From: Gary Weaver <lists@...>
Date: 2012-09-27T06:09:55+09:00
Subject: Re: Adding method on module class to yield and allow setting of attributes?

"Jesús Gabriel y Galán" <jgabrielygalan@gmail.com> wrote in post 
#1077681:
> On Wed, Sep 26, 2012 at 10:41 PM, Gary Weaver <lists@ruby-forum.com>
> wrote:
>>
>>> You could do this:
>>>
>> That is helpful, but I have a way to do a hash easily already via
>> exactly like that, but originally I thought this would be doable, and am
>> just kind of stuck. Ilia had suggested ActiveSupport::Configurable on
>> the list but it requires config to be sent in as a parameter and I was
>> hoping to allow method definition and not have to specify the
>> config.varname = ...
>
> I don't know if my previous message got through. If you can handle
> some changes in the syntax, using self. before the attributes and the
> method names should work if you do a class_eval:
>
> 1.9.2p290 :013 > module MyModule
> 1.9.2p290 :014?>     class << self
> 1.9.2p290 :015?>         attr_accessor :foo
> 1.9.2p290 :016?>     alias_method :foo?, :foo
> 1.9.2p290 :017?>     def configure(&blk)
> 1.9.2p290 :018?>       class_eval(&blk)
> 1.9.2p290 :019?>       end
> 1.9.2p290 :020?>     end
> 1.9.2p290 :021?>   end
>  => nil
> 1.9.2p290 :022 > MyModule.configure do
> 1.9.2p290 :023 >     def self.test; puts "test"; end
> 1.9.2p290 :024?>   end
>  => nil
> 1.9.2p290 :025 > MyModule.test
> test
>  => nil
>
>
>
> Jesus.

Thank you, Jesus! That's exactly what I was looking for!

module MyModule
  class << self
    attr_accessor :foo, :time
    alias_method :foo?, :foo
    def configure(&blk)
      class_eval(&blk)
    end
  end
end

MyModule.foo # nil
MyModule.time # nil

MyModule.configure do
  self.foo = false
  def self.time; Time.now; end
end

MyModule.foo # false
MyModule.time # current date and time

Gary

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