%D \module
%D   [       file=x-asciimath,
%D        version=2014.06.01, % 2006.04.24, % 1999.11.06,
%D          title=\CONTEXT\ Modules,
%D       subtitle=AsciiMath,
%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.

\registerctxluafile{x-asciimath}{}

%D When the Math4All project started, we immediately started using content \MATHML.
%D Because in school math there is often a reference to calculator input, we also
%D provided what we called \quote {calcmath}: a predictable expression based way
%D entering math. At some point \OPENMATH\ was also used but that was later
%D abandoned because editing is more cumbersome.
%D
%D Due to limitations in the web variant (which is independent of rendering for
%D paper but often determines the coding of document, not seldom for the worse) the
%D switch was made to presentational \MATHML. But even that proved to be too complex
%D for rendering on the web, so it got converted to so called \ASCIIMATH\ which
%D can be rendered using some \JAVASCRIPT\ magic. However, all the formulas (and
%D we're talking of tens of thousands of them) were very precisely coded by the main
%D author. Because in intermediate stages of the editing (by additional authors) a
%D mixture of \MATHML\ and \ASCIIMATH\ was used, we wrote the first version of this
%D module. As reference we took \url
%D {http://www1.chapman.edu/~jipsen/mathml/asciimath.html} and. The idea was to
%D stick to \MATHML\ as reference and if needed use \ASCIIMATH\ as annotation.
%D
%D Eventually we ended up with supporting several math encodings in \CONTEXT\ that
%D could be used mixed: content \MATHML\ (preferred), presentation \MATHML\ (often
%D messy), \OPENMATH\ (somewhat minimalistic) calcmath (handy for students who are
%D accustomed to calculators), \ASCIIMATH\ (to make web support easier) and of
%D course \TEX.
%D
%D The first version had some limitations as we didn't want to support all quirks of
%D \ASCIIMATH\ and also because I was not really in the mood to write a complex parser
%D when a bit of sane coding can work equally well. Some comments from that version:
%D
%D \startnarrower
%D \startitemize
%D \item We support only the syntactically clear variants and as long as lpeg does
%D       not support left recursion this is as far as we want to go.
%D \item The parser is rather insensitive for spaces but yet the advice is to avoid
%D       weird coding like \type {d/dxf(x)} but use \type {d/dx f(x)} instead. After
%D       all we're not in a compact coding cq.\ parser challenge.
%D \item We also don't support the somewhat confusing \type {sqrt sqrt 2} nor \type
%D       {root3x} (although the second one kind of works). A bit of defensive coding
%D       does not hurt.
%D \item We can process \type {a/b/c/d} but it's not compatible with the default
%D       behaviour of \ASCIIMATH. Use grouping instead. Yes, we do support the somewhat
%D       nonstandard grouping token mix.
%D \item You should use explicit \type {text(..)} directives as one can never be sure
%D       what is a reserved word and  not.
%D \stopitemize
%D
%D Actually, as the only parsing sensitive elements of \TEX\ are fractions (\type {\over}
%D and friends, a restricted use of \TEX\ coding is probably as comprehensive and
%D parsable. The webpage with examples served as starting point so anything beyond
%D what can be found there isn't supported.
%D \stopnarrower
%D
%D Then in 2014 something bad happened. Following the fashion of minimal encoding
%D (which of course means messy encoding of complex cases and which can make authors
%D sloppy too) the web based support workflow of the mentioned project ran into some
%D limitations and magically one day all carefully coded \MATHML\ was converted into
%D \ASCIIMATH. As there was no way to recover the original thousands of files and
%D tens of thousands of formulas we were suddenly stuck with \ASCIIMATH. Because the
%D conversion had be done automagically, we also saw numerous errors and were forced
%D to come up with some methods to check formulas. Because \MATHML\ poses some
%D restrictions it has predictable rendering; \ASCIIMATH\ on the other hand enforces
%D no structure. Also, because \MATHML\ has to be valid \XML\ it always processes.
%D Of course, during the decade that the project had run we also had to built in
%D some catches for abuse but at least we had a relatively stable and configurable
%D subsystem. So, in order to deal with less predictable cases as well as extensive
%D checking, a new \ASCIIMATH\ parser was written, one that could also be used to
%D trace bad coding.
%D
%D Because the formal description is incomplete, and because some links to resources
%D are broken, and because some testing on the web showed that sequences of characters
%D are interpreted that were not mentioned anywhere (visible), and because we noticed
%D that the parser was dangerously tolerant, the new code is quite different from the
%D old code.
%D
%D One need to keep in mind that because spaces are optional, the only robust way to
%D edit \ASCIIMATH\ is to use a \WYSIWYG\ editor and hope that the parser doesn't
%D change ever. Keys are picked up from spaceless sequences and when not recognized
%D a (sequence) of characters is considered to be variables. So, \type {xsqrtx} is
%D valid and renders as \type {$x\sqrt{x}$}, \type {xx} becomes \type {×} (times)
%D but \type {ac} becomes \type {$a c$} (a times c). We're lucky that \type {AC} is
%D not turned into Alternating Current, but who knows what happens a few years from
%D now. So, we do support this spaceless mess, but users are warned: best use a
%D spacy sequence. The extra amount of spaces (at one byte each) an author has to
%D include in his|/|her active writing time probably stays below the size of one
%D holiday picture. Another complication is that numbers (in Dutch) use commas instead
%D of periods, but vectors use commas as well. We also hav esome different names for
%D functions which then can conflict with the expectations about collapsed variables.
%D
%D It must be noted that simplified encodings (that seem to be the fashion today)
%D can demand from applications to apply fuzzy logic to make something work out
%D well. Because we have sequential data that gets rendered, sometimes wrong input
%D gets obscured simply by the rendering: like the comma's in numbers as well as
%D for separators (depending on space usage), or plain wrong symbols that somehow
%D get a representation anyway. This in itself is more a side effect of trying to
%D use the simplified encoding without applying rules (in the input) or to use it
%D beyong its intended usage, which then of course can lead to adapted parsers and
%D catches that themselves trigger further abuse. Imagine that instead of developing
%D new cars, planes, space ships, mobile phones, computers we would have adapted
%D horse cars, kites, firework, old fashioned phones and mechanical calculators in a
%D similar way: patch upon patch of traditional means for sure would not have
%D worked. So, when you use \ASCIIMATH\ best check immediately how it gets rendered
%D in the browser as well as on paper. And be prepared to check the more complex
%D code in the future again. We don't offer any guarantees but of course will try to
%D keep up.
%D
%D In retrospect I sometimes wonder if the energy put into constantly adapting to
%D the fashion of the day pays off. Probably not. It definitely doesn't pay of.
%D
%D More complex crap:
%D
%D 1: $x + \stackrel{comment}{\stackrel{\utfchar{"23DE}}{yyyyyyyy}} = y$ \blank
%D 2: \asciimath{x + stackrel{\utfchar{"23DE}}{yyyyyyyy} = y} \blank
%D 3: \asciimath{x + stackrel{yyyyyyyy}{\utfchar{"23DE}} = y} \blank
%D 4: \asciimath{x + stackrel{"comment"}{stackrel{\utfchar{"23DE}}{yyyyyyyy}} = y} \blank

\usemodule[mathml-basics]

\startmodule[asciimath]

\unprotect

\writestatus{asciimath}{beware, this is an experimental (m4all only) module}

%D Hacks:

\unexpanded\def\asciimathoptext        #1{\ifmmode\mathoptext{#1}\else#1\fi}
\unexpanded\def\asciimathoptexttraced  #1{\ifmmode\mathoptext{\color[darkgreen]{#1}}\else\color[darkgreen]{#1}\fi}
\unexpanded\def\asciimathstackrel    #1#2{\mathematics{\mathop{\let\limits\relax\mover{#2}{#1}}}}
\unexpanded\def\asciimathroot        #1#2{\sqrt[#1]{#2}}
\unexpanded\def\asciimathsqrt          #1{\sqrt{#1}}

%D The core commands:

% if we need to set

\installsetuponlycommandhandler {asciimath} {asciimath}

\appendtoks
    \ctxlua{moduledata.asciimath.setup {
        splitmethod = "\asciimathparameter\c!splitmethod",
        separator   = "\asciimathparameter\c!separator",
    }}%
\to \everysetupasciimath

\newtoks\everyascimath

% \appendtoks
%     \ignorediscretionaries
% \to \everyasciimath

\unexpanded\def\asciimath
  {\doifnextoptionalelse\asciimath_yes\asciimath_nop}

\def\asciimath_yes[#1]#2%
  {\mathematics[#1]{\clf_justasciimath{\detokenize\expandafter{\normalexpanded{#2}}}}}

\def\asciimath_nop#1%
  {\mathematics{\clf_justasciimath{\detokenize\expandafter{\normalexpanded{#1}}}}}

\unexpanded\def\ctxmoduleasciimath#1%
  {\ctxlua{moduledata.asciimath.#1}}

%D Some tracing commands. Using tex commands is 10\% slower that directly piping
%D from \LUA, but this is non|-|critical code.

\unexpanded\def\ShowAsciiMathLoad  [#1]{\ctxlua{moduledata.asciimath.show.load("#1")}}
\unexpanded\def\ShowAsciiMathIgnore[#1]{\ctxlua{moduledata.asciimath.show.ignore("#1")}}
\unexpanded\def\ShowAsciiMathXML   #1#2{\ctxlua{moduledata.asciimath.show.filter("#1","#2")}}
\unexpanded\def\ShowAsciiMathStats     {\ctxlua{moduledata.asciimath.show.statistics()}}
\unexpanded\def\ShowAsciiMathMax       {\ctxlua{moduledata.asciimath.show.max()}}

\unexpanded\def\ShowAsciiMathResult#1%
  {\begingroup
     \blank
     % if we are in vmode, we don't get positions i.e. a smaller tuc file
     \inleft{\ttbf#1\hfill\ctxlua{moduledata.asciimath.show.count(#1,true)}}%
     \dontleavehmode
     \begingroup
       \ttbf
       \ctxlua{moduledata.asciimath.show.files(#1)}
     \endgroup
     \blank[medium,samepage]
     \startcolor[darkblue]
     \ctxlua{moduledata.asciimath.show.input(#1,true)}
     \stopcolor
     \blank[medium,samepage]
     \doifmode{asciimath:show:dirty} {
        \dorecurse{\ctxlua{moduledata.asciimath.show.nofdirty(#1)}} {
          \ctxlua{moduledata.asciimath.show.dirty(\recurselevel,true)}
          \blank[medium,samepage]
        }
     }
     \ctxlua{moduledata.asciimath.show.result(#1)}
     \blank
   \endgroup}

\unexpanded\def\ShowAsciiMathStart
  {\begingroup
   \let\asciimathoptext\asciimathoptexttraced
   \setuptyping[\v!buffer][\c!before=,\c!after=]
   \setupmargindata[\v!left][\c!style=]}

\unexpanded\def\ShowAsciiMathStop
  {\endgroup}

\unexpanded\def\ShowAsciiMath
  {\dodoubleempty\doShowAsciiMath}

\unexpanded\def\doShowAsciiMath[#1][#2]%
  {\iffirstargument
     \ShowAsciiMathStart
     \ShowAsciiMathLoad[#1]
     \ifsecondargument
       \ShowAsciiMathIgnore[#2]
     \fi
     \dorecurse{\ShowAsciiMathMax}{\ShowAsciiMathResult\recurselevel}
     \page
     \ShowAsciiMathStats
     \ShowAsciiMathStop
  \fi}

\unexpanded\def\xmlShowAsciiMath#1#2%
  {\iffirstargument
     \ShowAsciiMathStart
     \ShowAsciiMathXML{#1}{#2}%
     \dorecurse{\ShowAsciiMathMax}{\ShowAsciiMathResult\recurselevel}
     \page
     \ShowAsciiMathStats
     \ShowAsciiMathStop
  \fi}

\unexpanded\def\ShowAsciiMathSave
  {\dosingleempty\doShowAsciiMathSave}

\unexpanded\def\doShowAsciiMathSave[#1]%
  {\ctxlua{moduledata.asciimath.show.save("#1")}}

\protect

\startsetups asciimath:layout

    \setupbodyfont
    % [pagella,10pt]
      [dejavu,10pt]

    \setuplayout
      [backspace=35mm,
       leftmargin=20mm,
       rightmargindistance=0pt,
       leftmargindistance=5mm,
       cutspace=1cm,
       topspace=1cm,
       bottomspace=1cm,
       width=middle,
       height=middle,
       header=0cm,
       footer=1cm]

    \setupheadertexts
      []

    \setupfootertexts
      [\currentdate][\pagenumber]

    \setupalign
      [flushleft,verytolerant,stretch]

    \dontcomplain

\stopsetups

\stopmodule

\continueifinputfile{x-asciimath.mkiv}

%D This will become an extra.

\showframe

\setups[asciimath:layout]

% \enabletrackers[modules.asciimath.mapping]
% \enabletrackers[modules.asciimath.detail]

% \starttext
%     \enablemode[asciimath:show:dirty]
%     \ShowAsciiMath[e:/temporary/asciimath/*.xml]
%   % \ShowAsciiMathSave[e:/temporary/asciimath/asciimath.lua]
% \stoptext

\starttext
\unexpanded\def\MyAsciiMath#1{\startformula\asciimath{#1}\stopformula}
\startlines
\MyAsciiMath{x^2 / 10 // z_12^34 / 20}
% \MyAsciiMath{{:{:x^2:} / 10:} // {:{:z_12^34 :} / 20:}}
% \MyAsciiMath{x^2+y_1+z_12^34}
% \MyAsciiMath{sin^-1(x)}
% \MyAsciiMath{d/dx f(x)=lim_(h->0) (f(x+h)-f(x))/h}
% \MyAsciiMath{f(x)=sum_(n=0)^oo(f^((n))(a))/(n!)(x-a)^n}
% \MyAsciiMath{int_0^1 f(x)dx}
% \MyAsciiMath{int^1_0 f(x)dx}
% \MyAsciiMath{a//b}
% \MyAsciiMath{a//\alpha}
% \MyAsciiMath{(a/b)/(d/c)}
% \MyAsciiMath{((a*b))/(d/c)}
% \MyAsciiMath{[[a,b],[c,d]]((n),(k))}
% \MyAsciiMath{1/x={(1,text{if } x!=0),(text{undefined},if x=0):}}
% \MyAsciiMath{{ (1,2), (x,(x + text(x))) }}
% \MyAsciiMath{{(1,2),(x,(x+text(x))),(x,text(x))}}
% \MyAsciiMath{{(1,2),(x,(x+text(x))),(x,x text(x))}}
% \MyAsciiMath{{(1,2/2),(x,(x+x^22+sqrt(xx))),(x,x text(xyz))}}
% \MyAsciiMath{{(1,2/2),(x,(x+x^22+sqrt(xx))),(x,text(xyz)+1+text(hans))}}
% \MyAsciiMath{<<a,b>> text{and} {:(x,y),(u,v):}}
% \MyAsciiMath{(a,b] = {x text(in) RR | a < x <= b}}
% \MyAsciiMath{a/b / c/d = (a * d) / (b * d) / (b * c) / (b * d) = (a * d) / (b * c)}
% \MyAsciiMath{ (a/b) // (c/d) =  ( (a * d) / (b * d) ) // ( (b * c) / (b * d) ) = (a * d) / (b * c)}
% \MyAsciiMath{sin(x+1)_3^2/b / c/d}
% \MyAsciiMath{{:{:sin(x+1)_3^2:}/b:} / {:c/d:}}
% \MyAsciiMath{cos(a) + sin(x+1)_3^2/b / c/d = (a * d) / (b * d) / (b * c) / (b * d) = (a * d) / (b * c)}
% \MyAsciiMath{S_(11)}
% \MyAsciiMath{f(x)}
% \MyAsciiMath{sin(x)}
% \MyAsciiMath{sin(x+1)}
% \MyAsciiMath{sin^-1(x)}
% \MyAsciiMath{sin(2x)}
% \MyAsciiMath{a_2^2}
% \MyAsciiMath{( (S_(11),S_(12),S_(1n)),(vdots,ddots,vdots),(S_(m1),S_(m2),S_(mn)) ]}
% \MyAsciiMath{frac a b}
% \MyAsciiMath{sin(x)/2 // cos(x)/pi}
% \MyAsciiMath{a/13 // c/d}
% \MyAsciiMath{a/b // c/d}
% \MyAsciiMath{x}
% \MyAsciiMath{x^2}
% \MyAsciiMath{sqrt x}
% \MyAsciiMath{sqrt (x)}
% \MyAsciiMath{root 2 x}
% \MyAsciiMath{x+x}
% \MyAsciiMath{x/3}
% \MyAsciiMath{x^2 / 10}
% \MyAsciiMath{x^2 / 10 // z_12^34 / 20}
% \MyAsciiMath{a^23}
% \MyAsciiMath{a^{:b^23:}+3x}
% \MyAsciiMath{a/b / c/d}
% \MyAsciiMath{sin(x)/b / c/d}
% \MyAsciiMath{sin(x)/b // c/d}
% \MyAsciiMath{a/b / c/d = (a * d) / (b * d) / (b * c) / (b * d) = (a * d) / (b * c) }
% \MyAsciiMath{{:{:x^2:} / 10:} // {:{:z_12^34 :} / 20:}}
% \MyAsciiMath{x^2+y_1+z_12^34}
% \MyAsciiMath{sin^-1(x)}
% \MyAsciiMath{d/dx f(x)=lim_(h->0) (f(x+h)-f(x))/h}
% \MyAsciiMath{f(x)=sum_(n=0)^oo(f^((n))(a))/(n!)(x-a)^n}
% \MyAsciiMath{int_0^1 f(x)dx}
% \MyAsciiMath{int^1_0 f(x)dx}
% \MyAsciiMath{2x}
% \MyAsciiMath{a//b}
% \MyAsciiMath{a//\alpha}
% \MyAsciiMath{(a/b)/(d/c)}
% \MyAsciiMath{((a*b))/(d/c)}
% \MyAsciiMath{[[a,b],[c,d]]((n),(k))}
% \MyAsciiMath{1/x={(1,text{if } x!=0),(text{undefined},if x=0):}}
% \MyAsciiMath{{ (1,2), (x,(x + text(x))) }}
% \MyAsciiMath{{(1,2),(x,(x+text(x))),(x,text(x))}}
% \MyAsciiMath{{(1,2),(x,(x+text(x))),(x,x text(x))}}
% \MyAsciiMath{{(1,2/2),(x,(x+x^22+sqrt(xx))),(x,x text(xyz))}}
% \MyAsciiMath{{(1,2/2),(x,(x+x^22+sqrt(xx))),(x,text(xyz)+1+text(hans))}}
% \MyAsciiMath{<<a,b>> text{and} {:(x,y),(u,v):}}
% \MyAsciiMath{(a,b] = {x text(in) RR | a < x <= b}}
% \MyAsciiMath{x^-2}
% \MyAsciiMath{x^2(x-1/16)=0}
% \MyAsciiMath{y= ((1/4)) ^x}
% \MyAsciiMath{log (0,002) / (log(1/4))}
% \MyAsciiMath{x=ax+b \ oeps}
% \MyAsciiMath{x=\ ^ (1/4) log(x)}
% \MyAsciiMath{x=\ ^ (1/4) log(0 ,002 )= log(0,002) / (log(1/4))}
% \MyAsciiMath{x^ (-1 1/2) =1/x^ (1 1/2)=1/ (x^1*x^ (1/2)) =1/ (xsqrt(x))}
% \MyAsciiMath{x^2(10 -x)&gt;2 x^2}
% \MyAsciiMath{x^4&gt;x}
\stoplines
\stoptext