On Fri, Oct 04, 2002 at 06:26:31PM -0400, Trey Harris wrote: > > But what does it mean to be "stronger"? How does Eiffel figure out if > > a given precondition is "stronger" or "weaker" than another? > > Like I said before, boolean logic. Preconditions are OR'd together > (starting with the deepest subclass and working back to the most ancestral > class, in order to short-circuit most effectively), postconditions are > AND'd together (in the opposite order, same reason).
I can see too many problems with that technique, I think one was already mentioned where subclasses can unintentionally weaken preconditions to the point of eliminating them. I'm sort of casting about looking for another way. -- Michael G Schwern <[EMAIL PROTECTED]> http://www.pobox.com/~schwern/ Perl Quality Assurance <[EMAIL PROTECTED]> Kwalitee Is Job One
