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annotate src/mono_reduce.sml @ 283:c0e4ac23522d

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'error' function
author Adam Chlipala <adamc@hcoop.net>
date Sun, 07 Sep 2008 10:02:27 -0400
parents fdd7a698be01
children df00701f2323
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@283 58 | EError (e, _) => impure e
adamc@283 59
adamc@252 60 | EStrcat (e1, e2) => impure e1 orelse impure e2
adamc@252 61
adamc@252 62 | ESeq (e1, e2) => impure e1 orelse impure e2
adamc@252 63 | ELet (_, _, e1, e2) => impure e1 orelse impure e2
adamc@252 64
adamc@252 65 | EClosure (_, es) => List.exists impure es
adamc@252 66
adamc@252 67
adamc@252 68 val liftExpInExp = Monoize.liftExpInExp
adamc@252 69
adamc@252 70 val subExpInExp' =
adamc@133 71 U.Exp.mapB {typ = fn t => t,
adamc@133 72 exp = fn (xn, rep) => fn e =>
adamc@133 73 case e of
adamc@133 74 ERel xn' =>
adamc@133 75 (case Int.compare (xn', xn) of
adamc@133 76 EQUAL => #1 rep
adamc@133 77 | GREATER=> ERel (xn' - 1)
adamc@133 78 | LESS => e)
adamc@133 79 | _ => e,
adamc@133 80 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 81 | (ctx, _) => ctx}
adamc@133 82
adamc@252 83 fun subExpInExp (n, e1) e2 =
adamc@252 84 let
adamc@252 85 val r = subExpInExp' (n, e1) e2
adamc@252 86 in
adamc@252 87 (*Print.prefaces "subExpInExp" [("e1", MonoPrint.p_exp MonoEnv.empty e1),
adamc@252 88 ("e2", MonoPrint.p_exp MonoEnv.empty e2),
adamc@252 89 ("r", MonoPrint.p_exp MonoEnv.empty r)];*)
adamc@252 90 r
adamc@252 91 end
adamc@133 92
adamc@133 93 fun typ c = c
adamc@133 94
adamc@258 95 datatype result = Yes of E.env | No | Maybe
adamc@258 96
adamc@183 97 fun match (env, p : pat, e : exp) =
adamc@183 98 case (#1 p, #1 e) of
adamc@258 99 (PWild, _) => Yes env
adamc@258 100 | (PVar (x, t), _) => Yes (E.pushERel env x t (SOME e))
adamc@183 101
adamc@280 102 | (PPrim (Prim.String s), EStrcat ((EPrim (Prim.String s'), _), _)) =>
adamc@280 103 if String.isPrefix s' s then
adamc@280 104 Maybe
adamc@280 105 else
adamc@280 106 No
adamc@280 107
adamc@183 108 | (PPrim p, EPrim p') =>
adamc@183 109 if Prim.equal (p, p') then
adamc@258 110 Yes env
adamc@183 111 else
adamc@258 112 No
adamc@183 113
adamc@188 114 | (PCon (_, PConVar n1, NONE), ECon (_, PConVar n2, NONE)) =>
adamc@183 115 if n1 = n2 then
adamc@258 116 Yes env
adamc@183 117 else
adamc@258 118 No
adamc@183 119
adamc@188 120 | (PCon (_, PConVar n1, SOME p), ECon (_, PConVar n2, SOME e)) =>
adamc@183 121 if n1 = n2 then
adamc@183 122 match (env, p, e)
adamc@183 123 else
adamc@258 124 No
adamc@183 125
adamc@188 126 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, NONE), ECon (_, PConFfi {mod = m2, con = con2, ...}, NONE)) =>
adamc@185 127 if m1 = m2 andalso con1 = con2 then
adamc@258 128 Yes env
adamc@185 129 else
adamc@258 130 No
adamc@185 131
adamc@188 132 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, SOME ep), ECon (_, PConFfi {mod = m2, con = con2, ...}, SOME e)) =>
adamc@185 133 if m1 = m2 andalso con1 = con2 then
adamc@185 134 match (env, p, e)
adamc@185 135 else
adamc@258 136 No
adamc@185 137
adamc@183 138 | (PRecord xps, ERecord xes) =>
adamc@183 139 let
adamc@183 140 fun consider (xps, env) =
adamc@183 141 case xps of
adamc@258 142 [] => Yes env
adamc@183 143 | (x, p, _) :: rest =>
adamc@183 144 case List.find (fn (x', _, _) => x' = x) xes of
adamc@258 145 NONE => No
adamc@183 146 | SOME (_, e, _) =>
adamc@183 147 case match (env, p, e) of
adamc@258 148 No => No
adamc@258 149 | Maybe => Maybe
adamc@258 150 | Yes env => consider (rest, env)
adamc@183 151 in
adamc@183 152 consider (xps, env)
adamc@183 153 end
adamc@183 154
adamc@258 155 | _ => Maybe
adamc@183 156
adamc@133 157 fun exp env e =
adamc@133 158 case e of
adamc@183 159 ERel n =>
adamc@183 160 (case E.lookupERel env n of
adamc@183 161 (_, _, SOME e') => #1 e'
adamc@183 162 | _ => e)
adamc@183 163 | ENamed n =>
adamc@133 164 (case E.lookupENamed env n of
adamc@133 165 (_, _, SOME e', _) => #1 e'
adamc@133 166 | _ => e)
adamc@133 167
adamc@252 168 | EApp ((EAbs (x, t, _, e1), loc), e2) =>
adamc@252 169 ((*Print.prefaces "Considering" [("e1", MonoPrint.p_exp env e1),
adamc@252 170 ("e2", MonoPrint.p_exp env e2)];*)
adamc@252 171 if impure e2 then
adamc@252 172 #1 (reduceExp env (ELet (x, t, e2, e1), loc))
adamc@252 173 else
adamc@252 174 #1 (reduceExp env (subExpInExp (0, e2) e1)))
adamc@133 175
adamc@184 176 | ECase (disc, pes, _) =>
adamc@258 177 let
adamc@258 178 fun search pes =
adamc@258 179 case pes of
adamc@258 180 [] => e
adamc@258 181 | (p, body) :: pes =>
adamc@258 182 case match (env, p, disc) of
adamc@258 183 No => search pes
adamc@258 184 | Maybe => e
adamc@258 185 | Yes env => #1 (reduceExp env body)
adamc@258 186 in
adamc@258 187 search pes
adamc@258 188 end
adamc@183 189
adamc@252 190 | EField ((ERecord xes, _), x) =>
adamc@252 191 (case List.find (fn (x', _, _) => x' = x) xes of
adamc@252 192 SOME (_, e, _) => #1 e
adamc@252 193 | NONE => e)
adamc@252 194
adamc@252 195 | ELet (x1, t1, (ELet (x2, t2, e1, b1), loc), b2) =>
adamc@252 196 let
adamc@252 197 val e' = (ELet (x2, t2, e1,
adamc@252 198 (ELet (x1, t1, b1,
adamc@252 199 liftExpInExp 1 b2), loc)), loc)
adamc@252 200 in
adamc@253 201 (*Print.prefaces "ELet commute" [("e", MonoPrint.p_exp env (e, loc)),
adamc@253 202 ("e'", MonoPrint.p_exp env e')];*)
adamc@252 203 #1 (reduceExp env e')
adamc@252 204 end
adamc@252 205 | EApp ((ELet (x, t, e, b), loc), e') =>
adamc@252 206 #1 (reduceExp env (ELet (x, t, e,
adamc@252 207 (EApp (b, liftExpInExp 0 e'), loc)), loc))
adamc@252 208 | ELet (x, t, e', b) =>
adamc@252 209 if impure e' then
adamc@252 210 e
adamc@252 211 else
adamc@252 212 #1 (reduceExp env (subExpInExp (0, e') b))
adamc@252 213
adamc@268 214 | EStrcat ((EPrim (Prim.String s1), _), (EPrim (Prim.String s2), _)) =>
adamc@268 215 EPrim (Prim.String (s1 ^ s2))
adamc@268 216
adamc@133 217 | _ => e
adamc@133 218
adamc@252 219 and bind (env, b) =
adamc@252 220 case b of
adamc@252 221 U.Decl.Datatype (x, n, xncs) => E.pushDatatype env x n xncs
adamc@252 222 | U.Decl.RelE (x, t) => E.pushERel env x t NONE
adamc@252 223 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t (Option.map (reduceExp env) eo) s
adamc@252 224
adamc@133 225 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@133 226
adamc@133 227 fun decl env d = d
adamc@133 228
adamc@133 229 val reduce = U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty
adamc@133 230
adamc@133 231 end