class Module

  #private  # (we'll leave this one public for AOP-like uses).

  # Creates a new method wrapping the previous of the same name.
  # Reference to the old method is passed into the new definition
  # block as the first parameter.
  #
  #   class WrapExample
  #     def foo
  #       "foo"
  #     end
  #
  #     wrap_method(:foo) do |old_meth, *args|
  #       old_meth.call + '!'
  #     end
  #   end
  #
  #   example = WrapExample.new
  #   example.foo #=> 'foo!'
  #
  # Keep in mind that this cannot be used to wrap methods
  # that take a block.
  #
  # CREDIT: Trans

  def wrap_method( sym, &blk )
    old = instance_method(sym)
    define_method(sym) { |*args| blk.call(old.bind(self), *args) }
  end

  alias_method :wrap, :wrap_method

end