From: Martin DeMello <martindemello@...>
Date: 2004-07-10T15:02:32+09:00
Subject: Re: Functional Ruby (Re: Why I don't use Ruby.)

Sean Russell <ser@germane-software.com> wrote:
> 
> Once again, if you remove the semantic difference between a "method"
> and a "function", you render both useless.  A method is a message sent
> to an object, which then reacts and exhibits some behavior.  A
> function is something that operates on some (optional) argument -- the
> functionality is in no way bound to the object.  One would say that
> given:
> 
>    Ruby:
>    class Obj
>      def foo ; end
>    end
> 
>    Haskell:
>    foo :: Obj
> 
> In Ruby, Obj *knows* about, and is intimate with, foo, which in turn
> knows about Obj[1].  In Haskell, foo() knows about Obj, but Obj knows
> nothing about foo.

I'd say that the difference between a function and a method is that a
method has a distinguished argument, 'this', *within whose scope it
runs*. It's not a matter of Obj knowing about foo, or foo knowing about
Obj, it's a matter of Obj defining its own personal scope within which
foo is run.

martin