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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 | ||
b3159a70 AC |
27 | val externFlag = ref false |
28 | fun allowExterns () = externFlag := true | |
29 | fun disallowExterns () = externFlag := false | |
30 | ||
27d9de59 AC |
31 | local |
32 | val unifCount = ref 0 | |
33 | in | |
34 | fun resetUnif () = unifCount := 0 | |
35 | ||
36 | fun newUnif () = | |
37 | let | |
38 | val c = !unifCount | |
39 | val name = | |
40 | if c < 26 then | |
41 | str (chr (ord #"A" + c)) | |
42 | else | |
43 | "UNIF" ^ Int.toString (c - 26) | |
44 | in | |
45 | unifCount := c + 1; | |
46 | TUnif (name, ref NONE) | |
47 | end | |
48 | end | |
49 | ||
50 | exception UnequalDomains | |
51 | ||
52 | fun eqRecord f (r1, r2) = | |
53 | (SM.appi (fn (k, v1) => | |
54 | case SM.find (r2, k) of | |
55 | NONE => raise UnequalDomains | |
56 | | SOME v2 => | |
57 | if f (v1, v2) then | |
58 | () | |
59 | else | |
60 | raise UnequalDomains) r1; | |
61 | SM.appi (fn (k, v2) => | |
62 | case SM.find (r1, k) of | |
63 | NONE => raise UnequalDomains | |
64 | | SOME v1 => | |
65 | if f (v1, v2) then | |
66 | () | |
67 | else | |
68 | raise UnequalDomains) r2; | |
69 | true) | |
70 | handle UnequalDomains => false | |
71 | ||
72 | fun eqPred ((p1, _), (p2, _)) = | |
73 | case (p1, p2) of | |
74 | (CRoot, CRoot) => true | |
75 | | (CConst s1, CConst s2) => s1 = s2 | |
76 | | (CPrefix p1, CPrefix p2) => eqPred (p1, p2) | |
77 | | (CNot p1, CNot p2) => eqPred (p1, p2) | |
78 | | (CAnd (p1, q1), CAnd (p2, q2)) => | |
79 | eqPred (p1, p2) andalso eqPred (q1, q2) | |
80 | ||
81 | | _ => false | |
82 | ||
83 | fun eqTy (t1All as (t1, _), t2All as (t2, _)) = | |
84 | case (t1, t2) of | |
85 | (TBase s1, TBase s2) => s1 = s2 | |
86 | | (TList t1, TList t2) => eqTy (t1, t2) | |
87 | | (TArrow (d1, r1), TArrow (d2, r2)) => | |
88 | eqTy (d1, d2) andalso eqTy (r1, r2) | |
89 | ||
90 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => | |
91 | eqPred (p1, p2) andalso eqRecord eqTy (d1, d2) | |
92 | andalso eqRecord eqTy (r1, r2) | |
93 | ||
234b917a | 94 | | (TNested (p1, q1), TNested (p2, q2)) => |
1a4e5a6c | 95 | eqPred (p1, p2) andalso eqTy (q1, q2) |
234b917a | 96 | |
27d9de59 AC |
97 | | (TUnif (_, ref (SOME t1)), _) => eqTy (t1, t2All) |
98 | | (_, TUnif (_, ref (SOME t2))) => eqTy (t1All, t2) | |
99 | ||
100 | | (TUnif (_, r1), TUnif (_, r2)) => r1 = r2 | |
101 | ||
102 | | (TError, TError) => true | |
103 | ||
104 | | _ => false | |
105 | ||
106 | datatype unification_error = | |
107 | UnifyPred of pred * pred | |
108 | | UnifyTyp of typ * typ | |
109 | | UnifyOccurs of string * typ | |
110 | ||
111 | exception Unify of unification_error | |
112 | ||
113 | datatype type_error = | |
114 | WrongType of string * exp * typ * typ * unification_error option | |
115 | | WrongForm of string * string * exp * typ * unification_error option | |
116 | | UnboundVariable of string | |
234b917a | 117 | | WrongPred of string * pred * pred |
27d9de59 | 118 | |
27d9de59 AC |
119 | fun describe_unification_error t ue = |
120 | case ue of | |
121 | UnifyPred (p1, p2) => | |
234b917a | 122 | (print "Reason: Incompatible contexts.\n"; |
27d9de59 AC |
123 | preface ("Have:", p_pred p1); |
124 | preface ("Need:", p_pred p2)) | |
125 | | UnifyTyp (t1, t2) => | |
126 | if eqTy (t, t1) then | |
127 | () | |
128 | else | |
129 | (print "Reason: Incompatible types.\n"; | |
130 | preface ("Have:", p_typ t1); | |
131 | preface ("Need:", p_typ t2)) | |
132 | | UnifyOccurs (name, t') => | |
133 | if eqTy (t, t') then | |
134 | () | |
135 | else | |
136 | (print "Reason: Occurs check failed for "; | |
137 | print name; | |
138 | print " in:\n"; | |
139 | printd (p_typ t)) | |
140 | ||
141 | fun describe_type_error loc te = | |
142 | case te of | |
143 | WrongType (place, e, t1, t2, ueo) => | |
144 | (ErrorMsg.error (SOME loc) (place ^ " has wrong type."); | |
145 | preface (" Expression:", p_exp e); | |
146 | preface ("Actual type:", p_typ t1); | |
147 | preface ("Needed type:", p_typ t2); | |
148 | Option.app (describe_unification_error t1) ueo) | |
149 | | WrongForm (place, form, e, t, ueo) => | |
150 | (ErrorMsg.error (SOME loc) (place ^ " has a non-" ^ form ^ " type."); | |
151 | preface ("Expression:", p_exp e); | |
152 | preface (" Type:", p_typ t); | |
153 | Option.app (describe_unification_error t) ueo) | |
154 | | UnboundVariable name => | |
155 | ErrorMsg.error (SOME loc) ("Unbound variable " ^ name ^ ".\n") | |
234b917a AC |
156 | | WrongPred (place, p1, p2) => |
157 | (ErrorMsg.error (SOME loc) ("Context incompatibility for " ^ place ^ "."); | |
158 | preface ("Have:", p_pred p1); | |
159 | preface ("Need:", p_pred p2)) | |
27d9de59 | 160 | |
db427c67 | 161 | fun predImplies (p1All as (p1, _), p2All as (p2, _)) = |
27d9de59 | 162 | case (p1, p2) of |
1a4e5a6c AC |
163 | (_, CAnd (p1, p2)) => predImplies (p1All, p1) andalso predImplies (p1All, p2) |
164 | | (CAnd (p1, p2), _) => predImplies (p1, p2All) orelse predImplies (p2, p2All) | |
165 | ||
166 | | (_, CPrefix (CRoot, _)) => true | |
db427c67 AC |
167 | | (CNot (CPrefix (CRoot, _), _), _) => true |
168 | ||
169 | | (CRoot, CRoot) => true | |
170 | ||
171 | | (CConst s1, CConst s2) => s1 = s2 | |
172 | ||
173 | | (CPrefix p1, CPrefix p2) => predImplies (p1, p2) | |
234b917a | 174 | | (_, CPrefix p2) => predImplies (p1All, p2) |
db427c67 AC |
175 | |
176 | | (CNot p1, CNot p2) => predImplies (p2, p1) | |
2882ee37 AC |
177 | | (CRoot, CNot (CConst _, _)) => true |
178 | | (CConst s1, CNot (CConst s2, _)) => s1 <> s2 | |
27d9de59 | 179 | |
db427c67 AC |
180 | | _ => false |
181 | ||
182 | fun predSimpl (pAll as (p, loc)) = | |
183 | case p of | |
184 | CRoot => pAll | |
185 | | CConst _ => pAll | |
186 | | CPrefix p => (CPrefix (predSimpl p), loc) | |
187 | | CNot p => (CNot (predSimpl p), loc) | |
188 | | CAnd (p1, p2) => | |
189 | let | |
190 | val p1' = predSimpl p1 | |
191 | val p2' = predSimpl p2 | |
192 | in | |
193 | case p1' of | |
194 | (CAnd (c1, c2), _) => predSimpl (CAnd (c1, (CAnd (c2, p2'), loc)), loc) | |
195 | | _ => if predImplies (p2', p1') then | |
196 | p2' | |
1a4e5a6c AC |
197 | else if predImplies (p1', p2') then |
198 | p1' | |
db427c67 AC |
199 | else |
200 | (CAnd (p1', p2'), loc) | |
201 | end | |
202 | ||
234b917a | 203 | fun subPred (p1, p2) = |
db427c67 AC |
204 | if predImplies (p1, p2) then |
205 | () | |
206 | else | |
207 | raise (Unify (UnifyPred (p1, p2))) | |
27d9de59 | 208 | |
234b917a AC |
209 | fun subRecord f (r1, r2) = |
210 | SM.appi (fn (k, v2) => | |
211 | case SM.find (r1, k) of | |
212 | NONE => raise UnequalDomains | |
213 | | SOME v1 => f (v1, v2)) r2 | |
27d9de59 AC |
214 | |
215 | fun occurs u (t, _) = | |
216 | case t of | |
217 | TBase _ => false | |
218 | | TList t => occurs u t | |
219 | | TArrow (d, r) => occurs u d orelse occurs u r | |
220 | | TAction (_, d, r) => | |
221 | List.exists (occurs u) (SM.listItems d) | |
222 | orelse List.exists (occurs u) (SM.listItems r) | |
1a4e5a6c | 223 | | TNested (_, t) => occurs u t |
27d9de59 AC |
224 | | TError => false |
225 | | TUnif (_, ref (SOME t)) => occurs u t | |
226 | | TUnif (_, u') => u = u' | |
227 | ||
234b917a | 228 | fun subTyp (t1All as (t1, _), t2All as (t2, _)) = |
27d9de59 AC |
229 | case (t1, t2) of |
230 | (TBase s1, TBase s2) => | |
231 | if s1 = s2 then | |
232 | () | |
233 | else | |
234 | raise Unify (UnifyTyp (t1All, t2All)) | |
234b917a | 235 | | (TList t1, TList t2) => subTyp (t1, t2) |
27d9de59 | 236 | | (TArrow (d1, r1), TArrow (d2, r2)) => |
234b917a AC |
237 | (subTyp (d2, d1); |
238 | subTyp (r1, r2)) | |
27d9de59 AC |
239 | |
240 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => | |
234b917a AC |
241 | ((subPred (p2, p1); |
242 | subRecord subTyp (d2, d1); | |
243 | subRecord subTyp (r1, r2); | |
244 | subRecord subTyp (r2, r1)) | |
27d9de59 AC |
245 | handle UnequalDomains => raise Unify (UnifyTyp (t1All, t2All))) |
246 | ||
234b917a AC |
247 | | (TNested (d1, r1), TNested (d2, r2)) => |
248 | (subPred (d2, d1); | |
1a4e5a6c | 249 | subTyp (r1, r2)) |
234b917a AC |
250 | |
251 | | (TUnif (_, ref (SOME t1)), _) => subTyp (t1, t2All) | |
252 | | (_, TUnif (_, ref (SOME t2))) => subTyp (t1All, t2) | |
27d9de59 AC |
253 | |
254 | | (TUnif (_, r1), TUnif (_, r2)) => | |
255 | if r1 = r2 then | |
256 | () | |
257 | else | |
258 | r1 := SOME t2All | |
259 | ||
260 | | (TUnif (name, r), _) => | |
261 | if occurs r t2All then | |
262 | raise (Unify (UnifyOccurs (name, t2All))) | |
263 | else | |
264 | r := SOME t2All | |
265 | ||
266 | | (_, TUnif (name, r)) => | |
267 | if occurs r t1All then | |
268 | raise (Unify (UnifyOccurs (name, t1All))) | |
269 | else | |
270 | r := SOME t1All | |
271 | ||
272 | | (TError, _) => () | |
273 | | (_, TError) => () | |
274 | ||
275 | | _ => raise Unify (UnifyTyp (t1All, t2All)) | |
276 | ||
277 | fun isError t = | |
278 | case t of | |
279 | (TError, _) => true | |
280 | | _ => false | |
281 | ||
db427c67 AC |
282 | fun whnorm (tAll as (t, loc)) = |
283 | case t of | |
284 | TUnif (_, ref (SOME tAll)) => whnorm tAll | |
285 | | _ => tAll | |
286 | ||
629a34f6 AC |
287 | fun baseCondition t = |
288 | case whnorm t of | |
289 | (TBase name, _) => typeRule name | |
290 | | (TList t, _) => | |
291 | (case baseCondition t of | |
292 | NONE => NONE | |
293 | | SOME f => SOME (fn (EList ls, _) => List.all f ls | |
294 | | _ => false)) | |
295 | | _ => NONE | |
296 | ||
6be996d4 | 297 | fun hasTyp (e, t1, t2) = |
629a34f6 AC |
298 | if (case baseCondition t2 of |
299 | NONE => false | |
300 | | SOME rule => rule e) then | |
301 | () | |
302 | else | |
303 | subTyp (t1, t2) | |
6be996d4 | 304 | |
095de39e AC |
305 | fun checkPred G (p, loc) = |
306 | let | |
307 | val err = ErrorMsg.error (SOME loc) | |
308 | in | |
309 | case p of | |
310 | CRoot => () | |
311 | | CConst s => | |
312 | if lookupContext G s then | |
313 | () | |
314 | else | |
315 | err ("Unbound context " ^ s) | |
316 | | CPrefix p => checkPred G p | |
317 | | CNot p => checkPred G p | |
318 | | CAnd (p1, p2) => (checkPred G p1; checkPred G p2) | |
319 | end | |
320 | ||
234b917a AC |
321 | fun checkTyp G (tAll as (t, loc)) = |
322 | let | |
323 | val err = ErrorMsg.error (SOME loc) | |
324 | in | |
325 | case t of | |
326 | TBase name => | |
327 | if lookupType G name then | |
328 | tAll | |
329 | else | |
330 | (err ("Unbound type name " ^ name); | |
331 | (TError, loc)) | |
332 | | TList t => (TList (checkTyp G t), loc) | |
333 | | TArrow (d, r) => (TArrow (checkTyp G d, checkTyp G r), loc) | |
095de39e AC |
334 | | TAction (p, d, r) => (checkPred G p; |
335 | (TAction (p, SM.map (checkTyp G) d, | |
336 | SM.map (checkTyp G) r), loc)) | |
337 | | TNested (p, t) => (checkPred G p; | |
338 | (TNested (p, checkTyp G t), loc)) | |
234b917a AC |
339 | | TError => raise Fail "TError in parser-generated type" |
340 | | TUnif _ => raise Fail "TUnif in parser-generated type" | |
341 | end | |
342 | ||
8a7c40fa AC |
343 | fun envVarSetFrom v (e, _) = |
344 | case e of | |
345 | ESet (v', e) => | |
346 | if v = v' then | |
347 | SOME e | |
348 | else | |
349 | NONE | |
350 | | EGet (_, _, e) => envVarSetFrom v e | |
351 | | ESeq es => foldr (fn (e, found) => | |
352 | case found of | |
353 | SOME _ => found | |
354 | | NONE => envVarSetFrom v e) | |
355 | NONE es | |
356 | | ELocal (_, e) => envVarSetFrom v e | |
357 | ||
358 | | _ => NONE | |
359 | ||
27d9de59 AC |
360 | fun checkExp G (eAll as (e, loc)) = |
361 | let | |
362 | val dte = describe_type_error loc | |
363 | in | |
364 | case e of | |
365 | EInt _ => (TBase "int", loc) | |
366 | | EString _ => (TBase "string", loc) | |
367 | | EList es => | |
368 | let | |
369 | val t = (newUnif (), loc) | |
370 | in | |
371 | foldl (fn (e', ret) => | |
372 | let | |
373 | val t' = checkExp G e' | |
374 | in | |
6be996d4 | 375 | (hasTyp (eAll, t', t); |
27d9de59 AC |
376 | if isError t' then |
377 | (TList (TError, loc), loc) | |
378 | else | |
379 | ret) | |
380 | handle Unify ue => | |
381 | (dte (WrongType ("List element", | |
382 | e', | |
383 | t', | |
384 | t, | |
385 | SOME ue)); | |
386 | (TError, loc)) | |
387 | end) (TList t, loc) es | |
388 | end | |
389 | ||
390 | | ELam (x, to, e) => | |
391 | let | |
392 | val t = | |
393 | case to of | |
394 | NONE => (newUnif (), loc) | |
234b917a | 395 | | SOME t => checkTyp G t |
27d9de59 | 396 | |
492c1cff | 397 | val G' = bindVal G (x, t, NONE) |
27d9de59 AC |
398 | val t' = checkExp G' e |
399 | in | |
400 | (TArrow (t, t'), loc) | |
401 | end | |
402 | | EVar x => | |
234b917a | 403 | (case lookupVal G x of |
27d9de59 AC |
404 | NONE => (dte (UnboundVariable x); |
405 | (TError, loc)) | |
406 | | SOME t => t) | |
407 | | EApp (func, arg) => | |
408 | let | |
409 | val dom = (newUnif (), loc) | |
410 | val ran = (newUnif (), loc) | |
411 | ||
412 | val tf = checkExp G func | |
413 | val ta = checkExp G arg | |
414 | in | |
6be996d4 AC |
415 | (hasTyp (func, tf, (TArrow (dom, ran), loc)); |
416 | hasTyp (arg, ta, dom) | |
27d9de59 AC |
417 | handle Unify ue => |
418 | dte (WrongType ("Function argument", | |
419 | arg, | |
420 | ta, | |
421 | dom, | |
422 | SOME ue)); | |
423 | ran) | |
424 | handle Unify ue => | |
425 | (dte (WrongForm ("Function to be applied", | |
426 | "function", | |
427 | func, | |
428 | tf, | |
429 | SOME ue)); | |
430 | (TError, loc)) | |
431 | end | |
db427c67 | 432 | |
6bb366c5 AC |
433 | | EALam (x, p, e) => |
434 | let | |
435 | val p' = checkPred G p | |
436 | ||
437 | val G' = bindVal G (x, (TAction (p, SM.empty, SM.empty), loc), NONE) | |
cdb376d4 | 438 | val t' = whnorm (checkExp G' e) |
6bb366c5 AC |
439 | in |
440 | case t' of | |
441 | (TAction _, _) => (TNested (p, t'), loc) | |
442 | | _ => (dte (WrongForm ("Body of nested configuration 'fn'", | |
443 | "action", | |
444 | e, | |
445 | t', | |
446 | NONE)); | |
447 | (TError, loc)) | |
448 | end | |
449 | ||
db427c67 AC |
450 | | ESet (evar, e) => |
451 | let | |
452 | val t = checkExp G e | |
453 | in | |
454 | (TAction ((CPrefix (CRoot, loc), loc), | |
455 | SM.empty, | |
456 | SM.insert (SM.empty, evar, t)), | |
457 | loc) | |
458 | end | |
459 | | EGet (x, evar, rest) => | |
460 | let | |
461 | val xt = (newUnif (), loc) | |
492c1cff | 462 | val G' = bindVal G (x, xt, NONE) |
db427c67 AC |
463 | |
464 | val rt = whnorm (checkExp G' rest) | |
465 | in | |
466 | case rt of | |
467 | (TAction (p, d, r), _) => | |
468 | (case SM.find (d, evar) of | |
469 | NONE => (TAction (p, SM.insert (d, evar, xt), r), loc) | |
470 | | SOME xt' => | |
234b917a | 471 | (subTyp (xt', xt) |
db427c67 AC |
472 | handle Unify ue => |
473 | dte (WrongType ("Retrieved environment variable", | |
474 | (EVar x, loc), | |
475 | xt', | |
476 | xt, | |
477 | SOME ue)); | |
478 | rt)) | |
234b917a | 479 | | (TError, _) => rt |
db427c67 AC |
480 | | _ => (dte (WrongForm ("Body of environment variable read", |
481 | "action", | |
482 | rest, | |
483 | rt, | |
484 | NONE)); | |
485 | (TError, loc)) | |
486 | end | |
487 | ||
488 | | ESeq [] => raise Fail "Empty ESeq" | |
489 | | ESeq [e1] => checkExp G e1 | |
490 | | ESeq (e1 :: rest) => | |
491 | let | |
492 | val e2 = (ESeq rest, loc) | |
493 | ||
494 | val t1 = whnorm (checkExp G e1) | |
495 | val t2 = whnorm (checkExp G e2) | |
496 | in | |
497 | case t1 of | |
498 | (TAction (p1, d1, r1), _) => | |
499 | (case t2 of | |
500 | (TAction (p2, d2, r2), _) => | |
501 | let | |
502 | val p' = predSimpl (CAnd (p1, p2), loc) | |
503 | ||
504 | val d' = SM.foldli (fn (name, t, d') => | |
505 | case SM.find (r1, name) of | |
506 | NONE => | |
507 | (case SM.find (d', name) of | |
508 | NONE => SM.insert (d', name, t) | |
509 | | SOME t' => | |
8a7c40fa AC |
510 | ((case envVarSetFrom name e1 of |
511 | NONE => subTyp (t, t') | |
512 | | SOME e => hasTyp (e, t, t')) | |
db427c67 AC |
513 | handle Unify ue => |
514 | dte (WrongType ("Shared environment variable", | |
515 | (EVar name, loc), | |
db427c67 | 516 | t', |
8a7c40fa | 517 | t, |
db427c67 AC |
518 | SOME ue)); |
519 | d')) | |
520 | | SOME t' => | |
8a7c40fa AC |
521 | ((case envVarSetFrom name e1 of |
522 | NONE => subTyp (t, t') | |
523 | | SOME e => hasTyp (e, t, t')) | |
db427c67 AC |
524 | handle Unify ue => |
525 | dte (WrongType ("Shared environment variable", | |
526 | (EVar name, loc), | |
db427c67 | 527 | t', |
8a7c40fa | 528 | t, |
db427c67 AC |
529 | SOME ue)); |
530 | d')) | |
531 | d1 d2 | |
532 | ||
533 | val r' = SM.foldli (fn (name, t, r') => SM.insert (r', name, t)) | |
534 | r1 r2 | |
535 | in | |
536 | (TAction (p', d', r'), loc) | |
537 | end | |
234b917a | 538 | | (TError, _) => t2 |
db427c67 AC |
539 | | _ => (dte (WrongForm ("Action to be sequenced", |
540 | "action", | |
541 | e2, | |
542 | t2, | |
543 | NONE)); | |
544 | (TError, loc))) | |
234b917a | 545 | | (TError, _) => t1 |
db427c67 AC |
546 | | _ => (dte (WrongForm ("Action to be sequenced", |
547 | "action", | |
548 | e1, | |
549 | t1, | |
550 | NONE)); | |
551 | (TError, loc)) | |
552 | end | |
553 | ||
1a4e5a6c | 554 | | ELocal (e1, e2) => |
db427c67 | 555 | let |
1a4e5a6c AC |
556 | val t1 = whnorm (checkExp G e1) |
557 | val t2 = whnorm (checkExp G e2) | |
db427c67 | 558 | in |
1a4e5a6c AC |
559 | case t1 of |
560 | (TAction (p1, d1, r1), _) => | |
561 | (case t2 of | |
562 | (TAction (p2, d2, r2), _) => | |
563 | let | |
564 | val p' = predSimpl (CAnd (p1, p2), loc) | |
565 | ||
566 | val d' = SM.foldli (fn (name, t, d') => | |
567 | case SM.find (r1, name) of | |
568 | NONE => | |
569 | (case SM.find (d', name) of | |
570 | NONE => SM.insert (d', name, t) | |
571 | | SOME t' => | |
8a7c40fa AC |
572 | ((case envVarSetFrom name e1 of |
573 | NONE => subTyp (t', t) | |
574 | | SOME e => hasTyp (e, t', t)) | |
1a4e5a6c AC |
575 | handle Unify ue => |
576 | dte (WrongType ("Shared environment variable", | |
577 | (EVar name, loc), | |
1a4e5a6c | 578 | t', |
8a7c40fa | 579 | t, |
1a4e5a6c AC |
580 | SOME ue)); |
581 | d')) | |
582 | | SOME t' => | |
8a7c40fa AC |
583 | ((case envVarSetFrom name e1 of |
584 | NONE => subTyp (t', t) | |
585 | | SOME e => hasTyp (e, t', t)) | |
1a4e5a6c AC |
586 | handle Unify ue => |
587 | dte (WrongType ("Shared environment variable", | |
588 | (EVar name, loc), | |
1a4e5a6c | 589 | t', |
8a7c40fa | 590 | t, |
1a4e5a6c AC |
591 | SOME ue)); |
592 | d')) | |
593 | d1 d2 | |
594 | in | |
595 | (TAction (p', d', r2), loc) | |
596 | end | |
597 | | (TError, _) => t2 | |
598 | | _ => (dte (WrongForm ("Action to be sequenced", | |
599 | "action", | |
600 | e2, | |
601 | t2, | |
602 | NONE)); | |
603 | (TError, loc))) | |
604 | | (TError, _) => t1 | |
605 | | _ => (dte (WrongForm ("Action to be sequenced", | |
db427c67 | 606 | "action", |
1a4e5a6c AC |
607 | e1, |
608 | t1, | |
db427c67 AC |
609 | NONE)); |
610 | (TError, loc)) | |
611 | end | |
234b917a | 612 | |
1a4e5a6c | 613 | |
234b917a AC |
614 | | EWith (e1, e2) => |
615 | let | |
616 | val t1 = whnorm (checkExp G e1) | |
617 | val t2 = whnorm (checkExp G e2) | |
618 | in | |
619 | case t1 of | |
1a4e5a6c | 620 | (TNested (pd, (TAction (pr, d1, r1), _)), _) => |
234b917a AC |
621 | (case t2 of |
622 | (TAction (p, d, r), _) => | |
623 | if predImplies (pd, p) then | |
1a4e5a6c AC |
624 | let |
625 | val combineRecs = | |
626 | SM.unionWithi (fn (name, t1, t2) => | |
627 | (subTyp (t1, t2) | |
628 | handle Unify ue => | |
629 | dte (WrongType ("Environment variable", | |
630 | (EVar name, loc), | |
631 | t1, | |
632 | t2, | |
633 | SOME ue)); | |
634 | t2)) | |
635 | in | |
636 | (TAction (pr, combineRecs (d, d1), | |
637 | combineRecs (r, r1)), loc) | |
638 | end | |
234b917a AC |
639 | else |
640 | (dte (WrongPred ("nested action", | |
641 | pd, | |
642 | p)); | |
643 | (TError, loc)) | |
644 | | (TError, _) => t2 | |
645 | | _ => | |
646 | (dte (WrongForm ("Body of nested action", | |
647 | "action", | |
648 | e2, | |
649 | t2, | |
650 | NONE)); | |
651 | (TError, loc))) | |
652 | | (TError, _) => t1 | |
653 | | _ => | |
654 | (dte (WrongForm ("Container of nested action", | |
655 | "action", | |
656 | e1, | |
657 | t1, | |
658 | NONE)); | |
659 | (TError, loc)) | |
660 | end | |
661 | ||
662 | | ESkip => (TAction ((CPrefix (CRoot, loc), loc), | |
663 | SM.empty, SM.empty), loc) | |
27d9de59 AC |
664 | end |
665 | ||
666 | exception Ununif | |
667 | ||
668 | fun ununif (tAll as (t, loc)) = | |
669 | case t of | |
670 | TBase _ => tAll | |
671 | | TList t => (TList (ununif t), loc) | |
672 | | TArrow (d, r) => (TArrow (ununif d, ununif r), loc) | |
673 | | TAction (p, d, r) => (TAction (p, SM.map ununif d, SM.map ununif r), loc) | |
674 | | TUnif (_, ref (SOME t)) => ununif t | |
234b917a | 675 | | TNested _ => tAll |
27d9de59 AC |
676 | | TError => tAll |
677 | ||
678 | | TUnif (_, ref NONE) => raise Ununif | |
679 | ||
680 | fun hasError (t, _) = | |
681 | case t of | |
682 | TBase _ => false | |
683 | | TList t => hasError t | |
684 | | TArrow (d, r) => hasError d orelse hasError r | |
685 | | TAction (p, d, r) => List.exists hasError (SM.listItems d) | |
686 | orelse List.exists hasError (SM.listItems r) | |
234b917a | 687 | | TNested _ => false |
27d9de59 AC |
688 | | TError => false |
689 | | TUnif (_, ref (SOME t)) => hasError t | |
690 | | TUnif (_, ref NONE) => false | |
691 | ||
692 | ||
693 | fun checkUnit G (eAll as (_, loc)) = | |
694 | let | |
695 | val _ = resetUnif () | |
696 | val t = checkExp G eAll | |
697 | in | |
698 | if hasError t then | |
699 | t | |
700 | else | |
701 | ununif t | |
702 | handle Ununif => | |
703 | (ErrorMsg.error (SOME loc) "Unification variables remain in type:"; | |
704 | printd (p_typ t); | |
705 | t) | |
706 | end | |
707 | ||
234b917a AC |
708 | fun checkDecl G (d, _, loc) = |
709 | case d of | |
b3159a70 AC |
710 | DExternType name => |
711 | if !externFlag then | |
712 | bindType G name | |
713 | else | |
714 | (ErrorMsg.error (SOME loc) "'extern type' not allowed in untrusted code"; | |
715 | G) | |
716 | | DExternVal (name, t) => | |
717 | if !externFlag then | |
718 | bindVal G (name, checkTyp G t, NONE) | |
719 | else | |
720 | (ErrorMsg.error (SOME loc) "'extern val' not allowed in untrusted code"; | |
721 | G) | |
492c1cff AC |
722 | | DVal (name, to, e) => |
723 | let | |
724 | val to = | |
725 | case to of | |
726 | NONE => (newUnif (), loc) | |
727 | | SOME to => checkTyp G to | |
728 | ||
729 | val t = checkExp G e | |
730 | in | |
6be996d4 | 731 | hasTyp (e, t, to) |
492c1cff AC |
732 | handle Unify ue => |
733 | describe_type_error loc | |
734 | (WrongType ("Bound value", | |
735 | e, | |
736 | t, | |
737 | to, | |
738 | SOME ue)); | |
739 | bindVal G (name, to, SOME e) | |
740 | end | |
095de39e | 741 | | DContext name => bindContext G name |
234b917a | 742 | |
095de39e | 743 | fun checkFile G tInit (_, ds, eo) = |
234b917a AC |
744 | let |
745 | val G' = foldl (fn (d, G) => checkDecl G d) G ds | |
746 | in | |
747 | case eo of | |
748 | NONE => () | |
749 | | SOME (e as (_, loc)) => | |
750 | let | |
751 | val t = checkExp G' e | |
752 | in | |
6be996d4 | 753 | hasTyp (e, t, tInit) |
234b917a AC |
754 | handle Unify ue => |
755 | (ErrorMsg.error (SOME loc) "Bad type for final expression of source file."; | |
756 | preface ("Actual:", p_typ t); | |
757 | preface ("Needed:", p_typ tInit)) | |
758 | end; | |
759 | G' | |
760 | end | |
761 | ||
27d9de59 | 762 | end |