%D \module
%D   [       file=font-mat,
%D        version=2011.01.13, % (copied fron font-ini)
%D          title=\CONTEXT\ Font 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.

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

\unprotect

%D The original (\MKIV) approach to bidi is that we have two extra families for
%D regular, bold and pseudobold:
%D
%D regular    normal=0 l2r=1 r2l=2
%D bold       normal=3 l2r=4 r2l=5
%D pseudobold normal=6 l2r=7 r2l=8
%D
%D where l2r is just an alias. Because we're now using the mirror lookup (like
%D we do a smaller lookup) in the engine we not just have:
%D
%D regular    normal=0
%D bold       normal=3
%D pseudobold normal=6
%D
%D And when one can wonder if pseudobold is needed (just bolden); we can then
%D actually go down to only two families. It is one of these cases when it hurts
%D to throw away a nice old mechanism that worked quite well so here we keep it
%D commented. For what it's worth: this variant switches a bit faster too and
%D produces less logging but I doubt if anyone will notice that.

%D We now have bidi handled via a tweak in the goodie file which means that we
%D could simplify the implementation and get rid of the (four) extra families
%D needed. For now we retain the zero/three designation for mr/mb but that might
%D go away. Actually we could drop the number of families in the engine to sixteen
%D again or even four if we need the space for more classes or something else.

%D Be nice:

\ifdefined\??fontinstanceready \else \installcorenamespace{fontinstanceready} \fi
\ifdefined\??fontinstancebasic \else \installcorenamespace{fontinstancebasic} \fi
\ifdefined\??fontinstanceclass \else \installcorenamespace{fontinstanceclass} \fi

%D The order 3 2 1 of size matters is historic and was needed for math-fbk relative
%D size storage! It is no longer relevant.

%D \macros
%D   {textonly}
%D
%D Traditionally math has a big impact on font definitions, mainly because we need
%D to define alphabet variants using families and fonts. This means that one can
%D easily get 10 fonts loaded per math size. In \MKIV\ we use a different approach:
%D one family which has either a virtual font made of traditional fonts, or an
%D \OPENTYPE\ font that has it all.
%D
%D We currently use only one math family but in the future we might consider using a
%D second one for bold math. For the moment we keep the \MKII\ method of using a
%D token register for definitions but we already dropped the text and symbols ones
%D since they now live in the same family. When we go always compact we can simplify
%D the code even more. For previous implementations see the \MKIV\ code and the
%D repository pre October 2022.

\newtoks       \t_font_math_strategies
\newconditional\c_font_synchronize_math_fonts \settrue\c_font_synchronize_math_fonts

\protected\def\font_helpers_synchronize_math % math stuff in mmode
  {\ifconditional\c_font_synchronize_math_fonts\the\t_font_math_strategies\fi}

\permanent\protected\def\textonly{\setfalse\c_font_synchronize_math_fonts} % document this

%D The main math font definer. We have removed some optimized code simply because we
%D now always have a fontclass. We could check for fontclass being default or empty
%D and save a few tests but it does not help us when no math is defined.
%D
%D Because we want to keep mr=.. and mb=... settings (read: not break downward
%D compatibility by enforcing mrlr etc) we need a bit more code that optimal.

\aliased\let\c_font_fam_mr\zerocount  % math regular
\aliased\let\c_font_fam_mb\plusthree  % math bold

\definesystemattribute[mathfamily][public]

% when we are always true we can as well remove this test:

\newconditional\c_font_complete_bold_mathstrategy  \settrue\c_font_complete_bold_mathstrategy

\immutable\def\mathtextsuffix        {-text}
\immutable\def\mathscriptsuffix      {-script}
\immutable\def\mathscriptscriptsuffix{-scriptscript}

%D Beware: truefontname also does a fallback on defaultfontclass so there can be
%D some interference here, which is why we use a different method for bold.

\def\font_helpers_set_math_family_a
  {\ifcsname\??fontinstanceready\fontclass       -\fontbody-\s!mm-\fontfamily-\fontsize\endcsname \setfalse\c_font_auto_size
     \lastnamedcs \orelse
   \ifcsname\??fontinstanceready\fontclass       -\fontbody-\s!mm-\fontfamily          \endcsname \settrue \c_font_auto_size
     \lastnamedcs \else
     \font_helpers_set_math_family_b
   \fi}

\def\font_helpers_set_math_family_b
  {\ifcsname\??fontinstanceready\defaultfontclass-\fontbody-\s!mm-\fontfamily-\fontsize\endcsname \setfalse\c_font_auto_size
     \lastnamedcs \orelse
   \ifcsname\??fontinstanceready\defaultfontclass-\fontbody-\s!mm-\fontfamily          \endcsname \settrue \c_font_auto_size
     \lastnamedcs \else
     \font_helpers_set_math_family_c
   \fi}

\def\font_helpers_set_math_family_c
  {\ifcsname\??fontinstanceready                  \fontbody-\s!mm-\fontfamily-\fontsize\endcsname \setfalse\c_font_auto_size
     \lastnamedcs \orelse
   \ifcsname\??fontinstanceready                  \fontbody-\s!mm-\fontfamily          \endcsname \settrue \c_font_auto_size
     \lastnamedcs \else
                                                                                                  \settrue \c_font_auto_size
   \fi}

\mutable\lettonothing\mathsizesuffix

\mutable\let\fontfamily\relax % for now public but it is a helper

\newcount      \c_math_last_family_used

\def\font_helpers_set_math_family_indeed_normal#mrtag#family% \fontface etc are also used later on
  {\let\savedfontbody\fontbody
   \let\fontfamily#family%
\c_math_last_family_used\zerocount
   % the order is important as we depend on known id's when completing fonts
   % enabling is needed when we have fallbacks which spoils the families; per
   % mid 2022 this is no longer true as we do fallbacks differently
   \let\mathsizesuffix\mathscriptscriptsuffix
   \let\fontface\!!plusthree
   \font_helpers_set_math_family_a\scriptscriptfont#mrtag\font % defines
   \font_helpers_set_math_family_a\scriptscriptfont#mrtag\font % enables / still needed ?
   \let\mathsizesuffix\mathscriptsuffix
   \let\fontface\!!plustwo
   \font_helpers_set_math_family_a\scriptfont      #mrtag\font % defines
   \font_helpers_set_math_family_a\scriptfont      #mrtag\font % enables / still needed ?
   \let\mathsizesuffix\mathtextsuffix
   \let\fontface\!!plusone
   \font_helpers_set_math_family_a\textfont        #mrtag\font % defines
   \font_helpers_set_math_family_a\textfont        #mrtag\font % enables / still needed ?
   \lettonothing\mathsizesuffix
   \let\fontface\!!zerocount
   \let\fontbody\savedfontbody
   \setfalse\c_font_auto_size}

\def\font_helpers_set_math_family_set_scales_compact
  {% these are used when no font setting is there, the settings come before setting the parameters
   % and are stored with the family ... this is not really needed because the size is used otherwise
   \glyphtextscale                 \plusthousand
   \glyphscriptscale       \numexpr\plusthousand*\dimexpr\scriptface      \relax/\dimexpr\textface\relax\relax
   \glyphscriptscriptscale \numexpr\plusthousand*\dimexpr\scriptscriptface\relax/\dimexpr\textface\relax\relax}

\def\font_helpers_set_math_family_set_scales_normal
  {\glyphtextscale        \plusthousand
   \glyphscriptscale      \plusthousand
   \glyphscriptscriptscale\plusthousand}

\def\font_helpers_set_math_family_indeed_compact#mrtag#family% \fontface etc are also used later on
  {\let\savedfontbody\fontbody
   \let\fontfamily#family%
\c_math_last_family_used\zerocount
   \font_helpers_set_math_family_set_scales_compact
   % the order is important as we depend on known id's when completing fonts
   % enabling is needed when we have fallbacks which spoils the families
   \let\mathsizesuffix\mathtextsuffix
   \let\fontface\!!plusone
   \font_helpers_set_math_family_a\textfont        #mrtag\font % defines
   \font_helpers_set_math_family_a\textfont        #mrtag\font % enables / still needed ?
                                  \scriptfont      #mrtag\font % reuses
                                  \scriptscriptfont#mrtag\font % reuses
   \lettonothing\mathsizesuffix
   \let\fontface\!!zerocount
   \let\fontbody\savedfontbody
   \setfalse\c_font_auto_size}

\def\font_helpers_set_math_family_indeed
  {\ifconditional\c_font_compact
     \expandafter\font_helpers_set_math_family_indeed_compact
   \else
     \expandafter\font_helpers_set_math_family_indeed_normal
   \fi}

\def\font_helpers_set_math_family_bold_indeed_normal#mbfam#familytag#mrfam% \c_font_fam_mb \s!mb \c_font_fam_mr
  {\let\savedfontclass\defaultfontclass
   \let\defaultfontclass\fontclass % else truefontname falls back on the wrong one
   \let\savedfontbody\fontbody
   \let\fontfamily#familytag%
\c_math_last_family_used\zerocount
   \font_helpers_set_math_family_set_scales_normal
   \let\mathsizesuffix\mathscriptscriptsuffix
   \let\fontface\!!plusthree
   \font_helpers_set_math_family_bold_a\scriptscriptfont#mbfam#mrfam% defines
   \font_helpers_set_math_family_bold_a\scriptscriptfont#mbfam#mrfam% enables / still needed ?
   \let\mathsizesuffix\mathscriptsuffix
   \let\fontface\!!plustwo
   \font_helpers_set_math_family_bold_a\scriptfont      #mbfam#mrfam% defines
   \font_helpers_set_math_family_bold_a\scriptfont      #mbfam#mrfam% enables / still needed ?
   \let\mathsizesuffix\mathtextsuffix
   \let\fontface\!!plusone
   \font_helpers_set_math_family_bold_a\textfont        #mbfam#mrfam% defines
   \font_helpers_set_math_family_bold_a\textfont        #mbfam#mrfam% enables / still needed ?
   \lettonothing\mathsizesuffix
   \let\fontface\!!zerocount
   \let\fontbody\savedfontbody
   \let\defaultfontclass\savedfontclass
   \setfalse\c_font_auto_size}

\def\font_helpers_set_math_family_bold_indeed_compact#mbfam#familytag#mrfam% \c_font_fam_mb \s!mb \c_font_fam_mr
  {\let\savedfontclass\defaultfontclass
   \let\defaultfontclass\fontclass % else truefontname falls back on the wrong one
   \let\savedfontbody\fontbody
   \let\fontfamily#familytag%
\c_math_last_family_used\zerocount
   \let\mathsizesuffix\mathtextsuffix
   \let\fontface\!!plusone
   \font_helpers_set_math_family_bold_a\textfont        #mbfam#mrfam% defines
   \font_helpers_set_math_family_bold_a\textfont        #mbfam#mrfam% enables / still needed ?
                                       \scriptfont      #mbfam\textfont#mbfam% reuses
                                       \scriptscriptfont#mbfam\textfont#mbfam% reuses
   \lettonothing\mathsizesuffix
   \let\fontface\!!zerocount
   \let\fontbody\savedfontbody
   \let\defaultfontclass\savedfontclass
   \setfalse\c_font_auto_size}

\def\font_helpers_set_math_family_bold_indeed
  {\ifconditional\c_font_compact
     \expandafter\font_helpers_set_math_family_bold_indeed_compact
   \else
     \expandafter\font_helpers_set_math_family_bold_indeed_normal
   \fi}

\def\font_helpers_set_math_family_bold_a#font#mbfam#mrfam%
  {\ifcsname\??fontinstanceready\fontclass-\fontbody-\s!mm-\fontfamily-\fontsize\endcsname \setfalse\c_font_auto_size
     \lastnamedcs #font#mbfam\font \orelse
   \ifcsname\??fontinstanceready\fontclass-\fontbody-\s!mm-\fontfamily          \endcsname \settrue \c_font_auto_size
     \lastnamedcs #font#mbfam\font \else
     #font#mbfam#font#mrfam%
   \fi}

% optimized: math fonts are never changed (10K \bfa $x$: 3.2 => 2.5 (baseline 1.0))
%
% sort of tricky: we cannot reset in \everybeforedefinetypeface as we don't know
% all sizes so we postpone the optimization to the first starttext
%
% pitfall: we should reset 'm when a fontclass name is reused

\newconditional\optimizemathfontdefinitions \settrue\optimizemathfontdefinitions

\def\font_helpers_set_math_family#mrfam#familytag%
  {\ifconditional\optimizemathfontdefinitions
     \ifcsname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-1\endcsname
       % \writestatus{fonts}{math: reusing \fontclass\fontbody\s!mm#familytag\fontsize1}%
       \font_helpers_preset_math_family_indeed#mrfam#familytag%
     \else
       % \writestatus{fonts}{math: defining \fontclass\fontbody\s!mm#familytag\fontsize1}%
       \font_helpers_set_math_family_indeed#mrfam#familytag%
     \fi
   \else
     \font_helpers_set_math_family_indeed#mrfam#familytag%
   \fi}

\def\font_helpers_set_math_family_bold#mbfam#familytag#mrfam%
  {\ifconditional\optimizemathfontdefinitions
    %\ifcsname\??fontinstanceclass\fontclass-\textface-\s!mm-#familytag-\fontsize-1\endcsname
     \ifcsname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-1\endcsname
       \font_helpers_preset_math_family_indeed#mbfam#familytag%
     \else
       \font_helpers_set_math_family_bold_indeed#mbfam#familytag#mrfam%
     \fi
   \else
     \font_helpers_set_math_family_bold_indeed#mbfam#familytag#mrfam%
   \fi}

%D It can happen that we use a bodyfont with no math in which case we have a problem
%D with setting the global bodyfont size in the page builder. For instance in:
%D
%D \starttext
%D     \definetypeface[test][rm][serif][pagella][default]
%D     \setupbodyfont[test]
%D     test
%D \stoptext
%D
%D This is why we need the check. At the cost of some extra checking we gain a
%D little in restoring global states and, what's more important, we get rid of large
%D math parameter push/pop in tracingall when not needed.

\def\font_helpers_preset_math_family_indeed_normal#fam#familytag%
  {\expandafter\let\expandafter\font_math_last_font\csname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-1\endcsname
   \font_math_last_font
   \ifnum\fontid\textfont#fam=\fontid\font\else
     \font_helpers_preset_math_family_indeed_changed_normal#fam#familytag%
   \fi}

\def\font_helpers_preset_math_family_indeed_changed_normal#fam#familytag%
  {\font_helpers_set_math_family_set_scales_normal
   \csname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-3\endcsname\scriptscriptfont#fam\font
   \csname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-2\endcsname\scriptfont      #fam\font
 % \csname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-1\endcsname\textfont        #fam\font}
   \font_math_last_font                                                                  \textfont        #fam\font}

\def\font_helpers_preset_math_family_indeed_compact#fam#familytag%
  {\csname\??fontinstanceclass\fontclass-\fontbody-\s!mm-#familytag-\fontsize-1\endcsname
   \ifnum\fontid\textfont#fam=\fontid\font\else
     \font_helpers_preset_math_family_indeed_changed_compact#fam%
   \fi}

\def\font_helpers_preset_math_family_indeed_changed_compact#fam%
  {\font_helpers_set_math_family_set_scales_compact
   \scriptscriptfont#fam\font
   \scriptfont      #fam\font
   \textfont        #fam\font}

\def\font_helpers_preset_math_family_indeed
  {\ifconditional\c_font_compact
     \expandafter\font_helpers_preset_math_family_indeed_compact
   \else
     \expandafter\font_helpers_preset_math_family_indeed_normal
   \fi}

\let\font_helpers_reset_fontclass_math_families\gobbleoneargument

%D It would be nice if characters could be defined in a neutral way (say fam 255)
%D and be mapped to a real family during noad list construction. However, this
%D changes tex in critical places so for the moment we simulate this using
%D manipulation.
%D
%D For tracing purposes we use three families but in l2r mode 1 and 2 are copies of
%D 0 while in rl mode 0 is a copy of 1. There is no real overhead involved in this.
%D This also permits different font definitions for normal and mixed.

\lettonothing\m_font_class_direction
\lettonothing\m_font_class_features
\lettonothing\m_font_class_fallbacks
\lettonothing\m_font_class_goodies

\lettonothing\m_font_direction
\lettonothing\m_font_features
\lettonothing\m_font_fallbacks
\lettonothing\m_font_goodies

\appendtoks
    \font_helpers_set_math_family\c_font_fam_mr\s!mr
\to \t_font_math_strategies

\def\font_helpers_complete_bold_mathstrategy_yes
  {\font_helpers_set_math_family_bold\c_font_fam_mb\s!mb\c_font_fam_mr\relax}

\def\font_helpers_complete_bold_mathstrategy_nop
  {\ifnum\fontid\textfont\c_font_fam_mb=\fontid\textfont\c_font_fam_mr\else
     \font_helpers_complete_bold_mathstrategy_nop_changed
   \fi}

\def\font_helpers_complete_bold_mathstrategy_nop_changed
  {\textfont        \c_font_fam_mb\textfont        \c_font_fam_mr
   \scriptfont      \c_font_fam_mb\scriptfont      \c_font_fam_mr
   \scriptscriptfont\c_font_fam_mb\scriptscriptfont\c_font_fam_mr}

\def\font_helpers_apply_complete_bold_mathstrategy
  {\ifconditional\c_font_complete_bold_mathstrategy
     \font_helpers_complete_bold_mathstrategy_yes
   \else
     \font_helpers_complete_bold_mathstrategy_nop
   \fi}

\appendtoks
    \font_helpers_apply_complete_bold_mathstrategy
\to \t_font_math_strategies

\ifdefined\defaultmathfamily \else
    \setnewconstant\defaultmathfamily\zerocount % no longer used, always zero
\fi

\appendtoks
    \fam\zerocount % all characters and symbols are in this family
\to \everymathematics

\protected\def\font_helpers_synchronize_math_family_mr
  {\c_attr_mathfamily\zerocount}

\protected\def\font_helpers_synchronize_math_family_mb
  {\c_attr_mathfamily\ifconditional\c_font_pseudo_bold_math_state\plussix\else\plusthree\fi}

\installcorenamespace{fontmathsynchronizer}
\installcorenamespace{fontmathstoredstrategy}

\letcsname\??fontmathsynchronizer\s!tf \endcsname\font_helpers_synchronize_math_family_mr
\letcsname\??fontmathsynchronizer\s!sl \endcsname\font_helpers_synchronize_math_family_mr
\letcsname\??fontmathsynchronizer\s!it \endcsname\font_helpers_synchronize_math_family_mr
\letcsname\??fontmathsynchronizer\s!bf \endcsname\font_helpers_synchronize_math_family_mb
\letcsname\??fontmathsynchronizer\s!bs \endcsname\font_helpers_synchronize_math_family_mb
\letcsname\??fontmathsynchronizer\s!bi \endcsname\font_helpers_synchronize_math_family_mb
\letcsname\??fontmathsynchronizer\empty\endcsname\font_helpers_synchronize_math_family_mr

\def\font_helpers_synchronize_math_family
  {\ifcsname\??fontmathsynchronizer\fontalternative\endcsname
     \lastnamedcs
   \else
     \font_helpers_synchronize_math_family_mr
   \fi}

\appendtoks
    \ifnum\fontid\textfont\zerocount=\fontid\textfont\plusthree
        \letcsname\??fontmathstoredstrategy\fontclass\endcsname\font_helpers_set_math_partial_bold_strategy
    \else
        \letcsname\??fontmathstoredstrategy\fontclass\endcsname\font_helpers_set_math_full_bold_strategy
    \fi
\to \t_font_math_strategies

\def\font_helpers_synchronize_math_bold_strategy{\begincsname\??fontmathstoredstrategy\fontclass\endcsname}

\newconditional\c_font_pseudo_bold_math_state

\def\font_helpers_set_math_partial_bold_strategy{\settrue \c_font_pseudo_bold_math_state}
\def\font_helpers_set_math_full_bold_strategy   {\setfalse\c_font_pseudo_bold_math_state}

\appendtoks
    \font_helpers_synchronize_math_bold_strategy
\to \everymathematics

%D Bold is somewhat special as we might want both full-bold-math mixed regular-math,
%D as well as automatic adaption to outer bold (in titles and inline text bold) so
%D we will need explicit switches as well as an automatic one. (We will use lucida
%D as an example.)

\ifdefined\mathdefault \else \let\mathdefault\relax \fi

\newconditional\c_math_bold

\permanent\protected\def\mr % math regular
  {\ifmmode
     \font_helpers_synchronize_math_family_mr
   \else
     \font_helpers_set_current_font_alternative\s!mr
   \fi
   \mathdefault
   \setfalse\c_math_bold}

\permanent\protected\def\mb % math bold
  {\ifmmode
     \font_helpers_synchronize_math_family_mb
   \else
     \font_helpers_set_current_font_alternative\s!mb
   \fi
   \mathdefault
   \settrue\c_math_bold}

\appendtoks
    \font_helpers_synchronize_math_family % auto bold
\to \everymathematics

\appendtoks
    \ifconditional\c_math_bold\mb\fi
\to \everymathematics

%D \macros
%D   {bigmath,nobigmath}
%D
%D We can inhibit this slow||downer with:

% these can best be combined

% 0=never 1=everymath 2=always

\setnewconstant\synchronizebigmathflag\plusone

\appendtoks
  \ifcase\synchronizebigmathflag
    % never
  \or
    \synchronizebigmath
  \or
    % always
  \fi
\to \everymathematics

\permanent\protected\def\nobigmath  {\synchronizebigmathflag\zerocount}
\permanent\protected\def\autobigmath{\synchronizebigmathflag\plusone\synchronizebigmath}
\permanent\protected\def\bigmath    {\synchronizebigmathflag\plustwo\synchronizebigmath}

\mutable\lettonothing\bigmathfontsize

\permanent\protected\def\synchronizebigmath
  {\ifconditional\c_font_compact
     % no need
   \orelse\ifx\bigmathfontsize\fontsize
     % already in sync
   \else
     \let\bigmathfontsize\fontsize
     \font_helpers_synchronize_math
   \fi}

\protected\def\font_helpers_check_big_math_synchronization
  {\ifcase\synchronizebigmathflag
     % never
   \or
     \ifmmode \synchronizebigmath \fi
   \or
     \synchronizebigmath
   \fi}

%D This is an experiment!

\permanent\protected\def\mx {\ifmmode\scaledmathstyle\dimexpression\plusthousand*(\xtextface /\textface)\relax\fi}
\permanent\protected\def\mxx{\ifmmode\scaledmathstyle\dimexpression\plusthousand*(\xxtextface/\textface)\relax\fi}

\permanent\protected\def\setmscale#1{\ifmmode\scaledmathstyle\numericscale#1\relax\fi}

%D This is nasty, as the engine only stores the last set family parameters (per style) which
%D in our case can be bold.

\def\font_helpers_synchronize_math_parameters
  {\c_math_last_family_used\mathstylefontid\textstyle\zerocount
   \textfont        \zerocount\textfont        \zerocount
   \scriptfont      \zerocount\scriptfont      \zerocount
   \scriptscriptfont\zerocount\scriptscriptfont\zerocount}

\appendtoks
    \ifnum\c_math_last_family_used=\mathstylefontid\textstyle\zerocount\else
      \font_helpers_synchronize_math_parameters
    \fi
\to\everybodyfont

\protect \endinput