From: Mathieu Bouchard <matju@...>
Date: 2002-08-12T02:05:13+09:00
Subject: Re: automagic

On Thu, 8 Aug 2002, Tom Sawyer wrote:
> here's the basic problem. if your are trying to bind to an array, for
> example, in the model, how are you going to "trap" changes to that
> array? a model may alter the array via #<< or #sort! or the like, and
> such changes are indifferent to accessor_methods. indeed, you can alter
> an array in this way via an attr_reader method!

MetaRuby (http://artengine.ca/matju/MetaRuby/) does what you want. It
contains a program that allows making arrays and hashes that have #undo
and #redo methods. That program is ~100 lines. I think one can write a
program for observable arrays and hashes (using MetaRuby too) in less than
50 lines.

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Mathieu Bouchard                       http://artengine.ca/matju