    indexing
    	description: "[
    		Objects that are able to iterate over cursor trees,
    		on which they can perform repeated actions and tests according
    		to a number of predefined control structures such as ``if'',
    		``until'' and others.
    	]"
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	names: iterators, iteration, cursor_tree_iterators, cursor_tree_iteration, tree_iterators, tree_iteration
    	exploration: depth_first, breadth_first
    	traversal: preorder, postorder, inorder
    	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
    	revision: "$Revision: 56675 $"

    class interface
    	CURSOR_TREE_ITERATOR [G]

    create
    	default_create
    			-- Process instances of classes with no creation clause.
    			-- (Default: do nothing.)
    			-- (from ANY)

    feature -- Initialization

    	set (s: like target)
    			-- Make `s' the new target of iterations.
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			target_exists: s /= Void
    		ensure -- from ITERATOR
    			target = s
    			target /= Void

    feature -- Access

    	generating_type: STRING_8
    			-- Name of current object's generating type
    			-- (type of which it is a direct instance)
    			-- (from ANY)

    	generator: STRING_8
    			-- Name of current object's generating class
    			-- (base class of the type of which it is a direct instance)
    			-- (from ANY)

    	item: G
    			-- The item at cursor position in target
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			traversable_exists: target /= Void

    	item_tuple: TUPLE [G]
    			-- Tuple containing a single element,
    			-- the item at cursor position in target''
    			-- (from LINEAR_ITERATOR)

    feature -- Comparison

    	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void
    			-- or attached to isomorphic object structures?
    			-- (from ANY)
    		ensure -- from ANY
    			shallow_implies_deep: standard_equal (some, other) implies Result
    			both_or_none_void: (some = Void) implies (Result = (other = Void))
    			same_type: (Result and (some /= Void)) implies some.same_type (other)
    			symmetric: Result implies deep_equal (other, some)

    	frozen equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached
    			-- to objects considered equal?
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

    	is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object considered
    			-- equal to current object?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			symmetric: Result implies other.is_equal (Current)
    			consistent: standard_is_equal (other) implies Result

    	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached to
    			-- field-by-field identical objects of the same type?
    			-- Always uses default object comparison criterion.
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

    	frozen standard_is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object of the same type
    			-- as current object, and field-by-field identical to it?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			same_type: Result implies same_type (other)
    			symmetric: Result implies other.standard_is_equal (Current)

    feature -- Status report

    	conforms_to (other: ANY): BOOLEAN
    			-- Does type of current object conform to type
    			-- of `other' (as per Eiffel: The Language, chapter 13)?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void

    	invariant_value: BOOLEAN
    			-- Is the invariant satisfied?
    			-- (Redefinitions of this feature will usually involve
    			-- target; if so, make sure that the result is defined
    			-- when `target = Void'.)
    			-- (from ITERATOR)

    	same_type (other: ANY): BOOLEAN
    			-- Is type of current object identical to type of `other'?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			definition: Result = (conforms_to (other) and other.conforms_to (Current))

    	target: CURSOR_TREE [G]
    			-- The structure to which iteration features will apply

    feature -- Cursor movement

    	breadth_forth
    			-- Move cursor of target to next position in breadth-first.

    	breadth_start
    			-- Move cursor of target to root position
    			-- (first position in preorder and breadth-first).
    			-- Was declared in CURSOR_TREE_ITERATOR as synonym of pre_start.

    	exhausted: BOOLEAN
    			-- Is target exhausted?
    			-- (from LINEAR_ITERATOR)

    	off: BOOLEAN
    			-- Is position of target off?
    			-- (from LINEAR_ITERATOR)

    	post_forth
    			-- Move cursor of target to next position in postorder.

    	post_start
    			-- Move cursor of target to first position in postorder.

    	pre_forth
    			-- Move cursor of target to next position in preorder.

    	pre_start
    			-- Move cursor of target to root position
    			-- (first position in preorder and breadth-first).
    			-- Was declared in CURSOR_TREE_ITERATOR as synonym of breadth_start.

    	start
    			-- Move to first position of target.
    			-- (from LINEAR_ITERATOR)

    feature -- Duplication

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

    	frozen deep_copy (other: like Current)
    			-- Effect equivalent to that of:
    			--		copy (`other' . deep_twin)
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, other)

    	frozen deep_twin: like Current
    			-- New object structure recursively duplicated from Current.
    			-- (from ANY)
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, Result)

    	frozen standard_copy (other: like Current)
    			-- Copy every field of `other' onto corresponding field
    			-- of current object.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_standard_equal: standard_is_equal (other)

    	frozen standard_twin: like Current
    			-- New object field-by-field identical to `other'.
    			-- Always uses default copying semantics.
    			-- (from ANY)
    		ensure -- from ANY
    			standard_twin_not_void: Result /= Void
    			equal: standard_equal (Result, Current)

    	frozen twin: like Current
    			-- New object equal to `Current'
    			-- twin calls copy; to change copying/twining semantics, redefine copy.
    			-- (from ANY)
    		ensure -- from ANY
    			twin_not_void: Result /= Void
    			is_equal: Result.is_equal (Current)

    feature -- Basic operations

    	frozen default: like Current
    			-- Default value of object's type
    			-- (from ANY)

    	frozen default_pointer: POINTER
    			-- Default value of type `POINTER'
    			-- (Avoid the need to write `p'.default for
    			-- some `p' of type `POINTER'.)
    			-- (from ANY)

    	default_rescue
    			-- Process exception for routines with no Rescue clause.
    			-- (Default: do nothing.)
    			-- (from ANY)

    	frozen do_nothing
    			-- Execute a null action.
    			-- (from ANY)

    feature -- Implementation

    	internal_item_tuple: TUPLE [G]
    			-- Field holding the last item of target
    			-- (from LINEAR_ITERATOR)

    feature -- Iteration

    	breadth_continue_for (action: PROCEDURE [ANY, TUPLE [G]]; n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	post_continue_for (action: PROCEDURE [ANY, TUPLE [G]]; n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	pre_continue_for (action: PROCEDURE [ANY, TUPLE [G]]; n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	post_continue_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target
    			-- satisfying: `test' equals to `b'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		ensure then -- from LINEAR_ITERATOR
    			found: not exhausted = (b = test.item (item_tuple))

    	breadth_continue_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target
    			-- satisfying: `test' equals to `b'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		ensure then -- from LINEAR_ITERATOR
    			found: not exhausted = (b = test.item (item_tuple))

    	pre_continue_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target
    			-- satisfying: `test' equals to `b'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		ensure then -- from LINEAR_ITERATOR
    			found: not exhausted = (b = test.item (item_tuple))

    	post_continue_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	breadth_continue_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	pre_continue_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	pre_continue_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require else -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	post_continue_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require else -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	breadth_continue_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'
    			-- (from the current position of target).
    			-- (from LINEAR_ITERATOR)
    		require else -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	post_do_all (action: PROCEDURE [ANY, TUPLE [G]])
    			-- Apply `action' to every item of target.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void

    	breadth_do_all (action: PROCEDURE [ANY, TUPLE [G]])
    			-- Apply `action' to every item of target.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void

    	pre_do_all (action: PROCEDURE [ANY, TUPLE [G]])
    			-- Apply `action' to every item of target.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void

    	pre_do_for (action: PROCEDURE [ANY, TUPLE [G]]; i, n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible, starting from `i'-th.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_start: i >= 1
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	breadth_do_for (action: PROCEDURE [ANY, TUPLE [G]]; i, n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible, starting from `i'-th.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_start: i >= 1
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	post_do_for (action: PROCEDURE [ANY, TUPLE [G]]; i, n, k: INTEGER_32)
    			-- Apply `action' to every `k'-th item,
    			-- `n' times if possible, starting from `i'-th.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			valid_start: i >= 1
    			valid_repetition: n >= 0
    			valid_skip: k >= 1

    	breadth_do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target satisfying `test'.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void

    	pre_do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target satisfying `test'.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void

    	post_do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target satisfying `test'.
    			-- (from ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void

    	post_do_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	pre_do_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	breadth_do_until (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	pre_do_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'.
    			-- (from the start of target)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	breadth_do_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'.
    			-- (from the start of target)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	post_do_while (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- and including first one not satisfying `test'.
    			-- (from the start of target)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	pre_for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- all items of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	breadth_for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- all items of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	post_for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- all items of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	breadth_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target for which `test'
    			-- has the same value as `b' (both true or both false).
    			-- (from LINEAR_ITERATOR)

    	post_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target for which `test'
    			-- has the same value as `b' (both true or both false).
    			-- (from LINEAR_ITERATOR)

    	pre_search (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]; b: BOOLEAN)
    			-- Search the first item of target for which `test'
    			-- has the same value as `b' (both true or both false).
    			-- (from LINEAR_ITERATOR)

    	post_there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- at least one item of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	breadth_there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- at least one item of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	pre_there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
    			-- Does `test' return true for
    			-- at least one item of target?
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			test_exists: test /= Void

    	until_continue (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target from current
    			-- position, up to but excluding first one satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		require -- from LINEAR_ITERATOR
    			invariant_satisfied: invariant_value
    		ensure -- from LINEAR_ITERATOR
    			achieved: exhausted or else test.item (item_tuple)
    			invariant_satisfied: invariant_value

    	breadth_until_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one satisfying `test'.
    			-- (Apply to full list if no item satisfies `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	pre_until_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one satisfying `test'.
    			-- (Apply to full list if no item satisfies `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	post_until_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one satisfying `test'.
    			-- (Apply to full list if no item satisfies `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			achieved: not exhausted implies test.item (item_tuple)

    	breadth_while_continue (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		ensure -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	pre_while_continue (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		ensure -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	post_while_continue (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (from LINEAR_ITERATOR)
    		ensure -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	breadth_while_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (Apply to full list if all items satisfy `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	pre_while_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (Apply to full list if all items satisfy `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    	post_while_do (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
    			-- Apply `action' to every item of target up to
    			-- but excluding first one not satisfying `test'.
    			-- (Apply to full list if all items satisfy `test'.)
    			-- (from LINEAR_ITERATOR)
    		require -- from ITERATOR
    			action_exists: action /= Void
    			test_exists: test /= Void
    		ensure then -- from LINEAR_ITERATOR
    			finished: not exhausted implies not test.item (item_tuple)

    feature -- Output

    	io: STD_FILES
    			-- Handle to standard file setup
    			-- (from ANY)

    	out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of tagged_out.
    			-- (from ANY)

    	print (some: ANY)
    			-- Write terse external representation of `some'
    			-- on standard output.
    			-- (from ANY)

    	frozen tagged_out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of out.
    			-- (from ANY)

    feature -- Platform

    	operating_environment: OPERATING_ENVIRONMENT
    			-- Objects available from the operating system
    			-- (from ANY)

    invariant
    		-- from LINEAR_ITERATOR
    	target_exists: target /= Void
    	item_tuple_exists: item_tuple /= Void
    	internal_item_tuple_exists: internal_item_tuple /= Void

    		-- from ITERATOR
    	traversable_exists: target /= Void

    		-- from ANY
    	reflexive_equality: standard_is_equal (Current)
    	reflexive_conformance: conforms_to (Current)

    indexing
    	library: "EiffelBase: Library of reusable components for Eiffel."
    	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
    	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
    	source: "[
    		Eiffel Software
    		356 Storke Road, Goleta, CA 93117 USA
    		Telephone 805-685-1006, Fax 805-685-6869
    		Website http://www.eiffel.com
    		Customer support http://support.eiffel.com
    	]"

    end -- class CURSOR_TREE_ITERATOR