On Sat, 26 Feb 2005 06:10:23 -0800, Ned Konz <ned at squeakland.org> wrote:

> Ruby has a single-inheritance scheme much like Smalltalk's, but also adds
> 'modules' which work almost exactly like including a text file that can hold
> more behavioral definitions. Of course, since Ruby doesn't require you to
> pre-declare instance variables, this also lets you have mixins that add
> instance variables as necessary (though there is no attempt at dealing with
> or even detecting name conflicts). Modules actually are nicer than text
> inclusion, as they are first class objects and so support reflection (I
> forget whether they provide a separate namespace).

They do - in fact, the idomatic way to define a namespace in Ruby is
to create a module, and you import that namespace by mixing the module
in to wherever you want to use it.  I would describe the mixin
semantics as being more like a superclass insertion than like textual
inclusion - and, in fact, I'm pretty sure that's how it's implemented.
 That is, if you have class C subclassed from class B, and you include
module M, you end up with single-inheritance lookup along the chain
C->M->B.  If anyone wants to play with an implementation of these
semantics, try my Mixins package on SqueakSource (I don't think it
ever made it to SqueakMap).

Avi