[Om] Multistep "equation" symbol?

David Carlisle davidc at nag.co.uk
Thu May 14 00:20:35 CEST 2009



> Then this could be something like
> @(M,R,a_0,a_1,\ldots,a_n) = @(and,@(R,a_0,a_1),@(M,R,a_1,\ldots,a_n))

with one syntactic variation, if I read this right it's the same as the
predicate_on_list symbol proposed to be added as part of the support for
MathML3, (obviously the idea is in the air...)  see

http://monet.nag.co.uk/~dpc/draft-spec/chapter4.html#contm.rewrite.reln

and

http://monet.nag.co.uk/~dpc/cdfiles2


I think that essentially the only difference  is that rather than being
cast as an n-ary operator redicate_on_list cast as a binary one taking
an explict list as second argument, so in the above notation the usage is

@(M,R,@(list,a_0,a_1,\ldots,a_n))

Having the explict list constructor there makes it slightly more verbose
but avoids the problem Michael alluded to that it's hard to  to
decompose an n-ary constructor to talk about the individual arguments
but a list arguent can be deconstructed with symbols from the list Cd to
refer to (say) the kth item, even if the items are not listed explitly.

David

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