comparison src/search.sml @ 2:64f09f7822c3

Start of elaboration
author Adam Chlipala <adamc@hcoop.net>
date Sat, 26 Jan 2008 14:27:33 -0500
parents
children 38bf996e1c2e
comparison
equal deleted inserted replaced
1:4202f6eda946 2:64f09f7822c3
1 (* Copyright (c) 2008, Adam Chlipala
2 * All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * - Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * - Redistributions in binary form must reproduce the above copyright notice,
10 * this list of conditions and the following disclaimer in the documentation
11 * and/or other materials provided with the distribution.
12 * - The names of contributors may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 * POSSIBILITY OF SUCH DAMAGE.
26 *)
27
28 structure Search :> SEARCH = struct
29
30 datatype ('state, 'abort) result =
31 Return of 'abort
32 | Continue of 'state
33
34 type ('data, 'state, 'abort) mapfold_arg =
35 'data * 'state -> ('data * 'state, 'abort) result
36
37 type ('data, 'state, 'abort) mapfolder =
38 'data -> 'state -> ('data * 'state, 'abort) result
39
40 fun return2 v acc = Continue (v, acc)
41
42 fun map (r, f) =
43 case r of
44 Continue acc => Continue (f acc)
45 | Return x => Return x
46
47 fun map2 (r, f) acc =
48 case r acc of
49 Continue (x, acc) => Continue (f x, acc)
50 | Return x => Return x
51
52 fun bind (r, f) =
53 case r of
54 Continue acc => f acc
55 | Return x => Return x
56
57 fun bind2 (r, f) acc =
58 case r acc of
59 Continue (x, acc) => f x acc
60 | Return x => Return x
61
62 fun bindP (r, f) =
63 case r of
64 Continue ((x, pos), acc) =>
65 map (f (x, acc),
66 fn (x', acc') =>
67 ((x', pos), acc'))
68 | Return x => Return x
69
70 end