annotate src/reduce.sml @ 1016:065ce3252090

Inlining threshold for Reduce
author Adam Chlipala <adamc@hcoop.net>
date Sun, 25 Oct 2009 12:08:21 -0400
parents 01a4d936395a
children 68ba074e260f
rev   line source
adamc@20 1 (* Copyright (c) 2008, Adam Chlipala
adamc@20 2 * All rights reserved.
adamc@20 3 *
adamc@20 4 * Redistribution and use in source and binary forms, with or without
adamc@20 5 * modification, are permitted provided that the following conditions are met:
adamc@20 6 *
adamc@20 7 * - Redistributions of source code must retain the above copyright notice,
adamc@20 8 * this list of conditions and the following disclaimer.
adamc@20 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@20 10 * this list of conditions and the following disclaimer in the documentation
adamc@20 11 * and/or other materials provided with the distribution.
adamc@20 12 * - The names of contributors may not be used to endorse or promote products
adamc@20 13 * derived from this software without specific prior written permission.
adamc@20 14 *
adamc@20 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@20 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@20 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@20 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@20 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@20 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@20 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@20 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@20 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@20 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@20 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@20 26 *)
adamc@20 27
adamc@20 28 (* Simplify a Core program algebraically *)
adamc@20 29
adamc@20 30 structure Reduce :> REDUCE = struct
adamc@20 31
adamc@20 32 open Core
adamc@20 33
adamc@1016 34 structure IS = IntBinarySet
adamc@508 35 structure IM = IntBinaryMap
adamc@20 36
adamc@908 37 structure E = CoreEnv
adamc@908 38
adamc@908 39 fun multiLiftExpInExp n e =
adamc@908 40 if n = 0 then
adamc@908 41 e
adamc@908 42 else
adamc@908 43 multiLiftExpInExp (n - 1) (E.liftExpInExp 0 e)
adamc@908 44
adamc@909 45 val dangling =
adamc@909 46 CoreUtil.Exp.existsB {kind = fn _ => false,
adamc@909 47 con = fn _ => false,
adamc@909 48 exp = fn (n, e) =>
adamc@909 49 case e of
adamc@909 50 ERel n' => n' >= n
adamc@909 51 | _ => false,
adamc@909 52 bind = fn (n, b) =>
adamc@909 53 case b of
adamc@909 54 CoreUtil.Exp.RelE _ => n + 1
adamc@909 55 | _ => n}
adamc@909 56
adamc@508 57 datatype env_item =
adamc@626 58 UnknownK
adamc@626 59 | KnownK of kind
adamc@626 60
adamc@626 61 | UnknownC
adamc@508 62 | KnownC of con
adamc@21 63
adamc@508 64 | UnknownE
adamc@508 65 | KnownE of exp
adamc@20 66
adamc@626 67 | Lift of int * int * int
adamc@20 68
adamc@909 69 val edepth = foldl (fn (UnknownE, n) => n + 1
adamc@909 70 | (KnownE _, n) => n + 1
adamc@909 71 | (_, n) => n) 0
adamc@909 72
adamc@909 73 val edepth' = foldl (fn (UnknownE, n) => n + 1
adamc@909 74 | (KnownE _, n) => n + 1
adamc@909 75 | (Lift (_, _, n'), n) => n + n'
adamc@909 76 | (_, n) => n) 0
adamc@909 77
adamc@508 78 type env = env_item list
adamc@20 79
adamc@510 80 fun ei2s ei =
adamc@510 81 case ei of
adamc@626 82 UnknownK => "UK"
adamc@626 83 | KnownK _ => "KK"
adamc@626 84 | UnknownC => "UC"
adamc@510 85 | KnownC _ => "KC"
adamc@510 86 | UnknownE => "UE"
adamc@510 87 | KnownE _ => "KE"
adamc@626 88 | Lift (_, n1, n2) => "(" ^ Int.toString n1 ^ ", " ^ Int.toString n2 ^ ")"
adamc@510 89
adamc@510 90 fun e2s env = String.concatWith " " (map ei2s env)
adamc@510 91
adamc@909 92 (*val deKnown = List.filter (fn KnownC _ => false
adamc@510 93 | KnownE _ => false
adamc@626 94 | KnownK _ => false
adamc@909 95 | _ => true)*)
adamc@909 96
adamc@909 97 val deKnown = ListUtil.mapConcat (fn KnownC _ => []
adamc@909 98 | KnownE _ => []
adamc@909 99 | KnownK _ => []
adamc@909 100 | Lift (nk, nc, ne) => List.tabulate (nk, fn _ => UnknownK)
adamc@909 101 @ List.tabulate (nc, fn _ => UnknownC)
adamc@909 102 @ List.tabulate (ne, fn _ => UnknownE)
adamc@909 103 | x => [x])
adamc@510 104
adamc@930 105 datatype result = Yes of env | No | Maybe
adamc@930 106
adamc@930 107 fun match (env, p : pat, e : exp) =
adamc@942 108 let
adamc@942 109 val baseline = length env
adamc@930 110
adamc@942 111 fun match (env, p, e) =
adamc@942 112 case (#1 p, #1 e) of
adamc@942 113 (PWild, _) => Yes env
adamc@942 114 | (PVar (x, t), _) => Yes (KnownE (multiLiftExpInExp (length env - baseline) e) :: env)
adamc@930 115
adamc@942 116 | (PPrim p, EPrim p') =>
adamc@942 117 if Prim.equal (p, p') then
adamc@942 118 Yes env
adamc@942 119 else
adamc@942 120 No
adamc@930 121
adamc@942 122 | (PCon (_, PConVar n1, _, NONE), ECon (_, PConVar n2, _, NONE)) =>
adamc@942 123 if n1 = n2 then
adamc@942 124 Yes env
adamc@942 125 else
adamc@942 126 No
adamc@930 127
adamc@942 128 | (PCon (_, PConVar n1, _, SOME p), ECon (_, PConVar n2, _, SOME e)) =>
adamc@942 129 if n1 = n2 then
adamc@942 130 match (env, p, e)
adamc@942 131 else
adamc@942 132 No
adamc@930 133
adamc@942 134 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, _, NONE),
adamc@942 135 ECon (_, PConFfi {mod = m2, con = con2, ...}, _, NONE)) =>
adamc@942 136 if m1 = m2 andalso con1 = con2 then
adamc@942 137 Yes env
adamc@942 138 else
adamc@942 139 No
adamc@930 140
adamc@942 141 | (PCon (_, PConFfi {mod = m1, con = con1, ...}, _, SOME ep),
adamc@942 142 ECon (_, PConFfi {mod = m2, con = con2, ...}, _, SOME e)) =>
adamc@942 143 if m1 = m2 andalso con1 = con2 then
adamc@942 144 match (env, p, e)
adamc@942 145 else
adamc@942 146 No
adamc@930 147
adamc@942 148 | (PRecord xps, ERecord xes) =>
adamc@942 149 if List.exists (fn ((CName _, _), _, _) => false
adamc@942 150 | _ => true) xes then
adamc@942 151 Maybe
adamc@942 152 else
adamc@942 153 let
adamc@942 154 fun consider (xps, env) =
adamc@942 155 case xps of
adamc@942 156 [] => Yes env
adamc@942 157 | (x, p, _) :: rest =>
adamc@942 158 case List.find (fn ((CName x', _), _, _) => x' = x
adamc@942 159 | _ => false) xes of
adamc@942 160 NONE => No
adamc@942 161 | SOME (_, e, _) =>
adamc@942 162 case match (env, p, e) of
adamc@942 163 No => No
adamc@942 164 | Maybe => Maybe
adamc@942 165 | Yes env => consider (rest, env)
adamc@942 166 in
adamc@942 167 consider (xps, env)
adamc@942 168 end
adamc@942 169
adamc@942 170 | _ => Maybe
adamc@942 171 in
adamc@942 172 match (env, p, e)
adamc@942 173 end
adamc@930 174
adamc@626 175 fun kindConAndExp (namedC, namedE) =
adamc@508 176 let
adamc@626 177 fun kind env (all as (k, loc)) =
adamc@626 178 case k of
adamc@626 179 KType => all
adamc@626 180 | KArrow (k1, k2) => (KArrow (kind env k1, kind env k2), loc)
adamc@626 181 | KName => all
adamc@626 182 | KRecord k => (KRecord (kind env k), loc)
adamc@626 183 | KUnit => all
adamc@626 184 | KTuple ks => (KTuple (map (kind env) ks), loc)
adamc@626 185
adamc@626 186 | KRel n =>
adamc@626 187 let
adamc@626 188 fun find (n', env, nudge, lift) =
adamc@626 189 case env of
adamc@626 190 [] => raise Fail "Reduce.kind: KRel"
adamc@626 191 | UnknownC :: rest => find (n', rest, nudge, lift)
adamc@626 192 | KnownC _ :: rest => find (n', rest, nudge, lift)
adamc@626 193 | UnknownE :: rest => find (n', rest, nudge, lift)
adamc@626 194 | KnownE _ :: rest => find (n', rest, nudge, lift)
adamc@626 195 | Lift (lift', _, _) :: rest => find (n', rest, nudge + lift', lift + lift')
adamc@626 196 | UnknownK :: rest =>
adamc@626 197 if n' = 0 then
adamc@626 198 (KRel (n + nudge), loc)
adamc@626 199 else
adamc@626 200 find (n' - 1, rest, nudge, lift + 1)
adamc@626 201 | KnownK k :: rest =>
adamc@626 202 if n' = 0 then
adamc@626 203 kind (Lift (lift, 0, 0) :: rest) k
adamc@626 204 else
adamc@626 205 find (n' - 1, rest, nudge - 1, lift)
adamc@626 206 in
adamc@626 207 find (n, env, 0, 0)
adamc@626 208 end
adamc@626 209 | KFun (x, k) => (KFun (x, kind (UnknownK :: env) k), loc)
adamc@626 210
adamc@508 211 fun con env (all as (c, loc)) =
adamc@510 212 ((*Print.prefaces "con" [("c", CorePrint.p_con CoreEnv.empty all)];*)
adamc@508 213 case c of
adamc@508 214 TFun (c1, c2) => (TFun (con env c1, con env c2), loc)
adamc@626 215 | TCFun (x, k, c2) => (TCFun (x, kind env k, con (UnknownC :: env) c2), loc)
adamc@626 216 | TKFun (x, c2) => (TKFun (x, con (UnknownK :: env) c2), loc)
adamc@508 217 | TRecord c => (TRecord (con env c), loc)
adamc@215 218
adamc@508 219 | CRel n =>
adamc@508 220 let
adamc@626 221 fun find (n', env, nudge, liftK, liftC) =
adamc@510 222 case env of
adamc@510 223 [] => raise Fail "Reduce.con: CRel"
adamc@626 224 | UnknownK :: rest => find (n', rest, nudge, liftK + 1, liftC)
adamc@626 225 | KnownK _ :: rest => find (n', rest, nudge, liftK, liftC)
adamc@626 226 | UnknownE :: rest => find (n', rest, nudge, liftK, liftC)
adamc@626 227 | KnownE _ :: rest => find (n', rest, nudge, liftK, liftC)
adamc@626 228 | Lift (liftK', liftC', _) :: rest => find (n', rest, nudge + liftC',
adamc@626 229 liftK + liftK', liftC + liftC')
adamc@510 230 | UnknownC :: rest =>
adamc@510 231 if n' = 0 then
adamc@510 232 (CRel (n + nudge), loc)
adamc@510 233 else
adamc@626 234 find (n' - 1, rest, nudge, liftK, liftC + 1)
adamc@510 235 | KnownC c :: rest =>
adamc@510 236 if n' = 0 then
adamc@626 237 con (Lift (liftK, liftC, 0) :: rest) c
adamc@510 238 else
adamc@626 239 find (n' - 1, rest, nudge - 1, liftK, liftC)
adamc@508 240 in
adamc@510 241 (*print (Int.toString n ^ ": " ^ e2s env ^ "\n");*)
adamc@626 242 find (n, env, 0, 0, 0)
adamc@508 243 end
adamc@508 244 | CNamed n =>
adamc@508 245 (case IM.find (namedC, n) of
adamc@508 246 NONE => all
adamc@508 247 | SOME c => c)
adamc@508 248 | CFfi _ => all
adamc@508 249 | CApp (c1, c2) =>
adamc@508 250 let
adamc@508 251 val c1 = con env c1
adamc@508 252 val c2 = con env c2
adamc@508 253 in
adamc@508 254 case #1 c1 of
adamc@508 255 CAbs (_, _, b) =>
adamc@510 256 con (KnownC c2 :: deKnown env) b
adamc@215 257
adamc@621 258 | CApp ((CMap (dom, ran), _), f) =>
adamc@508 259 (case #1 c2 of
adamc@626 260 CRecord (_, []) => (CRecord (kind env ran, []), loc)
adamc@621 261 | CRecord (_, (x, c) :: rest) =>
adamc@510 262 con (deKnown env)
adamc@621 263 (CConcat ((CRecord (ran, [(x, (CApp (f, c), loc))]), loc),
adamc@626 264 (CApp (c1, (CRecord (kind env dom, rest), loc)), loc)), loc)
adamc@508 265 | _ => (CApp (c1, c2), loc))
adamc@20 266
adamc@508 267 | _ => (CApp (c1, c2), loc)
adamc@508 268 end
adamc@626 269 | CAbs (x, k, b) => (CAbs (x, kind env k, con (UnknownC :: env) b), loc)
adamc@626 270
adamc@626 271 | CKApp (c1, k) =>
adamc@626 272 let
adamc@626 273 val c1 = con env c1
adamc@626 274 in
adamc@626 275 case #1 c1 of
adamc@626 276 CKAbs (_, b) =>
adamc@626 277 con (KnownK k :: deKnown env) b
adamc@626 278
adamc@626 279 | _ => (CKApp (c1, kind env k), loc)
adamc@626 280 end
adamc@626 281 | CKAbs (x, b) => (CKAbs (x, con (UnknownK :: env) b), loc)
adamc@20 282
adamc@508 283 | CName _ => all
adamc@21 284
adamc@626 285 | CRecord (k, xcs) => (CRecord (kind env k, map (fn (x, c) => (con env x, con env c)) xcs), loc)
adamc@508 286 | CConcat (c1, c2) =>
adamc@508 287 let
adamc@508 288 val c1 = con env c1
adamc@508 289 val c2 = con env c2
adamc@508 290 in
adamc@508 291 case (#1 c1, #1 c2) of
adamc@508 292 (CRecord (k, xcs1), CRecord (_, xcs2)) =>
adamc@626 293 (CRecord (kind env k, xcs1 @ xcs2), loc)
adamc@508 294 | _ => (CConcat (c1, c2), loc)
adamc@508 295 end
adamc@626 296 | CMap (dom, ran) => (CMap (kind env dom, kind env ran), loc)
adamc@74 297
adamc@508 298 | CUnit => all
adamc@21 299
adamc@508 300 | CTuple cs => (CTuple (map (con env) cs), loc)
adamc@508 301 | CProj (c, n) =>
adamc@508 302 let
adamc@508 303 val c = con env c
adamc@508 304 in
adamc@508 305 case #1 c of
adamc@508 306 CTuple cs => List.nth (cs, n - 1)
adamc@508 307 | _ => (CProj (c, n), loc)
adamc@510 308 end)
adamc@22 309
adamc@509 310 fun patCon pc =
adamc@509 311 case pc of
adamc@509 312 PConVar _ => pc
adamc@509 313 | PConFfi {mod = m, datatyp, params, con = c, arg, kind} =>
adamc@509 314 PConFfi {mod = m, datatyp = datatyp, params = params, con = c,
adamc@509 315 arg = Option.map (con (map (fn _ => UnknownC) params)) arg,
adamc@509 316 kind = kind}
adamc@509 317
adamc@509 318
adamc@509 319 val k = (KType, ErrorMsg.dummySpan)
adamc@509 320 fun doPart e (this as (x, t), rest) =
adamc@509 321 ((x, (EField (e, x, {field = t, rest = (CRecord (k, rest), #2 t)}), #2 t), t),
adamc@509 322 this :: rest)
adamc@509 323
adamc@509 324 fun exp env (all as (e, loc)) =
adamc@909 325 let
adamc@909 326 (*val () = Print.prefaces "exp" [("e", CorePrint.p_exp CoreEnv.empty all),
adamc@909 327 ("env", Print.PD.string (e2s env))]*)
adamc@910 328 val () = if dangling (edepth env) all then
adamc@909 329 (Print.prefaces "exp" [("e", CorePrint.p_exp CoreEnv.empty all),
adamc@909 330 ("env", Print.PD.string (e2s env))];
adamc@909 331 raise Fail "!")
adamc@909 332 else
adamc@910 333 ()
adamc@509 334
adamc@909 335 val r = case e of
adamc@909 336 EPrim _ => all
adamc@909 337 | ERel n =>
adamc@909 338 let
adamc@909 339 fun find (n', env, nudge, liftK, liftC, liftE) =
adamc@909 340 case env of
adamc@909 341 [] => raise Fail ("Reduce.exp: ERel (" ^ ErrorMsg.spanToString loc ^ ")")
adamc@909 342 | UnknownK :: rest => find (n', rest, nudge, liftK + 1, liftC, liftE)
adamc@909 343 | KnownK _ :: rest => find (n', rest, nudge, liftK, liftC, liftE)
adamc@909 344 | UnknownC :: rest => find (n', rest, nudge, liftK, liftC + 1, liftE)
adamc@909 345 | KnownC _ :: rest => find (n', rest, nudge, liftK, liftC, liftE)
adamc@909 346 | Lift (liftK', liftC', liftE') :: rest =>
adamc@909 347 find (n', rest, nudge + liftE',
adamc@909 348 liftK + liftK', liftC + liftC', liftE + liftE')
adamc@909 349 | UnknownE :: rest =>
adamc@909 350 if n' = 0 then
adamc@909 351 (ERel (n + nudge), loc)
adamc@909 352 else
adamc@909 353 find (n' - 1, rest, nudge, liftK, liftC, liftE + 1)
adamc@909 354 | KnownE e :: rest =>
adamc@909 355 if n' = 0 then
adamc@909 356 ((*print "SUBSTITUTING\n";*)
adamc@909 357 exp (Lift (liftK, liftC, liftE) :: rest) e)
adamc@909 358 else
adamc@909 359 find (n' - 1, rest, nudge - 1, liftK, liftC, liftE)
adamc@909 360 in
adamc@909 361 (*print (Int.toString n ^ ": " ^ e2s env ^ "\n");*)
adamc@909 362 find (n, env, 0, 0, 0, 0)
adamc@909 363 end
adamc@909 364 | ENamed n =>
adamc@909 365 (case IM.find (namedE, n) of
adamc@909 366 NONE => all
adamc@909 367 | SOME e => e)
adamc@909 368 | ECon (dk, pc, cs, eo) => (ECon (dk, patCon pc,
adamc@909 369 map (con env) cs, Option.map (exp env) eo), loc)
adamc@909 370 | EFfi _ => all
adamc@909 371 | EFfiApp (m, f, es) => (EFfiApp (m, f, map (exp env) es), loc)
adamc@908 372
adamc@909 373 (*| EApp (
adamc@909 374 (EApp
adamc@909 375 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _), t1), _), t2), _),
adamc@909 376 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@909 377 (ECase (ed, pes, {disc, ...}), _)), _),
adamc@909 378 trans2) =>
adamc@909 379 let
adamc@909 380 val e' = (EFfi ("Basis", "bind"), loc)
adamc@909 381 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@909 382 val e' = (ECApp (e', t1), loc)
adamc@909 383 val e' = (ECApp (e', t2), loc)
adamc@909 384 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@908 385
adamc@909 386 val pes = map (fn (p, e) =>
adamc@909 387 let
adamc@909 388 val e' = (EApp (e', e), loc)
adamc@909 389 val e' = (EApp (e',
adamc@909 390 multiLiftExpInExp (E.patBindsN p)
adamc@909 391 trans2), loc)
adamc@909 392 val e' = exp env e'
adamc@909 393 in
adamc@909 394 (p, e')
adamc@909 395 end) pes
adamc@909 396 in
adamc@909 397 (ECase (exp env ed,
adamc@909 398 pes,
adamc@909 399 {disc = con env disc,
adamc@909 400 result = (CApp ((CFfi ("Basis", "transaction"), loc), con env t2), loc)}),
adamc@909 401 loc)
adamc@909 402 end*)
adamc@908 403
adamc@909 404 | EApp (e1, e2) =>
adamc@909 405 let
adamc@910 406 val env' = deKnown env
adamc@910 407
adamc@910 408 fun reassoc e =
adamc@910 409 case #1 e of
adamc@910 410 EApp
adamc@910 411 ((EApp
adamc@910 412 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _),
adamc@910 413 t1),
adamc@910 414 _), t2), _),
adamc@910 415 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@910 416 (EServerCall (n, es, (EAbs (_, _, _, ke), _), dom, ran), _)), _),
adamc@910 417 trans3) =>
adamc@910 418 let
adamc@910 419 val e' = (EFfi ("Basis", "bind"), loc)
adamc@910 420 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@910 421 val e' = (ECApp (e', dom), loc)
adamc@910 422 val e' = (ECApp (e', t2), loc)
adamc@910 423 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@910 424 val e' = (EApp (e', ke), loc)
adamc@910 425 val e' = (EApp (e', E.liftExpInExp 0 trans3), loc)
adamc@910 426 val e' = reassoc e'
adamc@910 427 val e' = (EAbs ("x", dom, t2, e'), loc)
adamc@910 428 val e' = (EServerCall (n, es, e', dom, t2), loc)
adamc@910 429 in
adamc@910 430 e'
adamc@910 431 end
adamc@910 432
adamc@910 433 | EApp
adamc@910 434 ((EApp
adamc@910 435 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _),
adamc@910 436 t1),
adamc@910 437 _), t2), _),
adamc@910 438 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@910 439 (EServerCall (n, es, ke, dom, ran), _)), _),
adamc@910 440 trans3) =>
adamc@910 441 let
adamc@910 442 val e' = (EFfi ("Basis", "bind"), loc)
adamc@910 443 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@910 444 val e' = (ECApp (e', dom), loc)
adamc@910 445 val e' = (ECApp (e', t2), loc)
adamc@910 446 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@910 447 val e' = (EApp (e', exp (UnknownE :: env')
adamc@910 448 (EApp (E.liftExpInExp 0 ke, (ERel 0, loc)), loc)),
adamc@910 449 loc)
adamc@910 450 val e' = (EApp (e', E.liftExpInExp 0 trans3), loc)
adamc@910 451 val e' = reassoc e'
adamc@910 452 val e' = (EAbs ("x", dom, t2, e'), loc)
adamc@910 453 val e' = (EServerCall (n, es, e', dom, t2), loc)
adamc@910 454 in
adamc@910 455 e'
adamc@910 456 end
adamc@910 457
adamc@910 458 | EApp
adamc@910 459 ((EApp
adamc@955 460 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _),
adamc@955 461 t1),
adamc@955 462 _), t2), _),
adamc@955 463 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@955 464 (ETailCall (n, es, (EAbs (_, _, _, ke), _), dom, ran), _)), _),
adamc@955 465 trans3) =>
adamc@955 466 let
adamc@955 467 val e' = (EFfi ("Basis", "bind"), loc)
adamc@955 468 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@955 469 val e' = (ECApp (e', dom), loc)
adamc@955 470 val e' = (ECApp (e', t2), loc)
adamc@955 471 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@955 472 val e' = (EApp (e', ke), loc)
adamc@955 473 val e' = (EApp (e', E.liftExpInExp 0 trans3), loc)
adamc@955 474 val e' = reassoc e'
adamc@955 475 val e' = (EAbs ("x", dom, t2, e'), loc)
adamc@955 476 val e' = (ETailCall (n, es, e', dom, t2), loc)
adamc@955 477 in
adamc@955 478 e'
adamc@955 479 end
adamc@955 480
adamc@955 481 | EApp
adamc@955 482 ((EApp
adamc@955 483 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _),
adamc@955 484 t1),
adamc@955 485 _), t2), _),
adamc@955 486 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@955 487 (ETailCall (n, es, ke, dom, ran), _)), _),
adamc@955 488 trans3) =>
adamc@955 489 let
adamc@955 490 val e' = (EFfi ("Basis", "bind"), loc)
adamc@955 491 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@955 492 val e' = (ECApp (e', dom), loc)
adamc@955 493 val e' = (ECApp (e', t2), loc)
adamc@955 494 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@955 495 val e' = (EApp (e', exp (UnknownE :: env')
adamc@955 496 (EApp (E.liftExpInExp 0 ke, (ERel 0, loc)), loc)),
adamc@955 497 loc)
adamc@955 498 val e' = (EApp (e', E.liftExpInExp 0 trans3), loc)
adamc@955 499 val e' = reassoc e'
adamc@955 500 val e' = (EAbs ("x", dom, t2, e'), loc)
adamc@955 501 val e' = (ETailCall (n, es, e', dom, t2), loc)
adamc@955 502 in
adamc@955 503 e'
adamc@955 504 end
adamc@955 505
adamc@955 506 | EApp
adamc@955 507 ((EApp
adamc@910 508 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), mt),
adamc@910 509 _), _), _), t3), _),
adamc@910 510 me), _),
adamc@910 511 (EApp ((EApp
adamc@910 512 ((EApp ((ECApp ((ECApp ((ECApp (
adamc@910 513 (EFfi ("Basis", "bind"), _), _), _),
adamc@910 514 t1), _), t2), _),
adamc@910 515 _), _),
adamc@910 516 trans1), _), (EAbs (_, _, _, trans2), _)), _)), _),
adamc@910 517 trans3) =>
adamc@910 518 let
adamc@910 519 val e'' = (EFfi ("Basis", "bind"), loc)
adamc@910 520 val e'' = (ECApp (e'', mt), loc)
adamc@910 521 val e'' = (ECApp (e'', t2), loc)
adamc@910 522 val e'' = (ECApp (e'', t3), loc)
adamc@910 523 val e'' = (EApp (e'', me), loc)
adamc@910 524 val e'' = (EApp (e'', trans2), loc)
adamc@910 525 val e'' = (EApp (e'', E.liftExpInExp 0 trans3), loc)
adamc@910 526 val e'' = reassoc e''
adamc@910 527 val e'' = (EAbs ("xb", t1, (CApp (mt, t3), loc), e''), loc)
adamc@910 528
adamc@910 529 val e' = (EFfi ("Basis", "bind"), loc)
adamc@910 530 val e' = (ECApp (e', mt), loc)
adamc@910 531 val e' = (ECApp (e', t1), loc)
adamc@910 532 val e' = (ECApp (e', t3), loc)
adamc@910 533 val e' = (EApp (e', me), loc)
adamc@910 534 val e' = (EApp (e', trans1), loc)
adamc@910 535 val e' = (EApp (e', e''), loc)
adamc@910 536 in
adamc@910 537 e'
adamc@910 538 end
adamc@910 539
adamc@910 540 | EApp
adamc@910 541 ((EApp
adamc@910 542 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), mt),
adamc@910 543 _), _), _), t3), _),
adamc@910 544 me), _),
adamc@910 545 (EApp ((EApp
adamc@910 546 ((EApp ((ECApp ((ECApp ((ECApp (
adamc@910 547 (EFfi ("Basis", "bind"), _), _), _),
adamc@910 548 t1), _), t2), _),
adamc@910 549 _), _),
adamc@910 550 trans1), _), trans2), _)), _),
adamc@910 551 trans3) =>
adamc@910 552 let
adamc@910 553 val e'' = (EFfi ("Basis", "bind"), loc)
adamc@910 554 val e'' = (ECApp (e'', mt), loc)
adamc@910 555 val e'' = (ECApp (e'', t2), loc)
adamc@910 556 val e'' = (ECApp (e'', t3), loc)
adamc@910 557 val e'' = (EApp (e'', me), loc)
adamc@910 558 val () = print "In2\n"
adamc@910 559 val e'' = (EApp (e'', exp (UnknownE :: env')
adamc@910 560 (EApp (E.liftExpInExp 0 trans2, (ERel 0, loc)),
adamc@910 561 loc)),
adamc@910 562 loc)
adamc@910 563 val () = print "Out2\n"
adamc@910 564 val e'' = (EApp (e'', E.liftExpInExp 0 trans3), loc)
adamc@910 565 val e'' = reassoc e''
adamc@910 566 val e'' = (EAbs ("xb", t1, (CApp (mt, t3), loc), e''), loc)
adamc@910 567
adamc@910 568 val e' = (EFfi ("Basis", "bind"), loc)
adamc@910 569 val e' = (ECApp (e', mt), loc)
adamc@910 570 val e' = (ECApp (e', t1), loc)
adamc@910 571 val e' = (ECApp (e', t3), loc)
adamc@910 572 val e' = (EApp (e', me), loc)
adamc@910 573 val e' = (EApp (e', trans1), loc)
adamc@910 574 val e' = (EApp (e', e''), loc)
adamc@910 575 in
adamc@910 576 e'
adamc@910 577 end
adamc@910 578
adamc@931 579 | EApp
adamc@931 580 ((EApp
adamc@931 581 ((EApp ((ECApp ((ECApp ((ECApp ((EFfi ("Basis", "bind"), loc), _), _),
adamc@931 582 t1),
adamc@931 583 _), t2), _),
adamc@931 584 (EFfi ("Basis", "transaction_monad"), _)), _),
adamc@931 585 (ECase (e, pes, {disc, ...}), _)), _), trans) =>
adamc@931 586 let
adamc@931 587 val e' = (EFfi ("Basis", "bind"), loc)
adamc@931 588 val e' = (ECApp (e', (CFfi ("Basis", "transaction"), loc)), loc)
adamc@931 589 val e' = (ECApp (e', t1), loc)
adamc@931 590 val e' = (ECApp (e', t2), loc)
adamc@931 591 val e' = (EApp (e', (EFfi ("Basis", "transaction_monad"), loc)), loc)
adamc@931 592
adamc@931 593 fun doCase (p, e) =
adamc@931 594 let
adamc@931 595 val e' = (EApp (e', e), loc)
adamc@931 596 val e' = (EApp (e',
adamc@931 597 multiLiftExpInExp (E.patBindsN p)
adamc@931 598 trans), loc)
adamc@931 599 in
adamc@931 600 (p, reassoc e')
adamc@931 601 end
adamc@931 602 in
adamc@931 603 (ECase (e, map doCase pes,
adamc@931 604 {disc = disc,
adamc@931 605 result = (CApp ((CFfi ("Basis", "transaction"), loc),
adamc@931 606 t2), loc)}), loc)
adamc@931 607 end
adamc@931 608
adamc@910 609 | _ => e
adamc@910 610
adamc@909 611 val e1 = exp env e1
adamc@909 612 val e2 = exp env e2
adamc@910 613 val e12 = reassoc (EApp (e1, e2), loc)
adamc@909 614 in
adamc@910 615 case #1 e12 of
adamc@910 616 EApp ((EAbs (_, _, _, b), _), e2) =>
adamc@931 617 exp (KnownE e2 :: env') b
adamc@910 618 | _ => e12
adamc@909 619 end
adamc@509 620
adamc@909 621 | EAbs (x, dom, ran, e) => (EAbs (x, con env dom, con env ran, exp (UnknownE :: env) e), loc)
adamc@509 622
adamc@909 623 | ECApp (e, c) =>
adamc@909 624 let
adamc@909 625 val e = exp env e
adamc@909 626 val c = con env c
adamc@909 627 in
adamc@909 628 case #1 e of
adamc@909 629 ECAbs (_, _, b) => exp (KnownC c :: deKnown env) b
adamc@909 630 | _ => (ECApp (e, c), loc)
adamc@909 631 end
adamc@626 632
adamc@909 633 | ECAbs (x, k, e) => (ECAbs (x, kind env k, exp (UnknownC :: env) e), loc)
adamc@626 634
adamc@909 635 | EKApp (e, k) =>
adamc@909 636 let
adamc@909 637 val e = exp env e
adamc@909 638 in
adamc@909 639 case #1 e of
adamc@909 640 EKAbs (_, b) => exp (KnownK k :: deKnown env) b
adamc@909 641 | _ => (EKApp (e, kind env k), loc)
adamc@909 642 end
adamc@509 643
adamc@909 644 | EKAbs (x, e) => (EKAbs (x, exp (UnknownK :: env) e), loc)
adamc@509 645
adamc@909 646 | ERecord xcs => (ERecord (map (fn (x, e, t) => (con env x, exp env e, con env t)) xcs), loc)
adamc@909 647 | EField (e, c, {field, rest}) =>
adamc@909 648 let
adamc@909 649 val e = exp env e
adamc@909 650 val c = con env c
adamc@509 651
adamc@909 652 fun default () = (EField (e, c, {field = con env field, rest = con env rest}), loc)
adamc@909 653 in
adamc@909 654 case (#1 e, #1 c) of
adamc@909 655 (ERecord xcs, CName x) =>
adamc@909 656 (case List.find (fn ((CName x', _), _, _) => x' = x | _ => false) xcs of
adamc@909 657 NONE => default ()
adamc@909 658 | SOME (_, e, _) => e)
adamc@909 659 | _ => default ()
adamc@909 660 end
adamc@509 661
adamc@909 662 | EConcat (e1, c1, e2, c2) =>
adamc@909 663 let
adamc@909 664 val e1 = exp env e1
adamc@909 665 val e2 = exp env e2
adamc@909 666 in
adamc@909 667 case (#1 e1, #1 e2) of
adamc@909 668 (ERecord xes1, ERecord xes2) => (ERecord (xes1 @ xes2), loc)
adamc@909 669 | _ =>
adamc@909 670 let
adamc@909 671 val c1 = con env c1
adamc@909 672 val c2 = con env c2
adamc@909 673 in
adamc@909 674 case (#1 c1, #1 c2) of
adamc@909 675 (CRecord (k, xcs1), CRecord (_, xcs2)) =>
adamc@909 676 let
adamc@909 677 val (xes1, rest) = ListUtil.foldlMap (doPart e1) [] xcs1
adamc@909 678 val (xes2, _) = ListUtil.foldlMap (doPart e2) rest xcs2
adamc@909 679 in
adamc@909 680 exp (deKnown env) (ERecord (xes1 @ xes2), loc)
adamc@909 681 end
adamc@909 682 | _ => (EConcat (e1, c1, e2, c2), loc)
adamc@909 683 end
adamc@909 684 end
adamc@509 685
adamc@909 686 | ECut (e, c, {field, rest}) =>
adamc@909 687 let
adamc@909 688 val e = exp env e
adamc@909 689 val c = con env c
adamc@509 690
adamc@909 691 fun default () =
adamc@909 692 let
adamc@909 693 val rest = con env rest
adamc@909 694 in
adamc@909 695 case #1 rest of
adamc@909 696 CRecord (k, xcs) =>
adamc@909 697 let
adamc@909 698 val (xes, _) = ListUtil.foldlMap (doPart e) [] xcs
adamc@909 699 in
adamc@909 700 exp (deKnown env) (ERecord xes, loc)
adamc@909 701 end
adamc@909 702 | _ => (ECut (e, c, {field = con env field, rest = rest}), loc)
adamc@909 703 end
adamc@909 704 in
adamc@909 705 case (#1 e, #1 c) of
adamc@909 706 (ERecord xes, CName x) =>
adamc@909 707 if List.all (fn ((CName _, _), _, _) => true | _ => false) xes then
adamc@909 708 (ERecord (List.filter (fn ((CName x', _), _, _) => x' <> x
adamc@909 709 | _ => raise Fail "Reduce: ECut") xes), loc)
adamc@909 710 else
adamc@909 711 default ()
adamc@909 712 | _ => default ()
adamc@909 713 end
adamc@509 714
adamc@909 715 | ECutMulti (e, c, {rest}) =>
adamc@909 716 let
adamc@909 717 val e = exp env e
adamc@909 718 val c = con env c
adamc@509 719
adamc@909 720 fun default () =
adamc@909 721 let
adamc@909 722 val rest = con env rest
adamc@909 723 in
adamc@909 724 case #1 rest of
adamc@909 725 CRecord (k, xcs) =>
adamc@909 726 let
adamc@909 727 val (xes, _) = ListUtil.foldlMap (doPart e) [] xcs
adamc@909 728 in
adamc@909 729 exp (deKnown env) (ERecord xes, loc)
adamc@909 730 end
adamc@909 731 | _ => (ECutMulti (e, c, {rest = rest}), loc)
adamc@909 732 end
adamc@909 733 in
adamc@909 734 case (#1 e, #1 c) of
adamc@909 735 (ERecord xes, CRecord (_, xcs)) =>
adamc@909 736 if List.all (fn ((CName _, _), _, _) => true | _ => false) xes
adamc@909 737 andalso List.all (fn ((CName _, _), _) => true | _ => false) xcs then
adamc@909 738 (ERecord (List.filter (fn ((CName x', _), _, _) =>
adamc@909 739 List.all (fn ((CName x, _), _) => x' <> x
adamc@909 740 | _ => raise Fail "Reduce: ECutMulti [1]") xcs
adamc@909 741 | _ => raise Fail "Reduce: ECutMulti [2]") xes), loc)
adamc@909 742 else
adamc@909 743 default ()
adamc@909 744 | _ => default ()
adamc@909 745 end
adamc@823 746
adamc@909 747 | ECase (_, [((PRecord [], _), e)], _) => exp env e
adamc@909 748 | ECase (_, [((PWild, _), e)], _) => exp env e
adamc@509 749
adamc@909 750 | ECase (e, pes, {disc, result}) =>
adamc@909 751 let
adamc@909 752 fun patBinds (p, _) =
adamc@909 753 case p of
adamc@909 754 PWild => 0
adamc@909 755 | PVar _ => 1
adamc@909 756 | PPrim _ => 0
adamc@909 757 | PCon (_, _, _, NONE) => 0
adamc@909 758 | PCon (_, _, _, SOME p) => patBinds p
adamc@909 759 | PRecord xpts => foldl (fn ((_, p, _), n) => n + patBinds p) 0 xpts
adamc@509 760
adamc@909 761 fun pat (all as (p, loc)) =
adamc@909 762 case p of
adamc@909 763 PWild => all
adamc@909 764 | PVar (x, t) => (PVar (x, con env t), loc)
adamc@909 765 | PPrim _ => all
adamc@909 766 | PCon (dk, pc, cs, po) =>
adamc@909 767 (PCon (dk, patCon pc, map (con env) cs, Option.map pat po), loc)
adamc@909 768 | PRecord xpts => (PRecord (map (fn (x, p, t) => (x, pat p, con env t)) xpts), loc)
adamc@930 769
adamc@930 770 fun push () =
adamc@930 771 (ECase (exp env e,
adamc@930 772 map (fn (p, e) => (pat p,
adamc@930 773 exp (List.tabulate (patBinds p,
adamc@930 774 fn _ => UnknownE) @ env) e))
adamc@930 775 pes, {disc = con env disc, result = con env result}), loc)
adamc@930 776
adamc@930 777 fun search pes =
adamc@930 778 case pes of
adamc@930 779 [] => push ()
adamc@930 780 | (p, body) :: pes =>
adamc@930 781 case match (env, p, e) of
adamc@930 782 No => search pes
adamc@930 783 | Maybe => push ()
adamc@930 784 | Yes env' => exp env' body
adamc@909 785 in
adamc@930 786 search pes
adamc@909 787 end
adamc@509 788
adamc@909 789 | EWrite e => (EWrite (exp env e), loc)
adamc@909 790 | EClosure (n, es) => (EClosure (n, map (exp env) es), loc)
adamc@607 791
adamc@910 792 | ELet (x, t, e1, e2) =>
adamc@910 793 (ELet (x, con env t, exp env e1, exp (UnknownE :: env) e2), loc)
adamc@909 794
adamc@909 795 | EServerCall (n, es, e, t1, t2) => (EServerCall (n, map (exp env) es, exp env e,
adamc@909 796 con env t1, con env t2), loc)
adamc@954 797 | ETailCall (n, es, e, t1, t2) => (ETailCall (n, map (exp env) es, exp env e,
adamc@954 798 con env t1, con env t2), loc)
adamc@909 799 in
adamc@909 800 (*if dangling (edepth' (deKnown env)) r then
adamc@909 801 (Print.prefaces "exp" [("e", CorePrint.p_exp CoreEnv.empty all),
adamc@909 802 ("r", CorePrint.p_exp CoreEnv.empty r)];
adamc@909 803 raise Fail "!!")
adamc@909 804 else
adamc@909 805 ();*)
adamc@909 806 r
adamc@909 807 end
adamc@417 808 in
adamc@626 809 {kind = kind, con = con, exp = exp}
adamc@417 810 end
adamc@21 811
adamc@626 812 fun kind namedC env k = #kind (kindConAndExp (namedC, IM.empty)) env k
adamc@626 813 fun con namedC env c = #con (kindConAndExp (namedC, IM.empty)) env c
adamc@626 814 fun exp (namedC, namedE) env e = #exp (kindConAndExp (namedC, namedE)) env e
adamc@20 815
adamc@508 816 fun reduce file =
adamc@508 817 let
adamc@1016 818 val uses = CoreUtil.File.fold {kind = fn (_, m) => m,
adamc@1016 819 con = fn (_, m) => m,
adamc@1016 820 exp = fn (e, m) =>
adamc@1016 821 case e of
adamc@1016 822 ENamed n => IM.insert (m, n, 1 + Option.getOpt (IM.find (m, n), 0))
adamc@1016 823 | _ => m,
adamc@1016 824 decl = fn (_, m) => m}
adamc@1016 825 IM.empty file
adamc@1016 826
adamc@1016 827 fun isPoly names = CoreUtil.Con.exists {kind = fn _ => false,
adamc@1016 828 con = fn TCFun _ => true
adamc@1016 829 | TKFun _ => true
adamc@1016 830 | CNamed n => IS.member (names, n)
adamc@1016 831 | _ => false}
adamc@1016 832
adamc@1016 833 val size = CoreUtil.Exp.fold {kind = fn (_, n) => n,
adamc@1016 834 con = fn (_, n) => n,
adamc@1016 835 exp = fn (_, n) => n + 1} 0
adamc@1016 836
adamc@1016 837 fun mayInline (polyC, n, t, e) =
adamc@1016 838 case IM.find (uses, n) of
adamc@1016 839 NONE => false
adamc@1016 840 | SOME count => count <= 1
adamc@1016 841 orelse isPoly polyC t
adamc@1016 842 orelse size e <= Settings.getCoreInline ()
adamc@1016 843
adamc@1016 844 fun doDecl (d as (_, loc), st as (polyC, namedC, namedE)) =
adamc@508 845 case #1 d of
adamc@508 846 DCon (x, n, k, c) =>
adamc@508 847 let
adamc@626 848 val k = kind namedC [] k
adamc@509 849 val c = con namedC [] c
adamc@508 850 in
adamc@508 851 ((DCon (x, n, k, c), loc),
adamc@1016 852 (if isPoly polyC c then
adamc@1016 853 IS.add (polyC, n)
adamc@1016 854 else
adamc@1016 855 polyC,
adamc@1016 856 IM.insert (namedC, n, c),
adamc@1016 857 namedE))
adamc@508 858 end
adamc@807 859 | DDatatype dts =>
adamc@807 860 ((DDatatype (map (fn (x, n, ps, cs) =>
adamc@807 861 let
adamc@807 862 val env = map (fn _ => UnknownC) ps
adamc@807 863 in
adamc@807 864 (x, n, ps, map (fn (x, n, co) => (x, n, Option.map (con namedC env) co)) cs)
adamc@807 865 end) dts), loc),
adamc@1016 866 (if List.exists (fn (_, _, _, cs) => List.exists (fn (_, _, co) => case co of
adamc@1016 867 NONE => false
adamc@1016 868 | SOME c => isPoly polyC c) cs)
adamc@1016 869 dts then
adamc@1016 870 foldl (fn ((_, n, _, _), polyC) => IS.add (polyC, n)) polyC dts
adamc@1016 871 else
adamc@1016 872 polyC,
adamc@1016 873 namedC,
adamc@1016 874 namedE))
adamc@508 875 | DVal (x, n, t, e, s) =>
adamc@508 876 let
adamc@509 877 val t = con namedC [] t
adamc@509 878 val e = exp (namedC, namedE) [] e
adamc@508 879 in
adamc@508 880 ((DVal (x, n, t, e, s), loc),
adamc@1016 881 (polyC,
adamc@1016 882 namedC,
adamc@1016 883 if mayInline (polyC, n, t, e) then
adamc@1016 884 IM.insert (namedE, n, e)
adamc@1016 885 else
adamc@1016 886 namedE))
adamc@508 887 end
adamc@508 888 | DValRec vis =>
adamc@910 889 ((DValRec (map (fn (x, n, t, e, s) => (x, n, con namedC [] t,
adamc@910 890 exp (namedC, namedE) [] e, s)) vis), loc),
adamc@508 891 st)
adamc@508 892 | DExport _ => (d, st)
adamc@707 893 | DTable (s, n, c, s', pe, pc, ce, cc) => ((DTable (s, n, con namedC [] c, s',
adamc@707 894 exp (namedC, namedE) [] pe,
adamc@707 895 con namedC [] pc,
adamc@707 896 exp (namedC, namedE) [] ce,
adamc@707 897 con namedC [] cc), loc), st)
adamc@508 898 | DSequence _ => (d, st)
adamc@754 899 | DView (s, n, s', e, c) => ((DView (s, n, s', exp (namedC, namedE) [] e, con namedC [] c), loc), st)
adamc@508 900 | DDatabase _ => (d, st)
adamc@509 901 | DCookie (s, n, c, s') => ((DCookie (s, n, con namedC [] c, s'), loc), st)
adamc@720 902 | DStyle (s, n, s') => ((DStyle (s, n, s'), loc), st)
adamc@20 903
adamc@1016 904 val (file, _) = ListUtil.foldlMap doDecl (IS.empty, IM.empty, IM.empty) file
adamc@508 905 in
adamc@508 906 file
adamc@508 907 end
adamc@20 908
adamc@20 909 end