[ruby-core:33396] Re: [Ruby 1.9-Feature#4085][Open] Refinements and nested methods

Hi,

2010/11/26 Magnus Holm <[e-mail]>:
> Woah, this is very nice stuff! Some comments/questions:
>
> 1. Could you give an example of how it would behave if it had local
> rebinding as in classbox?

If it had local rebinding, the following code would print "Quux::Foo#bar".

class Foo
  def bar
    puts "Foo#bar"
  end

  def baz
    bar
  end
end

module Quux
  refine Foo do
    def bar
      puts "Quux::Foo#bar"
    end
  end
end

using Quux
foo =3D Foo.new
foo.baz

> 2. I don't like the idea of having both #using and #include. I don't
> want to think about which one to use; I just want to use the module! I
> think this is getting even more messy than with the new mixin-feature.
> Even right *now* people only use #include (and def included(mod);
> mod.extend ClassMethods; end) because That's How Modules Work=99.

Matz doesn't like it, but I think it's worth considering.
However, it's a problem that we have main#include, where main is self
at the top-level, but not Kernel#include now.

> 3. Is this expected behaviour?
>
> module Ext
> =A0refine(Object) do
> =A0 =A0def to_json; "something"; end
> =A0end
> end
>
> Fixnum.send(:using, Ext)
> "Hello".to_json # =3D> Works because #using worked at the file scope

It is intended.

> This makes it impossible to add refinements within a included-callback.

If a binding is passed to include, it may be possible as follows:

  module Foo
    refine XXX do ... end
    def do_something
    end
    ...
    def self.included(klass, binding)
      eval("using Foo", binding)
    end
  end

  class Bar
    include Foo
    # both do_something and refinements are available
  end

It's necessary to check the arity of included for backward compatibility.

Currenty, you can use a used-callback instead.

  module Foo
    refine XXX do ... end
    def do_something
    end
    ...
    def self.used(klass)
      klass.send(:include, self)
    end
  end

  class Bar
    using Foo
  end

--=20
Shugo Maeda