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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. |
ae3a5b8c |
17 | *) |
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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 | |
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115 | fun describe_unification_error t ue = |
116 | case ue of |
117 | UnifyPred (p1, p2) => |
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118 | (print "Reason: Incompatible contexts.\n"; |
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119 | preface ("Have:", p_pred p1); |
120 | preface ("Need:", p_pred p2)) |
121 | | UnifyTyp (t1, t2) => |
122 | if eqTy (t, t1) then |
123 | () |
124 | else |
125 | (print "Reason: Incompatible types.\n"; |
126 | preface ("Have:", p_typ t1); |
127 | preface ("Need:", p_typ t2)) |
128 | | UnifyOccurs (name, t') => |
129 | if eqTy (t, t') then |
130 | () |
131 | else |
132 | (print "Reason: Occurs check failed for "; |
133 | print name; |
134 | print " in:\n"; |
135 | printd (p_typ t)) |
136 | |
137 | fun describe_type_error loc te = |
138 | case te of |
139 | WrongType (place, e, t1, t2, ueo) => |
140 | (ErrorMsg.error (SOME loc) (place ^ " has wrong type."); |
141 | preface (" Expression:", p_exp e); |
142 | preface ("Actual type:", p_typ t1); |
143 | preface ("Needed type:", p_typ t2); |
144 | Option.app (describe_unification_error t1) ueo) |
145 | | WrongForm (place, form, e, t, ueo) => |
146 | (ErrorMsg.error (SOME loc) (place ^ " has a non-" ^ form ^ " type."); |
147 | preface ("Expression:", p_exp e); |
148 | preface (" Type:", p_typ t); |
149 | Option.app (describe_unification_error t) ueo) |
150 | | UnboundVariable name => |
151 | ErrorMsg.error (SOME loc) ("Unbound variable " ^ name ^ ".\n") |
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152 | | WrongPred (place, p1, p2) => |
153 | (ErrorMsg.error (SOME loc) ("Context incompatibility for " ^ place ^ "."); |
154 | preface ("Have:", p_pred p1); |
155 | preface ("Need:", p_pred p2)) |
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156 | |
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157 | fun predImplies (p1All as (p1, _), p2All as (p2, _)) = |
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158 | case (p1, p2) of |
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159 | (_, CAnd (p1, p2)) => predImplies (p1All, p1) andalso predImplies (p1All, p2) |
160 | | (CAnd (p1, p2), _) => predImplies (p1, p2All) orelse predImplies (p2, p2All) |
161 | |
162 | | (_, CPrefix (CRoot, _)) => true |
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163 | | (CNot (CPrefix (CRoot, _), _), _) => true |
164 | |
165 | | (CRoot, CRoot) => true |
166 | |
167 | | (CConst s1, CConst s2) => s1 = s2 |
168 | |
169 | | (CPrefix p1, CPrefix p2) => predImplies (p1, p2) |
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170 | | (_, CPrefix p2) => predImplies (p1All, p2) |
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171 | |
172 | | (CNot p1, CNot p2) => predImplies (p2, p1) |
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173 | |
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174 | | _ => false |
175 | |
176 | fun predSimpl (pAll as (p, loc)) = |
177 | case p of |
178 | CRoot => pAll |
179 | | CConst _ => pAll |
180 | | CPrefix p => (CPrefix (predSimpl p), loc) |
181 | | CNot p => (CNot (predSimpl p), loc) |
182 | | CAnd (p1, p2) => |
183 | let |
184 | val p1' = predSimpl p1 |
185 | val p2' = predSimpl p2 |
186 | in |
187 | case p1' of |
188 | (CAnd (c1, c2), _) => predSimpl (CAnd (c1, (CAnd (c2, p2'), loc)), loc) |
189 | | _ => if predImplies (p2', p1') then |
190 | p2' |
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191 | else if predImplies (p1', p2') then |
192 | p1' |
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193 | else |
194 | (CAnd (p1', p2'), loc) |
195 | end |
196 | |
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197 | fun subPred (p1, p2) = |
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198 | if predImplies (p1, p2) then |
199 | () |
200 | else |
201 | raise (Unify (UnifyPred (p1, p2))) |
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202 | |
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203 | fun subRecord f (r1, r2) = |
204 | SM.appi (fn (k, v2) => |
205 | case SM.find (r1, k) of |
206 | NONE => raise UnequalDomains |
207 | | SOME v1 => f (v1, v2)) r2 |
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208 | |
209 | fun occurs u (t, _) = |
210 | case t of |
211 | TBase _ => false |
212 | | TList t => occurs u t |
213 | | TArrow (d, r) => occurs u d orelse occurs u r |
214 | | TAction (_, d, r) => |
215 | List.exists (occurs u) (SM.listItems d) |
216 | orelse List.exists (occurs u) (SM.listItems r) |
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217 | | TNested (_, t) => occurs u t |
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218 | | TError => false |
219 | | TUnif (_, ref (SOME t)) => occurs u t |
220 | | TUnif (_, u') => u = u' |
221 | |
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222 | fun subTyp (t1All as (t1, _), t2All as (t2, _)) = |
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223 | case (t1, t2) of |
224 | (TBase s1, TBase s2) => |
225 | if s1 = s2 then |
226 | () |
227 | else |
228 | raise Unify (UnifyTyp (t1All, t2All)) |
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229 | | (TList t1, TList t2) => subTyp (t1, t2) |
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230 | | (TArrow (d1, r1), TArrow (d2, r2)) => |
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231 | (subTyp (d2, d1); |
232 | subTyp (r1, r2)) |
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233 | |
234 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => |
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235 | ((subPred (p2, p1); |
236 | subRecord subTyp (d2, d1); |
237 | subRecord subTyp (r1, r2); |
238 | subRecord subTyp (r2, r1)) |
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239 | handle UnequalDomains => raise Unify (UnifyTyp (t1All, t2All))) |
240 | |
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241 | | (TNested (d1, r1), TNested (d2, r2)) => |
242 | (subPred (d2, d1); |
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243 | subTyp (r1, r2)) |
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244 | |
245 | | (TUnif (_, ref (SOME t1)), _) => subTyp (t1, t2All) |
246 | | (_, TUnif (_, ref (SOME t2))) => subTyp (t1All, t2) |
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247 | |
248 | | (TUnif (_, r1), TUnif (_, r2)) => |
249 | if r1 = r2 then |
250 | () |
251 | else |
252 | r1 := SOME t2All |
253 | |
254 | | (TUnif (name, r), _) => |
255 | if occurs r t2All then |
256 | raise (Unify (UnifyOccurs (name, t2All))) |
257 | else |
258 | r := SOME t2All |
259 | |
260 | | (_, TUnif (name, r)) => |
261 | if occurs r t1All then |
262 | raise (Unify (UnifyOccurs (name, t1All))) |
263 | else |
264 | r := SOME t1All |
265 | |
266 | | (TError, _) => () |
267 | | (_, TError) => () |
268 | |
269 | | _ => raise Unify (UnifyTyp (t1All, t2All)) |
270 | |
271 | fun isError t = |
272 | case t of |
273 | (TError, _) => true |
274 | | _ => false |
275 | |
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276 | fun whnorm (tAll as (t, loc)) = |
277 | case t of |
278 | TUnif (_, ref (SOME tAll)) => whnorm tAll |
279 | | _ => tAll |
280 | |
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281 | fun baseCondition t = |
282 | case whnorm t of |
283 | (TBase name, _) => typeRule name |
284 | | (TList t, _) => |
285 | (case baseCondition t of |
286 | NONE => NONE |
287 | | SOME f => SOME (fn (EList ls, _) => List.all f ls |
288 | | _ => false)) |
289 | | _ => NONE |
290 | |
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291 | fun hasTyp (e, t1, t2) = |
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292 | if (case baseCondition t2 of |
293 | NONE => false |
294 | | SOME rule => rule e) then |
295 | () |
296 | else |
297 | subTyp (t1, t2) |
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298 | |
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299 | fun checkPred G (p, loc) = |
300 | let |
301 | val err = ErrorMsg.error (SOME loc) |
302 | in |
303 | case p of |
304 | CRoot => () |
305 | | CConst s => |
306 | if lookupContext G s then |
307 | () |
308 | else |
309 | err ("Unbound context " ^ s) |
310 | | CPrefix p => checkPred G p |
311 | | CNot p => checkPred G p |
312 | | CAnd (p1, p2) => (checkPred G p1; checkPred G p2) |
313 | end |
314 | |
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315 | fun checkTyp G (tAll as (t, loc)) = |
316 | let |
317 | val err = ErrorMsg.error (SOME loc) |
318 | in |
319 | case t of |
320 | TBase name => |
321 | if lookupType G name then |
322 | tAll |
323 | else |
324 | (err ("Unbound type name " ^ name); |
325 | (TError, loc)) |
326 | | TList t => (TList (checkTyp G t), loc) |
327 | | TArrow (d, r) => (TArrow (checkTyp G d, checkTyp G r), loc) |
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328 | | TAction (p, d, r) => (checkPred G p; |
329 | (TAction (p, SM.map (checkTyp G) d, |
330 | SM.map (checkTyp G) r), loc)) |
331 | | TNested (p, t) => (checkPred G p; |
332 | (TNested (p, checkTyp G t), loc)) |
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333 | | TError => raise Fail "TError in parser-generated type" |
334 | | TUnif _ => raise Fail "TUnif in parser-generated type" |
335 | end |
336 | |
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337 | fun checkExp G (eAll as (e, loc)) = |
338 | let |
339 | val dte = describe_type_error loc |
340 | in |
341 | case e of |
342 | EInt _ => (TBase "int", loc) |
343 | | EString _ => (TBase "string", loc) |
344 | | EList es => |
345 | let |
346 | val t = (newUnif (), loc) |
347 | in |
348 | foldl (fn (e', ret) => |
349 | let |
350 | val t' = checkExp G e' |
351 | in |
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352 | (hasTyp (eAll, t', t); |
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353 | if isError t' then |
354 | (TList (TError, loc), loc) |
355 | else |
356 | ret) |
357 | handle Unify ue => |
358 | (dte (WrongType ("List element", |
359 | e', |
360 | t', |
361 | t, |
362 | SOME ue)); |
363 | (TError, loc)) |
364 | end) (TList t, loc) es |
365 | end |
366 | |
367 | | ELam (x, to, e) => |
368 | let |
369 | val t = |
370 | case to of |
371 | NONE => (newUnif (), loc) |
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372 | | SOME t => checkTyp G t |
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373 | |
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374 | val G' = bindVal G (x, t, NONE) |
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375 | val t' = checkExp G' e |
376 | in |
377 | (TArrow (t, t'), loc) |
378 | end |
379 | | EVar x => |
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380 | (case lookupVal G x of |
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381 | NONE => (dte (UnboundVariable x); |
382 | (TError, loc)) |
383 | | SOME t => t) |
384 | | EApp (func, arg) => |
385 | let |
386 | val dom = (newUnif (), loc) |
387 | val ran = (newUnif (), loc) |
388 | |
389 | val tf = checkExp G func |
390 | val ta = checkExp G arg |
391 | in |
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392 | (hasTyp (func, tf, (TArrow (dom, ran), loc)); |
393 | hasTyp (arg, ta, dom) |
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394 | handle Unify ue => |
395 | dte (WrongType ("Function argument", |
396 | arg, |
397 | ta, |
398 | dom, |
399 | SOME ue)); |
400 | ran) |
401 | handle Unify ue => |
402 | (dte (WrongForm ("Function to be applied", |
403 | "function", |
404 | func, |
405 | tf, |
406 | SOME ue)); |
407 | (TError, loc)) |
408 | end |
dbd7a7d2 |
409 | |
410 | | ESet (evar, e) => |
411 | let |
412 | val t = checkExp G e |
413 | in |
414 | (TAction ((CPrefix (CRoot, loc), loc), |
415 | SM.empty, |
416 | SM.insert (SM.empty, evar, t)), |
417 | loc) |
418 | end |
419 | | EGet (x, evar, rest) => |
420 | let |
421 | val xt = (newUnif (), loc) |
add6f172 |
422 | val G' = bindVal G (x, xt, NONE) |
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423 | |
424 | val rt = whnorm (checkExp G' rest) |
425 | in |
426 | case rt of |
427 | (TAction (p, d, r), _) => |
428 | (case SM.find (d, evar) of |
429 | NONE => (TAction (p, SM.insert (d, evar, xt), r), loc) |
430 | | SOME xt' => |
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431 | (subTyp (xt', xt) |
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432 | handle Unify ue => |
433 | dte (WrongType ("Retrieved environment variable", |
434 | (EVar x, loc), |
435 | xt', |
436 | xt, |
437 | SOME ue)); |
438 | rt)) |
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439 | | (TError, _) => rt |
dbd7a7d2 |
440 | | _ => (dte (WrongForm ("Body of environment variable read", |
441 | "action", |
442 | rest, |
443 | rt, |
444 | NONE)); |
445 | (TError, loc)) |
446 | end |
447 | |
448 | | ESeq [] => raise Fail "Empty ESeq" |
449 | | ESeq [e1] => checkExp G e1 |
450 | | ESeq (e1 :: rest) => |
451 | let |
452 | val e2 = (ESeq rest, loc) |
453 | |
454 | val t1 = whnorm (checkExp G e1) |
455 | val t2 = whnorm (checkExp G e2) |
456 | in |
457 | case t1 of |
458 | (TAction (p1, d1, r1), _) => |
459 | (case t2 of |
460 | (TAction (p2, d2, r2), _) => |
461 | let |
462 | val p' = predSimpl (CAnd (p1, p2), loc) |
463 | |
464 | val d' = SM.foldli (fn (name, t, d') => |
465 | case SM.find (r1, name) of |
466 | NONE => |
467 | (case SM.find (d', name) of |
468 | NONE => SM.insert (d', name, t) |
469 | | SOME t' => |
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470 | (subTyp (t, t') |
dbd7a7d2 |
471 | handle Unify ue => |
472 | dte (WrongType ("Shared environment variable", |
473 | (EVar name, loc), |
474 | t, |
475 | t', |
476 | SOME ue)); |
477 | d')) |
478 | | SOME t' => |
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479 | (subTyp (t, t') |
dbd7a7d2 |
480 | handle Unify ue => |
481 | dte (WrongType ("Shared environment variable", |
482 | (EVar name, loc), |
483 | t, |
484 | t', |
485 | SOME ue)); |
486 | d')) |
487 | d1 d2 |
488 | |
489 | val r' = SM.foldli (fn (name, t, r') => SM.insert (r', name, t)) |
490 | r1 r2 |
491 | in |
492 | (TAction (p', d', r'), loc) |
493 | end |
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494 | | (TError, _) => t2 |
dbd7a7d2 |
495 | | _ => (dte (WrongForm ("Action to be sequenced", |
496 | "action", |
497 | e2, |
498 | t2, |
499 | NONE)); |
500 | (TError, loc))) |
e680130a |
501 | | (TError, _) => t1 |
dbd7a7d2 |
502 | | _ => (dte (WrongForm ("Action to be sequenced", |
503 | "action", |
504 | e1, |
505 | t1, |
506 | NONE)); |
507 | (TError, loc)) |
508 | end |
509 | |
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510 | | ELocal (e1, e2) => |
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511 | let |
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512 | val t1 = whnorm (checkExp G e1) |
513 | val t2 = whnorm (checkExp G e2) |
dbd7a7d2 |
514 | in |
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515 | case t1 of |
516 | (TAction (p1, d1, r1), _) => |
517 | (case t2 of |
518 | (TAction (p2, d2, r2), _) => |
519 | let |
520 | val p' = predSimpl (CAnd (p1, p2), loc) |
521 | |
522 | val d' = SM.foldli (fn (name, t, d') => |
523 | case SM.find (r1, name) of |
524 | NONE => |
525 | (case SM.find (d', name) of |
526 | NONE => SM.insert (d', name, t) |
527 | | SOME t' => |
528 | (subTyp (t, t') |
529 | handle Unify ue => |
530 | dte (WrongType ("Shared environment variable", |
531 | (EVar name, loc), |
532 | t, |
533 | t', |
534 | SOME ue)); |
535 | d')) |
536 | | SOME t' => |
537 | (subTyp (t, t') |
538 | handle Unify ue => |
539 | dte (WrongType ("Shared environment variable", |
540 | (EVar name, loc), |
541 | t, |
542 | t', |
543 | SOME ue)); |
544 | d')) |
545 | d1 d2 |
546 | in |
547 | (TAction (p', d', r2), loc) |
548 | end |
549 | | (TError, _) => t2 |
550 | | _ => (dte (WrongForm ("Action to be sequenced", |
551 | "action", |
552 | e2, |
553 | t2, |
554 | NONE)); |
555 | (TError, loc))) |
556 | | (TError, _) => t1 |
557 | | _ => (dte (WrongForm ("Action to be sequenced", |
dbd7a7d2 |
558 | "action", |
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559 | e1, |
560 | t1, |
dbd7a7d2 |
561 | NONE)); |
562 | (TError, loc)) |
563 | end |
e680130a |
564 | |
2dc33fa4 |
565 | |
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566 | | EWith (e1, e2) => |
567 | let |
568 | val t1 = whnorm (checkExp G e1) |
569 | val t2 = whnorm (checkExp G e2) |
570 | in |
571 | case t1 of |
2dc33fa4 |
572 | (TNested (pd, (TAction (pr, d1, r1), _)), _) => |
e680130a |
573 | (case t2 of |
574 | (TAction (p, d, r), _) => |
575 | if predImplies (pd, p) then |
2dc33fa4 |
576 | let |
577 | val combineRecs = |
578 | SM.unionWithi (fn (name, t1, t2) => |
579 | (subTyp (t1, t2) |
580 | handle Unify ue => |
581 | dte (WrongType ("Environment variable", |
582 | (EVar name, loc), |
583 | t1, |
584 | t2, |
585 | SOME ue)); |
586 | t2)) |
587 | in |
588 | (TAction (pr, combineRecs (d, d1), |
589 | combineRecs (r, r1)), loc) |
590 | end |
e680130a |
591 | else |
592 | (dte (WrongPred ("nested action", |
593 | pd, |
594 | p)); |
595 | (TError, loc)) |
596 | | (TError, _) => t2 |
597 | | _ => |
598 | (dte (WrongForm ("Body of nested action", |
599 | "action", |
600 | e2, |
601 | t2, |
602 | NONE)); |
603 | (TError, loc))) |
604 | | (TError, _) => t1 |
605 | | _ => |
606 | (dte (WrongForm ("Container of nested action", |
607 | "action", |
608 | e1, |
609 | t1, |
610 | NONE)); |
611 | (TError, loc)) |
612 | end |
613 | |
614 | | ESkip => (TAction ((CPrefix (CRoot, loc), loc), |
615 | SM.empty, SM.empty), loc) |
64014a03 |
616 | end |
617 | |
618 | exception Ununif |
619 | |
620 | fun ununif (tAll as (t, loc)) = |
621 | case t of |
622 | TBase _ => tAll |
623 | | TList t => (TList (ununif t), loc) |
624 | | TArrow (d, r) => (TArrow (ununif d, ununif r), loc) |
625 | | TAction (p, d, r) => (TAction (p, SM.map ununif d, SM.map ununif r), loc) |
626 | | TUnif (_, ref (SOME t)) => ununif t |
e680130a |
627 | | TNested _ => tAll |
64014a03 |
628 | | TError => tAll |
629 | |
630 | | TUnif (_, ref NONE) => raise Ununif |
631 | |
632 | fun hasError (t, _) = |
633 | case t of |
634 | TBase _ => false |
635 | | TList t => hasError t |
636 | | TArrow (d, r) => hasError d orelse hasError r |
637 | | TAction (p, d, r) => List.exists hasError (SM.listItems d) |
638 | orelse List.exists hasError (SM.listItems r) |
e680130a |
639 | | TNested _ => false |
64014a03 |
640 | | TError => false |
641 | | TUnif (_, ref (SOME t)) => hasError t |
642 | | TUnif (_, ref NONE) => false |
643 | |
644 | |
645 | fun checkUnit G (eAll as (_, loc)) = |
646 | let |
647 | val _ = resetUnif () |
648 | val t = checkExp G eAll |
649 | in |
650 | if hasError t then |
651 | t |
652 | else |
653 | ununif t |
654 | handle Ununif => |
655 | (ErrorMsg.error (SOME loc) "Unification variables remain in type:"; |
656 | printd (p_typ t); |
657 | t) |
658 | end |
659 | |
e680130a |
660 | fun checkDecl G (d, _, loc) = |
661 | case d of |
662 | DExternType name => bindType G name |
add6f172 |
663 | | DExternVal (name, t) => bindVal G (name, checkTyp G t, NONE) |
664 | | DVal (name, to, e) => |
665 | let |
666 | val to = |
667 | case to of |
668 | NONE => (newUnif (), loc) |
669 | | SOME to => checkTyp G to |
670 | |
671 | val t = checkExp G e |
672 | in |
4264c8ef |
673 | hasTyp (e, t, to) |
add6f172 |
674 | handle Unify ue => |
675 | describe_type_error loc |
676 | (WrongType ("Bound value", |
677 | e, |
678 | t, |
679 | to, |
680 | SOME ue)); |
681 | bindVal G (name, to, SOME e) |
682 | end |
51c32b45 |
683 | | DContext name => bindContext G name |
e680130a |
684 | |
51c32b45 |
685 | fun checkFile G tInit (_, ds, eo) = |
e680130a |
686 | let |
687 | val G' = foldl (fn (d, G) => checkDecl G d) G ds |
688 | in |
689 | case eo of |
690 | NONE => () |
691 | | SOME (e as (_, loc)) => |
692 | let |
693 | val t = checkExp G' e |
694 | in |
4264c8ef |
695 | hasTyp (e, t, tInit) |
e680130a |
696 | handle Unify ue => |
697 | (ErrorMsg.error (SOME loc) "Bad type for final expression of source file."; |
698 | preface ("Actual:", p_typ t); |
699 | preface ("Needed:", p_typ tInit)) |
700 | end; |
701 | G' |
702 | end |
703 | |
64014a03 |
704 | end |