#--
# BlankSlate
#
# Copyright 2004 by Jim Weirich (jim@weirichhouse.org).
# All rights reserved.
#
# Permission is granted for use, copying, modification, distribution,
# and distribution of modified versions of this work as long as the
# above copyright notice is included.
#
# ==========================================================================
# Revision History ::
# --------------------------------------------------------------------------
#  2005.04.28 Trans  * Ported to Mega Modules.
# ==========================================================================
#++

# :title: BlankSlate
#
# BlankSlate provides an abstract base class with no predefined
# methods (except for <tt>\_\_send__</tt> and <tt>\_\_id__</tt>).
# BlankSlate is useful as a base class when writing classes that
# depend upon <tt>method_missing</tt> (e.g. dynamic proxies).
class BlankSlate
  class << self
    def hide(name)
      undef_method name if
      instance_methods.include?(name.to_s) and
      name !~ /^(__|instance_eval)/
    end
  end
  instance_methods.each { |m| hide(m) }
end

# Since Ruby is very dynamic, methods added to the ancestors of
# BlankSlate <em>after BlankSlate is defined</em> will show up in the
# list of available BlankSlate methods.  We handle this by defining a hook
# in the Object and Kernel classes that will hide any defined.
module Kernel
  class << self
    alias_method :blank_slate_method_added, :method_added
    def method_added(name)
      blank_slate_method_added(name)
      return if self != Kernel
      BlankSlate.hide(name)
    end
  end
end

class Object
  class << self
    alias_method :blank_slate_method_added, :method_added
    def method_added(name)
      blank_slate_method_added(name)
      return if self != Object
      BlankSlate.hide(name)
    end
  end
end