From: Robert Klemme <bob.news@...>
Date: 2004-02-01T20:19:53+09:00
Subject: Re: Constant visibility


"Gavin Sinclair" <gsinclair@soyabean.com.au> schrieb im Newsbeitrag
news:1631699911313.20040201160309@soyabean.com.au...
> Folks,
>
> I know this sort of thing has been talked about before, but that's not
> going to stop me :)
>
>   module M
>     X = 5
>     class C
>       def foo
>         puts "X = #{X}"
>       end
>     end
>   end
>
>   class M::C
>     def bar
>       puts "X = #{X}"
>     end
>   end
>
>   M::C.new.foo            # X = 5
>   M::C.new.bar            # NameError: uninitialized constant M::C::X
>
>
> The problem is that when you use 'class M::C' to open a class, you
> can't access constants declared in M, whereas if you use 'module M;
> class C', you can.
>
> 1) Why is this?

Because when doing "class M::C" you're still in another scope while defining
class C.  So you have to explicitely scope constants from module M. (see
below)

> 2) Is is an intentional behaviour of Ruby?

I think so.

> I feel fairly confident that the new constant resolution rules will
> sort this out, but I'm wondering why it can't be made to work now.
>
> ruby 1.8.1 (2004-01-08) [i386-cygwin]
>
> Gavin

irb(main):014:0> module M
irb(main):015:1>   X = 5
irb(main):016:1>   class C
irb(main):017:2>     def foo
irb(main):018:3>       puts "X = #{X}"
irb(main):019:3>     end
irb(main):020:2>   end
irb(main):021:1> end
=> nil
irb(main):022:0>
irb(main):023:0* class M::C
irb(main):024:1>   def bar
irb(main):025:2>     puts "X = #{M::X}"
irb(main):026:2>   end
irb(main):027:1> end
=> nil
irb(main):028:0>
irb(main):029:0* M::C.new.foo
X = 5
=> nil
irb(main):030:0> M::C.new.bar
X = 5
=> nil
irb(main):031:0>

$ ruby --version
ruby 1.8.1 (2003-12-25) [i386-cygwin]

Regards

    robert