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*To*: srfi-70@xxxxxxxxxxxxxxxxx*Subject*: Re: My suggestions to the R6RS committee about numerics*From*: Bradley Lucier <lucier@xxxxxxxxxxxxxxx>*Date*: Mon, 23 May 2005 14:36:18 -0500*Cc*: Bradley Lucier <lucier@xxxxxxxxxxxxxxx>*Delivered-to*: srfi-70@xxxxxxxxxxxxxxxxx

Aubrey:

| From: Bradley Lucier <lucier@xxxxxxxxxxxxxxx> | Date: Fri, 20 May 2005 15:23:28 -0500 | | Hi, Aubrey: | | We already discussed many of these issues on various threads in | comp.lang.scheme. I can't find any subjects with "exact", "IEEE", or "inifinity" in the 3100 postings in my current usenet feed. How about a URL?

| On May 20, 2005, at 2:13 PM, Aubrey Jaffer wrote: | | > | From: Bradley Lucier <lucier@xxxxxxxxxxxxxxx> | > | Date: Wed, 18 May 2005 22:38:43 +0200 | > | | > | .., I sent document about proposed changes to numerics to| > | Marc Feeley last March to forward to the committee. Sincethen my| > | thinking has evolved a bit, but I thought I would justinclude my| > | comments verbatim here. ... | >| > Why are you restricting the specification of inexacts toIEEE-754/854| > arthmetic? | | I'm not doing as you suggest; perhaps you misinterpret my | recommendation. You have me at a disadvantage. Where I have written extensively about intent and motivations in SRFI-70, you have given no hint, even in response to my direct question.

OK, let's try this again. I wrote:

The first part deals with IEEE 754/854 arithmetic. If you don'tsupport this arithmetic, then things are still up in the air....Note: This section does not state under which conditions eqv?returns #t or #f for inexact numbers that are not in IEEE 754/854format....If an implementation uses IEEE 754/854 format for inexact numbersthen:

You wrote:

Why are you restricting the specification of inexacts toIEEE-754/854 arthmetic?

Is this right? If so, I don't understand why you think this. Again, I wrote:

(exact? z) procedure (inexact? z) procedureThese numerical predicates provide tests for the exactness of aquantity.For any Scheme number, precisely one of these predicates is true. <Add the following> For implementations that allow (real z) and (imag z) to have differentexactness, then (exact? z) returns #t if and only if both (exact?(real z))and (exact? (imag z)) return #t. <end of addition>

Now, I understand that "z is exact" if and only if "(exact? z) => #t" "z is inexact" if and only if "(inexact? z) => #t"

You wrote:

A number is either exact or inexact; and a complex number (like a rational number) is one number, not two. Exactness thus applies to the whole complex number, not to its components.

You wrote:

I will not anger you further with my guesses as to your intentions.

Angry? No, not angry, not at all. Bemused, perhaps, but not angry. Brad

**Follow-Ups**:**Re: My suggestions to the R6RS committee about numerics***From:*Aubrey Jaffer

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