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

\unprotect

\ifdefined \v!block \else \def\v!block{block} \fi

% compatibility issue:
%
% \def\setfullsectionnumber #1{}
% \def\preparefullnumber    #1{}
% \def\fullsectionnumber    {1--1--1}
% \def\makesectionnumber    [#1]{}
% \def\makesectionformat    {}
% \def\sectionformat        {1--1-1-1-1-1-1}
% \def\composedsectionnumber{}
% \def\@@kolist{}

% \setuphead[section]   [separator=\separatorlist{?,!,*}]
% \setuphead[subsection][separator=\separatorlist{??,!!,**}]
%
% \let\spr\separatorlist % this will enable this feature
%
% \setuphead[section]   [separator={?,!,*}]
% \setuphead[subsection][separator={??,!!,**}]
%
% \setupheads[separator={A,B,C,D,E,F}]
% \chapter{test}
% \section{test} \subsection{test} \subsection{test}
% \section{test} \subsection{test} \subsection{test}

% lua interface / names and interface might change

\def\setstructurelevel         #1#2{\ctxlua{structures.sections.setlevel("#1","#2")}}  % name, level|parent
\def\getstructurelevel           #1{\ctxlua{structures.sections.getcurrentlevel("#1")}}% name
\def\setstructurenumber        #1#2{\ctxlua{structures.sections.setnumber(#1,"#2")}}   % level, number (+/-)
\def\getstructurenumber          #1{\ctxlua{structures.sections.getnumber(#1)}}        % level
\def\getsomestructurenumber    #1#2{\ctxlua{structures.sections.getnumber(#1,"#2")}}   % level, what
\def\getfullstructurenumber      #1{\ctxlua{structures.sections.fullnumber(#1)}}       % level
\def\getsomefullstructurenumber#1#2{\ctxlua{structures.sections.fullnumber(#1,"#2")}}
\def\getspecificstructuretitle   #1{\ctxlua{structures.sections.structuredata(#1,"titledata.title",nil,"\structureheadparameter\s!catcodes")}}%

% interface

\def\structureheadparameter       #1{\csname\dostructureheadparameter{\??nh\currentstructurehead}#1\endcsname}
\def\structureheadparameterhash   #1{\dostructureheadparameterhash   {\??nh\currentstructurehead}#1}
\def\namedstructureheadparameter#1#2{\csname\dostructureheadparameter{\??nh#1}#2\endcsname}

\def\dostructureheadparameter    #1#2{\ifcsname#1#2\endcsname#1#2\else\expandafter\dostructureheadparentparameter    \csname#1\s!parent\endcsname#2\fi}
\def\dostructureheadparameterhash#1#2{\ifcsname#1#2\endcsname  #1\else\expandafter\dostructureheadparentparameterhash\csname#1\s!parent\endcsname#2\fi}

\def\dostructureheadparentparameter    #1#2{\ifx#1\relax\s!empty\else\dostructureheadparameter    #1#2\fi}
\def\dostructureheadparentparameterhash#1#2{\ifx#1\relax        \else\dostructureheadparameterhash#1#2\fi}

\def\structureheadparameterstrict#1{\csname\ifcsname\??nh\currentstructurehead#1\endcsname\??nh\currentstructurehead#1\else\s!empty\fi\endcsname}

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

% so far

\newcount\maxstructuredepth

\let\laststructuresectionname\empty

\let\resetallstructuremarks            \relax
\let\resetcurrentstructuremarks        \relax
\let\resetcurrentstructuremarkswithpage\relax

\def\resetallstructuremarks            {\resetmarking[\v!section-1]}              % will become option
\def\resetcurrentstructuremarks        {\resetmarking[\laststructuresectionname]} % will become option
%def\resetcurrentstructuremarkswithpage{\resetmarking[\laststructuresectionname]} % will become option

\unexpanded\def\definestructuresection[#1]%
  {\ifcsname\??nh#1\endcsname
     % rather fatal error
   \else
     \global\advance\maxstructuredepth\plusone
     \setevalue{\??nh#1\c!level}{\the\maxstructuredepth}%
     \setstructurelevel{#1}{\the\maxstructuredepth}%
     \normalexpanded{\noexpand\getparameters[\??nh#1][\s!parent=\??nh\laststructuresectionname]}%
     % this is a rather practical default that we don't want to be part of the parent chain
     % lookup mechanism; it's also mkii compativle; this might become \everystructureheaddefine
     \getparameters[\??nh#1]
       [  \c!textstyle=\structureheadparameterstrict\c!style,
          \c!textcolor=\structureheadparameterstrict\c!color,
        \c!numberstyle=\structureheadparameterstrict\c!style,
        \c!numbercolor=\structureheadparameterstrict\c!color]%
     % so far for these default inheritances
     \definemarking[#1]%
     \ifnum\maxstructuredepth>\plusone
       \normalexpanded{\noexpand\relatemarking[#1][\laststructuresectionname]}% so, the parent will reset the child
     \fi
     \xdef\laststructuresectionname{#1}%
  \fi}

\unexpanded\def\setupstructuresection
  {\dotripleempty\dosetupstructuresection}

\def\dosetupstructuresection[#1]%
  {\doifdefinedelse{\??nh#1}
     {\dodosetupstructuresection[#1]}
     {\dodosetupstructuresection[\structuresectionheadsection{#1}]}}

\def\dodosetupstructuresection[#1][#2][#3]%
  {\ifthirdargument
     \getparameters[\??nh#1#2][#3]% ? probably sectionblock
   \else
     \getparameters[\??nh#1][#2]%
   \fi}

% -2=text -1=manual 0=block 1+=structurelevel

\def\structuresectionlevel#1%
  {\executeifdefined{\??nh#1\c!level}{-1}}

\setvalue{\??nh\v!block\c!level}{0}
\setvalue{\??nh\v!none \c!level}{-1}
\setvalue{\??nh\v!text \c!level}{-2}

% head -> structurehead

\let\currentstructurehead\empty
\newtoks\everystructureheadsetup

\unexpanded\def\setupstructureheads{\dosingleargument\dosetupstructureheads}
\unexpanded\def\setupstructurehead {\dodoubleempty\dosetupstructurehead}
\unexpanded\def\definestructurehead{\dodoubleempty\dodefinestructurehead}

\newif\ifsectionnumber % maybe conditional

\def\dosetupstructureheads[#1]%
  {\getparameters[\??nh][#1]%
   \doifelse{\structureheadparameter\c!sectionnumber}\v!yes\sectionnumbertrue\sectionnumberfalse}

\def\dosetupstructurehead[#1][#2]% we move the test for command being nothing elsewhere (needed, else hard to trace)
  {\processcommalist[#1]{\dodosetupstructurehead{#2}}}

\def\dodosetupstructurehead#1#2%
  {\edef\currentstructurehead{#2}%
   \getparameters[\??nh#2][#1]%
   \the\everystructureheadsetup}

\def\dodefinestructurehead[#1][#2]%
  {\processcommalist[#1]{\dododefinestructurehead{#2}}}

\def\dododefinestructurehead#1#2% #1: parameters|parent, #2: self
  {\doifsomethingelse{#2}
     {\doifassignmentelse{#1}
        \dodefineuniquestructurehead
        {\doifdefinedelse{\??nh#1\s!parent} % just a check
           \dodefineclonedstructurehead
           \dodefineerrorstructurehead}}
     \dodefineerrorstructurehead
   {#2}{#1}}

\def\dodefineerrorstructurehead#1#2%
  {\setvalue{#1}{\par error: #1 is undefined\par}}

% deeptextcommand and deepnumbercommand are left undefined !

\def\dodefineuniquestructurehead#1#2% class, parent
  {\def\currentstructurehead{#1}%
   \presetlabeltext[#1=]%
   \getparameters[\??nh#1][\c!label=#1,#2]%
   \edef\currentstructureheaddefault{\structureheadparameter\c!default}%
   \edef\currentstructureheadsection{\structureheadparameter\c!section}%
   \edef\currentstructureheadparent
     {\ifx\currentstructurehead\currentstructureheaddefault
        \currentstructureheadsection
      \else\ifx\currentstructureheaddefault\empty
        \currentstructureheadsection
      \else
        \currentstructureheaddefault
      \fi\fi}%
   \normalexpanded{\noexpand\getparameters[\??nh#1][\s!parent=\??nh\currentstructureheadparent]}%
   % or just \setevalue{\??nh#1\s!parent}{\??nh\currentstructureheadparent}%
%    \ifx\currentstructureheadsection\empty
%      \definemarking[#1]%
%      \setupmarking[#1][\c!filtercommand=\sectionheadmarkingtitle{#1}]%
%    \else
%      \definemarking[#1][\currentstructureheadsection]%
%      \definemarking[#1\v!number][#1]%
%      \setupmarking[#1][\c!filtercommand=\sectionheadmarkingtitle{#1}]%
%      \setupmarking[#1\c!number][\c!filtercommand=\sectionheadmarkingnumber{#1}]%
%    \fi
   \definemarking[#1]         [\currentstructureheadsection]%
   \definemarking[#1\v!number][\currentstructureheadsection]%
   \setupmarking [#1]         [\c!filtercommand=\sectionheadmarkingtitle {#1}]%
   \setupmarking [#1\c!number][\c!filtercommand=\sectionheadmarkingnumber{#1}]%
   \doifundefined{\??li#1}{\definelist[#1][\c!prefix=\v!no]}% definestructurelist ?
   \the\everystructureheadsetup}

\def\sectionheadmarkingtitle #1#2{\ctxlua{structures.marks.title("#1","#2")}}
\def\sectionheadmarkingnumber#1#2{\ctxlua{structures.marks.number("#1","#2")}}

\def\dodefineclonedstructurehead#1#2% class parent
  {\def\currentstructurehead{#1}%
   \presetlabeltext[#1=]%
   \doifelse{#1}{#2}
     {\getparameters[\??nh#1][\c!label=#1]%
      \doifundefined{\??li#1}{\definelist[#1][\c!prefix=\v!no]}}%  definestructurelist ?
     {\getparameters[\??nh#1][\s!parent=\??nh#2,\c!label=#1,\c!coupling=#2]%
%       \definemarking[#1]         [#2]%
%       \definemarking[#1\v!number][#2\c!number]%
      \definemarking[#1]         [#2]%
      \definemarking[#1\v!number][#2\c!number]%
      \doifundefined{\??li#1}{\definelist[#1][#2][\c!prefix=\v!no]}}% definestructurelist ?
   \the\everystructureheadsetup}

\appendtoks
%    \setstructurelevel\currentstructurehead{\structuresectionheadsection{\structuresectionheadcoupling\currentstructurehead}}%
   \setstructurelevel\currentstructurehead{\thenamedstructureheadlevel\currentstructurehead}%
   \doifelse{\structureheadparameter\c!ownnumber}\v!yes
     {\setevalue\currentstructurehead{\dohandlestructureheadown[\currentstructurehead]}}
     {\setevalue\currentstructurehead{\dohandlestructureheadnop[\currentstructurehead]}}%
   \setevalue{\e!next \currentstructurehead}{\donextstructurehead [\currentstructurehead]}%
   \setevalue{\e!start\currentstructurehead}{\dostartstructurehead[\currentstructurehead]}%
   \setevalue{\e!stop \currentstructurehead}{\dostopstructurehead [\currentstructurehead]}%
\to \everystructureheadsetup

% todo, check if section is defined

\def\structuresectionheadcoupling#1%
  {\ifcsname\??nh#1\c!coupling\endcsname
     \expandafter\structuresectionheadcoupling\csname\??nh#1\c!coupling\endcsname\else#1%
   \fi}

\def\structuresectionheadsection#1%
  {\ifcsname\??nh#1\c!section\endcsname
     \expandafter\structuresectionheadcoupling\csname\??nh#1\c!section\endcsname\else#1%
   \fi}

% head construction

\unexpanded\def\dohandlestructureheadown{\dodoubleempty\dodohandlestructureheadown} % [ref] {nr} {title}
\unexpanded\def\dohandlestructureheadnop{\dodoubleempty\dodohandlestructureheadnop} % [ref] {title}
\unexpanded\def\dostartstructurehead    {\dotripleempty\dodostartstructurehead}     % [settings] [userdata]

\newconditional\currentstructureown

\newtoks\everybeforestructurehead % hook, todo: before/after keys
\newtoks\everyafterstructurehead  % hook, todo: before/after keys

\unexpanded\def\dodohandlestructureheadown[#1][#2]#3#4%
  {\settrue\currentstructureown
   \dohandlestructurehead{#1}{\c!reference={#2},\c!ownnumber={#3},\c!title={#4}}{}} % name ref nr title --

% \unexpanded\def\dodohandlestructureheadnop[#1][#2]#3%
%   {\setfalse\currentstructureown
%    \dohandlestructurehead{#1}{\c!reference={#2},\c!title={#3}}{}} % name ref nr title --

\unexpanded\def\dodohandlestructureheadnop[#1][#2]% for taco: [key=value] variant
  {\setfalse\currentstructureown
   \doifassignmentelse{#2}\dodohandlestructureheadnopA\dodohandlestructureheadnopB{#1}{#2}}

\unexpanded\def\dodohandlestructureheadnopA#1#2%
  {\dohandlestructurehead{#1}{#2}{}}

\unexpanded\def\dodohandlestructureheadnopB#1#2#3%
  {\dohandlestructurehead{#1}{\c!reference={#2},\c!title={#3}}{}} % name ref nr title --

\unexpanded\def\dodostartstructurehead[#1][#2][#3]% for the moment no grouping, too annoying with page breaks
  {\setfalse\currentstructureown
  %\globalpushmacro\currentstructurehead
   \xdef\currentstructurehead{#1}%
   \the\everybeforestructurehead
   \dohandlestructurehead{#1}{#2}{#3}} % name -- -- -- userdata

\unexpanded\def\dostopstructurehead[#1]%
  {%\globalpopmacro\currentstructurehead
   \xdef\currentstructurehead{#1}% recover
   \dostoptagged\dostoptagged
   \the\everyafterstructurehead}

\unexpanded\def\donextstructurehead[#1][#2][#3]%
  {\setfalse\currentstructureown
   \xdef\currentstructurehead{#1}%
   \dohandlestructurehead{#1}{#2}{#3}} % name -- -- -- userdata

% \newconditional\structurereversesectionnumbers  % todo: key/val

\newconditional\structureheadtolist
\newconditional\structureheaddoincrement
\newconditional\structureheaddoplace
\newconditional\structureheadleaveempty
\newconditional\structureheadhidden
\newconditional\structureheadshownumber
\newconditional\structureheadisdisplay

\let\structureheadprefix\empty \def\structureheadprefixplus{+}

% When do we reset the referenceprefix? This needs to be checked. Does it work
% at all? Todo: pushpop.

% \def\setstructureheadreference
%   {\edef\structureheadreference      {\structureheadparameter\c!reference}%
%    \edef\structureheadreferenceprefix{\structureheadparameter\c!prefix}%
%    \ifx\structureheadreferenceprefix\empty
%      \ifx\currentrefenceprefix\structureheadreferenceprefixplus
%        \setupreferenceprefix[]% yes or no? only when set by structure
%      \fi
%    \else\ifx\structureheadreferenceprefix\structureheadreferenceprefixplus
%      \ifx\structureheadreference\empty
%         \expanded{\setupreferenceprefix[\structureheadreferenceprefixplus]}%
%      \else
%         \expanded{\setupreferenceprefix[\structureheadreference]}% we assume just one reference
%      \fi
%    \else
%      \expanded{\setupreferenceprefix[\structureheadreferenceprefix]}%
%    \fi\fi}

% pop in stopsection commands unless empty

\def\setstructureheadreference
  {\edef\structureheadreference      {\structureheadparameter\c!reference}%
   \edef\structureheadreferenceprefix{\structureheadparameter\c!prefix}%
   \ifx\structureheadreferenceprefix\empty
     \let\structureheadreferenceprefix\referenceprefix
   \else
     \setupreferenceprefix[\structureheadreferenceprefix]% currenty no pop
   \fi}

\setvalue{\??nh:\c!incrementnumber:\v!yes  }{\settrue \structureheaddoincrement\settrue \structureheadtolist}
\setvalue{\??nh:\c!incrementnumber:\v!no   }{\setfalse\structureheaddoincrement\setfalse\structureheadtolist}
\setvalue{\??nh:\c!incrementnumber:\v!list }{\setfalse\structureheaddoincrement\settrue \structureheadtolist}
\setvalue{\??nh:\c!incrementnumber:\s!empty}{\settrue \structureheaddoincrement\settrue \structureheadtolist}

\def\setstructureheadincrement
  {\edef\currentstructureheadincrement{\structureheadparameter\c!incrementnumber}%
   \ifcsname\??nh:\c!incrementnumber:\currentstructureheadincrement\endcsname
     \csname\??nh:\c!incrementnumber:\currentstructureheadincrement\endcsname
   \else
     \settrue \structureheaddoincrement\settrue \structureheadtolist
     % \filterstructureheadnumber
   \fi}

\def\filterstructureheadnumber
  {\settrue\structureheaddoincrement
   \settrue\structureheadtolist
   \ifx\currentproduct\empty
     % todo : filter from other toc (number, file, title)
     % use  : \currentstructureheadincrement as spec
   \fi}

% \def\setstructureheadplacement
%   {\setfalse\structureheadleaveempty
%    \settrue \structureheaddoplace
%    \setfalse\structureheadhidden
%    \processaction
%      [\structureheadparameter\c!placehead]
%      [  \v!yes=>,
%       \v!empty=>\settrue\structureheadleaveempty,
%          \v!no=>\settrue\structureheadleaveempty\setfalse\structureheaddoplace,
%      \v!hidden=>\settrue\structureheadleaveempty\setfalse\structureheaddoplace\settrue\structureheadhidden]}

\setvalue{\??nh:\c!placehead:\v!yes}%
  {\setfalse\structureheadleaveempty
   \settrue \structureheaddoplace
   \setfalse\structureheadhidden}

\setvalue{\??nh:\c!placehead:\v!empty}%
  {\settrue \structureheadleaveempty
   \settrue \structureheaddoplace
   \setfalse\structureheadhidden}

\setvalue{\??nh:\c!placehead:\v!no}%
  {\settrue \structureheadleaveempty
   \setfalse\structureheaddoplace
   \setfalse\structureheadhidden}

\setvalue{\??nh:\c!placehead:\v!hidden}%
  {\settrue \structureheadleaveempty
   \setfalse\structureheaddoplace
   \settrue \structureheadhidden}

\def\setstructureheadplacement
  {\executeifdefined
     {\??nh:\c!placehead:\structureheadparameter\c!placehead}
     {\getvalue{\??nh:\c!placehead:\v!yes}}}

\def\setstructureheaddisplay
  {\doifelsevalue{\??nh:\structureheadparameter\c!alternative}\v!horizontal
     {\setfalse\structureheadisdisplay}
     {\settrue \structureheadisdisplay}}

\def\dosettructureheadnumbercontent
  {\setsystemmode  \v!sectionnumber
   \settrue\structureheadshownumber}

\def\doresettructureheadnumbercontent
  {\resetsystemmode\v!sectionnumber
   \setfalse\structureheadshownumber}

\def\setstructureheadnumber
  {\ifsectionnumber
     \doifelse{\structureblockparameter\c!number}\v!yes % todo
       {\doifelse{\structureheadparameter\c!number}\v!yes
         {\settrue\structureheadshownumber}
         {\setfalse\structureheadshownumber}}
       {\setfalse\structureheadshownumber}%
   \else
     \setfalse\structureheadshownumber
   \fi}

\unexpanded\def\thestructureheadsynchonization
  {\pagetype[\currentstructureheadcoupling]% hm also number
   \currentstructuresynchronize}

\unexpanded\def\setstructureheadmarking
  {\normalexpanded{\noexpand\setmarking[\currentstructurehead]{\currentstructurelistnumber}}}

% \unexpanded\def\fullstructureheadnumber{\labeltexts{\structureheadparameter\c!label}{\structurenumber}} % todo
% \def\fullstructureheadtitle {\structurevariable{titledata.title}} % no catcode!
% \unexpanded\def\fullstructureheadtitle{\structureautocatcodedget{titledata.title}{\structureheadparameter\s!catcodes}}

\let\deepstructurenumbercommand\relax
\let\deepstructuretitlecommand \relax

\unexpanded\def\fullstructureheadnumber
  {\edef\currentstructureheadlabeltag{\currentstructureblock\c!label}%
   \dostarttagged\t!sectionnumber\empty
   \labeltexts
     {\structureheadparameter\currentstructureheadlabeltag}
     {\ifx\deepstructurenumbercommand\relax
        \structurenumber
      \else
        \normalexpanded{\noexpand\deepstructurenumbercommand{\structurenumber}}%
      \fi}%
   \dostoptagged}

\unexpanded\def\fullstructureheadtitle
  {\dostarttagged\t!sectiontitle\empty
   \ifx\deepstructuretitlecommand\relax
     \structuretitle
   \else
     \normalexpanded{\noexpand\deepstructuretitlecommand{\structuretitle}}%
   \fi
   \dostoptagged}

\let\currentstructurehead        \empty
\let\currentstructureheadcoupling\empty
\let\currentstructureheadsection \empty
\let\currentstructureheadlevel   \!!zerocount
\let\currentstructureheadcounter \!!zerocount

% here we could inherit as well but it's a bit complex

\def\doregisterstructurehead#1#2#3% name data userdata
  {\structurecomponent
     [\c!label={\structureheadparameter\c!label}, % why { }
      \c!incrementnumber=\ifconditional\structureheaddoincrement\v!yes\else\v!no\fi, % not that needed
      \c!saveinlist=\ifconditional\structureheadtolist\v!yes\else\v!no\fi,
      \c!level=\currentstructureheadlevel,
      \c!name=#1,
      \c!number=\ifconditional\structureheaddoincrement\ifconditional\structureheadshownumber\v!yes\else\v!no\fi\else\v!no\fi,
      \c!bookmark=,
      \c!marking=,
      \c!list=,
      \c!expansion=\structureheadparameter\c!expansion,
      \c!xmlsetup=\structureheadparameter\c!xmlsetup,
      \s!catcodes=\structureheadparameter\s!catcodes,
      \c!sectionresetset=\structureheadparameter\c!sectionresetset,
      \c!sectionseparatorset=\structureheadparameter\c!sectionseparatorset,
      \c!sectionconversionset=\structureheadparameter\c!sectionconversionset,
      \c!sectionconversion=\structureheadparameter\c!conversion, % just for compatibility
      \c!sectionstarter=\structureheadparameter\c!sectionstarter,
      \c!sectionstopper=\structureheadparameter\c!sectionstopper,
      \c!sectionset=\structureheadparameter\c!sectionset,
      \c!sectionsegments=\structureheadparameter\c!sectionsegments,
      \c!reference=\structureheadreference,
      \c!referenceprefix=\structureheadreferenceprefix,
      \c!backreference=,
      \c!command=,
      #2]%
     [#3]%
     \reportcurrentstructure}

\unexpanded\def\placeheadtext  {\dosingleempty\doplaceheadtext  } % use with care
\unexpanded\def\placeheadnumber{\dosingleempty\doplaceheadnumber} % use with care

\ifdefined\setupheadcomponentfont \else

    \unexpanded\def\setupheadcomponentfont#1#2%
      {\dosetstructureheadattributes\c!style\c!color
       \dosetstructureheadattributes#1#2%
       \dontconvertfont
       \setupinterlinespace}

\fi

\def\doplaceheadtext[#1]%
  {\dontleavehmode
   \begingroup
   \edef\currentstructurehead{#1}%
   \setupheadcomponentfont\c!textstyle\c!textcolor
   \relax
   \getspecificstructuretitle{\thenamedstructureheadlevel{#1}}%
   \endgraf
   \endgroup}

\def\doplaceheadnumber[#1]%
  {\dontleavehmode
   \begingroup
   \edef\currentstructurehead{#1}%
   \setupheadcomponentfont\c!numberstyle\c!numbercolor
   \relax
   \getfullstructurenumber{\thenamedstructureheadlevel{#1}}%
   \endgraf
   \endgroup}

\ifdefined \else \let\presetnumberheadalternative\relax \fi

\def\dohandlestructurehead#1#2#3% name data userdata (we can move #1 to the caller)
  {\xdef\currentstructurehead        {#1}%
   \xdef\currentstructureheadcoupling{\structuresectionheadcoupling\currentstructurehead}%
   \xdef\currentstructureheadsection {\structuresectionheadsection \currentstructureheadcoupling}%
   \xdef\currentstructureheadlevel   {\structuresectionlevel       \currentstructureheadsection}%
   %writestatus\m!systems{setup: \currentstructurehead,\currentstructureheadcoupling,\currentstructureheadsection,\currentstructureheadlevel}%
   %
   \setstructureheadreference % does not do much currently
   \setstructureheadincrement
   \setstructureheadplacement
   \setstructureheaddisplay
   \setstructureheadnumber
   %
   \unexpanded\def\\{\space}%
   \flushingcolumnfloatsfalse
   %
   % todo: also mark (for header)
   %
   % we might remove the lower level
   %
   % not here, after optional \page: \doregisterstructurehead\currentstructurehead{#2}{#3}%
   %
%    \xdef\currentstructureheadcounter{\currentstructurecounter}% lua call
   %
   % \currentstructuresynchronize % will move
   %
   \edef\numberheaddistance   {\structureheadparameter\c!distance   }% compatibility
   \edef\numberheadalternative{\structureheadparameter\c!alternative}% compatibility
   \presetnumberheadalternative
   %
   \let\getstructureheadnumber\empty
   \let\getstructureheadtitle \empty
   \let\getstructureheadsyncs \empty
   \ifconditional\structureheaddoincrement
     \ifconditional\structureheaddoplace
       \dostructureheadspacingbeforeyes
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \let\getstructureheadtitle\fullstructureheadtitle
       \ifconditional\structureheadshownumber
         \let\getstructureheadnumber\fullstructureheadnumber
         \placestructureheadnumbertext
       \else
         \placestructureheadtext
       \fi
       \dostructureheadspacingafteryes
     \else\ifconditional\structureheadhidden
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \placestructureheadhidden % only something when tracing
     \else
       \dostructureheadspacingbeforenop % toegevoegd ivm subpaginanr / tug sheets
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \placestructureheadempty % just flush 'm
       \dostructureheadspacingafternop
     \fi\fi
   \else
     \ifconditional\structureheaddoplace
       \dostructureheadspacingbeforeyes
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \let\getstructureheadtitle\fullstructureheadtitle
       \placestructureheadtext
       \dostructureheadspacingafteryes
     \else\ifconditional\structureheadhidden
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \placestructureheadhidden % only something when tracing
     \else
       % do nothing / should be vbox to 0pt
       \dostructureheadspacingbeforenop
       \doregisterstructurehead\currentstructurehead{#2}{#3}% after optional \page
       \let\getstructureheadsyncs\thestructureheadsynchonization
       \placestructureheadempty % just flush 'm
       \dostructureheadspacingafternop
     \fi\fi
   \fi
   \flushingcolumnfloatstrue
   \setfalse\ignorehandlepagebreak
   % ignorespaces prevents spaces creeping in when after=\dontleavehmode
   \dostarttagged\t!sectioncontent\empty
   \ifconditional\structureheadisdisplay % \ifdisplaysectionhead
     \ignorespaces
   \else
     \expandafter\GotoPar
   \fi}

% typesetting

\unexpanded\def\placestructureheadnumbertext % dummy, will be overloaded
  {\setstructureheadmarking
   \getstructureheadnumber/\getstructureheadtitle
   \getstructureheadsyncs}

\unexpanded\def\placestructureheadtext % dummy, will be overloaded
  {\setstructureheadmarking
   \getstructureheadtitle
   \getstructureheadsyncs}

\unexpanded\def\placestructureheadempty % dummy, will be overloaded
  {\setstructureheadmarking
   \getstructureheadsyncs}

\unexpanded\def\placestructureheadhidden
  {\setxvalue{\currentstructurehead:sync}%
     {\noexpand\setgvalue{\currentstructurehead:sync}{}%
      \noexpand\pagetype[\currentstructureheadcoupling]% hm also number
      \noexpand\setmarking[\currentstructureheadcoupling]{\currentstructurelistnumber}%
      \currentstructuresynchronize}}

\def\synchronizestructurehead#1%
  {\getvalue{#1:sync}}

\unexpanded\def\placerawheaddata  [#1]{\synchronizestructurehead {#1}}
\unexpanded\def\placerawheadtext  [#1]{\getspecificstructuretitle{\thenamedstructureheadlevel{#1}}}
\unexpanded\def\placerawheadnumber[#1]{\getfullstructurenumber   {\thenamedstructureheadlevel{#1}}}

% \setuphead[chapter][placehead=hidden]
% \chapter {test}
%
% %(\synchronizestructurehead{chapter}) % \getstructureheadsyncs
% %(\getfullstructurenumber{\thenamedstructureheadlevel{chapter}})
% %(\getspecificstructuretitle{\thenamedstructureheadlevel{chapter}})
%
% (\placerawheaddata  [chapter])
% (\placerawheadnumber[chapter])
% (\placerawheadtext  [chapter])

% pagebreaks

\newcount\precedingstructurelevel \precedingstructurelevel\plusone
\newconditional\ignorehandlepagebreak

\def\dostructureheadspacingbeforeyes
  {\docheckstructureheadbefore
   \dohandlestructureheadpagebreakyes
   \structureheadparameter\c!inbetween
   \dostarttagged\t!section\currentstructurehead}

\def\dostructureheadspacingbeforenop
  {\docheckstructureheadbefore
   \dohandlestructureheadpagebreaknop
   \structureheadparameter\c!inbetween
   \dostarttagged\currentstructurehead\empty}

% \def\emptystructureheadcorrection
%   {\ifconditional\structureheadleaveempty % inlined \emptyheadcorrection (with after=\blank)
%      \vskip-\lineheight
%      \dosomebreak\nobreak % \penalty10000 in vspacing
%      \kern\zeropoint
%      \prevdepth\strutdepth
%    \fi}

\def\emptystructureheadcorrection
  {\ifconditional\structureheadleaveempty % inlined \emptyheadcorrection (with after=\blank)
     \penalty10000 % first ... we need to adapt this all to vspacing
     \vskip-\lineheight
     \kern\zeropoint
     \prevdepth\strutdepth
   \fi}

\def\dostructureheadspacingafteryes
  {\ifconditional\structureheadisdisplay
     \dosomebreak\nobreak % needs to be adapted to vspacing
     \emptystructureheadcorrection
     \structureheadparameter\c!after
   \fi}

\def\dostructureheadspacingafternop
  {}

\newsignal\continuousstructureheadsignal

\def\docheckstructureheadbefore#1%
  {\ifhmode
     \scratchcounter\lastpenalty\unpenalty % no beauty in this
     \ifdim\lastskip=\continuousstructureheadsignal
       % no page break
       \ifconditional\ignorehandlepagebreak
         \setfalse\ignorehandlepagebreak
       \else
         \global\precedingstructurelevel\currentstructureheadlevel
         \nobreak
       \fi
       \global\settrue\continuoussectionhead
     \else
       \penalty\scratchcounter
       \global\setfalse\continuoussectionhead
       #1%
     \fi
   \else
     \global\setfalse\continuoussectionhead
     #1%
   \fi}

\def\dodocheckstructureheadlayout#1#2%
  {\doifelselayouttextline{#1}
     {\doifsomething{\structureheadparameter#2}{\expanded{\setuplayouttext[#1][\c!state=\structureheadparameter#2]}}}
     \donothing}

\setvalue{\??nh:\??mk:n:\v!page }{}
\setvalue{\??nh:\??mk:n:\v!reset}{\resetcurrentstructuremarks}
\setvalue{\??nh:\??mk:y:\v!page }{\resetcurrentstructuremarks}
\setvalue{\??nh:\??mk:y:\v!reset}{\resetcurrentstructuremarks}

\def\docheckstructureheadlayout
  {\doifelsenothing{\structureheadparameter\c!page}
     {\getvalue{\??nh:\??mk:n:\structureheadparameter\c!marking}}
     {\page[\structureheadparameter\c!page]%
      \getvalue{\??nh:\??mk:y:\structureheadparameter\c!marking}%
      \dodocheckstructureheadlayout\v!header\c!header
      \dodocheckstructureheadlayout\v!text  \c!text
      \dodocheckstructureheadlayout\v!footer\c!footer}}

\def\currentstructurecounter {\ctxlua{structures.sections.depthnumber(\thenamedstructureheadlevel\currentstructurehead)}}
\def\previousstructurecounter{\ctxlua{structures.sections.depthnumber(\thenamedstructureheadlevel\currentstructurehead-1)}}

\def\dohandlestructureheadpagebreaknop
  {\doifelse{\structureheadparameter\c!continue}\v!yes
     {\ifnum\previousstructurecounter=\zerocount
        \docheckstructureheadlayout
      \else\ifnum\currentstructurecounter>\zerocount
        \docheckstructureheadlayout
      \fi\fi}%
     {\docheckstructureheadlayout}}

\def\dohandlestructureheadpagebreakyes
  {%[[\currentstructurehead @\thenamedstructureheadlevel\currentstructurehead/prev:\previousstructurecounter/curr:\currentstructurecounter]]
   \ifconditional\ignorehandlepagebreak
     \setfalse\ignorehandlepagebreak
   \else
     \ifnum\lastpenalty>\zerocount
%        \global\pagebreakdisabledtrue
     \fi
     % beware, these numbers are not yet know here
     \doifelse{\structureheadparameter\c!continue}\v!yes
       {\ifnum\previousstructurecounter=\zerocount
          \docheckstructureheadlayout
        \else\ifnum\currentstructurecounter>\zerocount
          \docheckstructureheadlayout
        \fi\fi}%
       {\docheckstructureheadlayout}%
     \doifnot{\structureheadparameter\c!aligntitle}\v!float\flushsidefloats
     \structureheadparameter\c!before
     \relax
%      \ifpagebreakdisabled
%        \global\pagebreakdisabledfalse
%      \else
%        \dopreventbreakafterstructureheadauto % not ok as it binds the prev par
%      \fi
     \doif{\structureheadparameter\c!aligntitle}\v!float\indent
     \global\precedingstructurelevel\currentstructureheadlevel
   \fi}

% the next one was: \somebreakmethod


% 0 = nothing, 1 = weighted, 2 = strict, 3 = vspacing

\setnewconstant\somestructureheadbreakmethod\plusthree

% \def\dopreventbreakafterstructureheadauto % used after \c!before
%   {\ifcase\somestructureheadbreakmethod
%      % 0 = nothing
%    \or
%      % 1 = old weighted version
%      \ifnum\currentstructureheadlevel>\precedingstructurelevel
%        \dosomebreak{\penalty\numexpr20000+500*\currentstructureheadlevel\relax}%
%      \else
%        \dosomebreak\allowbreak % brr
%      \fi
%    \or
%       % 2 = strict version
%      \dosomebreak{\penalty\maxdimen}%
%    \or
%       % 3 = vspacing
%       \vspacing[\v!samepage]% if preceded by ! then a loop
%    \else
%       % nothing
%    \fi}
%
% \def\dopreventbreakafterstructureheadspec#1% see enumerations etc
%   {\ifcase\somestructureheadbreakmethod
%      % 0 = nothing
%    \or
%      % 1 = old weighted version
%      \dosomebreak{\penalty\numexpr20000+500*(\currentstructureheadlevel+#1)\relax}%
%    \or
%      % 2 = strict version
%      \dosomebreak{\penalty\maxdimen}%
%    \or
%       % 3 = vspacing
%       \vspacing[\v!samepage]%
%    \else
%      % nothing
%    \fi}
%
% todo: \vspacing[category:8] == keep_together

\def\dopreventbreakafterstructureheadauto % used after \c!before
  {\ifcase\somestructureheadbreakmethod
     % 0 = nothing
   \else
      \vspacing[\v!samepage-\currentstructureheadlevel]%
   \fi}

\def\dopreventbreakafterstructureheadspec#1% see enumerations etc
  {\ifcase\somestructureheadbreakmethod
     % 0 = nothing
   \else
      \vspacing[\v!samepage-\the\numexpr\currentstructureheadlevel+1\relax]% todo #1
   \fi}

\def\dohandlepagebreakX{\dopreventbreakafterstructureheadspec} % no \let so we can redefind

% we do support negative numbers but it can have side effects that we won't
% catch
%
% \chapter{some} \setupheadnumber[chapter][3] \chapter{more}
% \setupheadnumber[section][8] \section{b} \section{c} \setupheadnumber[section][-1] \section{d}

% \def\thecurrentstructureheadlevel#1%
%   {\getcurrentstructurelevel{#1}}

\def\thenamedstructureheadlevel#1%
  {\structuresectionlevel{\structuresectionheadsection{\structuresectionheadcoupling{#1}}}}

\unexpanded\def\setupheadnumber
  {\dodoubleargument\dosetupheadnumber}

\def\dosetupheadnumber[#1][#2]% todo: reset if at other level
  {\setstructurenumber{\thenamedstructureheadlevel{#1}}{#2}}

\def\currentstructureheadnumber{0} % ==> \currentheadnumber

\unexpanded\def\determineheadnumber[#1]%
  {\xdef\currentstructureheadnumber{\getstructurenumber{\thenamedstructureheadlevel{#1}}}}

% The previous macro is been replaced by the expandable:

\def\namedheadnumber      #1{\getstructurenumber    {\thenamedstructureheadlevel{#1}}}
\def\somenamedheadnumber#1#2{\getsomestructurenumber{\thenamedstructureheadlevel{#1}}{#2}}

\unexpanded\def\structureheadnumber
  {\dodoubleempty\dostructureheadnumber}

\def\dostructureheadnumber[#1][#2]% simple case is just a number
  {\getsomefullstructurenumber{\iffirstargument\thenamedstructureheadlevel{#1}\fi}{#2}}

\def\somestructureheadnumber
  {\dodoubleempty\dosomestructureheadnumber}

\def\dosomestructureheadnumber[#1][#2]%
  {\dontleavehmode
   \begingroup
   \edef\currentstructurehead{#1}%
   \getsomefullstructurenumber{\thenamedstructureheadlevel{#1}}{#2}%
   \endgroup}

% compatibility code (after all, we might offer different structure handlers as well
% but we might as well remove the 'structure' substring at some point (we needed it
% in order to test the old and new methods alongside)

\let\definesectionblock \definestructureblock
\let\definesection      \definestructuresection
\let\setupsection       \setupstructuresection
\let\setupheads         \setupstructureheads
\let\definehead         \definestructurehead
\let\setuphead          \setupstructurehead
\let\headnumber         \structureheadnumber
\let\setupsectionblock  \setupstructureblock

\let\sectioncountervalue\structurevalue

\def\currentheadnumber  {\currentstructureheadnumber}
\def\currentheadtext    {obsolete, use marks}

% list references, will be redone in lua when we need it

\let\startlistreferences\relax
\let\stoplistreferences \relax

\protect \endinput