From: Brian Candler <b.candler@...>
Date: 2009-10-20T20:50:19+09:00
Subject: Re: instance_eval with method proc

Paul Carey wrote:
> I'm trying to invoke a method defined in one class with self set to an
> instance of a different class.

If the method is in a common superclass, then you can make an 
UnboundMethod and bind it to the new object. e.g.

>> class Foo; def foo; puts inspect; end; end
=> nil
>> class Bar < Foo; end
=> nil
>> b = Bar.new
=> #<Bar:0xb7c04998>
>> Foo.instance_method(:foo).bind(b).call
#<Bar:0xb7c04998>
=> nil
>> 

But otherwise I don't think you can detach arbitrary methods from one 
class and apply them to an object of an unrelated class. You'd probably 
be best putting the relevant method(s) in a mixin, and then sharing that 
between the classes, or adding those methods to the singleton class of 
the individual object you're interested in.

>> module Baz; def baz; puts "baz!"; end; end
=> nil
>> s = "hello"
=> "hello"
>> s.extend Baz
=> "hello"
>> s.baz
baz!
=> nil
>> 
-- 
Posted via http://www.ruby-forum.com/.