Newbie question about Pickaxe example

ruby-talk
1

Hi to everyone,

I'm just approaching ruby (so far I like it) coming from Python and other OO languages.

I've bought the new edition of the famous "Pickaxe" book and I'm having a little difficulties understanding a piece of code.

There's a paragraph (on page 354 for those who have that book) about "Module Definitions" which contains the following snippet of code:

CONST="outer"
module Mod
     CONST=1
     def Mod.method1()
         CONST + 1
     end
end

module Mod::Inner
     def (Mod::Inner).method2()
         CONST + " scope"
     end
end

well, this last part is the one causing me difficulties.

"::" is the scope resolutor, and so far so good, but "Mod::Inner" what is it?
"Inner" ought to be a constant judging from the name conventions.
Is it a predefinite one, or what?

I imagine that the definition under "Mod::Inner" are meant to insert "method2" in the module "Mod". Just can't figure why "Mod::Inner".

Thanks in advance for your help.

Regards,
Carmine Moleti

2

module Mod::Inner

here it define the module Inner under the module Mod

     def (Mod::Inner).method2()

it define a method for this module (Mod::Inner)

         CONST + " scope"
     end
end

it's written like this, to see the difference with this

   module Mod
      module Inner
         def self.method2
            CONST + "scope"
         end
      end
   end

   Mod::Inner.method2 # in `+': String can't be coerced into Fixnum

Guy Decoux

3

Hi Guy,

Thanks for your clarification. It's clear now.

Regards,
Carmine Moleti