/src/lib/backtracking/low_level/backtracking_alternative_list.e

 1-- This file is part of a Liberty Eiffel library.
 2-- See the full copyright at the end.
 3--
 4class BACKTRACKING_ALTERNATIVE_LIST
 5   --
 6   -- An alternative of a list of nodes.
 7   --
 8
 9inherit
10   ABSTRACT_BACKTRACKING_ALTERNATIVE
11      rename pool as pool_of_alternative_list
12      end
13
14insert
15   BACKTRACKING_GLOBALS
16
17feature {ABSTRACT_BACKTRACKING}
18   list: BACKTRACKING_NODE_OR_LIST
19         -- Iterator on the next item of the list.
20
21   set_list (value: BACKTRACKING_NODE_OR_LIST)
22      require
23         value_not_void: value /= Void
24      do
25         list := value
26      ensure
27         definition: list = value
28         list_not_void: list /= Void
29      end
30
31feature {ABSTRACT_BACKTRACKING}
32   next_alternative (explorer: BACKTRACKING)
33      do
34         -- Tell to evaluate 'list.node' now.
35         explorer.set_current_node(list.node)
36         -- Iterate
37         list := list.next
38         if list /= Void then
39            -- Alternative is still on, continue it.
40            explorer.continue_alternative
41         else
42            -- Alternative is off, remove it.
43            explorer.pop_alternative
44         end
45      end
46
47end -- class BACKTRACKING_ALTERNATIVE_LIST
48--
49-- Copyright (C) 2009-2017: by all the people cited in the AUTHORS file.
50--
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52-- of this software and associated documentation files (the "Software"), to deal
53-- in the Software without restriction, including without limitation the rights
54-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
55-- copies of the Software, and to permit persons to whom the Software is
56-- furnished to do so, subject to the following conditions:
57--
58-- The above copyright notice and this permission notice shall be included in
59-- all copies or substantial portions of the Software.
60--
61-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
62-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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67-- THE SOFTWARE.