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Re: Wrapping up SRFI-70

This page is part of the web mail archives of SRFI 70 from before July 7th, 2015. The new archives for SRFI 70 contain all messages, not just those from before July 7th, 2015.

 | Date: Tue, 09 Aug 2005 22:13:23 -0700
 | From: Per Bothner <per@xxxxxxxxxxx>
 | I think there are some good things here, but there may be too much
 | stuff in one SRFI.
 | ....
 | An SRFI dealing with inexact infinities should I think focus more
 | on IEEE infinities.  It is desirable that a Scheme implementation
 | can map (possibly compile) Scheme arithmetic on inexact reals into
 | IEEE floating-point arithmetic.  I think more dicussion of this
 | issue is needed.

The current (2005/08/12) revision of SRFI-70 makes clear that +inf.0
and -inf.0 correspond to the IEEE-754 infinities already supported by
nine implementations of Scheme.

 | Date: Tue, 09 Aug 2005 22:36:32 -0700
 | From: Per Bothner <per@xxxxxxxxxxx>
 | The rationale discusses NaN, but I think the solution that
 | 0/0. = 0/0. is wrong.  I think it is important to be compatible
 | with IEEE, and that 0/0. be the same as NaN.

0/0 is now an optional error object, completely unconstrained by

 | The Kawa solution (which I think is the right one):
 | (define NaN ...)
 | (= NaN NaN) => #f
 | (eq? NaN NaN) => #t
 | (eqv? NaN NaN) => #t
 | (equal? NaN NaN) => #t
 | This may technically violate R5RS, but I think it's the
 | best choice if we want to be compatible with IEEE, which
 | think we do.

I believe that the junking of 0/0 makes SRFI-70 compatible with
IEEE-754.  Do you agree?