From: Gavin Collings (gcollings_at_[hidden])
Date: 2000-03-04 04:56:32
Looks like a well implemented worthwhile addition to me. I've often
used a similar technique without formalizing it. One question though,
have you considered abandoning the class invariant low <= up in favour
of an approach where there are no constraints upon the individual
bounds. Reason: sometimes it's useful to distinguish a +/- from a -/+
Gavin.