From: Shannon Fang <xrfang@...>
Date: 2002-12-19T04:02:49+09:00
Subject: Re: Mommy, where do methods come from?

Probably you need to traverse through the ancestor tree and use a "-" 
operation on the arrays returned by #instance_method to decide which 
ancestor defined the method?

I remember I have asked the question before...

Shannon


>From: dblack@candle.superlink.net
>Reply-To: ruby-talk@ruby-lang.org
>To: ruby-talk@ruby-lang.org (ruby-talk ML)
>Subject: Re: Mommy, where do methods come from?
>Date: Thu, 19 Dec 2002 03:52:07 +0900
>
>Hi --
>
>On Thu, 19 Dec 2002, Chris Pine wrote:
>
> > (Sorry for the subject; couldn't help myself! :)
> >
> > My (quite serious) question:
> >
> > Is there a way to tell in which module an object's method was defined?
> >
> > For example:
> >
> >   class Foo
> >     def to_s; 'foo'; end
> >   end
> >
> >   class Bar; end
> >
> >   foo = Foo.new
> >   bar = Bar.new
> >
> >   foo.methodClass :to_s  #  Hopefully returns Foo.
> >   bar.methodClass :to_s  #  Hopefully returns Object.
> >
> >
> > Furthermore, is there a way to tell all of the modules which did define 
>a
> > method for a given object?
> >
> >   foo.methodClasses :to_s  #  Hopefully returns [Foo, Object].
>
>   class Object
>     def mc(meth,mess)
>       self.class.ancestors.send(mess) {|mod|
>	mod.instance_methods.include?(meth.to_s)
>       }
>     end
>
>     def method_class(meth)
>       mc(meth,:detect)
>     end
>
>     def method_classes(meth)
>       mc(meth,:select)
>     end
>   end
>
>   p "".method_class("to_s")          # String
>   p Object.new.method_class("to_s")  # Kernel
>   p "".method_classes("to_s")        # [String, Kernel]
>
>   class Foo
>     def to_s; end
>   end
>
>   foo = Foo.new
>   p foo.method_classes("to_s")       # [Foo, Kernel]
>
>
>David
>
>--
>David Alan Black
>home: dblack@candle.superlink.net
>work: blackdav@shu.edu
>Web:  http://pirate.shu.edu/~blackdav


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