deferred class
	BILINEAR [G]

General
	cluster: base.structures.traversing
	description: "Structures that may be traversed forward and backward"

Ancestors
	LINEAR [G]
	LINEAR [G]

Queries
	after: BOOLEAN
	before: BOOLEAN
	changeable_comparison_criterion: BOOLEAN
	exhausted: BOOLEAN
	for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
	has (v: [like item] G): BOOLEAN
	index: INTEGER
	index_of (v: [like item] G; i: INTEGER): INTEGER
	is_empty: BOOLEAN
	item: G
	linear_representation: LINEAR [G]
	object_comparison: BOOLEAN
	occurrences (v: G): INTEGER
	off: BOOLEAN
	there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN

Commands
	back
	compare_objects
	compare_references
	do_all (action: PROCEDURE [ANY, TUPLE [G]])
	do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
	finish
	forth
	search (v: [like item] G)
	start

Constraints
	not both
	before constraint