Contents

#--
# Uninheritable
#
# Copyright (c) 2003 Austin Ziegler
#
# Ruby License
#
# This module is free software. You may use, modify, and/or redistribute this
# software under the same terms as Ruby.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.
#
# ==========================================================================
#  Revision History
# ==========================================================================
#
#  2003.9.17  Austin Ziegler
#    - Minor modifications to documentation.
#
# ==========================================================================
#++

#:title: Uninheritable
#
# Allows an object to declare itself as unable to be subclassed. The
# technique behind this is very simple (redefinition of #inherited), so this
# just provides an easier way to do the same thing with a consistent error
# message.
#
# == Usage
#
#   require 'mega/uninheritable'
#
#   class A
#     extend Uninheritable
#   end
#
#   class B < A; end # => raises TypeError
#
# == Author(s)
#
# * Austin Ziegler
#

module Uninheritable
  # Redefines a class's #inherited definition to prevent subclassing of the
  # class extended by this module.
  def inherited(klass)
    raise TypeError, "Class #{self} cannot be subclassed."
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
mega-0.3.1	lib/mega/uninheritable.rb