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annotate src/mono_reduce.sml @ 279:8bb46d87b074

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Update MLton main file
author Adam Chlipala <adamc@hcoop.net>
date Tue, 02 Sep 2008 16:18:05 -0400
parents bacd0ba869e1
children fdd7a698be01
rev   line source
adamc@133 1 (* Copyright (c) 2008, Adam Chlipala
adamc@133 2 * All rights reserved.
adamc@133 3 *
adamc@133 4 * Redistribution and use in source and binary forms, with or without
adamc@133 5 * modification, are permitted provided that the following conditions are met:
adamc@133 6 *
adamc@133 7 * - Redistributions of source code must retain the above copyright notice,
adamc@133 8 * this list of conditions and the following disclaimer.
adamc@133 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@133 10 * this list of conditions and the following disclaimer in the documentation
adamc@133 11 * and/or other materials provided with the distribution.
adamc@133 12 * - The names of contributors may not be used to endorse or promote products
adamc@133 13 * derived from this software without specific prior written permission.
adamc@133 14 *
adamc@133 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@133 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@133 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@133 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@133 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@133 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@133 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@133 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@133 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@133 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@133 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@133 26 *)
adamc@133 27
adamc@133 28 (* Simplify a Mono program algebraically *)
adamc@133 29
adamc@133 30 structure MonoReduce :> MONO_REDUCE = struct
adamc@133 31
adamc@133 32 open Mono
adamc@133 33
adamc@133 34 structure E = MonoEnv
adamc@133 35 structure U = MonoUtil
adamc@133 36
adamc@133 37
adamc@252 38 fun impure (e, _) =
adamc@252 39 case e of
adamc@252 40 EWrite _ => true
adamc@252 41 | EQuery _ => true
adamc@252 42 | EAbs _ => false
adamc@252 43
adamc@252 44 | EPrim _ => false
adamc@252 45 | ERel _ => false
adamc@252 46 | ENamed _ => false
adamc@252 47 | ECon (_, _, eo) => (case eo of NONE => false | SOME e => impure e)
adamc@252 48 | EFfi _ => false
adamc@252 49 | EFfiApp _ => false
adamc@252 50 | EApp ((EFfi _, _), _) => false
adamc@252 51 | EApp _ => true
adamc@252 52
adamc@252 53 | ERecord xes => List.exists (fn (_, e, _) => impure e) xes
adamc@252 54 | EField (e, _) => impure e
adamc@252 55
adamc@252 56 | ECase (e, pes, _) => impure e orelse List.exists (fn (_, e) => impure e) pes
adamc@252 57
adamc@252 58 | EStrcat (e1, e2) => impure e1 orelse impure e2
adamc@252 59
adamc@252 60 | ESeq (e1, e2) => impure e1 orelse impure e2
adamc@252 61 | ELet (_, _, e1, e2) => impure e1 orelse impure e2
adamc@252 62
adamc@252 63 | EClosure (_, es) => List.exists impure es
adamc@252 64
adamc@252 65
adamc@252 66 val liftExpInExp = Monoize.liftExpInExp
adamc@252 67
adamc@252 68 val subExpInExp' =
adamc@133 69 U.Exp.mapB {typ = fn t => t,
adamc@133 70 exp = fn (xn, rep) => fn e =>
adamc@133 71 case e of
adamc@133 72 ERel xn' =>
adamc@133 73 (case Int.compare (xn', xn) of
adamc@133 74 EQUAL => #1 rep
adamc@133 75 | GREATER=> ERel (xn' - 1)
adamc@133 76 | LESS => e)
adamc@133 77 | _ => e,
adamc@133 78 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 79 | (ctx, _) => ctx}
adamc@133 80
adamc@252 81 fun subExpInExp (n, e1) e2 =
adamc@252 82 let
adamc@252 83 val r = subExpInExp' (n, e1) e2
adamc@252 84 in
adamc@252 85 (*Print.prefaces "subExpInExp" [("e1", MonoPrint.p_exp MonoEnv.empty e1),
adamc@252 86 ("e2", MonoPrint.p_exp MonoEnv.empty e2),
adamc@252 87 ("r", MonoPrint.p_exp MonoEnv.empty r)];*)
adamc@252 88 r
adamc@252 89 end
adamc@133 90
adamc@133 91 fun typ c = c
adamc@133 92
adamc@258 93 datatype result = Yes of E.env | No | Maybe
adamc@258 94
adamc@183 95 fun match (env, p : pat, e : exp) =
adamc@183 96 case (#1 p, #1 e) of
adamc@258 97 (PWild, _) => Yes env
adamc@258 98 | (PVar (x, t), _) => Yes (E.pushERel env x t (SOME e))
adamc@183 99
adamc@183 100 | (PPrim p, EPrim p') =>
adamc@183 101 if Prim.equal (p, p') then
adamc@258 102 Yes env
adamc@183 103 else
adamc@258 104 No
adamc@183 105
adamc@188 106 | (PCon (_, PConVar n1, NONE), ECon (_, PConVar n2, NONE)) =>
adamc@183 107 if n1 = n2 then
adamc@258 108 Yes env
adamc@183 109 else
adamc@258 110 No
adamc@183 111
adamc@188 112 | (PCon (_, PConVar n1, SOME p), ECon (_, PConVar n2, SOME e)) =>
adamc@183 113 if n1 = n2 then
adamc@183 114 match (env, p, e)
adamc@183 115 else
adamc@258 116 No
adamc@183 117
adamc@188 118 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, NONE), ECon (_, PConFfi {mod = m2, con = con2, ...}, NONE)) =>
adamc@185 119 if m1 = m2 andalso con1 = con2 then
adamc@258 120 Yes env
adamc@185 121 else
adamc@258 122 No
adamc@185 123
adamc@188 124 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, SOME ep), ECon (_, PConFfi {mod = m2, con = con2, ...}, SOME e)) =>
adamc@185 125 if m1 = m2 andalso con1 = con2 then
adamc@185 126 match (env, p, e)
adamc@185 127 else
adamc@258 128 No
adamc@185 129
adamc@183 130 | (PRecord xps, ERecord xes) =>
adamc@183 131 let
adamc@183 132 fun consider (xps, env) =
adamc@183 133 case xps of
adamc@258 134 [] => Yes env
adamc@183 135 | (x, p, _) :: rest =>
adamc@183 136 case List.find (fn (x', _, _) => x' = x) xes of
adamc@258 137 NONE => No
adamc@183 138 | SOME (_, e, _) =>
adamc@183 139 case match (env, p, e) of
adamc@258 140 No => No
adamc@258 141 | Maybe => Maybe
adamc@258 142 | Yes env => consider (rest, env)
adamc@183 143 in
adamc@183 144 consider (xps, env)
adamc@183 145 end
adamc@183 146
adamc@258 147 | _ => Maybe
adamc@183 148
adamc@133 149 fun exp env e =
adamc@133 150 case e of
adamc@183 151 ERel n =>
adamc@183 152 (case E.lookupERel env n of
adamc@183 153 (_, _, SOME e') => #1 e'
adamc@183 154 | _ => e)
adamc@183 155 | ENamed n =>
adamc@133 156 (case E.lookupENamed env n of
adamc@133 157 (_, _, SOME e', _) => #1 e'
adamc@133 158 | _ => e)
adamc@133 159
adamc@252 160 | EApp ((EAbs (x, t, _, e1), loc), e2) =>
adamc@252 161 ((*Print.prefaces "Considering" [("e1", MonoPrint.p_exp env e1),
adamc@252 162 ("e2", MonoPrint.p_exp env e2)];*)
adamc@252 163 if impure e2 then
adamc@252 164 #1 (reduceExp env (ELet (x, t, e2, e1), loc))
adamc@252 165 else
adamc@252 166 #1 (reduceExp env (subExpInExp (0, e2) e1)))
adamc@133 167
adamc@184 168 | ECase (disc, pes, _) =>
adamc@258 169 let
adamc@258 170 fun search pes =
adamc@258 171 case pes of
adamc@258 172 [] => e
adamc@258 173 | (p, body) :: pes =>
adamc@258 174 case match (env, p, disc) of
adamc@258 175 No => search pes
adamc@258 176 | Maybe => e
adamc@258 177 | Yes env => #1 (reduceExp env body)
adamc@258 178 in
adamc@258 179 search pes
adamc@258 180 end
adamc@183 181
adamc@252 182 | EField ((ERecord xes, _), x) =>
adamc@252 183 (case List.find (fn (x', _, _) => x' = x) xes of
adamc@252 184 SOME (_, e, _) => #1 e
adamc@252 185 | NONE => e)
adamc@252 186
adamc@252 187 | ELet (x1, t1, (ELet (x2, t2, e1, b1), loc), b2) =>
adamc@252 188 let
adamc@252 189 val e' = (ELet (x2, t2, e1,
adamc@252 190 (ELet (x1, t1, b1,
adamc@252 191 liftExpInExp 1 b2), loc)), loc)
adamc@252 192 in
adamc@253 193 (*Print.prefaces "ELet commute" [("e", MonoPrint.p_exp env (e, loc)),
adamc@253 194 ("e'", MonoPrint.p_exp env e')];*)
adamc@252 195 #1 (reduceExp env e')
adamc@252 196 end
adamc@252 197 | EApp ((ELet (x, t, e, b), loc), e') =>
adamc@252 198 #1 (reduceExp env (ELet (x, t, e,
adamc@252 199 (EApp (b, liftExpInExp 0 e'), loc)), loc))
adamc@252 200 | ELet (x, t, e', b) =>
adamc@252 201 if impure e' then
adamc@252 202 e
adamc@252 203 else
adamc@252 204 #1 (reduceExp env (subExpInExp (0, e') b))
adamc@252 205
adamc@268 206 | EStrcat ((EPrim (Prim.String s1), _), (EPrim (Prim.String s2), _)) =>
adamc@268 207 EPrim (Prim.String (s1 ^ s2))
adamc@268 208
adamc@133 209 | _ => e
adamc@133 210
adamc@252 211 and bind (env, b) =
adamc@252 212 case b of
adamc@252 213 U.Decl.Datatype (x, n, xncs) => E.pushDatatype env x n xncs
adamc@252 214 | U.Decl.RelE (x, t) => E.pushERel env x t NONE
adamc@252 215 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t (Option.map (reduceExp env) eo) s
adamc@252 216
adamc@133 217 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@133 218
adamc@133 219 fun decl env d = d
adamc@133 220
adamc@133 221 val reduce = U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty
adamc@133 222
adamc@133 223 end