From: matt@... (matt neuburg)
Date: 2009-06-07T04:30:07+09:00
Subject: Re: code organization

Li Chen <chen_li3@yahoo.com> wrote:

> Hi all,
> 
> What are the differences bewteen the following code organization?
> What situations are preferred by each one?
> 
> Thanks,
> 
> Li
> 
> #######code 1#############
> module A
>    class B end
>    class C end
> end
> 
> 
> 
> #######code 2#############
> class B
>    include module A
> end
> 
> class C
>   include module A
> end

They are totally different, and they illustrate the two main purposes of
a module. Neither is legal as you have it so I will change the code to
make it legal.

##### 1 ######

module A
   class B
   end
end
A::B.new

A is a namespace, so you must say A::B from outside module A to refer to
B.

##### 2 #####

module A
   def hello
     p "howdy"
   end
end
class B
  include A
end
B.new.hello

Module A's instance methods are copied into class B as instance methods
("mixin").

m.

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