Mercurial > urweb

annotate src/mono_reduce.sml @ 848:e8594cfa3236

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Fix MonoReduce unsoundness with lets and fns
author Adam Chlipala <adamc@hcoop.net>
date Sat, 13 Jun 2009 15:42:24 -0400
parents 20fe00fd81da
children 7a4b026e45dd
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@470 37 structure IM = IntBinaryMap
adamc@470 38
adamc@133 39
adamc@252 40 fun impure (e, _) =
adamc@252 41 case e of
adamc@252 42 EWrite _ => true
adamc@252 43 | EQuery _ => true
adamc@307 44 | EDml _ => true
adamc@338 45 | ENextval _ => true
adamc@463 46 | EUnurlify _ => true
adamc@252 47 | EAbs _ => false
adamc@252 48
adamc@252 49 | EPrim _ => false
adamc@252 50 | ERel _ => false
adamc@252 51 | ENamed _ => false
adamc@252 52 | ECon (_, _, eo) => (case eo of NONE => false | SOME e => impure e)
adamc@297 53 | ENone _ => false
adamc@290 54 | ESome (_, e) => impure e
adamc@252 55 | EFfi _ => false
adamc@765 56 | EFfiApp (m, x, _) => Settings.isEffectful (m, x)
adamc@252 57 | EApp ((EFfi _, _), _) => false
adamc@252 58 | EApp _ => true
adamc@252 59
adamc@387 60 | EUnop (_, e) => impure e
adamc@387 61 | EBinop (_, e1, e2) => impure e1 orelse impure e2
adamc@387 62
adamc@252 63 | ERecord xes => List.exists (fn (_, e, _) => impure e) xes
adamc@252 64 | EField (e, _) => impure e
adamc@252 65
adamc@252 66 | ECase (e, pes, _) => impure e orelse List.exists (fn (_, e) => impure e) pes
adamc@252 67
adamc@283 68 | EError (e, _) => impure e
adamc@741 69 | EReturnBlob {blob = e1, mimeType = e2, ...} => impure e1 orelse impure e2
adamc@283 70
adamc@252 71 | EStrcat (e1, e2) => impure e1 orelse impure e2
adamc@252 72
adamc@252 73 | ESeq (e1, e2) => impure e1 orelse impure e2
adamc@252 74 | ELet (_, _, e1, e2) => impure e1 orelse impure e2
adamc@252 75
adamc@252 76 | EClosure (_, es) => List.exists impure es
adamc@815 77 | EJavaScript (_, e) => impure e
adamc@568 78 | ESignalReturn e => impure e
adamc@572 79 | ESignalBind (e1, e2) => impure e1 orelse impure e2
adamc@574 80 | ESignalSource e => impure e
adamc@608 81 | EServerCall _ => true
adamc@670 82 | ERecv _ => true
adamc@695 83 | ESleep _ => true
adamc@252 84
adamc@252 85
adamc@252 86 val liftExpInExp = Monoize.liftExpInExp
adamc@252 87
adamc@829 88 fun multiLift n e =
adamc@829 89 case n of
adamc@829 90 0 => e
adamc@829 91 | _ => multiLift (n - 1) (liftExpInExp 0 e)
adamc@829 92
adamc@252 93 val subExpInExp' =
adamc@133 94 U.Exp.mapB {typ = fn t => t,
adamc@133 95 exp = fn (xn, rep) => fn e =>
adamc@133 96 case e of
adamc@133 97 ERel xn' =>
adamc@133 98 (case Int.compare (xn', xn) of
adamc@133 99 EQUAL => #1 rep
adamc@133 100 | GREATER=> ERel (xn' - 1)
adamc@133 101 | LESS => e)
adamc@133 102 | _ => e,
adamc@133 103 bind = fn ((xn, rep), U.Exp.RelE _) => (xn+1, liftExpInExp 0 rep)
adamc@133 104 | (ctx, _) => ctx}
adamc@133 105
adamc@252 106 fun subExpInExp (n, e1) e2 =
adamc@252 107 let
adamc@252 108 val r = subExpInExp' (n, e1) e2
adamc@252 109 in
adamc@252 110 (*Print.prefaces "subExpInExp" [("e1", MonoPrint.p_exp MonoEnv.empty e1),
adamc@252 111 ("e2", MonoPrint.p_exp MonoEnv.empty e2),
adamc@252 112 ("r", MonoPrint.p_exp MonoEnv.empty r)];*)
adamc@252 113 r
adamc@252 114 end
adamc@133 115
adamc@133 116 fun typ c = c
adamc@133 117
adamc@316 118 val swapExpVars =
adamc@316 119 U.Exp.mapB {typ = fn t => t,
adamc@316 120 exp = fn lower => fn e =>
adamc@316 121 case e of
adamc@316 122 ERel xn =>
adamc@316 123 if xn = lower then
adamc@316 124 ERel (lower + 1)
adamc@316 125 else if xn = lower + 1 then
adamc@316 126 ERel lower
adamc@316 127 else
adamc@316 128 e
adamc@316 129 | _ => e,
adamc@316 130 bind = fn (lower, U.Exp.RelE _) => lower+1
adamc@316 131 | (lower, _) => lower}
adamc@316 132
adamc@341 133 val swapExpVarsPat =
adamc@341 134 U.Exp.mapB {typ = fn t => t,
adamc@341 135 exp = fn (lower, len) => fn e =>
adamc@341 136 case e of
adamc@341 137 ERel xn =>
adamc@341 138 if xn = lower then
adamc@827 139 ERel (lower + len)
adamc@341 140 else if xn >= lower + 1 andalso xn < lower + 1 + len then
adamc@341 141 ERel (xn - 1)
adamc@341 142 else
adamc@341 143 e
adamc@341 144 | _ => e,
adamc@341 145 bind = fn ((lower, len), U.Exp.RelE _) => (lower+1, len)
adamc@341 146 | (st, _) => st}
adamc@341 147
adamc@814 148 datatype result = Yes of exp list | No | Maybe
adamc@258 149
adamc@183 150 fun match (env, p : pat, e : exp) =
adamc@183 151 case (#1 p, #1 e) of
adamc@258 152 (PWild, _) => Yes env
adamc@814 153 | (PVar (x, t), _) => Yes (e :: env)
adamc@183 154
adamc@280 155 | (PPrim (Prim.String s), EStrcat ((EPrim (Prim.String s'), _), _)) =>
adamc@280 156 if String.isPrefix s' s then
adamc@280 157 Maybe
adamc@280 158 else
adamc@280 159 No
adamc@280 160
adamc@183 161 | (PPrim p, EPrim p') =>
adamc@183 162 if Prim.equal (p, p') then
adamc@258 163 Yes env
adamc@183 164 else
adamc@258 165 No
adamc@183 166
adamc@188 167 | (PCon (_, PConVar n1, NONE), ECon (_, PConVar n2, NONE)) =>
adamc@183 168 if n1 = n2 then
adamc@258 169 Yes env
adamc@183 170 else
adamc@258 171 No
adamc@183 172
adamc@188 173 | (PCon (_, PConVar n1, SOME p), ECon (_, PConVar n2, SOME e)) =>
adamc@183 174 if n1 = n2 then
adamc@183 175 match (env, p, e)
adamc@183 176 else
adamc@258 177 No
adamc@183 178
adamc@188 179 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, NONE), ECon (_, PConFfi {mod = m2, con = con2, ...}, NONE)) =>
adamc@185 180 if m1 = m2 andalso con1 = con2 then
adamc@258 181 Yes env
adamc@185 182 else
adamc@258 183 No
adamc@185 184
adamc@188 185 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, SOME ep), ECon (_, PConFfi {mod = m2, con = con2, ...}, SOME e)) =>
adamc@185 186 if m1 = m2 andalso con1 = con2 then
adamc@185 187 match (env, p, e)
adamc@185 188 else
adamc@258 189 No
adamc@185 190
adamc@183 191 | (PRecord xps, ERecord xes) =>
adamc@183 192 let
adamc@183 193 fun consider (xps, env) =
adamc@183 194 case xps of
adamc@258 195 [] => Yes env
adamc@183 196 | (x, p, _) :: rest =>
adamc@183 197 case List.find (fn (x', _, _) => x' = x) xes of
adamc@258 198 NONE => No
adamc@183 199 | SOME (_, e, _) =>
adamc@183 200 case match (env, p, e) of
adamc@258 201 No => No
adamc@258 202 | Maybe => Maybe
adamc@258 203 | Yes env => consider (rest, env)
adamc@183 204 in
adamc@183 205 consider (xps, env)
adamc@183 206 end
adamc@183 207
adamc@726 208 | (PNone _, ENone _) => Yes env
adamc@726 209 | (PSome (_, p), ESome (_, e)) => match (env, p, e)
adamc@726 210
adamc@258 211 | _ => Maybe
adamc@183 212
adamc@318 213 datatype event =
adamc@318 214 WritePage
adamc@318 215 | ReadDb
adamc@318 216 | WriteDb
adamc@481 217 | UseRel
adamc@318 218 | Unsure
adamc@318 219
adamc@318 220 fun p_event e =
adamc@318 221 let
adamc@318 222 open Print.PD
adamc@318 223 in
adamc@318 224 case e of
adamc@318 225 WritePage => string "WritePage"
adamc@318 226 | ReadDb => string "ReadDb"
adamc@318 227 | WriteDb => string "WriteDb"
adamc@481 228 | UseRel => string "UseRel"
adamc@318 229 | Unsure => string "Unsure"
adamc@318 230 end
adamc@318 231
adamc@470 232 val p_events = Print.p_list p_event
adamc@470 233
adamc@318 234 fun patBinds (p, _) =
adamc@318 235 case p of
adamc@318 236 PWild => 0
adamc@318 237 | PVar _ => 1
adamc@318 238 | PPrim _ => 0
adamc@318 239 | PCon (_, _, NONE) => 0
adamc@318 240 | PCon (_, _, SOME p) => patBinds p
adamc@318 241 | PRecord xpts => foldl (fn ((_, p, _), n) => n + patBinds p) 0 xpts
adamc@318 242 | PNone _ => 0
adamc@318 243 | PSome (_, p) => patBinds p
adamc@318 244
adamc@470 245 fun reduce file =
adamc@470 246 let
adamc@470 247 fun countAbs (e, _) =
adamc@470 248 case e of
adamc@470 249 EAbs (_, _, _, e) => 1 + countAbs e
adamc@470 250 | _ => 0
adamc@318 251
adamc@470 252 val absCounts =
adamc@470 253 foldl (fn ((d, _), absCounts) =>
adamc@470 254 case d of
adamc@470 255 DVal (_, n, _, e, _) =>
adamc@470 256 IM.insert (absCounts, n, countAbs e)
adamc@470 257 | DValRec vis =>
adamc@470 258 foldl (fn ((_, n, _, e, _), absCounts) =>
adamc@470 259 IM.insert (absCounts, n, countAbs e))
adamc@470 260 absCounts vis
adamc@470 261 | _ => absCounts)
adamc@470 262 IM.empty file
adamc@387 263
adamc@470 264 fun summarize d (e, _) =
adamc@579 265 let
adamc@579 266 val s =
adamc@579 267 case e of
adamc@579 268 EPrim _ => []
adamc@579 269 | ERel n => if n = d then [UseRel] else []
adamc@579 270 | ENamed _ => []
adamc@579 271 | ECon (_, _, NONE) => []
adamc@579 272 | ECon (_, _, SOME e) => summarize d e
adamc@579 273 | ENone _ => []
adamc@579 274 | ESome (_, e) => summarize d e
adamc@579 275 | EFfi _ => []
adamc@765 276 | EFfiApp (m, x, es) =>
adamc@765 277 if Settings.isEffectful (m, x) then
adamc@765 278 List.concat (map (summarize d) es) @ [Unsure]
adamc@765 279 else
adamc@765 280 List.concat (map (summarize d) es)
adamc@579 281 | EApp ((EFfi _, _), e) => summarize d e
adamc@579 282 | EApp _ =>
adamc@579 283 let
adamc@694 284 fun unravel (e, passed, ls) =
adamc@579 285 case e of
adamc@579 286 ENamed n =>
adamc@579 287 let
adamc@579 288 val ls = rev ls
adamc@579 289 in
adamc@579 290 case IM.find (absCounts, n) of
adamc@579 291 NONE => [Unsure]
adamc@579 292 | SOME len =>
adamc@694 293 if passed < len then
adamc@579 294 ls
adamc@579 295 else
adamc@694 296 ls @ [Unsure]
adamc@579 297 end
adamc@579 298 | ERel n => List.revAppend (ls,
adamc@579 299 if n = d then
adamc@579 300 [UseRel, Unsure]
adamc@579 301 else
adamc@579 302 [Unsure])
adamc@579 303 | EApp (f, x) =>
adamc@694 304 unravel (#1 f, passed + 1, summarize d x @ ls)
adamc@579 305 | _ => [Unsure]
adamc@579 306 in
adamc@694 307 unravel (e, 0, [])
adamc@579 308 end
adamc@252 309
adamc@579 310 | EAbs (_, _, _, e) => List.filter (fn UseRel => true
adamc@579 311 | _ => false) (summarize (d + 1) e)
adamc@316 312
adamc@579 313 | EUnop (_, e) => summarize d e
adamc@579 314 | EBinop (_, e1, e2) => summarize d e1 @ summarize d e2
adamc@470 315
adamc@579 316 | ERecord xets => List.concat (map (summarize d o #2) xets)
adamc@579 317 | EField (e, _) => summarize d e
adamc@470 318
adamc@579 319 | ECase (e, pes, _) =>
adamc@579 320 let
adamc@579 321 val lss = map (fn (p, e) => summarize (d + patBinds p) e) pes
adamc@579 322 in
adamc@579 323 case lss of
adamc@579 324 [] => raise Fail "Empty pattern match"
adamc@579 325 | ls :: lss =>
adamc@579 326 if List.all (fn ls' => ls' = ls) lss then
adamc@579 327 summarize d e @ ls
adamc@579 328 else
adamc@579 329 [Unsure]
adamc@579 330 end
adamc@579 331 | EStrcat (e1, e2) => summarize d e1 @ summarize d e2
adamc@316 332
adamc@579 333 | EError (e, _) => summarize d e @ [Unsure]
adamc@741 334 | EReturnBlob {blob = e1, mimeType = e2, ...} => summarize d e1 @ summarize d e2 @ [Unsure]
adamc@318 335
adamc@579 336 | EWrite e => summarize d e @ [WritePage]
adamc@579 337
adamc@579 338 | ESeq (e1, e2) => summarize d e1 @ summarize d e2
adamc@579 339 | ELet (_, _, e1, e2) => summarize d e1 @ summarize (d + 1) e2
adamc@456 340
adamc@579 341 | EClosure (_, es) => List.concat (map (summarize d) es)
adamc@470 342
adamc@579 343 | EQuery {query, body, initial, ...} =>
adamc@579 344 List.concat [summarize d query,
adamc@579 345 summarize (d + 2) body,
adamc@579 346 summarize d initial,
adamc@579 347 [ReadDb]]
adamc@470 348
adamc@579 349 | EDml e => summarize d e @ [WriteDb]
adamc@579 350 | ENextval e => summarize d e @ [WriteDb]
adamc@579 351 | EUnurlify (e, _) => summarize d e
adamc@815 352 | EJavaScript (_, e) => summarize d e
adamc@579 353 | ESignalReturn e => summarize d e
adamc@579 354 | ESignalBind (e1, e2) => summarize d e1 @ summarize d e2
adamc@579 355 | ESignalSource e => summarize d e
adamc@608 356
adamc@736 357 | EServerCall (e, ek, _, _) => summarize d e @ summarize d ek @ [Unsure]
adamc@670 358 | ERecv (e, ek, _) => summarize d e @ summarize d ek @ [Unsure]
adamc@695 359 | ESleep (e, ek) => summarize d e @ summarize d ek @ [Unsure]
adamc@579 360 in
adamc@579 361 (*Print.prefaces "Summarize"
adamc@579 362 [("e", MonoPrint.p_exp MonoEnv.empty (e, ErrorMsg.dummySpan)),
adamc@579 363 ("d", Print.PD.string (Int.toString d)),
adamc@579 364 ("s", p_events s)];*)
adamc@579 365 s
adamc@579 366 end
adamc@470 367
adamc@470 368 fun exp env e =
adamc@470 369 let
adamc@470 370 (*val () = Print.prefaces "exp" [("e", MonoPrint.p_exp env (e, ErrorMsg.dummySpan))]*)
adamc@470 371
adamc@470 372 val r =
adamc@470 373 case e of
adamc@470 374 ERel n =>
adamc@470 375 (case E.lookupERel env n of
adamc@470 376 (_, _, SOME e') => #1 e'
adamc@470 377 | _ => e)
adamc@470 378 | ENamed n =>
adamc@470 379 (case E.lookupENamed env n of
adamc@470 380 (_, _, SOME e', _) => ((*Print.prefaces "Switch" [("n", Print.PD.string (Int.toString n)),
adamc@470 381 ("e'", MonoPrint.p_exp env e')];*)
adamc@470 382 #1 e')
adamc@470 383 | _ => e)
adamc@470 384
adamc@470 385 | EApp ((EAbs (x, t, _, e1), loc), e2) =>
adamc@470 386 ((*Print.prefaces "Considering" [("e1", MonoPrint.p_exp (E.pushERel env x t NONE) e1),
adamc@694 387 ("e2", MonoPrint.p_exp env e2),
adamc@694 388 ("sub", MonoPrint.p_exp env (reduceExp env (subExpInExp (0, e2) e1)))];*)
adamc@470 389 if impure e2 then
adamc@470 390 #1 (reduceExp env (ELet (x, t, e2, e1), loc))
adamc@470 391 else
adamc@470 392 #1 (reduceExp env (subExpInExp (0, e2) e1)))
adamc@470 393
adamc@470 394 | ECase (e', pes, {disc, result}) =>
adamc@442 395 let
adamc@470 396 fun push () =
adamc@470 397 case result of
adamc@470 398 (TFun (dom, result), loc) =>
adamc@470 399 if List.all (fn (_, (EAbs _, _)) => true | _ => false) pes then
adamc@827 400 let
adamc@827 401 val r =
adamc@827 402 EAbs ("y", dom, result,
adamc@827 403 (ECase (liftExpInExp 0 e',
adamc@827 404 map (fn (p, (EAbs (_, _, _, e), _)) =>
adamc@827 405 (p, swapExpVarsPat (0, patBinds p) e)
adamc@827 406 | _ => raise Fail "MonoReduce ECase") pes,
adamc@827 407 {disc = disc, result = result}), loc))
adamc@827 408 in
adamc@827 409 (*Print.prefaces "Swapped"
adamc@827 410 [("e", MonoPrint.p_exp env (e, ErrorMsg.dummySpan)),
adamc@827 411 ("r", MonoPrint.p_exp env (r, ErrorMsg.dummySpan))];*)
adamc@827 412 r
adamc@827 413 end
adamc@470 414 else
adamc@470 415 e
adamc@470 416 | _ => e
adamc@318 417
adamc@470 418 fun search pes =
adamc@470 419 case pes of
adamc@470 420 [] => push ()
adamc@470 421 | (p, body) :: pes =>
adamc@814 422 case match ([], p, e') of
adamc@470 423 No => search pes
adamc@470 424 | Maybe => push ()
adamc@814 425 | Yes subs =>
adamc@800 426 let
adamc@829 427 val (body, remaining) =
adamc@829 428 foldl (fn (e, (body, remaining)) =>
adamc@829 429 (subExpInExp (0, multiLift remaining e) body, remaining - 1))
adamc@829 430 (body, length subs - 1) subs
adamc@814 431 val r = reduceExp env body
adamc@800 432 in
adamc@829 433 (*Print.preface ("subs", Print.p_list (MonoPrint.p_exp env) subs);*)
adamc@800 434 (*Print.prefaces "ECase"
adamc@829 435 [("old", MonoPrint.p_exp env body),
adamc@829 436 ("body", MonoPrint.p_exp env body),
adamc@800 437 ("r", MonoPrint.p_exp env r)];*)
adamc@800 438 #1 r
adamc@800 439 end
adamc@470 440 in
adamc@470 441 search pes
adamc@470 442 end
adamc@318 443
adamc@470 444 | EField ((ERecord xes, _), x) =>
adamc@470 445 (case List.find (fn (x', _, _) => x' = x) xes of
adamc@470 446 SOME (_, e, _) => #1 e
adamc@470 447 | NONE => e)
adamc@398 448
adamc@470 449 | ELet (x1, t1, (ELet (x2, t2, e1, b1), loc), b2) =>
adamc@470 450 let
adamc@470 451 val e' = (ELet (x2, t2, e1,
adamc@470 452 (ELet (x1, t1, b1,
adamc@470 453 liftExpInExp 1 b2), loc)), loc)
adamc@442 454 in
adamc@470 455 (*Print.prefaces "ELet commute" [("e", MonoPrint.p_exp env (e, loc)),
adamc@470 456 ("e'", MonoPrint.p_exp env e')];*)
adamc@470 457 #1 (reduceExp env e')
adamc@470 458 end
adamc@470 459 | EApp ((ELet (x, t, e, b), loc), e') =>
adamc@470 460 #1 (reduceExp env (ELet (x, t, e,
adamc@470 461 (EApp (b, liftExpInExp 0 e'), loc)), loc))
adamc@470 462
adamc@470 463 | ELet (x, t, e', (EAbs (x', t' as (TRecord [], _), ran, e''), loc)) =>
adamc@848 464 if impure e' then
adamc@848 465 e
adamc@848 466 else
adamc@848 467 EAbs (x', t', ran, (ELet (x, t, liftExpInExp 0 e', swapExpVars 0 e''), loc))
adamc@470 468
adamc@470 469 | ELet (x, t, e', b) =>
adamc@470 470 let
adamc@470 471 fun doSub () =
adamc@800 472 let
adamc@800 473 val r = subExpInExp (0, e') b
adamc@800 474 in
adamc@800 475 (*Print.prefaces "doSub" [("e'", MonoPrint.p_exp env e'),
adamc@800 476 ("b", MonoPrint.p_exp (E.pushERel env x t NONE) b),
adamc@800 477 ("r", MonoPrint.p_exp env r)];*)
adamc@800 478 #1 (reduceExp env r)
adamc@800 479 end
adamc@470 480
adamc@470 481 fun trySub () =
adamc@470 482 case t of
adamc@470 483 (TFfi ("Basis", "string"), _) => doSub ()
adamc@568 484 | (TSignal _, _) => e
adamc@470 485 | _ =>
adamc@470 486 case e' of
adamc@470 487 (ECase _, _) => e
adamc@470 488 | _ => doSub ()
adamc@470 489 in
adamc@470 490 if impure e' then
adamc@470 491 let
adamc@470 492 val effs_e' = summarize 0 e'
adamc@489 493 val effs_e' = List.filter (fn x => x <> UseRel) effs_e'
adamc@470 494 val effs_b = summarize 0 b
adamc@470 495
adamc@470 496 (*val () = Print.prefaces "Try"
adamc@489 497 [("e", MonoPrint.p_exp env (e, ErrorMsg.dummySpan)),
adamc@489 498 ("e'", p_events effs_e'),
adamc@489 499 ("b", p_events effs_b)]*)
adamc@470 500
adamc@470 501 fun does eff = List.exists (fn eff' => eff' = eff) effs_e'
adamc@470 502 val writesPage = does WritePage
adamc@470 503 val readsDb = does ReadDb
adamc@470 504 val writesDb = does WriteDb
adamc@470 505
adamc@470 506 fun verifyUnused eff =
adamc@470 507 case eff of
adamc@481 508 UseRel => false
adamc@470 509 | _ => true
adamc@470 510
adamc@470 511 fun verifyCompatible effs =
adamc@470 512 case effs of
adamc@470 513 [] => false
adamc@470 514 | eff :: effs =>
adamc@470 515 case eff of
adamc@470 516 Unsure => false
adamc@481 517 | UseRel => List.all verifyUnused effs
adamc@470 518 | WritePage => not writesPage andalso verifyCompatible effs
adamc@470 519 | ReadDb => not writesDb andalso verifyCompatible effs
adamc@470 520 | WriteDb => not writesDb andalso not readsDb andalso verifyCompatible effs
adamc@470 521 in
adamc@470 522 (*Print.prefaces "verifyCompatible"
adamc@601 523 [("e'", MonoPrint.p_exp env e'),
adamc@601 524 ("b", MonoPrint.p_exp (E.pushERel env x t NONE) b),
adamc@601 525 ("effs_e'", Print.p_list p_event effs_e'),
adamc@601 526 ("effs_b", Print.p_list p_event effs_b)];*)
adamc@601 527 if List.null effs_e' orelse (List.all (fn eff => eff <> Unsure) effs_e'
adamc@601 528 andalso verifyCompatible effs_b) then
adamc@470 529 trySub ()
adamc@470 530 else
adamc@470 531 e
adamc@470 532 end
adamc@470 533 else
adamc@442 534 trySub ()
adamc@442 535 end
adamc@252 536
adamc@470 537 | EStrcat ((EPrim (Prim.String s1), _), (EPrim (Prim.String s2), _)) =>
adamc@470 538 EPrim (Prim.String (s1 ^ s2))
adamc@268 539
adamc@572 540 | ESignalBind ((ESignalReturn e1, loc), e2) =>
adamc@572 541 #1 (reduceExp env (EApp (e2, e1), loc))
adamc@572 542
adamc@470 543 | _ => e
adamc@470 544 in
adamc@829 545 (*Print.prefaces "exp'" [("e", MonoPrint.p_exp env (e, ErrorMsg.dummySpan)),
adamc@829 546 ("r", MonoPrint.p_exp env (r, ErrorMsg.dummySpan))];*)
adamc@470 547 r
adamc@470 548 end
adamc@470 549
adamc@470 550 and bind (env, b) =
adamc@470 551 case b of
adamc@470 552 U.Decl.Datatype (x, n, xncs) => E.pushDatatype env x n xncs
adamc@470 553 | U.Decl.RelE (x, t) => E.pushERel env x t NONE
adamc@470 554 | U.Decl.NamedE (x, n, t, eo, s) => E.pushENamed env x n t (Option.map (reduceExp env) eo) s
adamc@470 555
adamc@470 556 and reduceExp env = U.Exp.mapB {typ = typ, exp = exp, bind = bind} env
adamc@470 557
adamc@801 558 fun decl env d = ((*Print.preface ("d", MonoPrint.p_decl env (d, ErrorMsg.dummySpan));*)
adamc@801 559 d)
adamc@398 560 in
adamc@470 561 U.File.mapB {typ = typ, exp = exp, decl = decl, bind = bind} E.empty file
adamc@398 562 end
adamc@133 563
adamc@133 564 end