From: Robert Klemme <bob.news@...>
Date: 2004-11-24T18:23:01+09:00
Subject: Re: adding class-methods via modules


"John Wilger" <johnwilger@gmail.com> schrieb im Newsbeitrag
news:a05e51b6041123084753f0aa8@mail.gmail.com...
> Hello,
>
> I have a module which, when a class includes the module, I would like
> to have it add certain class-methods to the including class.
> Currently, I am doing the following:
>
> module Foo
>   def self.included(mod)
>     mod.class_eval <<-EOF, __FILE__, __LINE__+1
>     def self.bar
>       ...
>     end
>     EOF
>   end
> end
>
> class Baz
>   include Foo
> end
>
> This does accomplish the end goal---Baz::bar is a valid class
> method---but it has the downside that RDoc doesn't pick up the class
> methods defined inside Foo::included for documentation purposes.
>
> Is there either a) a way to get RDoc to pick up documentation for the
> ::bar method (and simply document it as Foo::bar), or b) a better way
> of creating these class methods on classes that include Foo that will
> also allow RDoc to document these methods?

Two options for b) come to mind:

# option 1
module Foo
  module FooClassMethods
    def bar() puts "#bar#" end
  end

  def self.included(mod)
    class <<mod
      include FooClassMethods
    end
  end
end

# option 2
module Foo2
  def self.included(mod)
    class <<mod
      def bar2() puts "#bar2#" end
    end
  end
end

class Baz
  include Foo
  include Foo2
end

Baz.bar
Baz.bar2

Personally I'd prefer option 1, because you end up with less method
definitions and if you change definitions in FooClassMethods later all
classes that included Foo will use the new definitions.

Kind regards

    robert