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Unpolyed a polymorphic function of two arguments
author Adam Chlipala <adamc@hcoop.net>
date Thu, 11 Sep 2008 10:14:59 -0400
parents 52d4c60518d4
children 60907c06b4c4
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@307 42 | EDml _ => true
adamc@252 43 | EAbs _ => false
adamc@252 44
adamc@252 45 | EPrim _ => false
adamc@252 46 | ERel _ => false
adamc@252 47 | ENamed _ => false
adamc@252 48 | ECon (_, _, eo) => (case eo of NONE => false | SOME e => impure e)
adamc@297 49 | ENone _ => false
adamc@290 50 | ESome (_, e) => impure e
adamc@252 51 | EFfi _ => false
adamc@252 52 | EFfiApp _ => false
adamc@252 53 | EApp ((EFfi _, _), _) => false
adamc@252 54 | EApp _ => true
adamc@252 55
adamc@252 56 | ERecord xes => List.exists (fn (_, e, _) => impure e) xes
adamc@252 57 | EField (e, _) => impure e
adamc@252 58
adamc@252 59 | ECase (e, pes, _) => impure e orelse List.exists (fn (_, e) => impure e) pes
adamc@252 60
adamc@283 61 | EError (e, _) => impure e
adamc@283 62
adamc@252 63 | EStrcat (e1, e2) => impure e1 orelse impure e2
adamc@252 64
adamc@252 65 | ESeq (e1, e2) => impure e1 orelse impure e2
adamc@252 66 | ELet (_, _, e1, e2) => impure e1 orelse impure e2
adamc@252 67
adamc@252 68 | EClosure (_, es) => List.exists impure es
adamc@252 69
adamc@252 70
adamc@252 71 val liftExpInExp = Monoize.liftExpInExp
adamc@252 72
adamc@252 73 val subExpInExp' =
adamc@133 74 U.Exp.mapB {typ = fn t => t,
adamc@133 75 exp = fn (xn, rep) => fn e =>
adamc@133 76 case e of
adamc@133 77 ERel xn' =>
adamc@133 78 (case Int.compare (xn', xn) of
adamc@133 79 EQUAL => #1 rep
adamc@133 80 | GREATER=> ERel (xn' - 1)
adamc@133 81 | LESS => e)
adamc@133 82 | _ => e,
adamc@133 83 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 84 | (ctx, _) => ctx}
adamc@133 85
adamc@252 86 fun subExpInExp (n, e1) e2 =
adamc@252 87 let
adamc@252 88 val r = subExpInExp' (n, e1) e2
adamc@252 89 in
adamc@252 90 (*Print.prefaces "subExpInExp" [("e1", MonoPrint.p_exp MonoEnv.empty e1),
adamc@252 91 ("e2", MonoPrint.p_exp MonoEnv.empty e2),
adamc@252 92 ("r", MonoPrint.p_exp MonoEnv.empty r)];*)
adamc@252 93 r
adamc@252 94 end
adamc@133 95
adamc@133 96 fun typ c = c
adamc@133 97
adamc@316 98 val swapExpVars =
adamc@316 99 U.Exp.mapB {typ = fn t => t,
adamc@316 100 exp = fn lower => fn e =>
adamc@316 101 case e of
adamc@316 102 ERel xn =>
adamc@316 103 if xn = lower then
adamc@316 104 ERel (lower + 1)
adamc@316 105 else if xn = lower + 1 then
adamc@316 106 ERel lower
adamc@316 107 else
adamc@316 108 e
adamc@316 109 | _ => e,
adamc@316 110 bind = fn (lower, U.Exp.RelE _) => lower+1
adamc@316 111 | (lower, _) => lower}
adamc@316 112
adamc@258 113 datatype result = Yes of E.env | No | Maybe
adamc@258 114
adamc@183 115 fun match (env, p : pat, e : exp) =
adamc@183 116 case (#1 p, #1 e) of
adamc@258 117 (PWild, _) => Yes env
adamc@258 118 | (PVar (x, t), _) => Yes (E.pushERel env x t (SOME e))
adamc@183 119
adamc@280 120 | (PPrim (Prim.String s), EStrcat ((EPrim (Prim.String s'), _), _)) =>
adamc@280 121 if String.isPrefix s' s then
adamc@280 122 Maybe
adamc@280 123 else
adamc@280 124 No
adamc@280 125
adamc@183 126 | (PPrim p, EPrim p') =>
adamc@183 127 if Prim.equal (p, p') then
adamc@258 128 Yes env
adamc@183 129 else
adamc@258 130 No
adamc@183 131
adamc@188 132 | (PCon (_, PConVar n1, NONE), ECon (_, PConVar n2, NONE)) =>
adamc@183 133 if n1 = n2 then
adamc@258 134 Yes env
adamc@183 135 else
adamc@258 136 No
adamc@183 137
adamc@188 138 | (PCon (_, PConVar n1, SOME p), ECon (_, PConVar n2, SOME e)) =>
adamc@183 139 if n1 = n2 then
adamc@183 140 match (env, p, e)
adamc@183 141 else
adamc@258 142 No
adamc@183 143
adamc@188 144 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, NONE), ECon (_, PConFfi {mod = m2, con = con2, ...}, NONE)) =>
adamc@185 145 if m1 = m2 andalso con1 = con2 then
adamc@258 146 Yes env
adamc@185 147 else
adamc@258 148 No
adamc@185 149
adamc@188 150 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, SOME ep), ECon (_, PConFfi {mod = m2, con = con2, ...}, SOME e)) =>
adamc@185 151 if m1 = m2 andalso con1 = con2 then
adamc@185 152 match (env, p, e)
adamc@185 153 else
adamc@258 154 No
adamc@185 155
adamc@183 156 | (PRecord xps, ERecord xes) =>
adamc@183 157 let
adamc@183 158 fun consider (xps, env) =
adamc@183 159 case xps of
adamc@258 160 [] => Yes env
adamc@183 161 | (x, p, _) :: rest =>
adamc@183 162 case List.find (fn (x', _, _) => x' = x) xes of
adamc@258 163 NONE => No
adamc@183 164 | SOME (_, e, _) =>
adamc@183 165 case match (env, p, e) of
adamc@258 166 No => No
adamc@258 167 | Maybe => Maybe
adamc@258 168 | Yes env => consider (rest, env)
adamc@183 169 in
adamc@183 170 consider (xps, env)
adamc@183 171 end
adamc@183 172
adamc@258 173 | _ => Maybe
adamc@183 174
adamc@133 175 fun exp env e =
adamc@133 176 case e of
adamc@183 177 ERel n =>
adamc@183 178 (case E.lookupERel env n of
adamc@183 179 (_, _, SOME e') => #1 e'
adamc@183 180 | _ => e)
adamc@183 181 | ENamed n =>
adamc@133 182 (case E.lookupENamed env n of
adamc@133 183 (_, _, SOME e', _) => #1 e'
adamc@133 184 | _ => e)
adamc@133 185
adamc@252 186 | EApp ((EAbs (x, t, _, e1), loc), e2) =>
adamc@252 187 ((*Print.prefaces "Considering" [("e1", MonoPrint.p_exp env e1),
adamc@252 188 ("e2", MonoPrint.p_exp env e2)];*)
adamc@252 189 if impure e2 then
adamc@252 190 #1 (reduceExp env (ELet (x, t, e2, e1), loc))
adamc@252 191 else
adamc@252 192 #1 (reduceExp env (subExpInExp (0, e2) e1)))
adamc@133 193
adamc@184 194 | ECase (disc, pes, _) =>
adamc@258 195 let
adamc@258 196 fun search pes =
adamc@258 197 case pes of
adamc@258 198 [] => e
adamc@258 199 | (p, body) :: pes =>
adamc@258 200 case match (env, p, disc) of
adamc@258 201 No => search pes
adamc@258 202 | Maybe => e
adamc@258 203 | Yes env => #1 (reduceExp env body)
adamc@258 204 in
adamc@258 205 search pes
adamc@258 206 end
adamc@183 207
adamc@252 208 | EField ((ERecord xes, _), x) =>
adamc@252 209 (case List.find (fn (x', _, _) => x' = x) xes of
adamc@252 210 SOME (_, e, _) => #1 e
adamc@252 211 | NONE => e)
adamc@252 212
adamc@252 213 | ELet (x1, t1, (ELet (x2, t2, e1, b1), loc), b2) =>
adamc@252 214 let
adamc@252 215 val e' = (ELet (x2, t2, e1,
adamc@252 216 (ELet (x1, t1, b1,
adamc@252 217 liftExpInExp 1 b2), loc)), loc)
adamc@252 218 in
adamc@253 219 (*Print.prefaces "ELet commute" [("e", MonoPrint.p_exp env (e, loc)),
adamc@253 220 ("e'", MonoPrint.p_exp env e')];*)
adamc@252 221 #1 (reduceExp env e')
adamc@252 222 end
adamc@252 223 | EApp ((ELet (x, t, e, b), loc), e') =>
adamc@252 224 #1 (reduceExp env (ELet (x, t, e,
adamc@252 225 (EApp (b, liftExpInExp 0 e'), loc)), loc))
adamc@316 226
adamc@316 227 | ELet (x, t, e, (EAbs (x', t' as (TRecord [], _), ran, e'), loc)) =>
adamc@316 228 EAbs (x', t', ran, (ELet (x, t, liftExpInExp 0 e, swapExpVars 0 e'), loc))
adamc@316 229
adamc@252 230 | ELet (x, t, e', b) =>
adamc@252 231 if impure e' then
adamc@252 232 e
adamc@252 233 else
adamc@252 234 #1 (reduceExp env (subExpInExp (0, e') b))
adamc@252 235
adamc@268 236 | EStrcat ((EPrim (Prim.String s1), _), (EPrim (Prim.String s2), _)) =>
adamc@268 237 EPrim (Prim.String (s1 ^ s2))
adamc@268 238
adamc@133 239 | _ => e
adamc@133 240
adamc@252 241 and bind (env, b) =
adamc@252 242 case b of
adamc@252 243 U.Decl.Datatype (x, n, xncs) => E.pushDatatype env x n xncs
adamc@252 244 | U.Decl.RelE (x, t) => E.pushERel env x t NONE
adamc@252 245 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t (Option.map (reduceExp env) eo) s
adamc@252 246
adamc@133 247 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@133 248
adamc@133 249 fun decl env d = d
adamc@133 250
adamc@133 251 val reduce = U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty
adamc@133 252
adamc@133 253 end