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[cellml-discussion] Content MathML editing language: Binary => n-ary syntax


Chronological Thread 
  • From: s.blackett at auckland.ac.nz (Shane Blackett)
  • Subject: [cellml-discussion] Content MathML editing language: Binary => n-ary syntax
  • Date: Fri, 24 Nov 2006 15:35:17 +1300
Hi,

I think that the second, reduced number of operators is preferable,
however I would like that any special brackets I choose to enter
in remained, even if they are redundant.

How this is recorded, either as metadata or by the MathML structure
I don't really mind.

It seems to me if someone is particularly worried about the exact
result in MathML then maybe they should be editing the MathML itself?

Shane.

Andrew Miller wrote:
> 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
>
> _______________________________________________
> cellml-discussion mailing list
> cellml-discussion at cellml.org
> http://www.cellml.org/mailman/listinfo/cellml-discussion



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