note

	description:
		"Cursors for linked lists";

	status: "See notice at end of class";
	names: linked_list_cursor, cursor;
	contents: generic;
	date: "$Date$";
	revision: "$Revision$"

class LINKED_LIST_CURSOR [G] inherit

	CURSOR

create

	make

feature {LINKED_LIST} -- Initialization

	make (active_element: like active; aft, bef: BOOLEAN)
			-- Create a cursor and set it up on `active_element'.
		do
			active := active_element;
			after := aft;
			before := bef
		end;

feature {LINKED_LIST} -- Implementation

	active: LINKABLE [G];
			-- Current element in linked list

	after: BOOLEAN;
			-- Is there no valid cursor position to the right of cursor?

	before: BOOLEAN;
			-- Is there no valid cursor position to the right of cursor?

invariant
	not_both: not (before and after);
	no_active_not_on: active = Void implies (before or after)

end -- class LINKED_LIST_CURSOR


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