%D \module
%D   [       file=core-pos,
%D        version=1999.08.01,
%D          title=\CONTEXT\ Core Macros,
%D       subtitle=Positioning Support,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\unprotect

%D A unique prefix used for storing data.

\def\POSprefix{POS::}

%D Reading form the utility file.

\def\pxypos    {\pospxy}     % obsolete
\def\pxyposwhd {\pospxywhd}  % obsolete
\def\pxyposplus{\pospxyplus} % obsolete

\def\resetpositions
  {\let\pospxy    \gobblefourarguments
   \let\pospxywhd \gobblesevenarguments
   \let\pospxyplus\gobbleeightarguments}

\def\setpositions
  {\let\pospxy    \setpospxy
   \let\pospxywhd \setpospxywhd
   \let\pospxyplus\setpospxyplus}

%D We need to initialize.

\resetpositions

\addutilityreset{positions}

%D Core set macros:

\def\setpospxy#1#2#3#4%
  {\@EA\xdef\csname\POSprefix#1\endcsname
     {\number#2,%
      \the\dimexpr#3\ifnum\positionanchormode=\plusone-\MPx\pageanchor\fi\relax,%
      \the\dimexpr#4\ifnum\positionanchormode=\plusone-\MPy\pageanchor\fi\relax}}

\def\setpospxywhd#1#2#3#4#5#6#7%
  {\@EA\xdef\csname\POSprefix#1\endcsname
     {\number#2,%
      \the\dimexpr#3\ifnum\positionanchormode=\plusone-\MPx\pageanchor\fi\relax,%
      \the\dimexpr#4\ifnum\positionanchormode=\plusone-\MPy\pageanchor\fi\relax,%
      \the\dimexpr#5\relax,%
      \the\dimexpr#6\relax,%
      \the\dimexpr#7\relax}}

\def\setpospxyplus#1#2#3#4#5#6#7#8%
  {\@EA\xdef\csname\POSprefix#1\endcsname
     {\number#2,%
      \the\dimexpr#3\ifnum\positionanchormode=\plusone-\MPx\pageanchor\fi\relax,%
      \the\dimexpr#4\ifnum\positionanchormode=\plusone-\MPy\pageanchor\fi\relax,%
      \the\dimexpr#5\relax,%
      \the\dimexpr#6\relax,%
      \the\dimexpr#7\relax,%
      #8}}

%D Sometimes we want to trick the position handler a bit:

\def\replacepospxywhd#1#2#3#4#5#6#7%
  {\@EA\xdef\csname\POSprefix#1\endcsname
     {\number#2,%
      \the\dimexpr#3\relax,%
      \the\dimexpr#4\relax,%
      \the\dimexpr#5\relax,%
      \the\dimexpr#6\relax,%
      \the\dimexpr#7\relax}}

%D Writing to the utility file.

\def\dolazysaveposition#1#2#3#4% tag page x y
  {\expanded{\writeutilitycommand{\noexpand\pospxy
     {#1}{#2}{#3}{#4}}}}

\def\dolazysavepositionwhd#1#2#3#4#5#6#7% tag page x y w h d
  {\expanded{\writeutilitycommand{\noexpand\pospxywhd
     {#1}{#2}{#3}{#4}{#5}{#6}{#7}}}}

\def\dolazysavepositionplus#1#2#3#4#5#6#7#8% tag page x y w h d list
  {\expanded{\writeutilitycommand{\noexpand\pospxyplus
     {#1}{#2}{#3}{#4}{#5}{#6}{#7}{#8}}}}

\def\dosaveposition#1#2#3#4% tag page x y
  {\expanded{\immediatewriteutilitycommand{\noexpand\pospxy
     {#1}{#2}{#3}{#4}}}}

\def\dosavepositionwhd#1#2#3#4#5#6#7% tag page x y w h d
  {\expanded{\immediatewriteutilitycommand{\noexpand\pospxywhd
     {#1}{#2}{#3}{#4}{#5}{#6}{#7}}}}

\def\dosavepositionplus#1#2#3#4#5#6#7#8% tag page x y w h d list
  {\expanded{\immediatewriteutilitycommand{\noexpand\pospxyplus
     {#1}{#2}{#3}{#4}{#5}{#6}{#7}{#8}}}}

\def\MPp  {\doMPxyhdwlr\doMPp  }
\def\MPx  {\doMPxyhdwlr\doMPx  }
\def\MPy  {\doMPxyhdwlr\doMPy  }
\def\MPw  {\doMPxyhdwlr\doMPw  }
\def\MPh  {\doMPxyhdwlr\doMPh  }
\def\MPd  {\doMPxyhdwlr\doMPd  }
\def\MPxy {\doMPxyhdwlr\doMPxy }
\def\MPll {\doMPxyhdwlr\doMPll }
\def\MPlr {\doMPxyhdwlr\doMPlr }
\def\MPur {\doMPxyhdwlr\doMPur }
\def\MPul {\doMPxyhdwlr\doMPul }
\def\MPpos{\doMPxyhdwlr\doMPpos}

\def\doMPp  #1,#2,#3,#4,#5,#6,#7\relax{#1}
\def\doMPx  #1,#2,#3,#4,#5,#6,#7\relax{#2}
\def\doMPy  #1,#2,#3,#4,#5,#6,#7\relax{#3}
\def\doMPw  #1,#2,#3,#4,#5,#6,#7\relax{#4}
\def\doMPh  #1,#2,#3,#4,#5,#6,#7\relax{#5}
\def\doMPd  #1,#2,#3,#4,#5,#6,#7\relax{#6}
\def\doMPxy #1,#2,#3,#4,#5,#6,#7\relax{(#2,#3)}
\def\doMPll #1,#2,#3,#4,#5,#6,#7\relax{(#2,#3-#6)}
\def\doMPlr #1,#2,#3,#4,#5,#6,#7\relax{(#2+#4,#3-#6)}
\def\doMPur #1,#2,#3,#4,#5,#6,#7\relax{(#2+#4,#3+#5)}
\def\doMPul #1,#2,#3,#4,#5,#6,#7\relax{(#2,#3+#5)}
\def\doMPpos#1,#2,#3,#4,#5,#6,#7\relax{#1,#2,#3,#4,#5,#6}

\def\doMPxyhdwlr#1#2%
  {\ifcsname\POSprefix#2\endcsname
     \@EA\@EA\@EA#1\csname\POSprefix#2\endcsname,0pt,0pt,0pt,0pt\relax
   \else
     #10,0pt,0pt,0pt,0pt,0pt,0pt\relax
   \fi}

% \def\doMPxyhdwlr#1#2% evt kan \s!unknown leeg zijn
%   {\@EA\@EA\@EA#1\csname\POSprefix
%      \ifcsname\POSprefix#2\endcsname#2\else\s!unknown\fi\endcsname
%      ,0pt,0pt,0pt,0pt\relax}
%
% \setvalue{\POSprefix\s!unknown}{0,0pt,0pt}

\def\MPplus  {\MPdoplus\doMPplus}
\def\MPrest#1{\MPdoplus\doMPrest{#1}{}}

\def\MPdoplus#1#2#3#4%
  {\ifcsname\POSprefix#2\endcsname
     \@EA\@EA\@EA#1\csname\POSprefix#2\endcsname,,,,,,,,,\relax{#3}%
   \else
     #4%
   \fi}

\def\doMPplus#1,#2,#3,#4,#5,#6,%
  {\dodoMPplus}

\def\dodoMPplus#1,#2,#3,#4,#5,#6,#7,#8\relax#9%
  {\ifcase#9\or#1\or#2\or#3\or#4\or#5\or#6\or#7\else\dododoMPplus#8\relax{#9}\fi}

\def\dododoMPplus#1,#2,#3,#4,#5,#6,#7,#8\relax#9%
  {\ifcase#9\or\or\or\or\or\or\or\or#1\or#2\or#3\or#4\or#5\or#6\or#7\fi}

\def\doMPrest#1,#2,#3,#4,#5,#6,#7,,#8\relax#9%
  {#7}

%D Testing:

\def\doifpositionelse#1%
  {\ifcsname\POSprefix#1\endcsname
     \expandafter\firstoftwoarguments
   \else
     \expandafter\secondoftwoarguments
   \fi}

%D Copying:

\def\copyposition#1#2%
  {\ifcsname\POSprefix#2\endcsname
     \global\@EA\let\csname\POSprefix#1\@EA\endcsname\csname\POSprefix#2\endcsname
   \fi}

\protect \endinput