From: Jean-Hugues ROBERT <jean_hugues_robert@...>
Date: 2004-05-01T01:12:11+09:00
Subject: Re: coerce(), what protocol to implement it

At 17:54 30/04/2004 +0900, you wrote:
>il Fri, 30 Apr 2004 14:04:38 +0900, Jean-Hugues ROBERT
><jean_hugues_robert@yahoo.com> ha scritto::
>
> >Is there something like
> >   Class.implementers( meth)
> >that would return a list of all known classes that implement
> >some method ?
>
>this?
>
>  ObjectSpace.each_object(Class){|x| p x if
>x.instance_methods.member?'coerce'}

I haven't played with ObjectSpace yet. Now I can see that it is
an interesting thing ! Thanks.

What I need is almost what you propose. The difference is that
I need to know what classes do actually implement some method,
versus inherit an existing implementation.

i.e.
class X; def meth() end end
class Y < X; end
Class.implementers( :meth) # => X does implement :meth, Y merely inherit it.

It is easy to assert that X actually implements :meth, because
X.superclass does not. However I still don't know how to
filter out Y.

Next step will be to figure out "where" X defines :meth.
A refactoring editor could use that to point to :meth
implementations that may need some refactoring.

Or, regarding my initial need, I could know which file to look
at where :coerce is defined (so that I can understand how it
works, which is something I don't need to do anymore, thanks
to all the gentle answers to my initial question).

Yours,

Jean-Hugues


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