From: "Chr. Rippel" <chr_news@...>
Date: 2001-12-09T18:38:11+09:00
Subject: [ruby-talk:28015] Re: Module ext not accessable by class function?


"Jim Freeze" <jim@freeze.org> wrote in message
news:20011208215921.P97542-100000@www.stelesys.com...
> Hi:
>
> Can someone explain why Base.in_C does not see the in_C function.
>
>  cat test.rb
> #! /usr/local/bin/ruby
>
> module A
>   module B
>     module C
>       def in_C
>         puts "in_C"
>       end#in_C
>     end# module C
>
>     class Base
>       include C
>       def initialize
>         in_C()
>       end#initialize
>       def Base.in_C
>         C::in_C()
>       end#Base.in_C
>     end# class Base
>
>   end# module B
> end# module A
>
> include A::B
> b = Base.new
> b.extend(C)
> b.in_C
> Base.in_C # <= why does this not see C::in_C?
>
>
>  ./test.rb
> in_C
> in_C
> /test.rb:17:in `in_C': undefined method `in_C' for A::B::C:Module
> (NameError)
>         from ./test.rb:28
You never defined a module method A::B::C.in_C (only an instance method
with the same name). The error would goes away if you add this snippet to
your code

-------------
module A
module B
def C.in_C
         puts "in_C"
       end#in_C
end
end
-------------

Furthermore your problem about the visiblity of class constants is
probably an effect of class constant scoping rules - Note the scoping
rules for  class/module variables are very different.

-------------
module A
  Veil = "Hitten Beauty"
end

module A
  def self.visible
    p Veil
  end
end

def A.explicit_scope
  p A::Veil
end

def A.constant_surprise?
  begin
      Veil
  rescue NameError => mes
    p mes
  end
end


A.visible             # => Hitten Beauty
A.explicit_scope # => Hitten Beauty
A.constant_surprise? # => <NameError: uninitialized constant Veil>

-------------



>
> Thanks
>
> =========================================================
> Jim Freeze
> jim@freeze.org
> ---------------------------------------------------------
> Today is a fine day for Ruby programming.
> http://www.freeze.org
> =========================================================
>