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Re: notation for extending precedence
Bruce Smith writes:
> At 4:34 PM 9/16/96, T. V. Raman wrote:
> >Eventually, if we did feel the need to allow author defined precedence
> >enhancements this can be done cleanly by providing definition syntax of the
> >form
> >(define-operator :operator-name 'foo :precedence :same-as "+")
> >;excuse the lisp:-)
> >Instead of :same-as the author would also be able to say :less-than and
> >:greater-than (I implemented the above in Aster and it worked reasonably well
> >for a sufficiently large collection of hairy math.
>
>
> Do you have a suggested way of specifying the original (built-in)
> list of operators (maybe 250 of them) with their associativities
> and precedences (maybe 80 precedence levels, since the operators
> come in groups of the same precedence), without each operator
> having to give the name of the previous one, and in which a few
> operators (though not most) have different left and right precedences,
AsTeR used about 12-15 precedence levels (I think)
and did not handle associativity but I could mail out the file of lisp code
> containing the precedence definitions.
Would this be useful?
--the file contains all the operators with the precedence defined (all this
> is from memory --I'll have to go back and look)
> with the out-of-order ones specified by reference to other operators?
>
> If so, we could dispense with numerical precedence levels
> even for the built-in list of operators.
>
--
Best Regards,
--raman
Adobe Systems Tel: 1 (408) 536 3945 (W14-129)
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