module Shared
  Shared::VERSION = 0.4.3 unless defined?(Shared::VERSION)
  def version() Shared::VERSION end

  Code = {}

  def shared name, &block
    key = key_for name

    return Code[key] if block.nil?

    m = (Code[key] || Module.new)

    singleton_class(m) do
      unless defined?(@@blocks)
        @@blocks = []

        define_method(:blocks){ @@blocks }

        define_method(:included) do |other|
          blocks.each{|b| other.send(:module_eval, &b)}
        end

        define_method(:extend_object) do |other|
          Shared.singleton_class(other) do
            m.blocks.each{|b| module_eval &b}
          end
        end
      end
    end

    m.blocks << block

    Code[key] ||= m
  end
  
  alias_method 'share', 'shared'

  def key_for name
    name.to_s.strip.downcase
  end

  def singleton_class object, &block
    singleton_class =
      class << object
        self
      end
    block ? singleton_class.module_eval(&block) : singleton_class
  end

  extend self
end

module Kernel
private
  def share *a, &b
    Shared.share *a, &b
  end

  def shared *a, &b
    Shared.shared *a, &b
  end
end