%D \module
%D   [       file=math-scr,
%D        version=2007.07.19,
%D          title=\CONTEXT\ Math Macros,
%D       subtitle=Scripts,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=\PRAGMA]
%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 Math Macros / Scripts}

\unprotect

%D \macros
%D   {super, sub}
%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{sub}.

\global\let\normalsuper=^
\global\let\normalsuber=_

\newcount\supersubmode

\newevery\everysupersub \EverySuperSub

\appendtoks \advance\supersubmode \plusone \to \everysupersub

\appendtoks
  \gridsupsubstyle
\to \everysupersub

\appendtoks
  \doifelse\@@mtsize\v!small
    {\let\gridsupsubstyle    \scriptscriptstyle
     \let\gridsupsubbodyfont \setsmallbodyfont}%
    {\let\gridsupsubstyle    \scriptstyle
     \let\gridsupsubbodyfont \relax}%
\to \everysetuptextformulas

\setuptextformulas
  [\c!size=\v!normal]

\def\dogridsupsub#1#2%
  {\begingroup
   \setbox\nextbox\iftracegridsnapping\ruledhbox\else\hbox\fi
     {\gridsupsubbodyfont
      $\strut^{\the\everysupersub#1}_{\the\everysupersub#2}$}%
   \nextboxht\strutheight
   \nextboxdp\strutdepth
   \flushnextbox
   \endgroup}

\def\gridsupsub
  {\ifconditional\crazymathsnapping
     \ifgridsnapping
       \@EAEAEA\dogridsupsub
     \else
       \@EAEAEA\normalsupsub
     \fi
   \else
     \@EA\normalsupsub
   \fi}

\def\normalsupsub#1#2%
  {^{\the\everysupersub#1}_{\the\everysupersub#2}}

\appendtoks
  \let\gridsupsubstyle   \relax
  \let\gridsupsubbodyfont\relax
  \let\gridsupsub        \normalsupsub
\to \everydisplay

\def\super#1{^{\the\everysupersub#1}}
\def\suber#1{_{\the\everysupersub#1}}
\def\supsub#1#2{\super{#1}\suber{#2}}
\def\subsup#1#2{\suber{#1}\super{#2}}

%\def\super#1{\gridsupsub{#1}{}} %
%\def\suber#1{\gridsupsub{}{#1}} %
%
%\def\supsub#1#2{\gridsupsub{#1}{#2}}
%\def\subsup#1#2{\gridsupsub{#2}{#1}}

\def\gridsuper#1{\gridsupsub{#1}{}}
\def\gridsuber#1{\gridsupsub{}{#1}}

% \let\sup\super % math char
% \let\sub\suber

% test set:
%
% \startbuffer
% \sform{x\frac{1}{2}}
% \sform{x\sup{\frac{1}{2}} + x\sup{2} + 2}
% \sform{x\supsub{\frac{1}{2}}{\frac{1}{2}} + x\sup{2} + 2}
% \stopbuffer
%
% \typebuffer
%
% \startlines
% \getbuffer
% \stoplines
%
% \startbuffer
% $x\frac{1}{2}$
% $x\sup{\frac{1}{2}} + x^2 + 2$
% $x\supsub{\frac{1}{2}}{\frac{1}{2}} + x^2 + 2$
% \stopbuffer
%
% \typebuffer
%
% \start
% \enablesupersub
% \enableautomath
% \startlines
% \getbuffer
% \stoplines
% \stop

%D \macros
%D   {enablesupersub,enablesimplesupersub}
%D
%D We can let \type {^} and \type {_} act like \type {\super}
%D and \type {\sub} by saying \type {\enablesupersub}.

\bgroup
\catcode`\^=\@@active
\catcode`\_=\@@active
\gdef\enablesupersub
  {\catcode`\^=\@@active
   \def^{\ifmmode\expandafter\super\else\expandafter\normalsuper\fi}%
   \catcode`\_=\@@active
   \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\supersubmode
       \textstyle
     \or
       \scriptstyle
     \else
       \scriptscriptstyle
     \fi
   \fi}

%D These macros were first needed by Frits Spijker (also
%D known as Gajes) for typesetting the minus sign that is
%D keyed into scientific calculators.

% This is the first alternative, which works okay for the
% minus, but less for the plus.
%
% \def\dodoraisedmathord#1#2#3%
%   {\mathord{{#2\raise.#1ex\hbox{#2#3}}}}
%
% \def\doraisedmathord#1%
%   {\mathchoice
%      {\dodoraisedmathord5\tf  #1}%
%      {\dodoraisedmathord5\tf  #1}%
%      {\dodoraisedmathord4\tfx #1}%
%      {\dodoraisedmathord3\tfxx#1}}
%
% \def\negative{\doraisedmathord-}
% \def\positive{\doraisedmathord+}
%
% So, now we use the monospaced signs, that we also
% define as symbol, so that they can be overloaded.

\def\dodoraisedmathord#1#2#3%
  {\mathord{{#2\raise.#1ex\hbox{#2\symbol[#3]}}}}

\def\doraisedmathord#1%
  {\mathchoice
     {\dodoraisedmathord5\tf {#1}}%
     {\dodoraisedmathord5\tf {#1}}%
     {\dodoraisedmathord4\tx {#1}}%
     {\dodoraisedmathord3\txx{#1}}}

\def\dodonumbermathord#1#2%
  {\setbox\scratchbox\hbox{0}%
   \mathord{\hbox to \wd\scratchbox{\hss#1\symbol[#2]\hss}}}

\def\donumbermathord#1%
  {\mathchoice
     {\dodonumbermathord\tf {#1}}%
     {\dodonumbermathord\tf {#1}}%
     {\dodonumbermathord\tx {#1}}%
     {\dodonumbermathord\txx{#1}}}

\definesymbol[positive]  [\getglyph{Mono}{+}]
\definesymbol[negative]  [\getglyph{Mono}{-}]
\definesymbol[zeroamount][\getglyph{Mono}{-}]

\def\negative  {\doraisedmathord{negative}}
\def\positive  {\doraisedmathord{positive}}
\def\zeroamount{\donumbermathord{zeroamount}}

%D How negative such a symbol looks is demonstrated in:
%D $\negative 10^{\negative 10^{\negative 10}}$.

\protect \endinput