Mercurial > urweb
comparison src/order.sml @ 193:8a70e2919e86
Specialization of single-parameter datatypes
| author | Adam Chlipala <adamc@hcoop.net> |
|---|---|
| date | Fri, 08 Aug 2008 17:55:51 -0400 |
| parents | |
| children | ffa18975e661 |
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| 192:9bbf4d383381 | 193:8a70e2919e86 |
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| 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 (* Utility code for implementing comparisons *) | |
| 29 | |
| 30 structure Order :> ORDER = struct | |
| 31 | |
| 32 fun join (o1, o2) = | |
| 33 case o1 of | |
| 34 EQUAL => o2 () | |
| 35 | v => v | |
| 36 | |
| 37 fun joinL f (os1, os2) = | |
| 38 case (os1, os2) of | |
| 39 (nil, nil) => EQUAL | |
| 40 | (nil, _) => LESS | |
| 41 | (h1 :: t1, h2 :: t2) => | |
| 42 join (f (h1, h2), fn () => joinL f (t1, t2)) | |
| 43 | (_ :: _, nil) => GREATER | |
| 44 | |
| 45 end |