Re: The wisdom of the object mentors (Was: Searching OO Associations with RDBMS Persistence Models)

David Cressey wrote:
> I thought the diffence between a "domain" and a "type" was precisely that
> types include operators while domains do not.

Neither types nor domains "include" operators. Functions can be defined over one or more types, but calling a function an operator is imprecise. I suppose "operator" generally means a function of type T -> X or of type X -> T (constructor), but really only functions of type T -> T -> ... -> T could properly be said to be "included" in type T.

This is why first-class functions, and multimethods, make so much sense; and one of the reasons why the forced bondage of every single function to a single class (as in Java) is so much nonsense.

• erk