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Re: Nitpick with FLOOR etc.

This page is part of the web mail archives of SRFI 70 from before July 7th, 2015. The new archives for SRFI 70 contain all messages, not just those from before July 7th, 2015.

 | Date: Sun, 17 Jul 2005 22:59:12 -0700 (PDT)
 | From: bear <bear@xxxxxxxxx>
 | One thing that is clear from inspecting code that actually
 | uses FLOOR, CEILING, etc, is that there is a very strong
 | usage pattern; the procedure inexact->exact is almost ALWAYS
 | called on the result.

Originally, I was going to propose changing ROUND, etc to return
exacts; but an inexact FLOOR was needed to avoid exact vs inexact
range problems in extending MODULO to the reals:

(define (modulo x1 x2)
  (if (and (integer? x1) (integer? x2))
      (integer-modulo x1 x2)
      (- x1 (* x2 (floor (/ x1 x2))))))

 | I think standard library macros ought to capture and standardize
 | this usage.
 | (xfloor x) <==> (inexact->exact (floor x))
 | (xceiling x) <==> (inexact->exact (ceiling x)
 | (xround x) <==> (inexact->exact (round x))

Why macros when procedures would be equivalent?

Also, is the prefixed `x' for exact; wouldn't `e' be more Schemely?