[r6rs-discuss] Two questions about writing inexact numbers

From: Alan Watson <alan>
Date: Mon, 28 May 2007 15:02:36 -0500

Replying to your own posts is widely regarded as a sign of insanity, but
nevertheless ...

Alan Watson wrote:
> (b) Is there a simple way to write a flonum in a way that will always be
> read as a flonum (i.e., with an e exponent and no explicit mantissa
> precision)?

I think this may depend on what I mean by "always".

If I mean "I want to be able to write a flonum on one implementation and
guarantee (within range restrictions) that it will be read as a flonum
on any other implementation", then I need to be able to write a flonum
using an e exponent and no explicit mantissa precision. I do not think
the standard gives me an easy way to do this. I believe I have to write
my own number->string (possibly on top of the standard version).

If I mean "I want to write a flonum on one implementation and guarantee
that it will be read a flonum on the same implementation", then I have
to play with the meaning of equal? for flonums. Two inexact integers are
equal? if the give the same results on Scheme's standard arithmetic
procedures.

Question: Is flonum? a "standard arithmetic procedure"?

Regards,

Alan
Received on Mon May 28 2007 - 16:02:36 UTC