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Hi all,

I have been developing a plain-text input language for the content
MathML in CellML documents (so that it can be efficiently edited by
users). Although CellML is a declarative language rather than a
procedural one, much of the expression syntax from languages like MATLAB
and C-like languages can be re-used, and is likely to be familiar to
many users. I have therefore tried to make my input language similar to
these languages, where possible (for example, I have in-order operators
like +, -, *, and / for plus, minus, times, divide, and a pre-order
syntax, e.g. sin(x), for other operators). Please ask off-list for my
bison grammar (a work in progress) if you would like to see it (I
haven't checked it in to the public Subversion yet). Any opinions or
suggestions on the overall structure of the language would be welcome.

I am also seeking opinions on the most intuitive way to deal with the
conversion between binary in-order operators like +. For example, if,
within the input language, you have
x = a + b + c + d + e + f
a naive parser might create MathML like...

<apply><eq/>
<ci>x</ci>
<apply><plus/>
<apply><plus/>
<apply><plus/>
<apply><plus/>
<apply><plus/>
<ci>a</ci>
<ci>b</ci>
</apply>
<ci>c</ci>
</apply>
<ci>d</ci>
</apply>
<ci>e</ci>
</apply>
<ci>f</ci>
</apply>
</apply>

A slightly more complex parser might instead produce:
<apply><eq/>
<ci>x</ci>
<apply><plus/>
<ci>a</ci>
<ci>b</ci>
<ci>c</ci>
<ci>d</ci>
<ci>e</ci>
<ci>f</ci>
</apply>
</apply>

I would be interested in opinions on whether you feel this automatic
translation from multiple binary in-order operators to a single
pre-order operation makes sense (note: all CellML tools available now
work with real numbers only, but future work could allow it to be
extended to support other mathematical constructs. Using a definitionURL
on an operator is technically valid CellML, but no tools can do anything
with this either).

The issue is complicated by what to do with bracketed expressions(which
I currently allow, to override ambiguity). For example, a user could
enter...
x = (((((a + b) + c) + d) + e) + f)
I would be interested to know if you believe that the first content
MathML encoding or the second is more appropriate.

Best regards,
Andrew Miller

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• [cellml-discussion] Content MathML editing language: Binary => n-ary syntax, Andrew Miller, 11/20/2006
  • [cellml-discussion] Content MathML editing language: Binary =>n-ary syntax, David Nickerson, 11/20/2006
    • [cellml-discussion] Content MathML editing language: Binary =>n-ary syntax, Alan Garny, 11/20/2006
    • [cellml-discussion] Content MathML editing language: Binary =>n-ary syntax, Andrew Miller, 11/20/2006
      • [cellml-discussion] Content MathML editing language: Binary=>n-ary syntax, David Nickerson, 11/20/2006
        • [cellml-discussion] Content MathML editing language: Binary=>n-ary syntax, Poul Nielsen, 11/21/2006
  • Message not available
    • [cellml-discussion] Content MathML editing language: Binary => n-ary syntax, Andrew Miller, 11/20/2006
  • [cellml-discussion] Content MathML editing language: Binary => n-ary syntax, Shane Blackett, 11/24/2006

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