[CM] About the implementation of sturms function in Notes from the Metalevel

Christophe Rhodes csr21@cam.ac.uk
Fri, 28 Oct 2005 22:52:10 +0100

"Bill Schottstaedt" <bil@ccrma.Stanford.EDU> writes:

> sbcl is picky about the step variable -- I complained about
> it a long time ago, and was told that it was a feature.  Here's an even better sbcl-ism:
> The value 0.0
>              is not of type
>                (OR (SINGLE-FLOAT (0.0)) (DOUBLE-FLOAT (0.0d0)) (RATIONAL (0)))
> which happens in cmn! 

The step variable is defined to be a positive real, in the ANSI
standard, section


    The loop keyword by marks the increment or decrement supplied by
    form3. The value of form3 can be any positive number. The default
    value is 1.

Neither 0.0 nor -1 is a positive number.  The type
  (or (single-float (0.0)) (double-float (0.0d0)) (rational (0)))
precisely means "positive number".  I'm sorry that you don't find this