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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 | |
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23 | open Ast Print Env |
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24 | |
25 | structure SM = StringMap |
26 | |
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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 | |
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90 | | (TNested (p1, q1), TNested (p2, q2)) => |
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91 | eqPred (p1, p2) andalso eqTy (q1, q2) |
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92 | |
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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 |
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113 | | WrongPred of string * pred * pred |
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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) => |
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121 | (print "Reason: Incompatible contexts.\n"; |
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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") |
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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)) |
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159 | |
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160 | fun predImplies (p1All as (p1, _), p2All as (p2, _)) = |
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161 | case (p1, p2) of |
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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 |
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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) |
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173 | | (_, CPrefix p2) => predImplies (p1All, p2) |
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174 | |
175 | | (CNot p1, CNot p2) => predImplies (p2, p1) |
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176 | |
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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' |
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194 | else if predImplies (p1', p2') then |
195 | p1' |
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196 | else |
197 | (CAnd (p1', p2'), loc) |
198 | end |
199 | |
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200 | fun subPred (p1, p2) = |
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201 | if predImplies (p1, p2) then |
202 | () |
203 | else |
204 | raise (Unify (UnifyPred (p1, p2))) |
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205 | |
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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 |
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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) |
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220 | | TNested (_, t) => occurs u t |
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221 | | TError => false |
222 | | TUnif (_, ref (SOME t)) => occurs u t |
223 | | TUnif (_, u') => u = u' |
224 | |
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225 | fun subTyp (t1All as (t1, _), t2All as (t2, _)) = |
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226 | case (t1, t2) of |
227 | (TBase s1, TBase s2) => |
228 | if s1 = s2 then |
229 | () |
230 | else |
231 | raise Unify (UnifyTyp (t1All, t2All)) |
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232 | | (TList t1, TList t2) => subTyp (t1, t2) |
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233 | | (TArrow (d1, r1), TArrow (d2, r2)) => |
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234 | (subTyp (d2, d1); |
235 | subTyp (r1, r2)) |
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236 | |
237 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => |
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238 | ((subPred (p2, p1); |
239 | subRecord subTyp (d2, d1); |
240 | subRecord subTyp (r1, r2); |
241 | subRecord subTyp (r2, r1)) |
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242 | handle UnequalDomains => raise Unify (UnifyTyp (t1All, t2All))) |
243 | |
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244 | | (TNested (d1, r1), TNested (d2, r2)) => |
245 | (subPred (d2, d1); |
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246 | subTyp (r1, r2)) |
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247 | |
248 | | (TUnif (_, ref (SOME t1)), _) => subTyp (t1, t2All) |
249 | | (_, TUnif (_, ref (SOME t2))) => subTyp (t1All, t2) |
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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 | |
dbd7a7d2 |
279 | fun whnorm (tAll as (t, loc)) = |
280 | case t of |
281 | TUnif (_, ref (SOME tAll)) => whnorm tAll |
282 | | _ => tAll |
283 | |
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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 | |
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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) |
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311 | | TNested (p, t) => (TNested (p, checkTyp G t), loc) |
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312 | | TError => raise Fail "TError in parser-generated type" |
313 | | TUnif _ => raise Fail "TUnif in parser-generated type" |
314 | end |
315 | |
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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 |
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331 | (hasTyp (eAll, t', t); |
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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) |
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351 | | SOME t => checkTyp G t |
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352 | |
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353 | val G' = bindVal G (x, t, NONE) |
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354 | val t' = checkExp G' e |
355 | in |
356 | (TArrow (t, t'), loc) |
357 | end |
358 | | EVar x => |
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359 | (case lookupVal G x of |
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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 |
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371 | (hasTyp (func, tf, (TArrow (dom, ran), loc)); |
372 | hasTyp (arg, ta, dom) |
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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 |
dbd7a7d2 |
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) |
add6f172 |
401 | val G' = bindVal G (x, xt, NONE) |
dbd7a7d2 |
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' => |
e680130a |
410 | (subTyp (xt', xt) |
dbd7a7d2 |
411 | handle Unify ue => |
412 | dte (WrongType ("Retrieved environment variable", |
413 | (EVar x, loc), |
414 | xt', |
415 | xt, |
416 | SOME ue)); |
417 | rt)) |
e680130a |
418 | | (TError, _) => rt |
dbd7a7d2 |
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' => |
e680130a |
449 | (subTyp (t, t') |
dbd7a7d2 |
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' => |
e680130a |
458 | (subTyp (t, t') |
dbd7a7d2 |
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 |
e680130a |
473 | | (TError, _) => t2 |
dbd7a7d2 |
474 | | _ => (dte (WrongForm ("Action to be sequenced", |
475 | "action", |
476 | e2, |
477 | t2, |
478 | NONE)); |
479 | (TError, loc))) |
e680130a |
480 | | (TError, _) => t1 |
dbd7a7d2 |
481 | | _ => (dte (WrongForm ("Action to be sequenced", |
482 | "action", |
483 | e1, |
484 | t1, |
485 | NONE)); |
486 | (TError, loc)) |
487 | end |
488 | |
2dc33fa4 |
489 | | ELocal (e1, e2) => |
dbd7a7d2 |
490 | let |
2dc33fa4 |
491 | val t1 = whnorm (checkExp G e1) |
492 | val t2 = whnorm (checkExp G e2) |
dbd7a7d2 |
493 | in |
2dc33fa4 |
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", |
dbd7a7d2 |
537 | "action", |
2dc33fa4 |
538 | e1, |
539 | t1, |
dbd7a7d2 |
540 | NONE)); |
541 | (TError, loc)) |
542 | end |
e680130a |
543 | |
2dc33fa4 |
544 | |
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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 |
2dc33fa4 |
551 | (TNested (pd, (TAction (pr, d1, r1), _)), _) => |
e680130a |
552 | (case t2 of |
553 | (TAction (p, d, r), _) => |
554 | if predImplies (pd, p) then |
2dc33fa4 |
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 |
e680130a |
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) |
64014a03 |
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 |
e680130a |
606 | | TNested _ => tAll |
64014a03 |
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) |
e680130a |
618 | | TNested _ => false |
64014a03 |
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 | |
e680130a |
639 | fun checkDecl G (d, _, loc) = |
640 | case d of |
641 | DExternType name => bindType G name |
add6f172 |
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 |
4264c8ef |
652 | hasTyp (e, t, to) |
add6f172 |
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 |
e680130a |
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 |
4264c8ef |
673 | hasTyp (e, t, tInit) |
e680130a |
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 | |
64014a03 |
682 | end |