From: Austin Ziegler <austin@...>
Date: 2002-11-13T23:51:29+09:00
Subject: Re: How do module functions work?

On Wed, 13 Nov 2002 18:41:50 +0900, Gavin Sinclair wrote:
> From: "Yukihiro Matsumoto" <matz@ruby-lang.org> 
>>| Why do you have to use Module#module_function in order to be
>>| able to call
>>| Foo::bar()

>>| And why does it create a copy of the method? I don't understand
>>| the mechanics at play here.
>> Instance methods and class methods (or module method) are totally
>> different entities, so that you have to copy instance methods to
>> make them callable as class methods.
> So how does it get copied? Can it be expressed in Ruby (like
> attr_accessor), or is it more magical that that.

  module Foo
    def bar
      "Foo::bar"
    end
  end

The only way you can get at this Foo#bar is to include it (which
strips the module as a namespace). The two definitions below are
functionally equivalent:

  module Foo
    def bar
      "Foo::bar"
    end
    def Foo.bar
      "Foo::bar"
    end
  end

  module Foo
    def bar
      "Foo::bar"
    end
    module_function :bar
  end

-austin
-- Austin Ziegler, austin@halostatue.ca on 2002.11.13 at 09.47.56