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annotate src/expl_util.sml @ 564:803b2f3bb86b

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Monad type class seems to be working
author Adam Chlipala <adamc@hcoop.net>
date Fri, 19 Dec 2008 10:27:58 -0500
parents ae03d09043c1
children 8998114760c1
rev   line source
adamc@38 1 (* Copyright (c) 2008, Adam Chlipala
adamc@38 2 * All rights reserved.
adamc@38 3 *
adamc@38 4 * Redistribution and use in source and binary forms, with or without
adamc@38 5 * modification, are permitted provided that the following conditions are met:
adamc@38 6 *
adamc@38 7 * - Redistributions of source code must retain the above copyright notice,
adamc@38 8 * this list of conditions and the following disclaimer.
adamc@38 9 * - Redistributions in binary form must reproduce the above copyright notice,
adamc@38 10 * this list of conditions and the following disclaimer in the documentation
adamc@38 11 * and/or other materials provided with the distribution.
adamc@38 12 * - The names of contributors may not be used to endorse or promote products
adamc@38 13 * derived from this software without specific prior written permission.
adamc@38 14 *
adamc@38 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@38 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@38 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@38 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@38 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
adamc@38 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@38 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@38 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@38 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@38 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@38 25 * POSSIBILITY OF SUCH DAMAGE.
adamc@38 26 *)
adamc@38 27
adamc@38 28 structure ExplUtil :> EXPL_UTIL = struct
adamc@38 29
adamc@38 30 open Expl
adamc@38 31
adamc@38 32 structure S = Search
adamc@38 33
adamc@38 34 structure Kind = struct
adamc@38 35
adamc@38 36 fun mapfold f =
adamc@38 37 let
adamc@38 38 fun mfk k acc =
adamc@38 39 S.bindP (mfk' k acc, f)
adamc@38 40
adamc@38 41 and mfk' (kAll as (k, loc)) =
adamc@38 42 case k of
adamc@38 43 KType => S.return2 kAll
adamc@38 44
adamc@38 45 | KArrow (k1, k2) =>
adamc@38 46 S.bind2 (mfk k1,
adamc@38 47 fn k1' =>
adamc@38 48 S.map2 (mfk k2,
adamc@38 49 fn k2' =>
adamc@38 50 (KArrow (k1', k2'), loc)))
adamc@38 51
adamc@38 52 | KName => S.return2 kAll
adamc@38 53
adamc@38 54 | KRecord k =>
adamc@38 55 S.map2 (mfk k,
adamc@38 56 fn k' =>
adamc@38 57 (KRecord k', loc))
adamc@87 58
adamc@87 59 | KUnit => S.return2 kAll
adamc@213 60
adamc@213 61 | KTuple ks =>
adamc@213 62 S.map2 (ListUtil.mapfold mfk ks,
adamc@213 63 fn ks' =>
adamc@213 64 (KTuple ks', loc))
adamc@38 65 in
adamc@38 66 mfk
adamc@38 67 end
adamc@38 68
adamc@38 69 fun exists f k =
adamc@38 70 case mapfold (fn k => fn () =>
adamc@38 71 if f k then
adamc@38 72 S.Return ()
adamc@38 73 else
adamc@38 74 S.Continue (k, ())) k () of
adamc@38 75 S.Return _ => true
adamc@38 76 | S.Continue _ => false
adamc@38 77
adamc@38 78 end
adamc@38 79
adamc@38 80 structure Con = struct
adamc@38 81
adamc@38 82 datatype binder =
adamc@38 83 Rel of string * Expl.kind
adamc@38 84 | Named of string * Expl.kind
adamc@38 85
adamc@38 86 fun mapfoldB {kind = fk, con = fc, bind} =
adamc@38 87 let
adamc@38 88 val mfk = Kind.mapfold fk
adamc@38 89
adamc@38 90 fun mfc ctx c acc =
adamc@38 91 S.bindP (mfc' ctx c acc, fc ctx)
adamc@38 92
adamc@38 93 and mfc' ctx (cAll as (c, loc)) =
adamc@38 94 case c of
adamc@38 95 TFun (c1, c2) =>
adamc@38 96 S.bind2 (mfc ctx c1,
adamc@38 97 fn c1' =>
adamc@38 98 S.map2 (mfc ctx c2,
adamc@38 99 fn c2' =>
adamc@38 100 (TFun (c1', c2'), loc)))
adamc@38 101 | TCFun (x, k, c) =>
adamc@38 102 S.bind2 (mfk k,
adamc@38 103 fn k' =>
adamc@38 104 S.map2 (mfc (bind (ctx, Rel (x, k))) c,
adamc@38 105 fn c' =>
adamc@38 106 (TCFun (x, k', c'), loc)))
adamc@38 107 | TRecord c =>
adamc@38 108 S.map2 (mfc ctx c,
adamc@38 109 fn c' =>
adamc@38 110 (TRecord c', loc))
adamc@38 111
adamc@38 112 | CRel _ => S.return2 cAll
adamc@38 113 | CNamed _ => S.return2 cAll
adamc@38 114 | CModProj _ => S.return2 cAll
adamc@38 115 | CApp (c1, c2) =>
adamc@38 116 S.bind2 (mfc ctx c1,
adamc@38 117 fn c1' =>
adamc@38 118 S.map2 (mfc ctx c2,
adamc@38 119 fn c2' =>
adamc@38 120 (CApp (c1', c2'), loc)))
adamc@38 121 | CAbs (x, k, c) =>
adamc@38 122 S.bind2 (mfk k,
adamc@38 123 fn k' =>
adamc@38 124 S.map2 (mfc (bind (ctx, Rel (x, k))) c,
adamc@38 125 fn c' =>
adamc@38 126 (CAbs (x, k', c'), loc)))
adamc@38 127
adamc@38 128 | CName _ => S.return2 cAll
adamc@38 129
adamc@38 130 | CRecord (k, xcs) =>
adamc@38 131 S.bind2 (mfk k,
adamc@38 132 fn k' =>
adamc@38 133 S.map2 (ListUtil.mapfold (fn (x, c) =>
adamc@38 134 S.bind2 (mfc ctx x,
adamc@38 135 fn x' =>
adamc@38 136 S.map2 (mfc ctx c,
adamc@38 137 fn c' =>
adamc@38 138 (x', c'))))
adamc@38 139 xcs,
adamc@38 140 fn xcs' =>
adamc@38 141 (CRecord (k', xcs'), loc)))
adamc@38 142 | CConcat (c1, c2) =>
adamc@38 143 S.bind2 (mfc ctx c1,
adamc@38 144 fn c1' =>
adamc@38 145 S.map2 (mfc ctx c2,
adamc@38 146 fn c2' =>
adamc@38 147 (CConcat (c1', c2'), loc)))
adamc@68 148 | CFold (k1, k2) =>
adamc@68 149 S.bind2 (mfk k1,
adamc@68 150 fn k1' =>
adamc@68 151 S.map2 (mfk k2,
adamc@68 152 fn k2' =>
adamc@68 153 (CFold (k1', k2'), loc)))
adamc@87 154
adamc@87 155 | CUnit => S.return2 cAll
adamc@213 156
adamc@213 157 | CTuple cs =>
adamc@213 158 S.map2 (ListUtil.mapfold (mfc ctx) cs,
adamc@213 159 fn cs' =>
adamc@213 160 (CTuple cs', loc))
adamc@213 161
adamc@213 162 | CProj (c, n) =>
adamc@213 163 S.map2 (mfc ctx c,
adamc@213 164 fn c' =>
adamc@213 165 (CProj (c', n), loc))
adamc@38 166 in
adamc@38 167 mfc
adamc@38 168 end
adamc@38 169
adamc@38 170 fun mapfold {kind = fk, con = fc} =
adamc@38 171 mapfoldB {kind = fk,
adamc@38 172 con = fn () => fc,
adamc@38 173 bind = fn ((), _) => ()} ()
adamc@38 174
adamc@38 175 fun mapB {kind, con, bind} ctx c =
adamc@38 176 case mapfoldB {kind = fn k => fn () => S.Continue (kind k, ()),
adamc@38 177 con = fn ctx => fn c => fn () => S.Continue (con ctx c, ()),
adamc@38 178 bind = bind} ctx c () of
adamc@38 179 S.Continue (c, ()) => c
adamc@38 180 | S.Return _ => raise Fail "ExplUtil.Con.mapB: Impossible"
adamc@38 181
adamc@38 182 fun map {kind, con} s =
adamc@38 183 case mapfold {kind = fn k => fn () => S.Continue (kind k, ()),
adamc@38 184 con = fn c => fn () => S.Continue (con c, ())} s () of
adamc@38 185 S.Return () => raise Fail "ExplUtil.Con.map: Impossible"
adamc@38 186 | S.Continue (s, ()) => s
adamc@38 187
adamc@38 188 fun exists {kind, con} k =
adamc@38 189 case mapfold {kind = fn k => fn () =>
adamc@38 190 if kind k then
adamc@38 191 S.Return ()
adamc@38 192 else
adamc@38 193 S.Continue (k, ()),
adamc@38 194 con = fn c => fn () =>
adamc@38 195 if con c then
adamc@38 196 S.Return ()
adamc@38 197 else
adamc@38 198 S.Continue (c, ())} k () of
adamc@38 199 S.Return _ => true
adamc@38 200 | S.Continue _ => false
adamc@38 201
adamc@38 202 end
adamc@38 203
adamc@38 204 structure Exp = struct
adamc@38 205
adamc@38 206 datatype binder =
adamc@38 207 RelC of string * Expl.kind
adamc@38 208 | NamedC of string * Expl.kind
adamc@38 209 | RelE of string * Expl.con
adamc@38 210 | NamedE of string * Expl.con
adamc@38 211
adamc@38 212 fun mapfoldB {kind = fk, con = fc, exp = fe, bind} =
adamc@38 213 let
adamc@38 214 val mfk = Kind.mapfold fk
adamc@38 215
adamc@38 216 fun bind' (ctx, b) =
adamc@38 217 let
adamc@38 218 val b' = case b of
adamc@38 219 Con.Rel x => RelC x
adamc@38 220 | Con.Named x => NamedC x
adamc@38 221 in
adamc@38 222 bind (ctx, b')
adamc@38 223 end
adamc@38 224 val mfc = Con.mapfoldB {kind = fk, con = fc, bind = bind'}
adamc@38 225
adamc@38 226 fun mfe ctx e acc =
adamc@38 227 S.bindP (mfe' ctx e acc, fe ctx)
adamc@38 228
adamc@38 229 and mfe' ctx (eAll as (e, loc)) =
adamc@38 230 case e of
adamc@38 231 EPrim _ => S.return2 eAll
adamc@38 232 | ERel _ => S.return2 eAll
adamc@38 233 | ENamed _ => S.return2 eAll
adamc@38 234 | EModProj _ => S.return2 eAll
adamc@38 235 | EApp (e1, e2) =>
adamc@38 236 S.bind2 (mfe ctx e1,
adamc@38 237 fn e1' =>
adamc@38 238 S.map2 (mfe ctx e2,
adamc@38 239 fn e2' =>
adamc@38 240 (EApp (e1', e2'), loc)))
adamc@38 241 | EAbs (x, dom, ran, e) =>
adamc@38 242 S.bind2 (mfc ctx dom,
adamc@38 243 fn dom' =>
adamc@38 244 S.bind2 (mfc ctx ran,
adamc@38 245 fn ran' =>
adamc@38 246 S.map2 (mfe (bind (ctx, RelE (x, dom'))) e,
adamc@38 247 fn e' =>
adamc@38 248 (EAbs (x, dom', ran', e'), loc))))
adamc@38 249
adamc@38 250 | ECApp (e, c) =>
adamc@38 251 S.bind2 (mfe ctx e,
adamc@38 252 fn e' =>
adamc@38 253 S.map2 (mfc ctx c,
adamc@38 254 fn c' =>
adamc@38 255 (ECApp (e', c'), loc)))
adamc@38 256 | ECAbs (x, k, e) =>
adamc@38 257 S.bind2 (mfk k,
adamc@38 258 fn k' =>
adamc@38 259 S.map2 (mfe (bind (ctx, RelC (x, k))) e,
adamc@38 260 fn e' =>
adamc@38 261 (ECAbs (x, k', e'), loc)))
adamc@38 262
adamc@38 263 | ERecord xes =>
adamc@38 264 S.map2 (ListUtil.mapfold (fn (x, e, t) =>
adamc@38 265 S.bind2 (mfc ctx x,
adamc@38 266 fn x' =>
adamc@38 267 S.bind2 (mfe ctx e,
adamc@38 268 fn e' =>
adamc@38 269 S.map2 (mfc ctx t,
adamc@38 270 fn t' =>
adamc@38 271 (x', e', t')))))
adamc@38 272 xes,
adamc@38 273 fn xes' =>
adamc@38 274 (ERecord xes', loc))
adamc@38 275 | EField (e, c, {field, rest}) =>
adamc@38 276 S.bind2 (mfe ctx e,
adamc@38 277 fn e' =>
adamc@38 278 S.bind2 (mfc ctx c,
adamc@38 279 fn c' =>
adamc@38 280 S.bind2 (mfc ctx field,
adamc@38 281 fn field' =>
adamc@38 282 S.map2 (mfc ctx rest,
adamc@38 283 fn rest' =>
adamc@38 284 (EField (e', c', {field = field', rest = rest'}), loc)))))
adamc@445 285 | EConcat (e1, c1, e2, c2) =>
adamc@339 286 S.bind2 (mfe ctx e1,
adamc@339 287 fn e1' =>
adamc@445 288 S.bind2 (mfc ctx c1,
adamc@445 289 fn c1' =>
adamc@339 290 S.bind2 (mfe ctx e2,
adamc@339 291 fn e2' =>
adamc@445 292 S.map2 (mfc ctx c2,
adamc@445 293 fn c2' =>
adamc@445 294 (EConcat (e1', c1', e2', c2'),
adamc@445 295 loc)))))
adamc@149 296 | ECut (e, c, {field, rest}) =>
adamc@149 297 S.bind2 (mfe ctx e,
adamc@149 298 fn e' =>
adamc@149 299 S.bind2 (mfc ctx c,
adamc@149 300 fn c' =>
adamc@149 301 S.bind2 (mfc ctx field,
adamc@149 302 fn field' =>
adamc@149 303 S.map2 (mfc ctx rest,
adamc@149 304 fn rest' =>
adamc@149 305 (ECut (e', c', {field = field', rest = rest'}), loc)))))
adamc@493 306 | ECutMulti (e, c, {rest}) =>
adamc@493 307 S.bind2 (mfe ctx e,
adamc@493 308 fn e' =>
adamc@493 309 S.bind2 (mfc ctx c,
adamc@493 310 fn c' =>
adamc@493 311 S.map2 (mfc ctx rest,
adamc@493 312 fn rest' =>
adamc@493 313 (ECutMulti (e', c', {rest = rest'}), loc))))
adamc@72 314 | EFold k =>
adamc@72 315 S.map2 (mfk k,
adamc@72 316 fn k' =>
adamc@72 317 (EFold k', loc))
adamc@109 318
adamc@109 319 | EWrite e =>
adamc@109 320 S.map2 (mfe ctx e,
adamc@109 321 fn e' =>
adamc@109 322 (EWrite e', loc))
adamc@176 323
adamc@182 324 | ECase (e, pes, {disc, result}) =>
adamc@176 325 S.bind2 (mfe ctx e,
adamc@176 326 fn e' =>
adamc@176 327 S.bind2 (ListUtil.mapfold (fn (p, e) =>
adamc@176 328 S.map2 (mfe ctx e,
adamc@176 329 fn e' => (p, e'))) pes,
adamc@176 330 fn pes' =>
adamc@182 331 S.bind2 (mfc ctx disc,
adamc@182 332 fn disc' =>
adamc@182 333 S.map2 (mfc ctx result,
adamc@182 334 fn result' =>
adamc@182 335 (ECase (e', pes', {disc = disc', result = result'}), loc)))))
adamc@449 336
adamc@449 337 | ELet (x, t, e1, e2) =>
adamc@449 338 S.bind2 (mfc ctx t,
adamc@449 339 fn t' =>
adamc@449 340 S.bind2 (mfe ctx e1,
adamc@449 341 fn e1' =>
adamc@453 342 S.map2 (mfe (bind (ctx, RelE (x, t))) e2,
adamc@449 343 fn e2' =>
adamc@449 344 (ELet (x, t', e1', e2'), loc))))
adamc@38 345 in
adamc@38 346 mfe
adamc@38 347 end
adamc@38 348
adamc@38 349 fun mapfold {kind = fk, con = fc, exp = fe} =
adamc@38 350 mapfoldB {kind = fk,
adamc@38 351 con = fn () => fc,
adamc@38 352 exp = fn () => fe,
adamc@38 353 bind = fn ((), _) => ()} ()
adamc@38 354
adamc@38 355 fun exists {kind, con, exp} k =
adamc@38 356 case mapfold {kind = fn k => fn () =>
adamc@38 357 if kind k then
adamc@38 358 S.Return ()
adamc@38 359 else
adamc@38 360 S.Continue (k, ()),
adamc@38 361 con = fn c => fn () =>
adamc@38 362 if con c then
adamc@38 363 S.Return ()
adamc@38 364 else
adamc@38 365 S.Continue (c, ()),
adamc@38 366 exp = fn e => fn () =>
adamc@38 367 if exp e then
adamc@38 368 S.Return ()
adamc@38 369 else
adamc@38 370 S.Continue (e, ())} k () of
adamc@38 371 S.Return _ => true
adamc@38 372 | S.Continue _ => false
adamc@38 373
adamc@38 374 end
adamc@38 375
adamc@38 376 structure Sgn = struct
adamc@38 377
adamc@38 378 datatype binder =
adamc@38 379 RelC of string * Expl.kind
adamc@38 380 | NamedC of string * Expl.kind
adamc@38 381 | Str of string * Expl.sgn
adamc@64 382 | Sgn of string * Expl.sgn
adamc@38 383
adamc@38 384 fun mapfoldB {kind, con, sgn_item, sgn, bind} =
adamc@38 385 let
adamc@38 386 fun bind' (ctx, b) =
adamc@38 387 let
adamc@38 388 val b' = case b of
adamc@38 389 Con.Rel x => RelC x
adamc@38 390 | Con.Named x => NamedC x
adamc@38 391 in
adamc@38 392 bind (ctx, b')
adamc@38 393 end
adamc@38 394 val con = Con.mapfoldB {kind = kind, con = con, bind = bind'}
adamc@38 395
adamc@38 396 val kind = Kind.mapfold kind
adamc@38 397
adamc@38 398 fun sgi ctx si acc =
adamc@38 399 S.bindP (sgi' ctx si acc, sgn_item ctx)
adamc@38 400
adamc@162 401 and sgi' ctx (siAll as (si, loc)) =
adamc@38 402 case si of
adamc@38 403 SgiConAbs (x, n, k) =>
adamc@38 404 S.map2 (kind k,
adamc@38 405 fn k' =>
adamc@38 406 (SgiConAbs (x, n, k'), loc))
adamc@38 407 | SgiCon (x, n, k, c) =>
adamc@38 408 S.bind2 (kind k,
adamc@38 409 fn k' =>
adamc@38 410 S.map2 (con ctx c,
adamc@38 411 fn c' =>
adamc@38 412 (SgiCon (x, n, k', c'), loc)))
adamc@191 413 | SgiDatatype (x, n, xs, xncs) =>
adamc@162 414 S.map2 (ListUtil.mapfold (fn (x, n, c) =>
adamc@162 415 case c of
adamc@162 416 NONE => S.return2 (x, n, c)
adamc@162 417 | SOME c =>
adamc@162 418 S.map2 (con ctx c,
adamc@162 419 fn c' => (x, n, SOME c'))) xncs,
adamc@162 420 fn xncs' =>
adamc@191 421 (SgiDatatype (x, n, xs, xncs'), loc))
adamc@191 422 | SgiDatatypeImp (x, n, m1, ms, s, xs, xncs) =>
adamc@162 423 S.map2 (ListUtil.mapfold (fn (x, n, c) =>
adamc@162 424 case c of
adamc@162 425 NONE => S.return2 (x, n, c)
adamc@162 426 | SOME c =>
adamc@162 427 S.map2 (con ctx c,
adamc@162 428 fn c' => (x, n, SOME c'))) xncs,
adamc@162 429 fn xncs' =>
adamc@191 430 (SgiDatatypeImp (x, n, m1, ms, s, xs, xncs'), loc))
adamc@38 431 | SgiVal (x, n, c) =>
adamc@38 432 S.map2 (con ctx c,
adamc@38 433 fn c' =>
adamc@38 434 (SgiVal (x, n, c'), loc))
adamc@38 435 | SgiStr (x, n, s) =>
adamc@38 436 S.map2 (sg ctx s,
adamc@38 437 fn s' =>
adamc@38 438 (SgiStr (x, n, s'), loc))
adamc@64 439 | SgiSgn (x, n, s) =>
adamc@64 440 S.map2 (sg ctx s,
adamc@64 441 fn s' =>
adamc@64 442 (SgiSgn (x, n, s'), loc))
adamc@38 443
adamc@38 444 and sg ctx s acc =
adamc@38 445 S.bindP (sg' ctx s acc, sgn ctx)
adamc@38 446
adamc@38 447 and sg' ctx (sAll as (s, loc)) =
adamc@38 448 case s of
adamc@38 449 SgnConst sgis =>
adamc@38 450 S.map2 (ListUtil.mapfoldB (fn (ctx, si) =>
adamc@38 451 (case #1 si of
adamc@38 452 SgiConAbs (x, _, k) =>
adamc@38 453 bind (ctx, NamedC (x, k))
adamc@38 454 | SgiCon (x, _, k, _) =>
adamc@38 455 bind (ctx, NamedC (x, k))
adamc@191 456 | SgiDatatype (x, n, _, xncs) =>
adamc@162 457 bind (ctx, NamedC (x, (KType, loc)))
adamc@191 458 | SgiDatatypeImp (x, _, _, _, _, _, _) =>
adamc@162 459 bind (ctx, NamedC (x, (KType, loc)))
adamc@38 460 | SgiVal _ => ctx
adamc@38 461 | SgiStr (x, _, sgn) =>
adamc@64 462 bind (ctx, Str (x, sgn))
adamc@64 463 | SgiSgn (x, _, sgn) =>
adamc@460 464 bind (ctx, Sgn (x, sgn)),
adamc@38 465 sgi ctx si)) ctx sgis,
adamc@38 466 fn sgis' =>
adamc@38 467 (SgnConst sgis', loc))
adamc@38 468
adamc@38 469 | SgnVar _ => S.return2 sAll
adamc@45 470
adamc@45 471 | SgnFun (m, n, s1, s2) =>
adamc@45 472 S.bind2 (sg ctx s1,
adamc@45 473 fn s1' =>
adamc@45 474 S.map2 (sg (bind (ctx, Str (m, s1'))) s2,
adamc@45 475 fn s2' =>
adamc@45 476 (SgnFun (m, n, s1', s2'), loc)))
adamc@45 477 | SgnWhere (sgn, x, c) =>
adamc@45 478 S.bind2 (sg ctx sgn,
adamc@45 479 fn sgn' =>
adamc@45 480 S.map2 (con ctx c,
adamc@45 481 fn c' =>
adamc@45 482 (SgnWhere (sgn', x, c'), loc)))
adamc@64 483 | SgnProj _ => S.return2 sAll
adamc@38 484 in
adamc@38 485 sg
adamc@38 486 end
adamc@38 487
adamc@38 488 fun mapfold {kind, con, sgn_item, sgn} =
adamc@38 489 mapfoldB {kind = kind,
adamc@38 490 con = fn () => con,
adamc@38 491 sgn_item = fn () => sgn_item,
adamc@38 492 sgn = fn () => sgn,
adamc@38 493 bind = fn ((), _) => ()} ()
adamc@38 494
adamc@38 495 fun map {kind, con, sgn_item, sgn} s =
adamc@38 496 case mapfold {kind = fn k => fn () => S.Continue (kind k, ()),
adamc@38 497 con = fn c => fn () => S.Continue (con c, ()),
adamc@38 498 sgn_item = fn si => fn () => S.Continue (sgn_item si, ()),
adamc@38 499 sgn = fn s => fn () => S.Continue (sgn s, ())} s () of
adamc@38 500 S.Return () => raise Fail "Expl_util.Sgn.map"
adamc@38 501 | S.Continue (s, ()) => s
adamc@38 502
adamc@38 503 end
adamc@38 504
adamc@38 505 end