% language=us

\startenvironment examples-style-math

\def\ExampleLanguages{\currentmainlanguage}

\setupframedtext
  [result]
  [align=flushleft]

%definefontfeature[fixedwidth][fixedwidth=0.30]
%definefontfeature[fixedwidth][fixedwidth=0.28]
\definefontfeature[fixedwidth][fixedwidth=0.27]

% \definefontfallback
%   [MonoMathMath]
%   [dejavusansmono.ttf*fixedwidth]
%   [0x0400-0x600][rscale=.8]

\definefontfallback
  [MonoMathMath]
  [cmuntt.otf*fixedwidth]
  [0x0400-0x600]

\definefontfallback
  [MonoMathMath]
  [concrete-math.otf*fixedwidth]
  [0x0600-0x1FFFF]

\definefontsynonym
  [MonoMathBase]
  [lmmono10-regular.otf*fixedwidth]
  [fallbacks=MonoMathMath]

% \definefontfallback
%   [MonoTextMath]
%   [dejavusansmono.ttf*fixedwidth]
%   [0x0400-0x600][rscale=.8]

\definefontfallback
  [MonoTextMath]
  [cmuntt.otf*fixedwidth]
  [0x0400-0x600]

\definefontfallback
  [MonoTextMath]
  [concrete-math.otf]
  [0x0600-0x1FFFF]

\definefontsynonym
  [MonoTextBase]
  [lmmono10-regular.otf]
  [fallbacks=MonoTextMath]

\definefontsynonym
  [MonoMathBaseBold]
  [lmmonolt10-bold.otf*fixedwidth]
  [fallbacks=MonoMathMath]

\definefont[MyMathFont]    [MonoMathBase]
\definefont[MyMathFontBold][MonoMathBaseBold]
\definefont[MyTextFont]    [MonoTextBase]

\setuptyping
  [style=MyMathFont]

% \setupmathematics[domain=default]

\starttexdefinition protected ShowExampleMeaning #1
    \begingroup
        \ifcstok{#1}\currentmainlanguage
            \darkblue
        \orelse\ifcstok{#1}{debug}%
            \darkgray
        \fi
        \getmathtextblob{#1}\currentmathblob
    \endgroup
    \blank[medium]
\stoptexdefinition

% \starttexdefinition protected StartExample
%     \begingroup
%     \obeylines
%     \doifnextcharelse[\StartExampleYES\StartExampleNOP
% \stoptexdefinition

% \starttexdefinition tolerant protected StartExampleYES[#1]
%     \doifelsemode {issues} {
%         \definecolor[issuecolor][darkred]
%         \doifelse {#1} {issue} {
%             \dostartbuffer[example][StartExample][StopExample]
%         } {
%             \endgroup
%             \gobbleuntil\StopExample
%         }
%     } {
%         \doif {#1} {issue} {
%             \definecolor[issuecolor][darkred]
%         }
%         \dostartbuffer[example][StartExample][StopExample]
%     }
% \stoptexdefinition

% \starttexdefinition tolerant protected StartExampleNOP
%     \doifelsemode {issues} {
%         \endgroup
%         \gobbleuntil\StopExample
%     } {
%         \dostartbuffer[example][StartExample][StopExample]
%     }
% \stoptexdefinition

\starttexdefinition protected StartExample
    \begingroup
    \begingroup
    \obeylines
    \doifnextcharelse[\StartExampleYES\StartExampleNOP
\stoptexdefinition

\starttexdefinition tolerant protected StartExampleYES[#1]
    \endgroup
    \doifelsemode {issues} {
        \definecolor[issuecolor][darkred]
        \doifelse {#1} {issue} {
            \dostartbuffer[example][StartExample][StopExample]
        } {
            \gobbleuntil\StopExample
        }
    } {
        \doif {#1} {issue} {
            \definecolor[issuecolor][darkred]
        }
        \dostartbuffer[example][StartExample][StopExample]
    }
\stoptexdefinition

\starttexdefinition tolerant protected StartExampleNOP
    \endgroup
    \doifelsemode {issues} {
        \endgroup
        \gobbleuntil\StopExample
    } {
        \dostartbuffer[example][StartExample][StopExample]
    }
\stoptexdefinition

\starttexdefinition protected StopExample
    \startresult[none][foregroundcolor=issuecolor]
        \getbuffer[example]
    \stopresult
    \vskip5mm
    \savemathexport[buffer=mmldata,xoption=ascii]
    \begingroup
        \MyTextFont \raggedright
        \processcommacommand[\ExampleLanguages]\ShowExampleMeaning
    \endgroup
    \begingroup
        \switchtobodyfont[6pt]
      % \switchtobodyfont[7pt]
      % \let\slxbold\relax
        \def\slxbold{\MyMathFontBold}%
        \typebuffer[example][option=TEX]
        \scratchcounterone\nofbufferlines{mmldata}
        \ifnum\scratchcounterone>\zerocount
            \scratchcountertwo\maxbufferwidth{mmldata}
            \scratchcounterthree\ctxlua{context(
                \number\textwidth//(\number\scratchcountertwo*\number\emwidth)
            )}\relax % columns needed
            \scratchcounterfour\ctxlua{context(
                \number\textheight//\number\pagetotal
            )}\relax % available
            \ifnum\scratchcounterthree=\zerocount
                \typebuffer[mmldata][option=XML,n=\the\currentmathblob]%
            \orelse\ifnum\scratchcounterone>\scratchcounterfour
                \startcolumns[n=\scratchcounterthree,balance=no]
                    \typebuffer[mmldata][option=XML,n=\the\currentmathblob]%
                \stopcolumns
            \else
                \typebuffer[mmldata][option=XML,n=\the\currentmathblob]%
            \fi
        \fi
    \endgroup
    \endgroup
    \page
\stoptexdefinition

% Setting up math:

% \setupnote[mathnote][location=page]
% \enabletrackers[math.textblobs]

\disabledirectives[structures.tags.shipout]
\enabledirectives [structures.tags.math.standalone]
% \disabledirectives[structures.tags.math.strip]

\setuptagging
  [state=start]

\definemathgroupset
  [demogroupset]
  [every]

\setmathgroupset
  [demogroupset]

% This depends on the math used:

% \registermathfunction[𝑓]
% \registermathfunction[𝑔]

% \registermathsymbol[default][en][𝐮][the vector]
% \registermathsymbol[default][en][𝐯][the vector]
% \registermathsymbol[default][en][𝖠][the matrix]

% \registermathsymbol[default][en][lowercasebold]           [the vector] % [of]
% \registermathsymbol[default][en][uppercasesansserifnormal][the matrix]

% \registermathsymbol[default][sv][𝐮][vektorn]
% \registermathsymbol[default][sv][𝐯][vektorn]

% \registermathsymbol[default][sv][lowercasebold]           [vektorn]
% \registermathsymbol[default][sv][uppercasesansserifnormal][matrisen]

% \registermathsymbol[default][en][𝒞][the continuous functions]
% \registermathsymbol[default][sv][𝒞][de kontinuerliga funktionerna]

% Take your choice:

% \def\ExampleLanguages{en,sv}
% \def\ExampleLanguages{debug,en,sv}
% \def\ExampleLanguages{debug,en,sv,nl}

% \enablemode[issues]

% \enabletrackers[structures.tags.math.times]
% \enabletrackers[structures.tags.math.keeplast=mmldata]
% \enabletrackers[structures.tags.math.save]

\stopenvironment