Smalltalk and Python

[Ian Wild]

Alex Martelli wrote:
> 
> Forget C++ -- we're talking OO _analysis_.  Assume you're
> trying to perform OOA on the universe of discourse "immutable
> planar 2D geometric polygons", for the sake of definiteness.
> 
> If Rectangle and Square are both concrete (instantiable)
> classes, with *overlapping* requirements for membership,
> how do you classify a given rectangular object which
> happens to have equal sides?  Toss a coin?

Both.

Unless you're using classes purely as an implementation
shortcut, why need an object be a member of precisely *one*
class?  What if your analysis is later implemented in
a language without classes (eg Self?), or one where
classes exist only by convention (Perl)?