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27d9de59 AC |
1 | (* HCoop Domtool (http://hcoop.sourceforge.net/) |
2 | * Copyright (c) 2006, Adam Chlipala | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
dac62e84 | 17 | *) |
27d9de59 AC |
18 | |
19 | (* Domtool configuration language type checking *) | |
20 | ||
21 | structure Tycheck :> TYCHECK = struct | |
22 | ||
492c1cff | 23 | open Ast Print Env |
27d9de59 AC |
24 | |
25 | structure SM = StringMap | |
26 | ||
27d9de59 AC |
27 | local |
28 | val unifCount = ref 0 | |
29 | in | |
30 | fun resetUnif () = unifCount := 0 | |
31 | ||
32 | fun newUnif () = | |
33 | let | |
34 | val c = !unifCount | |
35 | val name = | |
36 | if c < 26 then | |
37 | str (chr (ord #"A" + c)) | |
38 | else | |
39 | "UNIF" ^ Int.toString (c - 26) | |
40 | in | |
41 | unifCount := c + 1; | |
42 | TUnif (name, ref NONE) | |
43 | end | |
44 | end | |
45 | ||
46 | exception UnequalDomains | |
47 | ||
48 | fun eqRecord f (r1, r2) = | |
49 | (SM.appi (fn (k, v1) => | |
50 | case SM.find (r2, k) of | |
51 | NONE => raise UnequalDomains | |
52 | | SOME v2 => | |
53 | if f (v1, v2) then | |
54 | () | |
55 | else | |
56 | raise UnequalDomains) r1; | |
57 | SM.appi (fn (k, v2) => | |
58 | case SM.find (r1, k) of | |
59 | NONE => raise UnequalDomains | |
60 | | SOME v1 => | |
61 | if f (v1, v2) then | |
62 | () | |
63 | else | |
64 | raise UnequalDomains) r2; | |
65 | true) | |
66 | handle UnequalDomains => false | |
67 | ||
68 | fun eqPred ((p1, _), (p2, _)) = | |
69 | case (p1, p2) of | |
70 | (CRoot, CRoot) => true | |
71 | | (CConst s1, CConst s2) => s1 = s2 | |
72 | | (CPrefix p1, CPrefix p2) => eqPred (p1, p2) | |
73 | | (CNot p1, CNot p2) => eqPred (p1, p2) | |
74 | | (CAnd (p1, q1), CAnd (p2, q2)) => | |
75 | eqPred (p1, p2) andalso eqPred (q1, q2) | |
76 | ||
77 | | _ => false | |
78 | ||
79 | fun eqTy (t1All as (t1, _), t2All as (t2, _)) = | |
80 | case (t1, t2) of | |
81 | (TBase s1, TBase s2) => s1 = s2 | |
82 | | (TList t1, TList t2) => eqTy (t1, t2) | |
83 | | (TArrow (d1, r1), TArrow (d2, r2)) => | |
84 | eqTy (d1, d2) andalso eqTy (r1, r2) | |
85 | ||
86 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => | |
87 | eqPred (p1, p2) andalso eqRecord eqTy (d1, d2) | |
88 | andalso eqRecord eqTy (r1, r2) | |
89 | ||
234b917a | 90 | | (TNested (p1, q1), TNested (p2, q2)) => |
1a4e5a6c | 91 | eqPred (p1, p2) andalso eqTy (q1, q2) |
234b917a | 92 | |
27d9de59 AC |
93 | | (TUnif (_, ref (SOME t1)), _) => eqTy (t1, t2All) |
94 | | (_, TUnif (_, ref (SOME t2))) => eqTy (t1All, t2) | |
95 | ||
96 | | (TUnif (_, r1), TUnif (_, r2)) => r1 = r2 | |
97 | ||
98 | | (TError, TError) => true | |
99 | ||
100 | | _ => false | |
101 | ||
102 | datatype unification_error = | |
103 | UnifyPred of pred * pred | |
104 | | UnifyTyp of typ * typ | |
105 | | UnifyOccurs of string * typ | |
106 | ||
107 | exception Unify of unification_error | |
108 | ||
109 | datatype type_error = | |
110 | WrongType of string * exp * typ * typ * unification_error option | |
111 | | WrongForm of string * string * exp * typ * unification_error option | |
112 | | UnboundVariable of string | |
234b917a | 113 | | WrongPred of string * pred * pred |
27d9de59 AC |
114 | |
115 | fun preface (s, d) = printd (PD.hovBox (PD.PPS.Rel 0, | |
116 | [PD.string s, PD.space 1, d])) | |
117 | ||
118 | fun describe_unification_error t ue = | |
119 | case ue of | |
120 | UnifyPred (p1, p2) => | |
234b917a | 121 | (print "Reason: Incompatible contexts.\n"; |
27d9de59 AC |
122 | preface ("Have:", p_pred p1); |
123 | preface ("Need:", p_pred p2)) | |
124 | | UnifyTyp (t1, t2) => | |
125 | if eqTy (t, t1) then | |
126 | () | |
127 | else | |
128 | (print "Reason: Incompatible types.\n"; | |
129 | preface ("Have:", p_typ t1); | |
130 | preface ("Need:", p_typ t2)) | |
131 | | UnifyOccurs (name, t') => | |
132 | if eqTy (t, t') then | |
133 | () | |
134 | else | |
135 | (print "Reason: Occurs check failed for "; | |
136 | print name; | |
137 | print " in:\n"; | |
138 | printd (p_typ t)) | |
139 | ||
140 | fun describe_type_error loc te = | |
141 | case te of | |
142 | WrongType (place, e, t1, t2, ueo) => | |
143 | (ErrorMsg.error (SOME loc) (place ^ " has wrong type."); | |
144 | preface (" Expression:", p_exp e); | |
145 | preface ("Actual type:", p_typ t1); | |
146 | preface ("Needed type:", p_typ t2); | |
147 | Option.app (describe_unification_error t1) ueo) | |
148 | | WrongForm (place, form, e, t, ueo) => | |
149 | (ErrorMsg.error (SOME loc) (place ^ " has a non-" ^ form ^ " type."); | |
150 | preface ("Expression:", p_exp e); | |
151 | preface (" Type:", p_typ t); | |
152 | Option.app (describe_unification_error t) ueo) | |
153 | | UnboundVariable name => | |
154 | ErrorMsg.error (SOME loc) ("Unbound variable " ^ name ^ ".\n") | |
234b917a AC |
155 | | WrongPred (place, p1, p2) => |
156 | (ErrorMsg.error (SOME loc) ("Context incompatibility for " ^ place ^ "."); | |
157 | preface ("Have:", p_pred p1); | |
158 | preface ("Need:", p_pred p2)) | |
27d9de59 | 159 | |
db427c67 | 160 | fun predImplies (p1All as (p1, _), p2All as (p2, _)) = |
27d9de59 | 161 | case (p1, p2) of |
1a4e5a6c AC |
162 | (_, CAnd (p1, p2)) => predImplies (p1All, p1) andalso predImplies (p1All, p2) |
163 | | (CAnd (p1, p2), _) => predImplies (p1, p2All) orelse predImplies (p2, p2All) | |
164 | ||
165 | | (_, CPrefix (CRoot, _)) => true | |
db427c67 AC |
166 | | (CNot (CPrefix (CRoot, _), _), _) => true |
167 | ||
168 | | (CRoot, CRoot) => true | |
169 | ||
170 | | (CConst s1, CConst s2) => s1 = s2 | |
171 | ||
172 | | (CPrefix p1, CPrefix p2) => predImplies (p1, p2) | |
234b917a | 173 | | (_, CPrefix p2) => predImplies (p1All, p2) |
db427c67 AC |
174 | |
175 | | (CNot p1, CNot p2) => predImplies (p2, p1) | |
27d9de59 | 176 | |
db427c67 AC |
177 | | _ => false |
178 | ||
179 | fun predSimpl (pAll as (p, loc)) = | |
180 | case p of | |
181 | CRoot => pAll | |
182 | | CConst _ => pAll | |
183 | | CPrefix p => (CPrefix (predSimpl p), loc) | |
184 | | CNot p => (CNot (predSimpl p), loc) | |
185 | | CAnd (p1, p2) => | |
186 | let | |
187 | val p1' = predSimpl p1 | |
188 | val p2' = predSimpl p2 | |
189 | in | |
190 | case p1' of | |
191 | (CAnd (c1, c2), _) => predSimpl (CAnd (c1, (CAnd (c2, p2'), loc)), loc) | |
192 | | _ => if predImplies (p2', p1') then | |
193 | p2' | |
1a4e5a6c AC |
194 | else if predImplies (p1', p2') then |
195 | p1' | |
db427c67 AC |
196 | else |
197 | (CAnd (p1', p2'), loc) | |
198 | end | |
199 | ||
234b917a | 200 | fun subPred (p1, p2) = |
db427c67 AC |
201 | if predImplies (p1, p2) then |
202 | () | |
203 | else | |
204 | raise (Unify (UnifyPred (p1, p2))) | |
27d9de59 | 205 | |
234b917a AC |
206 | fun subRecord f (r1, r2) = |
207 | SM.appi (fn (k, v2) => | |
208 | case SM.find (r1, k) of | |
209 | NONE => raise UnequalDomains | |
210 | | SOME v1 => f (v1, v2)) r2 | |
27d9de59 AC |
211 | |
212 | fun occurs u (t, _) = | |
213 | case t of | |
214 | TBase _ => false | |
215 | | TList t => occurs u t | |
216 | | TArrow (d, r) => occurs u d orelse occurs u r | |
217 | | TAction (_, d, r) => | |
218 | List.exists (occurs u) (SM.listItems d) | |
219 | orelse List.exists (occurs u) (SM.listItems r) | |
1a4e5a6c | 220 | | TNested (_, t) => occurs u t |
27d9de59 AC |
221 | | TError => false |
222 | | TUnif (_, ref (SOME t)) => occurs u t | |
223 | | TUnif (_, u') => u = u' | |
224 | ||
234b917a | 225 | fun subTyp (t1All as (t1, _), t2All as (t2, _)) = |
27d9de59 AC |
226 | case (t1, t2) of |
227 | (TBase s1, TBase s2) => | |
228 | if s1 = s2 then | |
229 | () | |
230 | else | |
231 | raise Unify (UnifyTyp (t1All, t2All)) | |
234b917a | 232 | | (TList t1, TList t2) => subTyp (t1, t2) |
27d9de59 | 233 | | (TArrow (d1, r1), TArrow (d2, r2)) => |
234b917a AC |
234 | (subTyp (d2, d1); |
235 | subTyp (r1, r2)) | |
27d9de59 AC |
236 | |
237 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => | |
234b917a AC |
238 | ((subPred (p2, p1); |
239 | subRecord subTyp (d2, d1); | |
240 | subRecord subTyp (r1, r2); | |
241 | subRecord subTyp (r2, r1)) | |
27d9de59 AC |
242 | handle UnequalDomains => raise Unify (UnifyTyp (t1All, t2All))) |
243 | ||
234b917a AC |
244 | | (TNested (d1, r1), TNested (d2, r2)) => |
245 | (subPred (d2, d1); | |
1a4e5a6c | 246 | subTyp (r1, r2)) |
234b917a AC |
247 | |
248 | | (TUnif (_, ref (SOME t1)), _) => subTyp (t1, t2All) | |
249 | | (_, TUnif (_, ref (SOME t2))) => subTyp (t1All, t2) | |
27d9de59 AC |
250 | |
251 | | (TUnif (_, r1), TUnif (_, r2)) => | |
252 | if r1 = r2 then | |
253 | () | |
254 | else | |
255 | r1 := SOME t2All | |
256 | ||
257 | | (TUnif (name, r), _) => | |
258 | if occurs r t2All then | |
259 | raise (Unify (UnifyOccurs (name, t2All))) | |
260 | else | |
261 | r := SOME t2All | |
262 | ||
263 | | (_, TUnif (name, r)) => | |
264 | if occurs r t1All then | |
265 | raise (Unify (UnifyOccurs (name, t1All))) | |
266 | else | |
267 | r := SOME t1All | |
268 | ||
269 | | (TError, _) => () | |
270 | | (_, TError) => () | |
271 | ||
272 | | _ => raise Unify (UnifyTyp (t1All, t2All)) | |
273 | ||
274 | fun isError t = | |
275 | case t of | |
276 | (TError, _) => true | |
277 | | _ => false | |
278 | ||
db427c67 AC |
279 | fun whnorm (tAll as (t, loc)) = |
280 | case t of | |
281 | TUnif (_, ref (SOME tAll)) => whnorm tAll | |
282 | | _ => tAll | |
283 | ||
6be996d4 AC |
284 | fun hasTyp (e, t1, t2) = |
285 | case whnorm t2 of | |
286 | (TBase name, _) => | |
287 | (case typeRule name of | |
288 | NONE => subTyp (t1, t2) | |
289 | | SOME rule => | |
290 | if rule e then | |
291 | () | |
292 | else | |
293 | subTyp (t1, t2)) | |
294 | | _ => subTyp (t1, t2) | |
295 | ||
234b917a AC |
296 | fun checkTyp G (tAll as (t, loc)) = |
297 | let | |
298 | val err = ErrorMsg.error (SOME loc) | |
299 | in | |
300 | case t of | |
301 | TBase name => | |
302 | if lookupType G name then | |
303 | tAll | |
304 | else | |
305 | (err ("Unbound type name " ^ name); | |
306 | (TError, loc)) | |
307 | | TList t => (TList (checkTyp G t), loc) | |
308 | | TArrow (d, r) => (TArrow (checkTyp G d, checkTyp G r), loc) | |
309 | | TAction (p, d, r) => (TAction (p, SM.map (checkTyp G) d, | |
310 | SM.map (checkTyp G) r), loc) | |
1a4e5a6c | 311 | | TNested (p, t) => (TNested (p, checkTyp G t), loc) |
234b917a AC |
312 | | TError => raise Fail "TError in parser-generated type" |
313 | | TUnif _ => raise Fail "TUnif in parser-generated type" | |
314 | end | |
315 | ||
27d9de59 AC |
316 | fun checkExp G (eAll as (e, loc)) = |
317 | let | |
318 | val dte = describe_type_error loc | |
319 | in | |
320 | case e of | |
321 | EInt _ => (TBase "int", loc) | |
322 | | EString _ => (TBase "string", loc) | |
323 | | EList es => | |
324 | let | |
325 | val t = (newUnif (), loc) | |
326 | in | |
327 | foldl (fn (e', ret) => | |
328 | let | |
329 | val t' = checkExp G e' | |
330 | in | |
6be996d4 | 331 | (hasTyp (eAll, t', t); |
27d9de59 AC |
332 | if isError t' then |
333 | (TList (TError, loc), loc) | |
334 | else | |
335 | ret) | |
336 | handle Unify ue => | |
337 | (dte (WrongType ("List element", | |
338 | e', | |
339 | t', | |
340 | t, | |
341 | SOME ue)); | |
342 | (TError, loc)) | |
343 | end) (TList t, loc) es | |
344 | end | |
345 | ||
346 | | ELam (x, to, e) => | |
347 | let | |
348 | val t = | |
349 | case to of | |
350 | NONE => (newUnif (), loc) | |
234b917a | 351 | | SOME t => checkTyp G t |
27d9de59 | 352 | |
492c1cff | 353 | val G' = bindVal G (x, t, NONE) |
27d9de59 AC |
354 | val t' = checkExp G' e |
355 | in | |
356 | (TArrow (t, t'), loc) | |
357 | end | |
358 | | EVar x => | |
234b917a | 359 | (case lookupVal G x of |
27d9de59 AC |
360 | NONE => (dte (UnboundVariable x); |
361 | (TError, loc)) | |
362 | | SOME t => t) | |
363 | | EApp (func, arg) => | |
364 | let | |
365 | val dom = (newUnif (), loc) | |
366 | val ran = (newUnif (), loc) | |
367 | ||
368 | val tf = checkExp G func | |
369 | val ta = checkExp G arg | |
370 | in | |
6be996d4 AC |
371 | (hasTyp (func, tf, (TArrow (dom, ran), loc)); |
372 | hasTyp (arg, ta, dom) | |
27d9de59 AC |
373 | handle Unify ue => |
374 | dte (WrongType ("Function argument", | |
375 | arg, | |
376 | ta, | |
377 | dom, | |
378 | SOME ue)); | |
379 | ran) | |
380 | handle Unify ue => | |
381 | (dte (WrongForm ("Function to be applied", | |
382 | "function", | |
383 | func, | |
384 | tf, | |
385 | SOME ue)); | |
386 | (TError, loc)) | |
387 | end | |
db427c67 AC |
388 | |
389 | | ESet (evar, e) => | |
390 | let | |
391 | val t = checkExp G e | |
392 | in | |
393 | (TAction ((CPrefix (CRoot, loc), loc), | |
394 | SM.empty, | |
395 | SM.insert (SM.empty, evar, t)), | |
396 | loc) | |
397 | end | |
398 | | EGet (x, evar, rest) => | |
399 | let | |
400 | val xt = (newUnif (), loc) | |
492c1cff | 401 | val G' = bindVal G (x, xt, NONE) |
db427c67 AC |
402 | |
403 | val rt = whnorm (checkExp G' rest) | |
404 | in | |
405 | case rt of | |
406 | (TAction (p, d, r), _) => | |
407 | (case SM.find (d, evar) of | |
408 | NONE => (TAction (p, SM.insert (d, evar, xt), r), loc) | |
409 | | SOME xt' => | |
234b917a | 410 | (subTyp (xt', xt) |
db427c67 AC |
411 | handle Unify ue => |
412 | dte (WrongType ("Retrieved environment variable", | |
413 | (EVar x, loc), | |
414 | xt', | |
415 | xt, | |
416 | SOME ue)); | |
417 | rt)) | |
234b917a | 418 | | (TError, _) => rt |
db427c67 AC |
419 | | _ => (dte (WrongForm ("Body of environment variable read", |
420 | "action", | |
421 | rest, | |
422 | rt, | |
423 | NONE)); | |
424 | (TError, loc)) | |
425 | end | |
426 | ||
427 | | ESeq [] => raise Fail "Empty ESeq" | |
428 | | ESeq [e1] => checkExp G e1 | |
429 | | ESeq (e1 :: rest) => | |
430 | let | |
431 | val e2 = (ESeq rest, loc) | |
432 | ||
433 | val t1 = whnorm (checkExp G e1) | |
434 | val t2 = whnorm (checkExp G e2) | |
435 | in | |
436 | case t1 of | |
437 | (TAction (p1, d1, r1), _) => | |
438 | (case t2 of | |
439 | (TAction (p2, d2, r2), _) => | |
440 | let | |
441 | val p' = predSimpl (CAnd (p1, p2), loc) | |
442 | ||
443 | val d' = SM.foldli (fn (name, t, d') => | |
444 | case SM.find (r1, name) of | |
445 | NONE => | |
446 | (case SM.find (d', name) of | |
447 | NONE => SM.insert (d', name, t) | |
448 | | SOME t' => | |
234b917a | 449 | (subTyp (t, t') |
db427c67 AC |
450 | handle Unify ue => |
451 | dte (WrongType ("Shared environment variable", | |
452 | (EVar name, loc), | |
453 | t, | |
454 | t', | |
455 | SOME ue)); | |
456 | d')) | |
457 | | SOME t' => | |
234b917a | 458 | (subTyp (t, t') |
db427c67 AC |
459 | handle Unify ue => |
460 | dte (WrongType ("Shared environment variable", | |
461 | (EVar name, loc), | |
462 | t, | |
463 | t', | |
464 | SOME ue)); | |
465 | d')) | |
466 | d1 d2 | |
467 | ||
468 | val r' = SM.foldli (fn (name, t, r') => SM.insert (r', name, t)) | |
469 | r1 r2 | |
470 | in | |
471 | (TAction (p', d', r'), loc) | |
472 | end | |
234b917a | 473 | | (TError, _) => t2 |
db427c67 AC |
474 | | _ => (dte (WrongForm ("Action to be sequenced", |
475 | "action", | |
476 | e2, | |
477 | t2, | |
478 | NONE)); | |
479 | (TError, loc))) | |
234b917a | 480 | | (TError, _) => t1 |
db427c67 AC |
481 | | _ => (dte (WrongForm ("Action to be sequenced", |
482 | "action", | |
483 | e1, | |
484 | t1, | |
485 | NONE)); | |
486 | (TError, loc)) | |
487 | end | |
488 | ||
1a4e5a6c | 489 | | ELocal (e1, e2) => |
db427c67 | 490 | let |
1a4e5a6c AC |
491 | val t1 = whnorm (checkExp G e1) |
492 | val t2 = whnorm (checkExp G e2) | |
db427c67 | 493 | in |
1a4e5a6c AC |
494 | case t1 of |
495 | (TAction (p1, d1, r1), _) => | |
496 | (case t2 of | |
497 | (TAction (p2, d2, r2), _) => | |
498 | let | |
499 | val p' = predSimpl (CAnd (p1, p2), loc) | |
500 | ||
501 | val d' = SM.foldli (fn (name, t, d') => | |
502 | case SM.find (r1, name) of | |
503 | NONE => | |
504 | (case SM.find (d', name) of | |
505 | NONE => SM.insert (d', name, t) | |
506 | | SOME t' => | |
507 | (subTyp (t, t') | |
508 | handle Unify ue => | |
509 | dte (WrongType ("Shared environment variable", | |
510 | (EVar name, loc), | |
511 | t, | |
512 | t', | |
513 | SOME ue)); | |
514 | d')) | |
515 | | SOME t' => | |
516 | (subTyp (t, t') | |
517 | handle Unify ue => | |
518 | dte (WrongType ("Shared environment variable", | |
519 | (EVar name, loc), | |
520 | t, | |
521 | t', | |
522 | SOME ue)); | |
523 | d')) | |
524 | d1 d2 | |
525 | in | |
526 | (TAction (p', d', r2), loc) | |
527 | end | |
528 | | (TError, _) => t2 | |
529 | | _ => (dte (WrongForm ("Action to be sequenced", | |
530 | "action", | |
531 | e2, | |
532 | t2, | |
533 | NONE)); | |
534 | (TError, loc))) | |
535 | | (TError, _) => t1 | |
536 | | _ => (dte (WrongForm ("Action to be sequenced", | |
db427c67 | 537 | "action", |
1a4e5a6c AC |
538 | e1, |
539 | t1, | |
db427c67 AC |
540 | NONE)); |
541 | (TError, loc)) | |
542 | end | |
234b917a | 543 | |
1a4e5a6c | 544 | |
234b917a AC |
545 | | EWith (e1, e2) => |
546 | let | |
547 | val t1 = whnorm (checkExp G e1) | |
548 | val t2 = whnorm (checkExp G e2) | |
549 | in | |
550 | case t1 of | |
1a4e5a6c | 551 | (TNested (pd, (TAction (pr, d1, r1), _)), _) => |
234b917a AC |
552 | (case t2 of |
553 | (TAction (p, d, r), _) => | |
554 | if predImplies (pd, p) then | |
1a4e5a6c AC |
555 | let |
556 | val combineRecs = | |
557 | SM.unionWithi (fn (name, t1, t2) => | |
558 | (subTyp (t1, t2) | |
559 | handle Unify ue => | |
560 | dte (WrongType ("Environment variable", | |
561 | (EVar name, loc), | |
562 | t1, | |
563 | t2, | |
564 | SOME ue)); | |
565 | t2)) | |
566 | in | |
567 | (TAction (pr, combineRecs (d, d1), | |
568 | combineRecs (r, r1)), loc) | |
569 | end | |
234b917a AC |
570 | else |
571 | (dte (WrongPred ("nested action", | |
572 | pd, | |
573 | p)); | |
574 | (TError, loc)) | |
575 | | (TError, _) => t2 | |
576 | | _ => | |
577 | (dte (WrongForm ("Body of nested action", | |
578 | "action", | |
579 | e2, | |
580 | t2, | |
581 | NONE)); | |
582 | (TError, loc))) | |
583 | | (TError, _) => t1 | |
584 | | _ => | |
585 | (dte (WrongForm ("Container of nested action", | |
586 | "action", | |
587 | e1, | |
588 | t1, | |
589 | NONE)); | |
590 | (TError, loc)) | |
591 | end | |
592 | ||
593 | | ESkip => (TAction ((CPrefix (CRoot, loc), loc), | |
594 | SM.empty, SM.empty), loc) | |
27d9de59 AC |
595 | end |
596 | ||
597 | exception Ununif | |
598 | ||
599 | fun ununif (tAll as (t, loc)) = | |
600 | case t of | |
601 | TBase _ => tAll | |
602 | | TList t => (TList (ununif t), loc) | |
603 | | TArrow (d, r) => (TArrow (ununif d, ununif r), loc) | |
604 | | TAction (p, d, r) => (TAction (p, SM.map ununif d, SM.map ununif r), loc) | |
605 | | TUnif (_, ref (SOME t)) => ununif t | |
234b917a | 606 | | TNested _ => tAll |
27d9de59 AC |
607 | | TError => tAll |
608 | ||
609 | | TUnif (_, ref NONE) => raise Ununif | |
610 | ||
611 | fun hasError (t, _) = | |
612 | case t of | |
613 | TBase _ => false | |
614 | | TList t => hasError t | |
615 | | TArrow (d, r) => hasError d orelse hasError r | |
616 | | TAction (p, d, r) => List.exists hasError (SM.listItems d) | |
617 | orelse List.exists hasError (SM.listItems r) | |
234b917a | 618 | | TNested _ => false |
27d9de59 AC |
619 | | TError => false |
620 | | TUnif (_, ref (SOME t)) => hasError t | |
621 | | TUnif (_, ref NONE) => false | |
622 | ||
623 | ||
624 | fun checkUnit G (eAll as (_, loc)) = | |
625 | let | |
626 | val _ = resetUnif () | |
627 | val t = checkExp G eAll | |
628 | in | |
629 | if hasError t then | |
630 | t | |
631 | else | |
632 | ununif t | |
633 | handle Ununif => | |
634 | (ErrorMsg.error (SOME loc) "Unification variables remain in type:"; | |
635 | printd (p_typ t); | |
636 | t) | |
637 | end | |
638 | ||
234b917a AC |
639 | fun checkDecl G (d, _, loc) = |
640 | case d of | |
641 | DExternType name => bindType G name | |
492c1cff AC |
642 | | DExternVal (name, t) => bindVal G (name, checkTyp G t, NONE) |
643 | | DVal (name, to, e) => | |
644 | let | |
645 | val to = | |
646 | case to of | |
647 | NONE => (newUnif (), loc) | |
648 | | SOME to => checkTyp G to | |
649 | ||
650 | val t = checkExp G e | |
651 | in | |
6be996d4 | 652 | hasTyp (e, t, to) |
492c1cff AC |
653 | handle Unify ue => |
654 | describe_type_error loc | |
655 | (WrongType ("Bound value", | |
656 | e, | |
657 | t, | |
658 | to, | |
659 | SOME ue)); | |
660 | bindVal G (name, to, SOME e) | |
661 | end | |
234b917a AC |
662 | |
663 | fun checkFile G tInit (ds, eo) = | |
664 | let | |
665 | val G' = foldl (fn (d, G) => checkDecl G d) G ds | |
666 | in | |
667 | case eo of | |
668 | NONE => () | |
669 | | SOME (e as (_, loc)) => | |
670 | let | |
671 | val t = checkExp G' e | |
672 | in | |
6be996d4 | 673 | hasTyp (e, t, tInit) |
234b917a AC |
674 | handle Unify ue => |
675 | (ErrorMsg.error (SOME loc) "Bad type for final expression of source file."; | |
676 | preface ("Actual:", p_typ t); | |
677 | preface ("Needed:", p_typ tInit)) | |
678 | end; | |
679 | G' | |
680 | end | |
681 | ||
27d9de59 | 682 | end |