[r6rs-discuss] Re: [Formal] eq?/eqv? misbehave around NaNs

From: Alan Watson <alan>
Date: Thu Nov 23 17:50:23 2006

Abdulaziz Ghuloum wrote:
>> I think it is important to not break:
>> (eq? x x) implies (eqv? x x)
>> and:
>> (let ((x expr)) (eq? x x))
>
>
> These are not axioms in Scheme.

I think the first is, at least for numbers. For numbers, eq? returns
true only when eqv? returns true (see the second paragraph of the
description of eq?). So, for numbers, (eq? x x) does indeed imply (eqv?
x x). (Or I have misunderstood something fundamental here.)

On further consideration, I agree that the second expression need not
evaluate to #t.

Regards,

Alan
Received on Thu Nov 23 2006 - 17:49:11 UTC