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