From: David Alan Black <dblack@...>
Date: 2001-12-09T03:31:23+09:00
Subject: [ruby-talk:27953] Re: Module and object extend. Can someone please explain

Hi --

On Sun, 9 Dec 2001, Jim Freeze wrote:

> Hi
>
> Ok, I thought that I had done this in the past, but
> now I cannot seem to get it to work.
> Can someone explain how to extend an object and
> access a Constant?
>
> module M; C=2; def c; puts "c"; end; end
> nil
> irb(main):002:0> class A; end
> nil
> irb(main):003:0> a=A.new
> #<A:0x19e818>
> irb(main):004:0> a.extend(M)
> #<A:0x19e818>
> irb(main):005:0> a.c
> c   # => good, this works
> nil
> irb(main):006:0> a.C
> NameError: undefined method `C' for #<A:0x19e818> # => ??
>         from (irb):6
> irb(main):007:0> a::C  # => ?? How does a access C?
> NameError: undefined method `C' for #<A:0x19e818>
>         from (irb):7


I don't think #extend will give you access to constants defined
in a module:

$ ri extend

---------------------------------------------------------- Object#extend
     obj.extend( [aModule]+> ) -> obj
------------------------------------------------------------------------
     Adds to obj the instance methods from each module given as a
     parameter.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav