From: itsme213@... (you CAN teach an old dog ...)
Date: 2003-06-18T18:32:59+09:00
Subject: re-open a class --> re-open a method?

Ruby's ability to re-open a class is great! Among other things it
enables separately modularizing issues that cross-cut across multiple
classes. The accessible 'internal' points of the class being re-opened
include its existing methods, and modules it includes or classes it
inherits. Through these accessible points we can incrementally and
modularly define a class.

It appears that re-opening a class could have been approximated by:
- aliasing the orginal class
- creating a new class 
  - defining its methods, modules, etc.
  - inheriting from the original class
- binding the new class to the constant symbol of the original

Of course this would be much more painful.

In exactly the same spirit, wouldn't it make sense to allow some kind
of re-open of a method, rather than only the current :alias mechanism
(which is itself wonderful after some other languages)? The accessible
'internal' points could include method-entry, method return, method
exception exit. Through these accessible points we could incrementally
and modularly define a method (or, perhaps more importantly, some
cross-cutting aspect of a bunch of methods across a bunch of classes).

Thoughts?