From: Ed Howland <ed.howland@...>
Date: 2005-10-27T08:24:33+09:00
Subject: Re: [ANN] [RCR] Cut-based AOP

On 10/18/05, Trans <transfire@gmail.com> wrote:
> This is to "officially" announce an RCR that I posted to RCR archive
> two days ago. I realize the RCR itself is a bit dense and techincial,
> so (with thanks to ES) I thought it might be a good idea to provide a
> little summary and some examples of what it's all about and why it's a
> such a good approach to AOP for Ruby.
>

The concept seems clear to me. But I have an aditional question. Will 
cuts be allowed on root classes that are themselves extruded from a
'C' extension? E.g. I don't really know if class IO is mostly C
extension stuff, but could a cut be applied to these class types?
Kernel? Object?

cut AspectIO < IO
   def puts(*args)
      # do something with the args
      super
   end
end

If I am understanding the syntax correctly. I don't know how the
internal hooking mechanism works here. But even if IO#puts is a
low-level C funtion, then super could just map to it, instead of the
normal ruby implementation of the method.

If so, then this could be a very powerful mechanism in Unit Testing:
(Again, forgive me if the syntax is wrong, here.)

class IOTest < Test::Unit::TestCase
   @output = ''
   cut AspectIO < IO
      def puts(*args)
         @output = args.to_s
         super
      end
   end

   def setup
      @oldio = $stdio
      $stdio = IO.new
   end

   def test_hello
      puts "Hello world"    # having the advantage of making @output
avail to assertions
                                    # and spewing contents in the console.
      assert_equals "Hello world", @output
   end

   def teardown
      $stdio = @oldio
   end
end

Is this acceptable in the RCR design? Was it already implied?

Thanks
Ed