Contents

require 'facets/more/functor.rb'

module Kernel

  # Returns a Functor that allows one to call any parent method directly.
  #
  #   class A
  #     def x ; 1 ; end
  #   end
  #
  #   class B < A
  #     def x ; 2 ; end
  #   end
  #
  #   class C < B
  #     def x ; as(A).x ; end
  #   end
  #
  #   C.new.x  #=> 1
  #
  def as( klass=nil, &blk )
    selfclass = Kernel.instance_method(:class).bind(self).call
    klass ||= selfclass.superclass
    if selfclass.ancestors.include?(klass)
      Functor.new do |meth, *args|  # &blk|
        klass.instance_method(meth).bind(self).call(*args) # ,&blk)
      end
    else
      raise ArgumentError, "#{klass} is not an ancestor"
    end
  end

=begin
  def as( role, &blk )
    unless role.is_a?(Class)
      role = self.class.const_get( role )
    end
    @roles ||= {}
    @roles[role] ||= role.allocate
    robj = @roles[role]
    robj.assign_from( self )
    result = robj.instance_eval( &blk )
    self.assign_from( robj )  # w/o this much like namespaces
    result
  end
=end

end



#  _____         _
# |_   _|__  ___| |_
#   | |/ _ \/ __| __|
#   | |  __/\__ \ |_
#   |_|\___||___/\__|
#
=begin test

  require 'test/unit'

  class TCKernel < Test::Unit::TestCase
    class A
      def x; "A.x"; end
      def y; "A.y"; end
    end
    class B < A
      def x; "B.x" end
      def y; "B.y" end
    end
    class C < B
      def x; "C.x"; end
      def y; as.x ; end
    end

    def setup
      @c = C.new
    end

    def test_as
      assert_equal("B.x", @c.y)
      assert_equal("C.x", @c.x)
    end
  end

=end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
facets-1.2.0	lib/facets/core/kernel/as.rb
facets-1.2.1	lib/facets/core/kernel/as.rb