%D \module
%D   [       file=m-formay,
%D        version=ancient,
%D          title=\CONTEXT\ Modules,
%D       subtitle=Ancient Formatting Code,
%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.

%D Here is some code that I had laying around and had forgotten
%D about. Let's make it a module and see if there is interest in
%D such things.

% \defineformatblock   [poem]
% \defineformatsegment [verse] % [poem]
% \defineformatline    [line]  % [verse]
%
% \startpoem  [title] [author]
% \startverse [ref]
% \startline  [ref]
%
% block   : voor na tussen *tekstletter *tekstkleur
%
% segment : voor na tussen *tekstletter *tekstkleur
%         : links rechts linkeroffset rechteroffset
%         : ?marge *evenmarge *onevenmarge breedte
%         : nummer *nummercommando *conversie
%         : nummerletter nummerkleur *label
%
% line    : voor na tussen *tekstletter *tekstkleur
%         : nummer *nummercommando *conversie
%         : nummerletter nummerkleur *label
%
% * = todo

\unprotect

\definesystemvariable {fx}   % format block
\definesystemvariable {fy}   % format segment
\definesystemvariable {fz}   % format line

\def\defineformatblock
  {\dodoubleempty\dodefineformatblock}

\def\dodefineformatblock[#1][#2]%
  {\setupformatblock
     [#1]
     [\c!before=\blank,\c!after=\blank,\c!inbetween=\blank,
      \c!textstyle=,\c!textcolor=,#2]%
   \setvalue{\e!start#1}{\startformatblock[#1]}%
   \setvalue{\e!stop #1}{\stopformatblock}}

\def\setupformatblock
  {\dodoubleempty\dosetupformatblock}

\def\setupformatblock[#1]%
  {\getparameters[\??fx#1]}

\def\startformatblock[#1]%
  {\dotriplegroupempty\dostartformatblock{#1}}

\def\dostartformatblock#1#2#3
  {\bgroup
   \getvalue{\??fx#1\c!before}
   \doglobal\newcounter\formatsegmentcounter
   \doglobal\newcounter\formatlinecounter
   \doglobal\newcounter\formatlinesubcounter
   \doglobal\newcounter\formatlinemaxcounter
   \doifsomething{#2}{\leftaligned{#2}\getvalue{\??fx#1\c!inbetween}}
   \def\stopformatblock%
     {\doifsomething{#3}{\getvalue{\??fx#1\c!inbetween}\leftaligned{#3}}
      \getvalue{\??fx#1\c!after}
      \egroup}}

\def\defineformatsegment
  {\dodoubleempty\dodefineformatsegment}

\def\dodefineformatsegment[#1][#2]%
  {\setupformatsegment
     [#1]
     [\c!before=\blank,\c!after=\blank,\c!inbetween=\blank,
      \c!textstyle=,\c!textcolor=,\c!left=,\c!right=,
      \c!leftoffset=\!!zeropoint,\c!rightoffset=\!!zeropoint,
     %\c!margin=\!!zeropoint,\c!evenmargin=\!!zeropoint,\c!oddmargin=\hsize,
      \c!width=\hsize,\c!numberstyle=,\c!numbercolor=,\c!number=\v!no,
      \c!numbercommand=,\c!conversion=,\c!label=,
      #2]%
   \setvalue{\e!start#1}{\startformatsegment[#1]}%
   \setvalue{\e!stop #1}{\stopformatsegment}}

\def\setupformatsegment
  {\dodoubleempty\dosetupformatsegment}

\def\setupformatsegment[#1]%
  {\getparameters[\??fy#1]}

\def\placeformatsegmentcounter
  {\formatsegmentcounter\quad\hphantom{\placeformatlinecounter}}

\def\placeformatlinecounter
  {\formatlinecounter}

\def\startformatsegment[#1]%
  {\bgroup
   \doifelsevalue{\??fy#1\c!number}\v!yes
     {\def\doplaceformatsegmentcounter
        {\inleftmargin
           {\doattributes{\??fy#1}\c!numberstyle\c!numbercolor
              {\placeformatsegmentcounter}}}}
     {\let\doplaceformatsegmentcounter\relax}%
   \getvalue{\??fy#1\c!before}
   \doglobal\increment\formatsegmentcounter
   \def\formatrightoffset{\getvalue{\??fy#1\c!rightoffset}}
   \def\formatleftoffset {\getvalue{\??fy#1\c!leftoffset}}
   \def\formatminwidth   {\getvalue{\??fy#1\c!minwidth}}
   \def\formatwidth      {\getvalue{\??fy#1\c!width}}
  %\def\formatmargin     {\getvalue{\??fy#1\c!margin}}
   \def\formatbefore     {\getvalue{\??fy#1\c!before}}
   \def\formatinbetween  {\getvalue{\??fy#1\c!inbetween}}
   \def\formatafter      {\getvalue{\??fy#1\c!after}}
   \def\formatleft       {\getvalue{\??fy#1\c!left}}
   \def\formatright      {\getvalue{\??fy#1\c!right}}
   \@@segmentvarianta
   \getvalue{@@segmentvariant\getvalue{\??fy#1\c!alternative}}
   \def\stopformatsegment
     {\getvalue{\??fy#1\c!after}
      \egroup}}

\newif\iftraceformatblock

\def\@@segmentvarianta % ragged right, symbols
  {\let\formatraggedness\raggedright
   \let\dostartformatline\dostartformatlineab
   \let\formatleftfirst\relax \let\formatrightfirst\hfill
   \let\formatleftnext \hfill \let\formatrightnext \relax}

\def\@@segmentvariantb % ragged right, equal parts, symbols
  {\let\formatraggedness\raggedcenter
   \let\dostartformatline\dostartformatlineab
   \let\formatleftfirst\relax \let\formatrightfirst\hfill
   \let\formatleftnext \hfill \let\formatrightnext \relax}

\def\@@segmentvariantc % ragged right
  {\let\formatraggedness\veryraggedright
   \let\dostartformatline\dostartformatlinecde
   \let\formatleftnext\relax \let\formatrightnext\hfill}

\def\@@segmentvariantd % ragged center
  {\let\formatraggedness\veryraggedcenter
   \let\dostartformatline\dostartformatlinecde
   \let\formatleftnext\hfill \let\formatrightnext\hfill}

\def\@@segmentvariante % ragged left
  {\let\formatraggedness\veryraggedleft
   \let\dostartformatline\dostartformatlinecde
   \let\formatleftnext\hfill \let\formatrightnext\relax}

\def\defineformatline
  {\dodoubleempty\dodefineformatline}

\def\dodefineformatline[#1][#2]%
  {\setupformatline
     [#1]
     [\c!before=\blank,\c!after=\blank,\c!inbetween=\blank,
      \c!textstyle=,\c!textcolor=,
      \c!number=\v!no,\c!numbercommand=,\c!conversion=,
      \c!numberstyle=,\c!numbercolor=,\c!label=,
      #2]%
   \setvalue{\e!start#1}{\startformatline[#1]}%
   \setvalue{\e!stop #1}{\stopformatline}}

\def\setupformatline
  {\dodoubleempty\dosetupformatline}

\def\setupformatline[#1]%
  {\getparameters[\??fz#1]}

\newconditional\formatforcedbreak

\def\startformatline[#1]%
  {\bgroup
   \doifelsevalue{\??fz#1\c!number}\v!yes
    {\def\doplaceformatlinecounter
       {\inleftmargin
          {\doattributes{\??fz#1}\c!numberstyle\c!numbercolor
             {\placeformatlinecounter}}}}
     {\let\doplaceformatlinecounter\relax}%
   \global\setfalse\formatforcedbreak
   \def\\{\break\global\settrue\formatforcedbreak}%
   \hsize\formatwidth
   \doglobal\increment\formatlinecounter
   \par
   \nobreak
   \def\stopformatline
     {\unskip\unskip\unskip\unskip\unskip\egroup
      \let\doplaceformatsegmentcounter\relax}
   \postponenotes
   \dowithnextbox{\dostartformatline}\hbox\bgroup\ignorespaces}

\def\dostartformatlineab
  {%\dosetleftskipadaption\formatmargin
   %\advance\hsize-\leftskipadaption\relax
   \ifdim\nextboxwd>\hsize
     \beginofshapebox
       \forgetall
       \hangafter\plusone
       \hangindent\formatleftoffset
       \formatraggedness
       \hskip\formatrightoffset
       \unhbox\nextbox\par
     \endofshapebox
    %\advance\hsize \leftskipadaption
     \doglobal\newcounter\formatlinesubcounter
     \reshapebox
       {\doglobal\increment\formatlinesubcounter}
     \glet\formatlinemaxcounter\formatlinesubcounter
     \reshapebox
       {\doglobal\decrement\formatlinesubcounter
        \ifnum\formatlinesubcounter=\zerocount
          \doplaceformatsegmentcounter
          \doplaceformatlinecounter
          \hskip-\formatrightoffset
         %\hskip\leftskipadaption
          \formatleftfirst
          \unhbox\shapebox
          \ifnum\formatlinemaxcounter>\plusone
            \ifx\formatright\empty\else
              \shapedhbox to \zeropoint{\formatright\hss}%
            \fi
          \fi
          \formatrightfirst
          \iftraceformatblock
            \ruledhskip\formatrightoffset\hskip-\formatrightoffset
          \fi
        \else
         %\hskip\leftskipadaption
          \iftraceformatblock
            \ruledhskip\formatleftoffset\hskip-\formatleftoffset
          \fi
          \formatleftnext
          \ifx\formatleft\empty\else
            \shapedhbox to \zeropoint{\hss\formatleft}%
          \fi
          \unhbox\shapebox
          \formatrightnext
        \fi}
     \flushshapebox
   \else
     \dontleavehmode\hbox
       {\doplaceformatsegmentcounter
        \doplaceformatlinecounter
       %\hskip\leftskipadaption
        \formatleftfirst
        \unhbox\nextbox
        \formatrightfirst}
   \fi
   \par
   \egroup}

\def\dostartformatlinecde
  {%\dosetleftskipadaption\formatmargin
   %\advance\hsize -\leftskipadaption\relax
   \dimen0=\hsize
   \ifconditional\formatforcedbreak\else
     \ifdim\formatminwidth>\zeropoint\relax
       \ifdim\nextboxwd>\hsize
         \doloop
           {\global\dimen1=\dimen0
            \beginofshapebox
              \hsize\dimen0
              \forgetall
              \formatraggedness
              \unhcopy\nextbox\par
            \endofshapebox
            \reshapebox
              {\setbox\scratchbox=\hbox{\unhbox\shapebox}%
               \ifdim\wd\scratchbox<\dimen1
                 \global\dimen1=\wd\scratchbox
               \fi}
            \ifdim\dimen1<\formatminwidth\relax
              \advance\dimen0 by -.25em
            \else
              \exitloop
            \fi
            \ifdim\dimen0<10em
              \dimen0=\hsize
              \exitloop
            \fi}
       \fi
     \fi
   \fi
   \beginofshapebox
     \hsize\dimen0
     \forgetall
     \formatraggedness
     \unhcopy\nextbox\par
   \endofshapebox
  %\advance\hsize \leftskipadaption
   \doglobal\newcounter\formatlinesubcounter
   \reshapebox
     {\doglobal\increment\formatlinesubcounter}%
   \glet\formatlinemaxcounter\formatlinesubcounter
   \reshapebox
     {\doglobal\decrement\formatlinesubcounter
      \ifnum\formatlinesubcounter=\zerocount
        \doplaceformatsegmentcounter
        \doplaceformatlinecounter
      \fi
     %\hskip\leftskipadaption
      \formatleftnext
      \unhbox\shapebox
      \formatrightnext\strut}% strut prevents unskip
   \flushshapebox
   \par
   \egroup}

\defineformatblock[poem]
  [\c!before=\blank,
   \c!inbetween={\blank[\v!medium]},
   \c!after=\blank]

\defineformatsegment[verse]
  [\c!alternative=\v!left,
   \c!width=\hsize,
  %\c!margin=\!!zeropoint,
   \c!before={\blank[\v!medium]},
   \c!after={\blank[\v!medium]},
   \c!inbetween={\blank[\v!medium]},
   \c!leftoffset=3em,
   \c!rightoffset=2em,
   \c!minwidth=5em,
   \c!left={\mathematics{[}\enspace},
   \c!right={\enspace\mathematics{]}}]

\defineformatline[line]
  []

\protect

\doifnotmode{demo} {\endinput}

% evt defineblank[formatbefore,formatinbetween,formatafter]

%\showframe \traceformatblocktrue

\usemodule[visual]

\setuplayout[height=middle,topspace=1cm,header=0pt,footer=0pt]
\setupbodyfont[10pt]

% All interfaces supported, but testing with english; todo:
% more options, more alternatives, inheritance and mixed
% definitions, and so.

\starttext

\startbuffer
\startbuffer[poem]
\startpoem{A Random Poem}{Hans Hagen}
  \startverse
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
  \stopverse
  \startverse
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
    \startline \fakewords{4}{8} \stopline
  \stopverse
\stoppoem
\stopbuffer

\setupformatsegment[verse][width=.4\hsize,number=yes,numberstyle=slanted]
\setupformatline   [line] [number=yes,numberstyle=smallslanted]

\startbuffer[x]
\setupformatsegment[verse][leftoffset=0pt,rightoffset=0pt,left=,right=]
\stopbuffer

\section{Alternative A}

\setupformatsegment[verse][alternative=a] {\getbuffer[poem]}
\setupformatsegment[verse][alternative=a] {\getbuffer[x,poem]}

\section{Alternative B}

\setupformatsegment[verse][alternative=b] {\getbuffer[poem]}
\setupformatsegment[verse][alternative=b] {\getbuffer[x,poem]}

\section{Alternative C}

\setupformatsegment[verse][alternative=c] {\getbuffer[poem]}

\section{Alternative D}

\setupformatsegment[verse][alternative=d] {\getbuffer[poem]}

\section{Alternative E}

\setupformatsegment[verse][alternative=e] {\getbuffer[poem]}
\stopbuffer

\typebuffer \getbuffer

\stoptext