annotate src/prim.sml @ 213:0343557355fc

Explifying type classes
author Adam Chlipala <adamc@hcoop.net>
date Sat, 16 Aug 2008 14:45:23 -0400
parents c0ea24dcb86f
children ed4af33681d8
rev   line source
adamc@14 1 (* Copyright (c) 2008, Adam Chlipala
adamc@14 2 * All rights reserved.
adamc@14 3 *
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adamc@14 5 * modification, are permitted provided that the following conditions are met:
adamc@14 6 *
adamc@14 7 * - Redistributions of source code must retain the above copyright notice,
adamc@14 8 * this list of conditions and the following disclaimer.
adamc@14 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@14 10 * this list of conditions and the following disclaimer in the documentation
adamc@14 11 * and/or other materials provided with the distribution.
adamc@14 12 * - The names of contributors may not be used to endorse or promote products
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adamc@14 14 *
adamc@14 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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adamc@14 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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adamc@14 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@14 26 *)
adamc@14 27
adamc@14 28 structure Prim :> PRIM = struct
adamc@14 29
adamc@14 30 datatype t =
adamc@14 31 Int of Int64.int
adamc@14 32 | Float of Real64.real
adamc@14 33 | String of string
adamc@14 34
adamc@14 35 open Print.PD
adamc@14 36 open Print
adamc@14 37
adamc@14 38 fun p_t t =
adamc@14 39 case t of
adamc@14 40 Int n => string (Int64.toString n)
adamc@14 41 | Float n => string (Real64.toString n)
adamc@95 42 | String s => box [string "\"", string (String.toString s), string "\""]
adamc@14 43
adamc@183 44 fun equal x =
adamc@183 45 case x of
adamc@183 46 (Int n1, Int n2) => n1 = n2
adamc@183 47 | (Float n1, Float n2) => Real64.== (n1, n2)
adamc@183 48 | (String s1, String s2) => s1 = s2
adamc@183 49
adamc@183 50 | _ => false
adamc@183 51
adamc@14 52 end