step.icn: Procedure to generate in real increments

link step
April 6, 1993; Ralph E. Griswold
This file is in the public domain.

step(r1, r2, r3) generates real values from r1 to r2 in increments of
r3 (default 1.0).  It is the real equivalent of i to j by k.
If r2 is null, the sequence is infinite and is the real equivalent
of seq().

Beware the usual problems of floating-point precision.