| Class DS_TRAVERSABLE |
indexing
description:
"Data structures that can be traversed. Traversable containers %
%are equipped with an internal cursor and external cursors which %
%can be used for simultaneous traversals."
library: "Gobo Eiffel Structure Library"
author: "Eric Bezault <ericb@gobosoft.com>"
copyright: "Copyright (c) 1999, Eric Bezault and others"
license: "Eiffel Forum Freeware License v1 (see forum.txt)"
deferred class interface
DS_TRAVERSABLE [G]
inherit
DS_CONTAINER [G]
feature -- Access
item_for_iteration: G -- Item at internal cursor position require not_off: not offnew_cursor: DS_CURSOR [G] -- New external cursor for traversal deferred ensure cursor_not_void: Result /= Void valid_cursor: valid_cursor (Result)
feature -- Measurement
count: INTEGER
-- Number of items in container
-- (From DS_CONTAINER.)
deferred
feature -- Status report
is_empty: BOOLEAN -- Is container empty? -- (From DS_CONTAINER.)off: BOOLEAN -- Is there no item at internal cursor position?same_position (a_cursor: like new_cursor): BOOLEAN -- Is internal cursor at same position as a_cursor? require a_cursor_not_void: a_cursor /= Voidvalid_cursor (a_cursor: DS_CURSOR [G]): BOOLEAN -- Is a_cursor a valid cursor? require a_cursor_not_void: a_cursor /= Void ensure definition: Result = (a_cursor.container = Current)
feature -- Comparison
is_equal (other: like Current): BOOLEAN
-- Is current container equal to other?
-- (From GENERAL.)
require
other_not_void: other /= Void
deferred
ensure
consistent: standard_is_equal (other) implies Result
same_type: Result implies same_type (other)
symmetric: Result implies other.is_equal (Current)
same_count: Result implies count = other.count
feature -- Duplication
copy (other: like Current)
-- Copy other to current container.
-- (From GENERAL.)
require
other_not_void: other /= Void
type_identity: same_type (other)
deferred
ensure
is_equal: is_equal (other)
feature -- Cursor movement
go_to (a_cursor: like new_cursor)
-- Move internal cursor to a_cursor's position.
require
cursor_not_void: a_cursor /= Void
valid_cursor: valid_cursor (a_cursor)
ensure
same_position: same_position (a_cursor)
feature -- Removal
wipe_out
-- Remove all items from container.
-- (From DS_CONTAINER.)
deferred
ensure
wiped_out: is_empty
invariant
positive_count: count >= 0 empty_definition: is_empty = (count = 0) -- (From DS_CONTAINER.)empty_constraint: is_empty implies off
end -- class DS_TRAVERSABLE
|
Copyright © 1999, Eric
Bezault mailto:ericb@gobosoft.com http://www.gobosoft.com Last Updated: 5 July 1999 |