From: Trans <transfire@...>
Date: 2008-04-01T09:27:15+09:00
Subject: Re: Suggest alternatives for Facets paramix?



On Mar 31, 7:34 pm, Trans <transf...@gmail.com> wrote:
> I worked on it last night, but it's a tough nut.

Huh... it may have just a fallen into place. What do you think of:

  require 'facets/module/basename'
  require 'facets/module/modspace'

  module Paramix  # or PatrametricMixin ?

    def self.append_features(base)
      base.modspace.module_eval %{
        def #{base.basename.to_s}(parameters, &block)
          Delegator.new(#{base}, parameters, &block)
        end
      }
    end

    # It you want to define the module method by hand. You
    # can use Parmix.new instead of Parmix::Delegator.new.

    def self.new(delegate_module, parameters={}, &base_block)
      Delegator.new(delegate_module, parameters, &base_block)
    end

    #

    class Delegator < Module

      attr :delegate_module
      attr :parameters
      attr :base_block

      def initialize(delegate_module, parameters={}, &base_block)
        @delegate_module = delegate_module
        @parameters      = parameters
        @base_block      = base_block
      end

      def append_features(base)
        base.__send__(:include, delegate_module)
        base.parametric_options[delegate_module] = parameters
        base.module_eval do
          define_method(:parametric_options) do
            base.parametric_options
          end
        end
        base.module_eval(&@base_block) if base_block
      end

      def [](name)
        @parameters[name]
      end

    end

  end


  class Module

    # Store for parametric mixin parameters.
    #
    # Returns a hash, the keys of which are the parametric mixin
module
    # and the values are the parameters associacted with this module/
class.
    #
    #   class C
    #     include P(:x=>1)
    #   end
    #
    #   C.parametric_options[P]   #=> {:x=>1}
    #
    def parametric_options
      @parametric_options ||= {}
    end

  end

  # Try it out

  if __FILE__ == $0

    module O
      include Paramix

      def x
        parametric_options[O][:x]
      end
    end

    # If doing it by hand instead of using include Paramix.
    #def O(options)
    #  Paramix.new(O, options)
    #end

    class X
      include O(:x=>1)
    end

    x = X.new
    p x.x

    p X.ancestors

  end


T.