From: Trans Date: 2005-02-11T22:55:01+09:00 Subject: Re: Building a Better Functor > Interesting. So how exactly would you define a functor? > What you have shown above seems to be an object that > knows how to do some kind of operation using a > user-defined method. Is this how you would define a functor? A good question. By standard definition, Method objects and Proc objects are Functors. Since Ruby already has these I'm simply defining a Functor as a "MetaMethod" for the sake of a distinction. By this I mean an object the represents a method which can act on another method. Function composition, represented as a 1st class object, for instance, would also be a Functor of this sort. T.