% style color
  {\edef\fontattributehash {\registerparameterhash#1}%
   \edef\colorattributehash{\registerparameterhash#2}%
   \ifx\fontattributehash \empty\else\dosetfontattribute \fontattributehash #1\fi
   \ifx\colorattributehash\empty\else\dosetcolorattribute\colorattributehash#2\fi}

%D Setup:

\newtoks\everysetupregister

\unexpanded\def\setupregisters
  {\dotripleempty\dosetupregisters}

\def\dosetupregisters[#1][#2][#3]%
  {\ifthirdargument
     \def\dodosetupregister##1{\getparameters[\??id##1#2][#3]}%
     \processcommalist[#1]\dodosetupregister
   \else\ifsecondargument
     \def\dodosetupregister##1{\edef\currentregister{##1}\getparameters[\??id##1][#2]\the\everysetupregister}%
     \processcommalist[#1]\dodosetupregister
   \else
     \getparameters[\??id][#1]%
   \fi\fi}

\let\setupregister\setupregisters

\setupregisters
  [\c!n=2,
   \c!balance=\v!yes,  % \v!no komt niet zo vaak voor
   \c!align=\v!flushleft,
   \c!tolerance=\v!stretch,
   \c!before=\blank,
  %\c!after=,
  %\c!symbol=,
   \c!compress=\v!no,
   \c!interaction=\v!pagenumber,
   \c!alternative=\v!a,
   \c!distance=1em,
   \c!style=\v!bold,
   \c!pagestyle=\v!slanted,
   \c!indicator=\v!yes,
   \c!criterium=\v!all,
  %\c!command=,
   \c!referencing=\v!on,
   \c!location=\v!middle,
  %\c!maxwidth=,
   \c!number=\v!no,
   \c!unknownreference=\v!empty,
   \c!prefix=\v!both,
  %\c!expansion=,
%\c!xmlsetup=,
   \c!pageprefixconnector=\endash,
   \c!pagesegments=2:2,
   \c!file=\jobname,
  %\c!deeptextcommand=, % undefined by default !
   \s!language=\currentmainlanguage]%

%D Definition:

\unexpanded\def\defineregister
  {\dodoubleargument\dodefineregister}

\def\dodefineregister[#1][#2]% #2?
  {\setupregister[#1][\s!parent=\??id]%
   \ctxlua{jobregisters.define('#1')}%
   \presetheadtext[#1=\Word{#1}]%
   \setuvalue{#1}{\dodoubleempty\doregister[#1]}%
   \setuvalue{\e!see#1}{\dodoubleempty\doseeregister[#1]}%
%  \setuvalue{\e!coupled#1}{\dolinkedregister{#1}}%
   \setvalue{\e!place#1}{\placeregister[#1]}%
   \setvalue{\e!complete#1}{\completeregister[#1]}%
   \setvalue{\e!setup#1\e!endsetup}[##1]{\getparameters[\??id#1][##1]}}

%D Registering:

\newif\ifwritetoregister \writetoregistertrue

% tzt variant met n entries, parameters en userdata (altnum)

\getparameters
  [\??id]
  [\c!label=,
   \c!entries=,
   \c!entries:1=,\c!entries:2=,\c!entries:3=,
   \c!keys:1=,\c!keys:2=,\c!keys:3=,
   \c!alternative=]

\def\doregisterstructurepageregister
  {\iftrialtypesetting
     \expandafter\gobblethreearguments
   \else
     \expandafter\dodoregisterstructurepageregister
   \fi}

\def\dodoregisterstructurepageregister#1#2#3% register data userdata
  {\begingroup
   \edef\currentregister{#1}%
   %getparameters[\??id][\c!entries=,\c!label=,\c!keys=,\c!alternative=,#2]%
   \getparameters[\??id][#2]%
   \edef\currentregisterlabel    {\registerparameter\c!label}%
   \edef\currentregisterexpansion{\registerparameter\c!expansion}%
   \edef\currentregisterownnumber{\registerparameter\c!ownnumber}%
   \xdef\currentregisterkeys     {\registerparameter\c!keys}%
   \xdef\currentregisterentries  {\registerparameter\c!entries}%
   \xdef\currentregisterxmlsetup {\registerparameter\c!xmlsetup}%
   \ifx\currentregisterentries\empty
     \ifx\currentregisterexpansion\s!xml
       \xmlstartraw
         \xdef\currentregisterentriesa{\registerparameter{\c!entries:1}}%
         \xdef\currentregisterentriesb{\registerparameter{\c!entries:2}}%
         \xdef\currentregisterentriesc{\registerparameter{\c!entries:3}}%
       \xmlstopraw
       \globallet\currentregistercoding\s!xml
     \else
       \ifx\currentregisterexpansion\v!yes
         \xdef\currentregisterentriesa{\registerparameter{\c!entries:1}}%
         \xdef\currentregisterentriesb{\registerparameter{\c!entries:2}}%
         \xdef\currentregisterentriesc{\registerparameter{\c!entries:3}}%
       \else
         \xdef\currentregisterentriesa{\detokenizedregisterparameter{\c!entries:1}}%
         \xdef\currentregisterentriesb{\detokenizedregisterparameter{\c!entries:2}}%
         \xdef\currentregisterentriesc{\detokenizedregisterparameter{\c!entries:3}}%
       \fi
       \globallet\currentregistercoding\s!tex
     \fi
   \else
     \ifx\currentregisterexpansion\s!xml
       \xmlstartraw
         \xdef\currentregisterentries{\registerparameter\c!entries}%
       \xmlstopraw
       \globallet\currentregistercoding\s!xml
     \else
       \ifx\currentregisterexpansion\v!yes
         \xdef\currentregisterentries{\registerparameter\c!entries}%
       \else
         \xdef\currentregisterentries{\detokenizedregisterparameter\c!entries}%
       \fi
       \globallet\currentregistercoding\s!tex
     \fi
   \fi
   \ifx\currentregisterkeys\empty
     \ifx\currentregistercoding\s!xml
       \xmlstartraw
         \xdef\currentregisterkeysa{\registerparameter{\c!keys:1}}%
         \xdef\currentregisterkeysb{\registerparameter{\c!keys:2}}%
         \xdef\currentregisterkeysc{\registerparameter{\c!keys:3}}%
       \xmlstopraw
     \else
       \xdef\currentregisterkeysa{\registerparameter{\c!keys:1}}%
       \xdef\currentregisterkeysb{\registerparameter{\c!keys:2}}%
       \xdef\currentregisterkeysc{\registerparameter{\c!keys:3}}%
     \fi
   \fi
   \setnextinternalreference
   % we could consider storing register entries in a list which we
   % could then sort
   \xdef\currentregisternumber{\ctxlua{
    jobregisters.store { % 'own' should not be in metadata
        metadata = {
            kind     = "entry",
            name     = "\currentregister",
            level    = structure.sections.currentlevel(),
            coding   = "\currentregistercoding",
            catcodes = \the\catcodetable,
        \ifx\currentregisterownnumber\v!yes
            own      = "\registerparameter\c!alternative", % can be used instead of pagenumber
        \fi
            xmlroot  = \ifx\currentreferencecoding\s!xml "\xmldocument" \else nil \fi, % only useful when text
\ifx\currentregisterxmlsetup\empty \else
    xmlsetup = "\currentregisterxmlsetup",
\fi
        },
        references = {
            internal = \nextinternalreference,
            section  = structure.sections.currentid(), % hm, why then not also lastsection the same way
            label    = "\currentregisterlabel",
        },
%     \ifx\currentregisterentries\empty \else
        entries = {
            % we need a special one for xml, this is just a single one
            \ifx\currentregisterentries\empty
                { \!!bs\currentregisterentriesa\!!es, \!!bs\currentregisterentriesb\!!es, \!!bs\currentregisterentriesc\!!es },
            \else
                \!!bs\currentregisterentries\!!es,
            \fi
            \ifx\currentregisterkeys\empty
                { \!!bs\currentregisterkeysa\!!es, \!!bs\currentregisterkeysb\!!es, \!!bs\currentregisterkeysc\!!es },
            \else
                \!!bs\currentregisterkeys\!!es,
            \fi
        },
%     \fi
        userdata = structure.helpers.touserdata(\!!bs\detokenize{#3}\!!es)
     }
   } }%
   \ctxlua{jobreferences.setinternalreference(nil,nil,\nextinternalreference)}%
   \ifx\currentregisterownnumber\v!yes
     \glet\currentregistersynchronize\relax
   \else
     \xdef\currentregistersynchronize{\ctxlatelua{jobregisters.enhance("\currentregister",\currentregisternumber)}}%
   \fi
   \currentregistersynchronize % here?
   \attribute\destinationattribute\lastdestinationattribute \forcecolorhack % no \strut as it will be removed during cleanup
   \endgroup}

\def\doregister[#1][#2]%
  {\def\currentregister{#1}%
   \doifelse{\registerparameter\c!ownnumber}\v!yes\dodoregister\donoregister{#1}{#2}}

\def\donoregister  #1#2#3{\doflushatpar{\doregisterstructurepageregister{#1}{\c!keys={#2},\c!entries={#3}}{}}}
\def\dodoregister#1#2#3#4{\doflushatpar{\doregisterstructurepageregister{#1}{\c!keys={#2},\c!alternative=#3,\c!entries={#4}}{}}}

\unexpanded\def\startregister{\doquadrupleempty\dostartregister}
\unexpanded\def\stopregister {\dodoubleargument\dostopregister}

% a synonym, so that we can nest with overlap without syntax check problems

\let\openregisterrange \startregister
\let\closeregisterrange\stopregister

\def\dostartregister[#1][#2][#3][#4]#5%
  {\iffourthargument
     % #1=register #2=tag #3=own #4=sortkey #5=entry
     \doflushatpar{\doregisterstructurepageregister{#1}{\c!label=#2,\c!alternative=#3,\c!keys={#4},\c!entries={#5}}{}}%
   \else
     % #1=register #2=tag #3=sortkey #5=entry
     \doflushatpar{\doregisterstructurepageregister{#1}{\c!label=#2,\c!keys={#3},\c!entries={#5}}{}}%
   \fi}

\def\dostopregister[#1][#2]%
  {\normalexpanded{\ctxlatelua{jobregisters.extend("#1","#2")}}}

\def\setregisterentry   {\dotripleempty\dosetregisterentry}
\def\finishregisterentry{\dotripleempty\dofinishregisterentry}

% not yet document, not sure if this will stay:

\def\dosetregisterentry   [#1][#2][#3]{\doflushatpar{\doregisterstructurepageregister{#1}{#2}{#3}}}
\def\dofinishregisterentry[#1][#2][#3]{\dofinishregisterstructurepageregister{#1}{#2}{#3}}

\def\dofinishregisterstructurepageregister#1#2#3% register data userdata
  {\begingroup
   \edef\currentregister{#1}%
   \getparameters[\??id][\c!entries=,\c!label=,\c!keys=,\c!alternative=,#2]%
   \edef\currentregisterlabel    {\registerparameter\c!label}%
   \edef\currentregisterexpansion{\registerparameter\c!expansion}%
   \edef\currentregisterownnumber{\registerparameter\c!ownnumber}%
   \xdef\currentregisterkeys     {\registerparameter\c!keys}%
   \ifx\currentregisterexpansion\s!xml
     \xmlstartraw
       \xdef\currentregisterentries{\registerparameter\c!entries}%
     \xmlstopraw
     \globallet\currentregistercoding\s!xml
   \else
     \ifx\currentregisterexpansion\v!yes
       \xdef\currentregisterentries{\registerparameter\c!entries}%
     \else
       \xdef\currentregisterentries{\detokenizedregisterparameter\c!entries}%
     \fi
     \globallet\currentregistercoding\s!tex
   \fi
   \ifx\currentregisterentries\empty
       \normalexpanded{\ctxlua{jobregisters.extend("\currentregister","\currentregisterlabel", {
            metadata = {
            \ifx\currentregisterownnumber\v!yes
                own      = "\registerparameter\c!alternative", % can be used instead of pagenumber
            \fi
            },
            userdata = structure.helpers.touserdata(\!!bs\detokenize{#3}\!!es)
         })%
       }}%
   \else
       \normalexpanded{\ctxlua{jobregisters.extend("\currentregister","\currentregisterlabel", {
            metadata = {
                catcodes = \the\catcodetable,
                coding   = "\currentregistercoding",
            \ifx\currentregisterownnumber\v!yes
                own      = "\registerparameter\c!alternative", % can be used instead of pagenumber
            \fi
            },
            entries = {
                % we need a special one for xml, this is just a single one
                \!!bs\currentregisterentries\!!es, \!!bs\currentregisterkeys\!!es
            },
            userdata = structure.helpers.touserdata(\!!bs\detokenize{#3}\!!es)
         })
       }}%
   \fi
   \endgroup}

% The following variants are meant for (for instance xml). There is some
% overlap with previously defined macros.
%
% \starttext
%     \setstructurepageregister[index][entries=alpha]a
%     \setstructurepageregister[index][entries=gamma]g
%     \setstructurepageregister[index][entries=beta]b
%     \setstructurepageregister[index][entries:1=alpha,keys:1=z]a
%     \setstructurepageregister[index][entries:1=gamma,keys:1=x]g
%     \setstructurepageregister[index][entries:1=beta, keys:1=y]b
%     \index{alpha}a
%     \index{gamma}g
%     \index{beta}b
%     \placeregister[index][n=1]
% \stoptext

\def\setstructurepageregister{\dotripleempty\dosetstructurepageregister}

\def\dosetstructurepageregister[#1][#2][#3]% [register][settings][userdata]
  {\doflushatpar{\doregisterstructurepageregister{#1}{#2}{#3}}}

\unexpanded\def\startstructurepageregister{\doquadrupleempty\dostartstructurepageregister}
\unexpanded\def\stopstructurepageregister {\dodoubleargument\dostopstructurepageregister}

\let\openstructurepageregisterrange \startstructurepageregister
\let\closestructurepageregisterrange\stopstructurepageregister

\def\dostartstructurepageregister[#1][#2][#3][#4]% [register][tag][settings][userdata]
  {\doflushatpar{\doregisterstructurepageregister{#1}{\c!label=#2,#3}{#4}}}

\def\dostopstructurepageregister[#1][#2]%
  {\normalexpanded{\ctxlatelua{jobregisters.extend("#1","#2")}}}

% So far.

\def\doseeregister[#1][#2]#3#4%
  {\doflushatpar{\doprocessseeregister{#1}{#2}{#3}{#4}}}

\def\doprocessseeregister#1#2#3#4% register key entry seeword
  {\begingroup
   \edef\currentregister{#1}%
   \edef\currentregisterexpansion{\registerparameter\c!expansion}%
   \ifx\currentregisterexpansion\s!xml
     \xmlstartraw
       \xdef\currentregisterentries{\detokenize{#3}}% not ok yet
       \xdef\currentregisterseeword{\detokenize{#4}}% not ok yet
     \xmlstopraw
     \globallet\currentregistercoding\s!xml
   \else
     \ifx\currentregisterexpansion\v!yes
       \xdef\currentregisterentries{#3}% not ok yet
       \xdef\currentregisterseeword{#4}% not ok yet
     \else
       \xdef\currentregisterentries{\detokenize{#3}}% not ok yet
       \xdef\currentregisterseeword{\detokenize{#4}}% not ok yet
     \fi
     \globallet\currentregistercoding\s!tex
   \fi
   \setnextinternalreference
   % we could consider storing register entries in list
   \edef\temp{\ctxlua{ jobregisters.store {
        metadata = {
            kind     = "see",
            name     = "\currentregister",
            level    = structure.sections.currentlevel(),
            catcodes = \the\catcodetable,
        },
        references = {
            internal = \nextinternalreference,
            section  = structure.sections.currentid(),
        },
        entries = {
            % we need a special one for xml, this is just a single one
            "\currentregisterentries", "#2"
        },
        seeword = {
            text = "\currentregisterseeword"
        },
     }
   }}%
   \endgroup}

%D Rendering:

\let\utilityregisterlength\!!zerocount

\def\determineregistercharacteristics
  {\dodoubleempty\dodetermineregistercharacteristics}

\def\dodetermineregistercharacteristics[#1][#2]%
  {\begingroup
   \edef\currentregister{#1}%
   \setupregister[\currentregister][#2]%
   \normalexpanded{\endgroup\noexpand\xdef\noexpand\utilityregisterlength{\ctxlua{jobregisters.analyse('\currentregister',{
        language  = "\registerparameter\s!language",
        compress  = "\registerparameter\c!compress",
        criterium = "\registerparameter\c!criterium",
   })}}}% brrr
   \ifcase\utilityregisterlength\relax
     \resetsystemmode\v!register
   \else
     \setsystemmode  \v!register
   \fi}

\newtoks\everyplaceregister

\appendtoks
    \dontcomplain
\to \everyplaceregister

\unexpanded\def\placeregister
  {\dodoubleempty\doplaceregister}

\def\doplaceregister[#1][#2]%
  {\iffirstargument
     \begingroup
%      \forgetall
     \edef\currentregister{#1}%
     \setupregister[\currentregister][#2]%
     \the\everyplaceregister
     \startcolumns
       [\c!n=\registerparameter\c!n,
        \c!balance=\registerparameter\c!balance,
        \c!align=\registerparameter\c!align,
        \c!tolerance=\registerparameter\c!tolerance]%
       \startpacked[\v!blank]%
         \ctxlua{jobregisters.process('\currentregister',{
            language  = "\registerparameter\s!language",
            compress  = "\registerparameter\c!compress",
            criterium = "\registerparameter\c!criterium",
         },
        {
%             prefix        = "\registerparameter\c!pageprefix",
            separatorset  = "\registerparameter\c!pageprefixseparatorset",
            conversionset = "\registerparameter\c!pageprefixconversionset",
            starter       = \!!bs\registerparameter\c!pageprefixstarter\!!es,
            stopper       = \!!bs\registerparameter\c!pageprefixstopper\!!es,
            set           = "\registerparameter\c!pageprefixset",
            segments      = "\registerparameter\c!pageprefixsegments",
            connector     = \!!bs\registerparameter\c!pageprefixconnector\!!es,
        },
        {
            prefix        = "\registerparameter\c!pageprefix",
            separatorset  = "\registerparameter\c!pageseparatorset",
            conversionset = "\registerparameter\c!pageconversionset",
            starter       = \!!bs\registerparameter\c!pagestarter\!!es,
            stopper       = \!!bs\registerparameter\c!pagestopper\!!es,
            segments      = "\registerparameter\c!pagesegments",
        }
         )}%
       \stoppacked
     \stopcolumns
     \endgroup
   \fi}

\def\dolimitedregisterentry#1{\limitatetext{#1}\currentregistermaxwidth\unknown}%

\appendtoks
    \edef\currentregistermaxwidth{\registerparameter\c!maxwidth}%
    \ifx\currentregistermaxwidth\empty
      \let\limitedregisterentry\firstofoneargument
    \else
      \let\limitedregisterentry\dolimitedregisterentry
    \fi
\to \everyplaceregister

\def\completeregister
  {\dodoubleempty\docompleteregister}

\def\docompleteregister[#1][#2]%
  {\iffirstargument
     \begingroup
     \edef\currentregister{#1}%
     % the expansion is needed because we don't want \v!'s in the tuo file (french)
     \normalexpanded{\systemsuppliedchapter[\currentregister]{\noexpand\headtext{\currentregister}}}%
     \placeregister[\currentregister][#2]%
     \page[\v!yes]%
     \endgroup
   \fi}

% test case for collapsing (experimental, for Steffen Wolfrum)
%
% \starttext
% \placeregister[index][compress=no]  \blank[2*big]
% \placeregister[index][compress=yes] \blank[2*big]
% \placeregister[index][compress=all] \page
% \dorecurse{10}{test 1:!\index{test} test \page}
% \dorecurse{5} {test 2:\recurselevel      \page}
% \dorecurse{10}{test 3:!\index{test} test \page}
% \dorecurse{5} {test 4:\recurselevel      \page}
% \dorecurse{1} {test 5:!\index{test} test \page}
% \dorecurse{5} {test 6:\recurselevel      \page}
% \dorecurse{10}{test 7:!\index{test} test \page}
% \dorecurse{5} {test 8:\recurselevel      \page}
% oeps \index{oeps}
% xxxx \index{xxxx}
% todo \index{todo}
% \stoptext

%D Character rendering (sections):

\def\defaultregistercharacter#1%
  {\doifsomething{#1}
     {\doifnot{#1}\s!unknown
        {\doifelse{\registerparameter\c!indicator}\v!yes
           {\expandcheckedcsname{\??id:\c!indicator:}{\registerparameter\c!alternative}{a}{#1}}
           {\noregistercharacter{#1}}}}}

\def\noregistercharacter#1%
  {\registerparameter\c!before
   \goodbreak}

% a = <before> <goodbreak> <character> <par> <after> <nobreak>

\setvalue{\??id:\c!indicator:a}#1%
  {\registerparameter\c!before
   % bugged, why does leftskip gets set: \vskip\lineheight\goodbreak\vskip-\lineheight
   \begingroup\dosetregisterattributes\c!style\c!color
   \registerparameter\c!command{\strut#1}%
   \endgroup
   \registerparameter\c!after
   \par\nobreak}


% b = <goodbreak> <before> <character> <after> <nobreak>

\setvalue{\??id:\c!indicator:b}#1%
  {\registerparameter\c!before
   \begingroup\dosetregisterattributes\c!style\c!color
   \registerparameter\c!command{\strut#1}%
   \endgroup
   \registerparameter\c!after
   \nobreak}

\setvalue{\??id:\c!indicator:A}#1{\getvalue{\??id:\c!indicator:a}{\WORD{#1}}}
\setvalue{\??id:\c!indicator:B}#1{\getvalue{\??id:\c!indicator:b}{\WORD{#1}}}

%D The following macros are the interface to the rendering. These are
%D generated by \LUA. This might change.

%D Beware, we get funny side effects when a dangling \index precedes an
%D placeindex as then flushing takes place inside the index. Took me hours
%D to notice that.

\unexpanded\def\startregisteroutput
  {\endgraf
   \begingroup
   \forgetparindent
   \forgetparskip}

\unexpanded\def\stopregisteroutput
  {\endgraf
   \endgroup}

\unexpanded\def\startregisterentries#1% depth
  {\endgraf
   \begingroup
   \dosetregisterattributes\c!textstyle\c!textcolor
   \advance\leftskip\numexpr#1-1\relax\dimexpr\registerparameter\c!distance\relax
   \hangindent\registerparameter\c!distance\hangafter\plusone}

\unexpanded\def\stopregisterentries
  {\endgraf
   \endgroup}

\unexpanded\def\startregistersection#1% title
  {\registercharacter{#1}\endgraf}

\unexpanded\def\stopregistersection
  {\endgraf}

\newconditional\registerpagedone

\unexpanded\def\startregisterpages
  {\begingroup
   \setfalse\registerpagedone
   \dosetregisterattributes\c!pagestyle\c!pagecolor}

\unexpanded\def\stopregisterpages
  {\endgroup}

\unexpanded\def\startregisterseewords
  {\begingroup
   \setfalse\registerpagedone
   \dosetregisterattributes\c!pagestyle\c!pagecolor}

\unexpanded\def\stopregisterseewords
  {\endgroup}

\def\registerpageseparator% todo: , configurable
  {\ifconditional\registerpagedone
     \registerpageseparatorsymbol
   \else
     \hskip\registerparameter\c!distance\relax
     \settrue\registerpagedone
   \fi}

\def\registeronepagerangeseparator{|\endash|}

\def\withregisterpagecommand#1#2#3%
  {\def\currentregisterpageindex{#1}%
   \iflocation
     \goto{\registerparameter\c!pagecommand{#3}}[internal(#1)]%
   \else
     \registerparameter\c!pagecommand{#3}%
   \fi}

\def\registeronepage#1#2#3% content
  {\registerpageseparator
   \withregisterpagecommand{#1}{#2}{#3}}

\def\registerpagerange#1#2#3#4#5#6% content, content todo: -- configurable
  {\registerpageseparator
   \withregisterpagecommand{#1}{#2}{#3}%
   \registeronepagerangeseparator
   \withregisterpagecommand{#4}{#5}{#6}}

\def\registeroneword#1#2#3% content
  {\registerpageseparator
   \registerseeword{#3}}

\def\defaultregisterentry  #1{\registerparameter\c!textcommand{\limitedregisterentry{\registerparameter\c!deeptextcommand{#1}}}}
\def\defaultregisterseeword#1{\labeltexts\v!see{#1}}

\let\registerseeword  \defaultregisterseeword
\let\registerentry    \defaultregisterentry
\let\registercharacter\defaultregistercharacter

%D A few specific rendering variants:

% \def\doregisterpagelocation#1#2%
%   {\nextregisterpage
%    \hbox to 1em{\hss\doregisterpagehowto{#1}{#2}\hss}}

% todo: \installregisterpagehandler

% \def\MyRegisterPageCommand#1%
%   {#1\currentregisterpageuserdata{whatever}}
%
% \starttext
%     \setregisterentry[index][entries=aaa][whatever=f.] test \index{bbb} test
%     \placeregister[index][n=1,pagecommand=\MyRegisterPageCommand]
% \stoptext

\def\registerpageuserdata       #1#2{\ctxlua{jobregisters.userdata(#1,"#2")}}
\def\currentregisterpageuserdata    {\registerpageuserdata\currentregisterpageindex} % {#1}

% not yet ok : new internal handler names

\def\registerpagebuttonsymbol{\vrule\!!width1em\!!height1ex\!!depth\zeropoint\relax}

\setvalue{\??id:\c!symbol:\c!n}%
  {\def\registerpageseparatorsymbol{, }}

\setvalue{\??id:\c!symbol:\c!a}%
  {\def\registerpageseparatorsymbol{, }} % now done via conversion

\setvalue{\??id:\c!symbol:\v!none}%
  {\let\registerpageseparatorsymbol\empty
   \let\registeronepage            \gobblethreearguments
   \let\registerpagerange          \gobblesixarguments}

\setvalue{\??id:\c!symbol:1}%
  {\let\registerpageseparatorsymbol\space
   \def\registeronepage           {\symbol[1]\gobblethreearguments}%
   \def\registerpagerange         {\symbol[1]\gobblesixarguments}}

\setvalue{\??id:\c!symbol:2}%
  {\let\registerpageseparatorsymbol\space
   \def\registeronepage           {\registerpagebuttonsymbol\gobblethreearguments}%
   \def\registerpagerange         {\registerpagebuttonsymbol\gobblesixarguments}}

\def\setregisterpagerendering
  {\edef\currentregisterpagesymbol{\registerparameter\c!symbol}%
   \ifx\currentregisterpagesymbol\empty
     \csname\??id:\c!symbol:\c!n\endcsname
   \else\ifcsname\??id:\c!symbol:\currentregisterpagesymbol\endcsname
     \csname\??id:\c!symbol:\currentregisterpagesymbol\endcsname
   \else
     \let\registerpageseparatorsymbol\space
     \def\registeronepage           {\registerparameter\c!symbol\gobblethreearguments}%
     \def\registerpagerange         {\registerparameter\c!symbol\gobblesixarguments}%
   \fi\fi}

\appendtoks
     \setregisterpagerendering
\to \everyplaceregister

% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %
% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %
% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % %

%D The following code will be reimplemented (not that hard) when it's needed
%D again and/or when I'm bored.

% \def\getalllistreferences#1#2%
%   {\gdefconvertexpanded\currentregisterentry{\getvalue{\??id#1\c!expansion}}{#2}%
%    \doifdefinedelse{\??id#1\??id\currentregisterentry}
%      {\edef\alllistreferences%
%         {\getvalue{\??id#1\??id\currentregisterentry}}%
%       \beforesplitstring\alllistreferences\at::\to\internallistreference
%       \aftersplitstring \alllistreferences\at::\to\alllistreferences}
%      {\let\alllistreferences\empty
%       \def\internallistreference{0}}}

% \def\dosetlinkregister#1% is die page reference echt nodig?
%   {\setregisterpage{#1}%
%    \global\let\currentregisterentry\empty
%    \global\firstsubentrytrue % not needed
%    \global\firstsubsubentrytrue % not needed too
%    \setvalue{#1\s!entrya}##1{\dosetlinkregisterentrya{#1}{##1}}%
%    \setvalue{#1\s!entry }##1{\dosetpageregisterletter{#1}{##1}}}

% \def\dosetlinkregisterentrya#1#2%
%    {\global\utilitydonetrue
%     \c!entryletter
%     \iflocation
%       \getalllistreferences{#1}{#2}%
%       % no \endgraf
%       \hangindent1em\noindent\c!entryreference
%       %
%       %\thisissomeinternal{\s!lin}{\internallistreference}%
%       %
%       \pagereference[-:\s!lin:\internallistreference]% -: added
%       %
%       \getcommacommandsize[\alllistreferences]%
%       \getfromcommacommand[\alllistreferences][1]%
%       \ifnum\commalistsize=1
%         \let\firstlistreference\empty
%         \let\midlistreference\commalistelement
%         \let\lastlistreference\empty
%       \else
%         \let\firstlistreference\commalistelement
%         \getfromcommacommand[\alllistreferences][\commalistsize]%
%         \let\lastlistreference\commalistelement
%         \ifnum\commalistsize=2
%           \let\midlistreference\empty
%         \else
%           \!!counta\commalistsize
%           \divide\!!counta 2
%           \getfromcommacommand[\alllistreferences][\!!counta]%
%           \let\midlistreference\commalistelement
%         \fi
%       \fi
%       % aangepast
%       \def\dodocommand[##1-##2]%
%         {\gotonextinternal{\s!ind}{##1}{##2}{\box0}}%
%       \doifelsevalue{\??id#1\c!interaction}\v!pagenumber
%         {\limitedregisterentry{#1}{#2}} % paginanummer
%         {{\setbox0\hbox{\limitedregisterentry{#1}{\begstrut#2}}%
%           \ifx\firstlistreference\empty  % tekst,alles
%             \ifx\midlistreference\empty
%               \box0
%             \else
%               \expandafter\dodocommand\expandafter[\midlistreference]%
%             \fi
%           \else
%             \expandafter\dodocommand\expandafter[\firstlistreference]%
%           \fi}}%
%       \doifvalue{\??id#1\c!number}\v!yes
%         {\hskip\getvalue{\??id#1\c!distance}(\commalistsize)}%
%       \doifnotvalue{\??id#1\c!interaction}\v!text % paginanummer,alles
%         {\def\docommand##1##2%
%            {{\setbox0\hbox{\showlocation{\hbox to 1em{\hss\symbol[##2]\hss}}}%
%              \ifx##1\empty
%                % \hskip\wd0 % (optioneel maken)
%              \else
%                \expandafter\dodocommand\expandafter[##1]%
%              \fi}}%
%          \hskip\getvalue{\??id#1\c!distance}%
%          \docommand\firstlistreference\v!previous
%          \docommand\midlistreference\v!somewhere
%          \docommand\lastlistreference\v!next}%
%       % tot hier
%     \else
%       % no \endgraf
%       \noindent\c!entryreference
%       \limitedregisterentry{#1}{#2}%
%     \fi
%     \endgraf}

% \def\dosetregister#1%
%   {\doifelsevalue{\??id#1\c!coupling}\v!yes
%      {\ifautoregisterhack
%         \dosetautoregister{#1}%
%       \else
%         \dosetlinkregister{#1}%
%       \fi}
%      {\dosetpageregister{#1}}}

% \def\dosetregister#1%
%   {\dosetpageregister{#1}}

% \newcounter\internallistreference

% \def\doloadregisterlinks#1%
%   {\setregisterpage{#1}%
%    \global\let\currentregisterentry\empty
%    \global\firstregisterpagetrue
%    \setvalue{#1\s!entrya}##1%
%      {\global\firstregisterpagetrue
%       \gdefconvertedargument\currentregisterentry{##1}% global nodig?
%       \doglobal\increment\internallistreference}%
%    \setvalue{#1\s!from}%
%      {\getvalue{#1\s!page}}%
%    \ifautoregisterhack
%      \setvalue{#1\s!page}##1##2##3##4%
%        {\doifreglevelelse[##3]
%           {\global\utilitydonetrue
%            \iffirstregisterpage
%              \@EA\xdef\csname\??id#1\??id\currentregisterentry\endcsname
%                {\internallistreference::##4}%
%            \else % catches errors in index
%              \ifcsname\??id#1\??id\currentregisterentry\endcsname
%                \@EA\xdef\csname\??id#1\??id\currentregisterentry\endcsname
%                  {\csname\??id#1\??id\currentregisterentry\endcsname,##4}%
%              \fi
%            \fi}
%           {}}%
%    \else
%      \setvalue{#1\s!page}##1##2##3##4%
%        {\doifreglevelelse[##3]
%           {\global\utilitydonetrue
%            \iffirstregisterpage
%              \global\firstregisterpagefalse
%              \@EA\xdef\csname\??id#1\??id\currentregisterentry\endcsname
%                {\internallistreference::##2-##4}%
%            \else % catches errors in index
%              \ifcsname\??id#1\??id\currentregisterentry\endcsname
%                \@EA\xdef\csname\??id#1\??id\currentregisterentry\endcsname
%                  {\csname\??id#1\??id\currentregisterentry\endcsname,##2-##4}%
%              \fi
%            \fi}
%           {}}%
%    \fi}

% \def\docoupleregister[#1][#2]%
%   {\iflocation
%      \ifcase0\countervalue{autolink:#1}\relax % only once
%        \begingroup
%        \let\dosetregister\doloadregisterlinks
%        \def\currentregister{#1}%
%        \setupregister[#1][#2]%
%        \mkloadregister\currentregister\dobeforeplaceregister\doafterplaceregister
%        \endgroup
%        \ifautoregisterhack
%          \doinitializeautoregister{#1}%
%        \else
%          \doinitializelinkregister{#1}%
%        \fi
%      \fi
%    \fi}

% \def\coupleregister
%   {\dodoubleempty\docoupleregister}

% \def\dodocommandprolinrefAA[#1-#2]%
%   {\def\lastlistreference{#1-#2}}

% \def\dodocommandprolinrefA[#1-#2]%
%   {\def\lastlistreference{#1-#2}%
%    \ifx\firstlistreference\empty
%      \let\firstlistreference\lastlistreference
%    \fi
%    \ifnum#1<\nextinternalreference\relax
%      \let\prevlistreference\lastlistreference
%    \else\ifnum#1>\nextinternalreference\relax
%      \let\nextlistreference\lastlistreference
%      \let\dodocommandprolinrefA\dodocommandprolinrefAA
%    \else
%      \let\selflistreference\lastlistreference
%    \fi\fi}

% \def\docommandprolinrefA#1%
%   {\dodocommandprolinrefA[#1]}

% \def\dodocommandprolinrefB[#1-#2]%
%   {\gotonextinternal{\s!ind}{#1}{#2}{\box0}}

% \def\docommandprolinrefB#1#2#3%
%   {\bgroup
%    \ifx#2\empty
%      \doifvalue{\??id#1\c!unknownreference}\v!empty{\hskip1em}%
%    \else
%      \setbox0\hbox to 1em{\hss\showlocation{\symbol[#3]}\hss}%
%      \expandafter\dodocommandprolinrefB\expandafter[#2]%
%    \fi
%    \egroup}

% \def\doprocesslinkregister[#1][#2]#3%
%   {\hbox
%      {\doprocesspageregister{}{#2}{}{#3}%
%       \let\firstlistreference\empty
%       \let\lastlistreference\empty
%       \let\selflistreference\empty
%       \let\prevlistreference\empty
%       \let\nextlistreference\empty
%       \getalllistreferences{#1}{#3}%
%       \ifx\alllistreferences\empty \else
%         \normalexpanded{\noexpand\rawprocesscommalist[\alllistreferences]}\docommandprolinrefA
%       \fi
%        \ifx\prevlistreference\empty
%          \let\prevlistreference\lastlistreference
%        \fi
%        \ifx\nextlistreference\empty
%          \let\nextlistreference\firstlistreference
%        \fi
%        \ifx\prevlistreference\selflistreference
%          \let\prevlistreference\empty
%          \let\nextlistreference\empty
%        \fi
%        \setalignmentswitch{\getvalue{\??id#1\c!location}}%
%        \ifcase\alignmentswitch
%          % links
%          \docommandprolinrefB{#1}\prevlistreference\v!previous
%          \docommandprolinrefB{#1}\nextlistreference\v!next
%        \or
%          % midden
%          \docommandprolinrefB{#1}\prevlistreference\v!previous
%        \or
%          % rechts
%        \fi
%        \doifreferencefoundelse{\s!lin:\internallistreference}
%          {\gotosomeinternal
%             \s!lin \internallistreference \currentrealreference
%             {\showlocation{\limitedregisterentry{#1}{#3}}}}
%          {\hbox{\limitedregisterentry{#1}{#3}}}%
%        \ifcase\alignmentswitch
%          % links
%        \or
%          % midden
%          \docommandprolinrefB{#1}\nextlistreference\v!next
%        \or
%          % rechts
%          \docommandprolinrefB{#1}\prevlistreference\v!previous
%          \docommandprolinrefB{#1}\nextlistreference\v!next
%        \fi}}

% \def\doprocesslinkedregister[#1][#2]#3% page auto link
%   {\bgroup
%    \chardef\registerpagestatus\plusone
%    \def\currentregister{#1}%
%    \iflocation % \next is not needed
%      \ifautoregisterhack
%        \def\next{\doprocessautoregister[#1][#2]}%
%      \else
%        \def\next{\doprocesslinkregister[#1][#2]}%
%      \fi
%    \else
%      \def\next{\doprocesspageregister{}{#2}{}}%
%    \fi
%    \next{#3}%
%    \egroup}

% \def\dodolinkedregister[#1][#2]#3% page auto link
%   {\doflushatpar{\doprocesslinkedregister[#1][#2]{#3}}}

% \def\dolinkedregister#1%
%   {\dodoubleempty\dodolinkedregister[#1]}

% \def\dosetautoregister#1%
%   {\makecounter{autolink:#1}%
%    \setregisterpage{#1}%
%    \global\let\currentregisterentry\empty
%    \global\firstsubentrytrue % not needed
%    \global\firstsubsubentrytrue % not needed too
%    \setvalue{#1\s!entrya}##1{\dosetautoregisterentrya{#1}{##1}}%
%    \setvalue{#1\s!entry }##1{\dosetpageregisterletter{#1}{##1}}}

% \def\dosetautoregisterentrya#1#2%
%   {\global\utilitydonetrue
%    \c!entryletter
%    \iflocation
%      \getalllistreferences{#1}{#2}%
%      \endgraf\hangindent1em\noindent\c!entryreference
%      \pagereference[-:\s!lin:\internallistreference]%
%      \pluscounter{autolink:#1}%
%      \bgroup
%     %\setupinteraction[\c!color=,\c!contrastcolor=,\c!style=]% kan sneller
%      \resetinteractionparameter\c!color
%      \resetinteractionparameter\c!contrastcolor
%      \resetinteractionparameter\c!style
%      \gotobox
%        {\limitedregisterentry{#1}{\begstrut#2}}%
%        [JS(SetRegisterEntry{\v!register,\countervalue{autolink:#1},#2,{\alllistreferences}})]%
%      \egroup
%    \else
%      \endgraf\noindent\c!entryreference
%      \limitedregisterentry{#1}{#2}%
%    \fi}

% \def\doprocessautoregister[#1][#2]#3%
%   {\hbox
%      {\doprocesspageregister{}{#2}{}{#3}%
%       \doifreferencefoundelse{\s!lin:\internallistreference}
%         {\gotosomeinternal \s!lin
%            {\internallistreference}{\currentrealreference}
%            {\showlocation{\limitedregisterentry{#1}{#3}}}}
%         {\hbox{\limitedregisterentry{#1}{#3}}}}}

% \appendmacro aan openpaginaactie (in shipout)

%D The first implementation used one main field with clones.
%D In a 2500 page document this resulted in a rather (anoying)
%D long start||up time. This \quote {every page its own field}
%D solution, combined with a \quote {page open action}, works
%D much faster, but is conceptually pretty weak.

% \def\complexregisterfield[#1]%
%   {\definefield[#1:\realfolio][line][\v!register]%
%    \field[#1:\realfolio]}

% \def\simpleregisterfield
%   {\complexregisterfield[\v!register]}

% \definecomplexorsimple\registerfield

% \appendtoks
%     % for now
%     \setupfield
%       [\v!register]
%       [\c!width=10em,
%        \c!height=3ex,
%        \c!align=\v!middle,
%        \c!option=\v!readonly,
%        \c!location=\v!low]
% \to \everydump

% \def\doinitializeautoregister#1%
%   {\useJSscripts[reg]%
%    \useJSpreamblenow{LinkedRegisters}%
%    \setupinteraction[\c!openpageaction=JS(UpdateRegisterField{\v!register})]%
%    \definereference[\v!reset\v!register][JS(ResetRegisterEntry{\v!register})]%
%    \definereference[\v!first\v!register][JS(GotoFirstRegisterEntry{\v!register})]%
%    \definereference[\v!previous\v!register][JS(GotoPreviousRegisterEntry{\v!register})]%
%    \definereference[\v!next\v!register][JS(GotoNextRegisterEntry{\v!register})]%
%    \definereference[\v!last\v!register][JS(GotoLastRegisterEntry{\v!register})]}

% \def\doinitializelinkregister#1%
%   {}

% todo ruwe register

%D Default index:

\defineregister
  [\v!index]
  [\v!indices]

% \setupregister[index][koppeling=ja]
%
% \stelveldenin
%   [register][achtergrond=raster,kader=uit]
%
% \stelvoettekstenin
%   [{\field[index]}]
%
% \stelhoofdtekstenin
%   [{\naar   {first}[eersteindex]\quad
%     \naar{previous}[vorigeindex]\quad
%     \naar    {next}[volgendeindex]\quad
%     \naar    {last}[laatsteindex]\quad\quad
%     \naar   {index}[index]}]
%
% \starttekst
%
% oeps~~~\gekoppeldeindex{oeps} \blanko
% flop~~~\gekoppeldeindex{flop} \blanko
% test~~~\gekoppeldeindex{test} \pagina
% flop~~~\gekoppeldeindex{flop} \blanko
% test~~~\gekoppeldeindex{test} \pagina
% oeps~~~\gekoppeldeindex{oeps} \blanko
% test~~~\gekoppeldeindex{test} \pagina
% flop~~~\gekoppeldeindex{flop} \blanko
% oeps~~~\gekoppeldeindex{oeps} \pagina
%
% \volledigeindex

\protect \endinput