From: Gary Wright <gwtmp01@...>
Date: 2011-04-07T05:50:38+09:00
Subject: Re: Proc#== behaviour (from Ruby-Core)


On Apr 6, 2011, at 9:11 AM, Adam Prescott wrote:
> I've encountered a problem when using Proc#== (with both lambdas and procs)
> in my code, where the result does not match up with what the documentation
> says. 1.9.2 differs from 1.8.7 in result and in the source code, so that
> suggests attention has been given to the method, at least. It was suggested
> that ruby-core was the place to go for this.

I've run into this issue in the past.  One of the issues is that the binding associated with a proc can be different even if the 'source' of the binding is the same.  I think that is enough to ensure that the proc's won't be considered equal via ==.

You can dup or clone a proc in 1.9.2 to get equivalent procs even though the bindings still aren't equal:

l1 =ruby-1.9.2-p180 > l1 = lambda { 1 + 1 }
 => #<Proc:0x8aa8a4@(irb):1 (lambda)> 
ruby-1.9.2-p180 > l2 = lambda { 1 + 1 }
 => #<Proc:0x87a848@(irb):2 (lambda)> 
ruby-1.9.2-p180 > l1 == l2
 => false 
ruby-1.9.2-p180 > l3 = l1.clone
 => #<Proc:0x8759ec@(irb):1 (lambda)> 
ruby-1.9.2-p180 > l1 == l3
 => true 
ruby-1.9.2-p180 > l1.binding == l3.binding
 => false 


I don't really have a conclusion, just wanted to point out the binding issue and the dup/clone behavior.

Gary Wright