[r6rs-discuss] Confusion over |p

[Aubrey Jaffer]

 | Date: Fri, 29 Jun 2007 10:24:28 -0500
 | From: Alan Watson <alan at alan-watson.org>
 | 
 | Here is the problem I want to solve. I want to be able to read IEEE
 | singles and doubles and have them represented by the nearest
 | inexact real. I want to be able to write the IEEE single and double
 | that is nearest to a given inexact real. I am prepared to accept a
 | solution that works on many but not all implementations and I am
 | prepared to do some of the work myself.
 | 
 | I can see a number of solutions. First, the input problem:
 | 
 | (b) Throw out |p and return to the R5RS syntax for inexact numbers.
 | Actually, we're a bit better than the R5RS, as I can generate IEEE
 | single-precision and double-precision values using byte vectors
 | literals and procedures. Someone smarter than I might be able to
 | wrap this in a nice macro, which would work well for programs. Data
 | will be a bit messy, as I will have to process it an convert byte
 | vectors to inexacts as appropriate.
 | 
 | ...
 | 
 | Now the output problem. First, we should accept that inexact
 | arithmetic is ... inexact. Therefore we do the best we can:
 | 
 | (b) We throw out |p and the third argument to number->string. I
 | will have to write IEEE singles and doubles using byte vectors,
 | which won't work so well for data but I can live with that.

SLIB provides IEEE single and double number-byte conversions:

  http://swiss.csail.mit.edu/~jaffer/slib_7.html#SEC189