From: Sean O'Dell <sean@...>
Date: 2004-06-09T05:50:46+09:00
Subject: Re: [ANN] Ruby/Interface

On Tuesday 08 June 2004 13:23, Mauricio Fern�ndez wrote:
> On Wed, Jun 09, 2004 at 03:46:30AM +0900, Sean O'Dell wrote:
> > Ruby/Interface tries to solve this problem by ???tagging??? objects as
> > implementing an interface. The implementation is enforced by comparing an
> > object???s methods against the methods expected by the interface.
>
> Some comments:
>
> I see you're using per-class tagging, hence being unable to track
> changes in the singleton class. I'd point you again to the last sections
> of http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/102555
> which I believe you didn't read.
> There's an inconsistency in the code: you're checking the methods of the
> object (including its singleton methods) with Object#method but storing
> the result in a per-class structure; that won't fly.
>
> Also, using class variables instead of class instance variables ties the
> notion of interface to inheritance, which I believe you wanted to avoid.
>
> I would consider storing the conformance information in
> ROBJECT(self)->klass directly; this will be either the real class or
> the singleton class. In the first case, the "conformity table" is
> shared by all objects of that class; in the second, it will be "owned"
> by the object. The advantage is that this new table would be created
> on demand, only when the object is extended/a singleton method is
> defined and has_interface? is called. You wouldn't even need to capture
> singleton_method_added this way.

I have to ponder this a bit.  I admit I am not entirely clear how Ruby works 
internally, and singletons are something I don't quite get.  Let me digest 
the suggestions.

	Sean O'Dell