Re: [Scheme-reports] Formal Comment: R7RS 'eqv?' cannot be used for reliable memoization

[Mark H Weaver <mhw@x>]

Alex Shinn <alexshinn@x> writes:

> On these two issues I just want it to be possible to
> have an ideal Scheme implementation where characters
> are really parts of scripts and numbers are really
> mathematical values.

I agree that a Scheme implementation without signed zeroes should be
permitted by the standard.  An 'eqv?' based on operational equivalence
does not conflict with that.  In your ideal Scheme implementation, -0.0
and +0.0 would be operationally equivalent, and thus (eqv? +0.0 -0.0)
would justifiably be #true, and indeed that would follow from my
proposed language.

What I want, indeed what I *require*, is the ability to memoize
procedures without having to worry that my code might produce the wrong
answers on some future implementation of R7RS.

Therefore, it appears likely that I will not be able to use R7RS.

      Mark

_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports