From: Rob Biedenharn <Rob@...>
Date: 2010-08-10T05:46:14+09:00
Subject: Re: modules


On Aug 9, 2010, at 4:36 PM, Andrew Wagner wrote:
>
> On Mon, Aug 9, 2010 at 4:23 PM, Mickael Faivre-Macon <faivrem@gmail.com 
> >wrote:
>
>> Hi,
>>
>> I don't understand how to use modules.
>> Could someone explain this to me please ?
>>
>> module Test
>> def yo
>>   puts 'yo'
>> end
>> end
>>
>> Test.yo # undefined method `yo' for Test:Module
>>
>> Mickael.
>> --
>> Posted via http://www.ruby-forum.com/.

>
> Modules in ruby have a lot of similarities to classes (in fact, Class
> inherits from Module). Anyway, for this reason, it should make sense  
> that
> you want to define "self.yo" instead of just "yo", because it's a
> module-level method, not some sort of instance method.
>
> Once you do that, to use the module as a scope, you use two colons.  
> So, the
> correct code is:
>
> module Test
>  def self.yo
>    puts 'yo'
>  end
> end
>
> Test::yo #=> yo

Or, if you want to use a module to hold methods to be mixed in to  
another class:

irb> module Test
irb>    def yo
irb>        puts 'yo'
irb>      end
irb>   end
=> nil
irb> class Toy
irb>   include Test
irb>   end
=> Toy
irb> Toy.new.yo
yo
=> nil

It all depends on what you want to do.

-Rob

Rob Biedenharn		
Rob@AgileConsultingLLC.com	http://AgileConsultingLLC.com/
rab@GaslightSoftware.com		http://GaslightSoftware.com/