%D \module
%D   [       file=typo-scr,
%D        version=2012.01.23, % very old ... 1995.10.10 .. moved from core-mis
%D          title=\CONTEXT\ Typesetting Macros,
%D       subtitle=Scripts,
%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.

\writestatus{loading}{ConTeXt Typesetting Macros / Scripts}

\unprotect

%D I addition to the commands implemented here, we have alternative commands
%D \type {shiftup} and \type {shiftdown} that can work across paragraphs.

%D \macros
%D   {low, high, lohi, hilo}
%D
%D Although \TEX\ is pretty well aware of super- and subscripts, its mechanism
%D is mainly tuned for math mode. The next few commands take care of script
%D texts both modes.
%D
%D \startbuffer
%D The higher\high{one goes} the lower\low{one drops}, or\lohi{yes}{no}?
%D \stopbuffer
%D
%D \typebuffer
%D \getbuffer
%D
%D Note the different placement of \type {\lohi}, where we need a bit more
%D space. The implementation looks a bit fuzzy, since some \type {\fontdimen}'s
%D are involved to determine the optimal placement.

% These might become parameters: \setupscripts but we need fo come up with
% nice keys.

\def\highvfraction   {0}
\def\lowvfraction    {0}
\def\highlowvfraction{.1}
\def\highlowhfraction{.1}

\unexpanded\def\low {\typo_scripts_high_low\lower\mathsubnormal{.48}\lowvfraction \t!sub}
\unexpanded\def\high{\typo_scripts_high_low\raise\mathsupnormal{.86}\highvfraction\t!sup}

\def\typo_scripts_high_low#1#2#3#4#5#6% textscript mathscript fraction extra tag
  {\dontleavehmode
   \begingroup
   \scratchdimen\dimexpr#3\exheight+#4\exheight\relax
   \kern\highlowhfraction\exheight
   \setbox\scratchbox\hbox{#1\scratchdimen\hbox
     {\ifx\fontsize\empty\ifmmode\mr\else\tx\fi\else\tx\fi
      \dostarttagged
      #5\empty#6%
      \dostoptagged}}%
   \ht\scratchbox\strutheight
   \dp\scratchbox\strutdepth
   \box\scratchbox
   \endgroup}

%D You can provide an optional keyword \type {left}, in which case the super and
%D subscripts will be aligned in a way that permits placement at the left of a word
%D (which means that it will be right aligned).
%D
%D \startbuffer
%D \lohi{aha}{ah} test \lohi{aha}{ah} test
%D \lohi[left]{aha}{ah} test \lohi[left]{aha}{ah} test
%D \lohi{aha}{ah} test\lohi{aha}{ah} test
%D \lohi[left]{aha}{ah}test \lohi[left]{aha}{ah}test
%D \stopbuffer
%D
%D \typebuffer
%D \getbuffer

\unexpanded\def\lohi{\dosingleempty\typo_scripts_lohi}
\unexpanded\def\hilo{\dosingleempty\typo_scripts_hilo}

\def\typo_scripts_lohi[#1]#2#3%
  {\dontleavehmode
   \hbox
     {\dostarttagged\t!subsup\empty
      \setbox4\hbox{\typo_scripts_high_low\lower\mathsubnormal{.48}\highlowvfraction\t!sub{#2}}%
      \setbox6\hbox{\typo_scripts_high_low\raise\mathsupnormal{.86}\highlowvfraction\t!sup{#3}}%
      \doif{#1}{\v!left}
        {\ifdim\wd4<\wd6
           \setbox4\hbox to \wd6{\hss\box4}%
         \else
           \setbox6\hbox to \wd4{\hss\box6}%
         \fi}%
      \ifdim\wd4<\wd6
        \wd4=\zeropoint\box4\box6
      \else
        \wd6=\zeropoint\box6\box4
      \fi
      \dostoptagged}}

\def\typo_scripts_hilo[#1]#2#3%
  {\typo_scripts_lohi[#1]{#3}{#2}}

\protect \endinput