From: Paul Brannan <pbrannan@...>
Date: 2002-09-14T00:43:26+09:00
Subject: Re: not grasping the method overloading/multi-dispatch thing

On Fri, Sep 13, 2002 at 05:51:48PM +0900, Pit Capitain wrote:
> Paul, in the former thread Robert Feldt showed another 
> implementation in [ruby-talk:26792] that lets you do what you 
> asked for. I came up with the following implementation based on 
> Robert's code. Don't know why I didn't post it to the list then. 
> Maybe because it still lacks some necessary features.
> 

Definitely looks cool!

Some issues (and "necessary features" that are lacking):

  1) Passing a block to overload() means that you don't have access to
     instance variables (self isn't set properly when the block is
     called).

     Maybe it would be nifty if Ruby gave the user an interface to
     change a Proc's "self".

  2) I don't like passing a string to class_eval.  I think this could be
     implemented with define_method.

  3) Ideally I should be able to pass a block to the method.

  4) The dispatch method is O(n).  I wish I had a good solution to this
     problem; iterating over all the ancestors of all the arguments is
     likely to be slower (a giant table of all possible signatures could
     be kept, if we had a callback for knowing when a class gets a new
     subclass).

Paul