From: matz@... (Yukihiro Matsumoto)
Date: 2003-02-20T01:54:55+09:00
Subject: Re: module This::Encompassing::That

Hi,

In message "Re: module This::Encompassing::That"
    on 03/02/20, nathaniel@NOSPAMtalbott.ws <nathaniel@NOSPAMtalbott.ws> writes:

|Do you mean that
|
|  module A
|  end
|
|  class A::B
|  end
|
|and
|
|  class C
|  end
|
|  module C::D
|  end
|
|would both be errors?

No, the former would not be an error, since

  class A::B
  end

is equivalent to

  module A
    class B
    end
  end

The latter would be an error, because

  module C::D
  end

is equivalent to

  module C
    module D
    end
  end

that causes class/module contradiction.

|Why? It seems that if I already created the
|container(s) (which I think should be required), I should be able to put
|either a module or a class inside of them, regardless of whether they're
|a module, a class, or both.

Because classes and modules are not always exchangeable.  Making them
too "smart" delays error detection.  For example, two files use name A
for different purpose, one for module, one for class:

 a.rb:
  class A
  end

 b.rb:
  module A::B
  end

then if you load "b.rb" first, you will get error.  What if you load
"a.rb" first?  I think it should report error.  Otherwise you can't
tell whether A is a class or a module from the source without global
analysis, or worse, it might vary time to time.

							matz.