From: Robert Klemme <bob.news@...>
Date: 2004-01-22T04:24:59+09:00
Subject: Re: Modules as namespace


"Hal Fulton" <hal9000@hypermetrics.com> schrieb im Newsbeitrag
news:400EBE6A.4080106@hypermetrics.com...
> George Moschovitis wrote:
> > Hello everyone,
> >
> > I would like to now if the following snippets of code are equivalent:
> >
> > --->
> >
> > module My; module Little; module Namespace;
> >
> > class Foo
> > end;
> >
> > end; end; end
> >
> > <---
> >
> > module My::Little::Namespace;
> >
> > class Foo
> > end;
> >
> > end;

That doesn't work.  However, you can do

irb(main):003:0> module Outer; module Inner; end; end
=> nil
irb(main):004:0> class Outer::Inner::Foo;end
=> nil
irb(main):005:0> Outer::Inner::Foo.new
=> #<Outer::Inner::Foo:0x10194548>

> > are those snippets exactly the same? Ie i can do:
> >
> > foo = My::Little::Namespace::Foo.new?

Yes, you can.  But that's not the same as code snippet 1 and code snippet 2
are "exactly the same". :-)

> First of all, you can only do this when the modules already
> exist. (How should the interpreter know whether Little is
> a class or module?)
>
> Second of all, I think you need parens because of a
> precedence issue:
>
>    foo = (My::Little::Namespace::Foo).new?
>
> Refer to a question I asked last week, something like "Nested
> classes and the Singleton pattern", and see Nobu's reply.

Hmmm...

irb(main):001:0> module Outer; module Inner; class Foo; end; end; end
=> nil
irb(main):002:0> Outer::Inner::Foo.new
=> #<Outer::Inner::Foo:0x10199f60>

Regards

    robert