[r6rs-discuss] Confusion over |p

From: Alan Watson <alan>
Date: Thu, 28 Jun 2007 17:05:57 -0500

William D Clinger wrote:
> I can't imagine a rationale for requiring (b), however.

The only one I can think of is that I want to compare IEEE singles
(doubles) obtained from a byte vector with numbers obtained by read and
I know my implementation implements inexact real numbers with sufficient
precision to express all IEEE singles (doubles).

But your comment prompts a wider question: what problem is x|p trying to
solve?

In other news:

The current draft also implies that 1.1f0 should be interpreted as
1.1f0|53. This seems bizarre. Regardless of the meaning of |p, perhaps
the default values of p should be f exponents and 53 for e and l
exponents. I am not sure what the default should be for s exponents.

Furthermore, suppose I have a Scheme with that uses both IEEE
single-precision and IEEE double-precision formats for real numbers.
Suppose I write x|24. If x is a normalized number, the implementation
"should" represent it using a single-precision format. If x is a
denormalized number, the representation "should" represent it using a
double-precision format (because denormalized single-precision numbers
have fewer than 24 bits of precision).

Regards,

Alan
Received on Thu Jun 28 2007 - 18:05:57 UTC