    deferred class
    	CURSOR_STRUCTURE [G]

    General
    	cluster: base
    	description:
    		"Active structures, which always have a current position
    		accessible through a cursor."

    Ancestors
    	ACTIVE* [G]

    Queries
    	changeable_comparison_criterion: BOOLEAN
    	cursor: CURSOR
    	extendible: BOOLEAN
    	has (v: G): BOOLEAN
    	is_empty: BOOLEAN
    	is_inserted (v: G): BOOLEAN
    	item: G
    	linear_representation: LINEAR [G]
    	object_comparison: BOOLEAN
    	occurrences (v: G): INTEGER_32
    	prunable: BOOLEAN
    	readable: BOOLEAN
    	valid_cursor (p: CURSOR): BOOLEAN
    	writable: BOOLEAN

    Commands
    	compare_objects
    	compare_references
    	extend (v: G)
    	fill (other: CONTAINER [G])
    	go_to (p: CURSOR)
    	prune (v: G)
    	prune_all (v: G)
    	put (v: G)
    	remove
    	replace (v: G)
    	wipe_out