note
	description: "[
		Finite sequences: structures where existing items are arranged
		and accessed sequentially, and new ones can be added at the end.
		]"
	library: "Free implementation of ELKS library"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	names: sequence;
	access: cursor, membership;
	contents: generic;
	date: "$Date$"
	revision: "$Revision$"

deferred class SEQUENCE [G] inherit

	ACTIVE [G]
		redefine
			prune_all
		end

	BILINEAR [G]

	FINITE [G]

feature -- Status report

	readable: BOOLEAN
			-- Is there a current item that may be read?
		do
			Result := not off
		end

	writable: BOOLEAN
			-- Is there a current item that may be modified?
		do
			Result := not off
		end

feature -- Element change

	force (v: like item)
			-- Add `v' to end.
		require
			extendible: extendible
		do
			extend (v)
		ensure then
	 		new_count: count = old count + 1
			item_inserted: has (v)
		end

	append (s: SEQUENCE [G])
			-- Append a copy of `s'.
		require
			argument_not_void: s /= Void
		local
			l: like s
		do
			l := s
			if s = Current then
				l := twin
			end
			from
				l.start
			until
				l.exhausted
			loop
				extend (l.item)
				l.forth
			end
		ensure
	 		new_count: count >= old count
		end

	put (v: like item)
			-- Add `v' to end.
		do
			extend (v)
		ensure then
	 		new_count: count = old count + 1
		end

feature -- Removal

	prune (v: like item)
			-- Remove the first occurrence of `v' if any.
			-- If no such occurrence go `off'.
		do
			start
			search (v)
			if not exhausted then
				remove
			end
		end

	prune_all (v: like item)
			-- Remove all occurrences of `v'; go `off'.
		do
			from
				start
			until
				exhausted
			loop
				search (v)
				if not exhausted then
					remove
				end
			end
		end

note
	copyright: "Copyright (c) 1984-2018, Eiffel Software and others"
	license:   "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
			Eiffel Software
			5949 Hollister Ave., Goleta, CA 93117 USA
			Telephone 805-685-1006, Fax 805-685-6869
			Website http://www.eiffel.com
			Customer support http://support.eiffel.com
		]"

end