From: Gary Weaver <lists@...>
Date: 2012-09-27T06:15:16+09:00
Subject: Re: Adding method on module class to yield and allow setting of attributes?

Calvin B. wrote in post #1077674:
> Hi,
>
> first off, you're not that wrong with your idea. There are two things
> which need to be changed.
>> MyModule.configure do
>>    foo = false
>> end
> The local variable foo is just that - a local variable. You want it to
> be a class instance variable, so you need to precede it with an @.
>
>> etc. I just want to be able to call the methods created by the
>> attr_accessor I used to set and get attributes. The reasons I'm doing
>> this to a module and not a class is it is convenient since it is the
>> module that my Gem's classes use.
> You don't need to use an external library. The thing you did wrong in
> your configure method is that it executes the block in the scope of it's
> creation, so even if you use the @, it is not a variable in the
> class/module scope. So what you need to do is call class_eval with the
> block as a parameter:
>    def configure( &block ); class_eval &block; end

Calvin,

Thanks! That is even shorter. It is nice to have both options available, 
so when do:

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

can do either:

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

or

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

That is so awesome! Thanks for everyone's help!

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