indexing
	description: "Abstraction for objects that may be parented."
	status: "See notice at end of class"
	keywords: "parentable, containable, child"
	date: "$Date$"
	revision: "$Revision$"

deferred class interface
	EV_CONTAINABLE

feature -- Access

	data: ANY
			-- Arbitrary user data may be stored here.
			-- (from EV_ANY)
	
feature -- Status report

	parent: EV_ANY
			-- The parent that Current is contained within, if any.
		require
			not_destroyed: not is_destroyed
	
feature -- Element change

	set_data (some_data: like data)
			-- Assign some_data to data.
			-- (from EV_ANY)
		require -- from EV_ANY
			not_destroyed: not is_destroyed
		ensure -- from EV_ANY
			data_assigned: data = some_data
	
feature -- Duplication

	copy (other: like Current)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
			-- (from EV_ANY)
		require -- from ANY
			other_not_void: other /= void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)
	
feature -- Command

	destroy
			-- Destroy underlying native toolkit object.
			-- Render Current unusable.
			-- (from EV_ANY)
		ensure -- from EV_ANY
			is_destroyed: is_destroyed
	
feature -- Status Report

	is_destroyed: BOOLEAN
			-- Is Current no longer usable?
			-- (from EV_ANY)
		ensure -- from EV_ANY
			bridge_ok: Result = implementation.is_destroyed
	
invariant

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)
		-- from EV_ANY
	is_initialized: is_initialized
	is_coupled: implementation /= void and then implementation.interface = Current
	default_create_called: default_create_called

end -- class EV_CONTAINABLE