[Prev][Next][Index][Thread]

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)
      Advanced Technology Group     Fax: 1 (408) 537 4042 
      (W14 129) 345 Park Avenue     Email: raman@adobe.com 
      San Jose , CA 95110 -2704     Email:  raman@cs.cornell.edu
      http://labrador.corp.adobe.com/~raman/raman.html (Adobe  Internal)
      http://www.cs.cornell.edu/Info/People/raman/raman.html  (Cornell)
-----------------------------------------------------------------------
    Disclaimer: The opinions expressed are my own and in no way should be taken
as representative of my employer, Adobe Systems Inc.
____________________________________________________________


References: