From: Florian Gross <flgr@...>
Date: 2005-01-26T06:10:53+09:00
Subject: Re: Injecting methods from one class into another.

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George Moschovitis wrote:

> Can anyone give me an example, where this #bind method is usefull? I
> mean,  you can only bind a Method back to an object of the original
> method's Class or a Subclass. But such an object allready has this
> method, so whats the point?

If you're subclass provides an overwritten version of the base method 
this trick still allows you to call the base one:

irb(main):012:0> Object.instance_method(:to_s).bind(2459).call
=> "#<Fixnum:0x1337>"
irb(main):013:0> Object.instance_method(:to_s).bind(nil).call
=> "#<NilClass:0x4>"

This can for example be used to implement a super() that skips over some 
of the inheritance chain members (see attachment.) or for sand boxes 
were you want to make sure that you are calling a secure method that is 
defined in Object and not an eventually overwritten version of it.


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