[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: external representations



Aubrey Jaffer wrote:

 > SRFI-70 mandates no connection between IEEE-754 NaN and 0/0.

No one said it did.  In the discussion of SRFI-70,
however, Bradley Lucier proposed having external
representations for NaNs.  I was responding to
Lucier's proposal as much as to yours.

 > One of the notations being floated is #i1/0 and #i-1/0 (and #i0/0).
 > This notation looks inexact; and requires no rule complications.
 > Does that assuage your concerns?

Yes, but I still prefer +inf.0 and -inf.0.

> On June 28, 2003 I posted to rrrs-authors@xxxxxxxxxxxxxxxxx a survey
> <http://swiss.csail.mit.edu/~jaffer/III/RAWI <http://swiss.csail.mit.edu/%7Ejaffer/III/RAWI>> of infinity behaviors
> and notations in Kawa-1.7, SCM-5d8, Guile-1.3.4, Bigloo-2.5c,
> glibc-2.2, Elk-3.0, Gambit-3.0, Mz-Scheme-202, MIT-Scheme-7.8, and
> Scheme-48-0.57.  At that time, there was no notation common to more
> than one Scheme implementation.  That it is "not terribly
> controversial" could only be arrived at by ignoring most
> Scheme implementations.

To say that something is "not terribly controversial"
is hardly the same as saying that most implementations
already do it.  If you doubt the intended meaning of
that phrase, please take a look at the other things
that were regarded as not terribly controversial.

Will