%D \module
%D   [       file=supp-mat,
%D        version=1998.09.10,
%D          title=\CONTEXT\ Support Macros,
%D       subtitle=Math,
%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 For practical reasons, I decided to move some math things to
%D a support module. There is nothing spectacular here. It may move
%D back to math-ini.

\writestatus{loading}{ConTeXt Support Macros / Math}

\unprotect

%D \macros
%D   {mathematics, math, nomathematics, startmathmode}
%D
%D The \type{$} can be both an begin and end math character.
%D This can lead to confusing and errorprone situations when
%D macros insert \type{$}. When for instance we have defined:
%D
%D \starttyping
%D \def\MyPlus{$\,+\,$}
%D \stoptyping
%D
%D the sequence \type{$x^2 \MyPlus y^2 = r^2$} will expand to:
%D
%D \starttyping
%D $x^2 $\,+\,$ y^2 = r^2$
%D \stoptyping
%D
%D Here the \type{\,} are given outside math mode and \TEX\ will
%D definitely complain about this. A more save definition would
%D have been:
%D
%D \starttyping
%D \def\MyPlus{\mathematics{\,+\,}}
%D \stoptyping
%D
%D Which is implemented as:

\let\normalsuperscript \Usuperscript
\let\normalsubscript   \Usubscript
\let\normalstartimath  \Ustartmath
\let\normalstopimath   \Ustopmath
\let\normalstartdmath  \Ustartdisplaymath
\let\normalstopdmath   \Ustopmath
\def\normalmathaligntab{&} % \let\normalmathaligntab\aligntab does to work well in a let to & (a def works ok)

\let\normalsuper      \Usuperscript             % obsolete
\let\normalsuber      \Usubscript               % obsolete
\let\startimath       \Ustartmath               % obsolete, less safe
\let\stopimath        \Ustopmath                % obsolete, less safe
\let\startdmath       \Ustartdisplaymath        % obsolete, less safe
\let\stopdmath        \Ustopmath                % obsolete, less safe

\unexpanded\def\mathematics#1{\relax         \ifmmode#1\else\normalstartimath#1\normalstopimath\fi}
\unexpanded\def\displaymath#1{\noindent      \ifmmode#1\else\normalstartdmath#1\normalstopdmath\fi}
\unexpanded\def\inlinemath #1{\dontleavehmode\ifmmode#1\else\normalstartimath#1\normalstopimath\fi}
\unexpanded\def\textmath   #1{\dontleavehmode\ifmmode#1\else\begingroup\everymath\emptytoks\normalstartimath#1\normalstopimath\endgroup\fi} % \mathsurround\zeropoint

\let\m\mathematics % unexpanded?

\let\stopmathmode\relax

% \unexpanded\def\startmathmode % cannot be used nested
%   {\relax\ifmmode
%      \let\stopmathmode\relax
%    \else
%      \normalstartimath\let\stopmathmode\normalstopimath
%    \fi}

\unexpanded\def\startmathmode % nested variant
  {\relax\ifmmode
     \begingroup
     \let\stopmathmode\endgroup
   \else
     \normalstartimath
     \let\stopmathmode\normalstopimath
   \fi}

\unexpanded\def\nomathematics#1%
  {\relax\ifmmode\hbox{#1}\else#1\fi}

\let\math\mathematics

%D \macros
%D   {displaymathematics,inlinemathematics,automathematics}
%D
%D An example of usage of the following can be found in the MathML module:

\unexpanded\def\displaymathematics#1{\relax\ifmmode#1\else\dostartformula{}#1\dostopformula\fi}
\unexpanded\def\inlinemathematics   {\dontleavehmode\mathematics}
\unexpanded\def\automathematics     {\relax\ifhmode\expandafter\inlinemathematics\else\expandafter\displaymathematics\fi}

% better, esp when used in bTABLE ... eTABLE

\unexpanded\def\automathematics
  {\relax
   \ifhmode
     \expandafter\inlinemathematics
   \else\ifintable
     \doubleexpandafter\inlinemathematics
   \else
     \doubleexpandafter\displaymathematics
   \fi\fi}

%D \macros
%D   {dimension, nodimension}
%D
%D The next few macros are used for typesetting dimensions in
%D such a way that spacing is acceptable. I won't spend much
%D words on these macros, because they will be overloaded in
%D the units module.
%D
%D REPLACED (keep commented):

\newsignal\dimensionsignal

\def\dimensiontypeface  {\tf}
\def\dimensionhalfspace {\,}

\unexpanded\def\dimension#1%
  {\def\dodimensionsignal{\kern\dimensionsignal}%
   \ifdim\lastskip=\zeropoint\relax
     \ifdim\lastkern=\zeropoint\relax
       \ifmmode
         \mathematics{\dimensionhalfspace\dimensionhalfspace\dimensiontypeface#1}%
       \else
         \mathematics{\dimensiontypeface#1}%
       \fi
     \else\ifdim\lastkern=\dimensionsignal
       \mathematics{\dimensionhalfspace\dimensiontypeface#1}%
     \else
       \unkern\mathematics{\dimensionhalfspace\dimensionhalfspace\dimensiontypeface#1}%
     \fi\fi
   \else
     \unskip\mathematics{\dimensionhalfspace\dimensionhalfspace\dimensiontypeface#1}%
   \fi
   \dodimensionsignal}

\unexpanded\def\nodimension#1%
  {\unskip#1\global\let\dodimensionsignal\relax}

% %D \macros
% %D   {super, suber}
% %D
% %D \TEX\ uses \type{^} and \type{_} for entering super- and
% %D subscript mode. We want however a bit more control than
% %D normally provided, and therefore provide \type {\super}
% %D and \type{\suber} (\type {\sub} is already taken).
%
% \global\let\normalsuper=\normalsuperscript % will become obsolete
% \global\let\normalsuber=\normalsubscript   % will become obsolete
%
% \newcount\supersubmode
%
% \newevery\everysupersub \EverySuperSub
%
% \appendtoks \advance\supersubmode\plusone \to \everysupersub
%
% \def\super#1{\normalsuperscript{\the\everysupersub#1}}
% \def\suber#1{\normalsubscript  {\the\everysupersub#1}}
%
% %D \macros
% %D   {enablesupsub}
% %D
% %D We can let \type {^} and \type {_} act like \type {\super}
% %D and \type {\suber} by saying \type {\enablesupsub}.
%
% \bgroup
% \catcode\circumflexasciicode\activecatcode
% \catcode\underscoreasciicode\activecatcode
% \gdef\enablesupsub
%   {\catcode\circumflexasciicode\activecatcode
%    \catcode\underscoreasciicode\activecatcode
%    \def^{\ifmmode\expandafter\super\else\expandafter\normalsuper\fi}%
%    \def_{\ifmmode\expandafter\suber\else\expandafter\normalsuber\fi}}
% \egroup
%
% %D \macros
% %D   {restoremathstyle}
% %D
% %D We can pick up the current math style by calling \type
% %D {\restoremathstyle}.
%
% \def\restoremathstyle
%   {\ifmmode
%      \ifcase\supsubmode
%        \textstyle
%      \or
%        \scriptstyle
%      \else
%        \scriptscriptstyle
%      \fi
%    \fi}

%D \macros
%D   {cramped}
%D
%D \TEX provides no primitive to force in cramped math mode. Here is
%D a macro that does so. It is based on a solution by Don Knuth (\useurl
%D {http://www.ctan.org/tex-archive/digests/tex-implementors/042}).
%D
%D \startbuffer
%D \ruledhbox{$\left\{{x^2\over y^2}\right\}$}
%D \ruledhbox{$\cramped{\left\{ {x^2\over y^2}\right\}}$}
%D \stopbuffer
%D
%D \typebuffer \getbuffer

\unexpanded\def\cramped
  {\mathpalette\math_cramped}

%D We force a cramped style by issuing a non||existing radical (box).
%D After that we make sure the height is correct. (Comment taken from
%D Morten Høgholm's mathtools package.) Macro suggested by AM and
%D cleaned up a bit by HH.

% original
%
% \def\docramped#1#2%
%   {\setbox\scratchbox\hbox
%     {\nulldelimiterspace\zeropoint
%      $\mathsurround\zeropoint#1\radical\zerocount{#2}$}%
%    \ifx#1\displaystyle
%       \scratchdimen\fontdimen8\textfont3
%       \advance\scratchdimen .25\fontdimen5\textfont2
%    \else
%       \scratchdimen1.25\fontdimen8
%       \ifx#1\textstyle\textfont
%       \else
%         \ifx#1\scriptstyle\scriptfont\else\scriptscriptfont\fi
%       \fi
%       3
%     \fi
%     \advance\scratchdimen-\ht\scratchbox
%     \ht\scratchbox-\scratchdimen
%     \box\scratchbox}

\def\math_cramped#1#2%
  {\begingroup % added HH, made even more cramped
   \setbox\scratchbox\hbox
     {\nulldelimiterspace\zeropoint
      \normalstartimath\mathsurround\zeropoint#1\radical\zerocount{#2}\normalstopimath}%
   \ht\scratchbox-\dimexpr
     \ifx#1\displaystyle
       \fontdimen8\textfont3
       +.25\fontdimen5\textfont2
     \else
        1.25\fontdimen8
          \ifx#1\textstyle
            \textfont
          \else\ifx#1\scriptstyle
            \scriptfont
          \else
            \scriptscriptfont
          \fi \fi
          \plusthree
     \fi
     -\ht\scratchbox
   \relax
   \box\scratchbox
   \endgroup}

%D \macros
%D    {cramedllap, crampedrlap, crampedclap}
%D
%D In many cases, one wants to use the \tex {clap} macro in
%D math mode while using subscripts. Normally, subscripts are
%D in cramped mode, and these macros allow you to go to
%D cramped mode. For example:
%D
%D \startbuffer
%D \startformula
%D   \sum_{a^2 < b^2 < c^2} \quad
%D   \sum_{\clap{a^2 < b^2 < c^2}} \quad
%D   \sum_{\crampedclap{a^2 < b^2 < c^2}}
%D \stopformula
%D \stopbuffer
%D
%D \start
%D   \typebuffer
%D   \switchtobodyfont[24pt]
%D   \getbuffer
%D \stop
%D
%D Notice that \type {\clap{\cramped ... }} would also work,
%D but it requires \TEX\ to typeset it arguments 16 times.

\unexpanded\def\crampedllap{\mathpalette\math_cramped_llap}
\unexpanded\def\crampedrlap{\mathpalette\math_cramped_rlap}
\unexpanded\def\crampedclap{\mathpalette\math_cramped_clap}

\def\math_cramped_llap#1#2{{}\dollap{\math_cramped #1{#2}}}
\def\math_cramped_rlap#1#2{{}\dorlap{\math_cramped #1{#2}}}
\def\math_cramped_clap#1#2{{}\doclap{\math_cramped #1{#2}}}

% experiment, not yet to be used

% \def\displaybreak
%   {\ifhmode
%      \removeunwantedspaces
%      \ifcase\raggedstatus\hfill\fi
%      \strut\penalty-9999 % \break fails on case (3)
%    \fi}
%
% \def\startdisplay{\displaybreak\ignorespaces\startpacked}
% \def\stopdisplay {\stoppacked\displaybreak\ignorespaces}

\protect \endinput