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1 | (* HCoop Domtool (http://hcoop.sourceforge.net/) |
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2 | * Copyright (c) 2006-2007, Adam Chlipala |
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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. |
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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 | val externFlag = ref false |
28 | fun allowExterns () = externFlag := true |
29 | fun disallowExterns () = externFlag := false |
30 | |
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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 | |
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50 | |
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51 | fun predImplies (p1All as (p1, _), p2All as (p2, _)) = |
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52 | case (p1, p2) of |
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53 | (_, CAnd (p1, p2)) => predImplies (p1All, p1) andalso predImplies (p1All, p2) |
54 | | (CAnd (p1, p2), _) => predImplies (p1, p2All) orelse predImplies (p2, p2All) |
55 | |
56 | | (_, CPrefix (CRoot, _)) => true |
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57 | | (CNot (CPrefix (CRoot, _), _), _) => true |
58 | |
59 | | (CRoot, CRoot) => true |
60 | |
61 | | (CConst s1, CConst s2) => s1 = s2 |
62 | |
63 | | (CPrefix p1, CPrefix p2) => predImplies (p1, p2) |
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64 | | (_, CPrefix p2) => predImplies (p1All, p2) |
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65 | |
66 | | (CNot p1, CNot p2) => predImplies (p2, p1) |
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67 | | (CRoot, CNot (CConst _, _)) => true |
68 | | (CConst s1, CNot (CConst s2, _)) => s1 <> s2 |
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69 | |
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70 | | _ => false |
71 | |
72 | fun predSimpl (pAll as (p, loc)) = |
73 | case p of |
74 | CRoot => pAll |
75 | | CConst _ => pAll |
76 | | CPrefix p => (CPrefix (predSimpl p), loc) |
77 | | CNot p => (CNot (predSimpl p), loc) |
78 | | CAnd (p1, p2) => |
79 | let |
80 | val p1' = predSimpl p1 |
81 | val p2' = predSimpl p2 |
82 | in |
83 | case p1' of |
84 | (CAnd (c1, c2), _) => predSimpl (CAnd (c1, (CAnd (c2, p2'), loc)), loc) |
85 | | _ => if predImplies (p2', p1') then |
86 | p2' |
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87 | else if predImplies (p1', p2') then |
88 | p1' |
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89 | else |
90 | (CAnd (p1', p2'), loc) |
91 | end |
92 | |
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93 | fun subPred (p1, p2) = |
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94 | if predImplies (p1, p2) then |
95 | () |
96 | else |
97 | raise (Unify (UnifyPred (p1, p2))) |
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98 | |
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99 | fun subRecord f (r1, r2) = |
100 | SM.appi (fn (k, v2) => |
101 | case SM.find (r1, k) of |
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102 | NONE => raise Describe.UnequalDomains |
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103 | | SOME v1 => f (v1, v2)) r2 |
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104 | |
105 | fun occurs u (t, _) = |
106 | case t of |
107 | TBase _ => false |
108 | | TList t => occurs u t |
109 | | TArrow (d, r) => occurs u d orelse occurs u r |
110 | | TAction (_, d, r) => |
111 | List.exists (occurs u) (SM.listItems d) |
112 | orelse List.exists (occurs u) (SM.listItems r) |
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113 | | TNested (_, t) => occurs u t |
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114 | | TError => false |
115 | | TUnif (_, ref (SOME t)) => occurs u t |
116 | | TUnif (_, u') => u = u' |
117 | |
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118 | fun subTyp (t1All as (t1, _), t2All as (t2, _)) = |
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119 | case (t1, t2) of |
120 | (TBase s1, TBase s2) => |
121 | if s1 = s2 then |
122 | () |
123 | else |
124 | raise Unify (UnifyTyp (t1All, t2All)) |
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125 | | (TList t1, TList t2) => subTyp (t1, t2) |
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126 | | (TArrow (d1, r1), TArrow (d2, r2)) => |
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127 | (subTyp (d2, d1); |
128 | subTyp (r1, r2)) |
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129 | |
130 | | (TAction (p1, d1, r1), TAction (p2, d2, r2)) => |
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131 | ((subPred (p2, p1); |
132 | subRecord subTyp (d2, d1); |
133 | subRecord subTyp (r1, r2); |
134 | subRecord subTyp (r2, r1)) |
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135 | handle UnequalDomains => raise Unify (UnifyTyp (t1All, t2All))) |
136 | |
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137 | | (TNested (d1, r1), TNested (d2, r2)) => |
138 | (subPred (d2, d1); |
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139 | subTyp (r1, r2)) |
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140 | |
141 | | (TUnif (_, ref (SOME t1)), _) => subTyp (t1, t2All) |
142 | | (_, TUnif (_, ref (SOME t2))) => subTyp (t1All, t2) |
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143 | |
144 | | (TUnif (_, r1), TUnif (_, r2)) => |
145 | if r1 = r2 then |
146 | () |
147 | else |
148 | r1 := SOME t2All |
149 | |
150 | | (TUnif (name, r), _) => |
151 | if occurs r t2All then |
152 | raise (Unify (UnifyOccurs (name, t2All))) |
153 | else |
154 | r := SOME t2All |
155 | |
156 | | (_, TUnif (name, r)) => |
157 | if occurs r t1All then |
158 | raise (Unify (UnifyOccurs (name, t1All))) |
159 | else |
160 | r := SOME t1All |
161 | |
162 | | (TError, _) => () |
163 | | (_, TError) => () |
164 | |
165 | | _ => raise Unify (UnifyTyp (t1All, t2All)) |
166 | |
167 | fun isError t = |
168 | case t of |
169 | (TError, _) => true |
170 | | _ => false |
171 | |
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172 | fun whnorm (tAll as (t, loc)) = |
173 | case t of |
174 | TUnif (_, ref (SOME tAll)) => whnorm tAll |
175 | | _ => tAll |
176 | |
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177 | fun baseCondition t = |
178 | case whnorm t of |
179 | (TBase name, _) => typeRule name |
180 | | (TList t, _) => |
181 | (case baseCondition t of |
182 | NONE => NONE |
183 | | SOME f => SOME (fn (EList ls, _) => List.all f ls |
184 | | _ => false)) |
185 | | _ => NONE |
186 | |
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187 | fun simplifyKindOf e = |
188 | case e of |
189 | (EApp ((EVar s, _), e'), _) => |
190 | (case Env.function s of |
191 | NONE => e |
192 | | SOME f => |
193 | case f [e'] of |
194 | NONE => e |
195 | | SOME e => e) |
196 | | _ => e |
197 | |
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198 | fun hasTyp (e, t1, t2) = |
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199 | if (case baseCondition t2 of |
200 | NONE => false |
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201 | | SOME rule => rule (simplifyKindOf e)) then |
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202 | () |
203 | else |
204 | subTyp (t1, t2) |
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205 | |
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206 | fun checkPred G (p, loc) = |
207 | let |
208 | val err = ErrorMsg.error (SOME loc) |
209 | in |
210 | case p of |
211 | CRoot => () |
212 | | CConst s => |
213 | if lookupContext G s then |
214 | () |
215 | else |
216 | err ("Unbound context " ^ s) |
217 | | CPrefix p => checkPred G p |
218 | | CNot p => checkPred G p |
219 | | CAnd (p1, p2) => (checkPred G p1; checkPred G p2) |
220 | end |
221 | |
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222 | fun checkTyp G (tAll as (t, loc)) = |
223 | let |
224 | val err = ErrorMsg.error (SOME loc) |
225 | in |
226 | case t of |
227 | TBase name => |
228 | if lookupType G name then |
229 | tAll |
230 | else |
231 | (err ("Unbound type name " ^ name); |
232 | (TError, loc)) |
233 | | TList t => (TList (checkTyp G t), loc) |
234 | | TArrow (d, r) => (TArrow (checkTyp G d, checkTyp G r), loc) |
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235 | | TAction (p, d, r) => (checkPred G p; |
236 | (TAction (p, SM.map (checkTyp G) d, |
237 | SM.map (checkTyp G) r), loc)) |
238 | | TNested (p, t) => (checkPred G p; |
239 | (TNested (p, checkTyp G t), loc)) |
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240 | | TError => raise Fail "TError in parser-generated type" |
241 | | TUnif _ => raise Fail "TUnif in parser-generated type" |
242 | end |
243 | |
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244 | fun envVarSetFrom v (e, _) = |
245 | case e of |
246 | ESet (v', e) => |
247 | if v = v' then |
248 | SOME e |
249 | else |
250 | NONE |
251 | | EGet (_, _, e) => envVarSetFrom v e |
252 | | ESeq es => foldr (fn (e, found) => |
253 | case found of |
254 | SOME _ => found |
255 | | NONE => envVarSetFrom v e) |
256 | NONE es |
257 | | ELocal (_, e) => envVarSetFrom v e |
258 | |
259 | | _ => NONE |
260 | |
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261 | fun checkExp G (eAll as (e, loc)) = |
262 | let |
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263 | val dte = Describe.describe_type_error loc |
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264 | in |
265 | case e of |
266 | EInt _ => (TBase "int", loc) |
267 | | EString _ => (TBase "string", loc) |
268 | | EList es => |
269 | let |
270 | val t = (newUnif (), loc) |
271 | in |
272 | foldl (fn (e', ret) => |
273 | let |
274 | val t' = checkExp G e' |
275 | in |
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276 | (hasTyp (eAll, t', t); |
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277 | if isError t' then |
278 | (TList (TError, loc), loc) |
279 | else |
280 | ret) |
281 | handle Unify ue => |
282 | (dte (WrongType ("List element", |
283 | e', |
284 | t', |
285 | t, |
286 | SOME ue)); |
287 | (TError, loc)) |
288 | end) (TList t, loc) es |
289 | end |
290 | |
291 | | ELam (x, to, e) => |
292 | let |
293 | val t = |
294 | case to of |
295 | NONE => (newUnif (), loc) |
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296 | | SOME t => checkTyp G t |
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297 | |
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298 | val G' = bindVal G (x, t, NONE) |
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299 | val t' = checkExp G' e |
300 | in |
301 | (TArrow (t, t'), loc) |
302 | end |
303 | | EVar x => |
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304 | (case lookupVal G x of |
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305 | NONE => (dte (UnboundVariable x); |
306 | (TError, loc)) |
307 | | SOME t => t) |
308 | | EApp (func, arg) => |
309 | let |
310 | val dom = (newUnif (), loc) |
311 | val ran = (newUnif (), loc) |
312 | |
313 | val tf = checkExp G func |
314 | val ta = checkExp G arg |
315 | in |
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316 | (hasTyp (func, tf, (TArrow (dom, ran), loc)); |
317 | hasTyp (arg, ta, dom) |
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318 | handle Unify ue => |
319 | dte (WrongType ("Function argument", |
320 | arg, |
321 | ta, |
322 | dom, |
323 | SOME ue)); |
324 | ran) |
325 | handle Unify ue => |
326 | (dte (WrongForm ("Function to be applied", |
327 | "function", |
328 | func, |
329 | tf, |
330 | SOME ue)); |
331 | (TError, loc)) |
332 | end |
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333 | |
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334 | | EALam (x, p, e) => |
335 | let |
336 | val p' = checkPred G p |
337 | |
338 | val G' = bindVal G (x, (TAction (p, SM.empty, SM.empty), loc), NONE) |
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339 | val t' = whnorm (checkExp G' e) |
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340 | in |
341 | case t' of |
342 | (TAction _, _) => (TNested (p, t'), loc) |
343 | | _ => (dte (WrongForm ("Body of nested configuration 'fn'", |
344 | "action", |
345 | e, |
346 | t', |
347 | NONE)); |
348 | (TError, loc)) |
349 | end |
350 | |
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351 | | ESet (evar, e) => |
352 | let |
353 | val t = checkExp G e |
354 | in |
355 | (TAction ((CPrefix (CRoot, loc), loc), |
356 | SM.empty, |
357 | SM.insert (SM.empty, evar, t)), |
358 | loc) |
359 | end |
360 | | EGet (x, evar, rest) => |
361 | let |
362 | val xt = (newUnif (), loc) |
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363 | val G' = bindVal G (x, xt, NONE) |
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364 | |
365 | val rt = whnorm (checkExp G' rest) |
366 | in |
367 | case rt of |
368 | (TAction (p, d, r), _) => |
369 | (case SM.find (d, evar) of |
370 | NONE => (TAction (p, SM.insert (d, evar, xt), r), loc) |
371 | | SOME xt' => |
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372 | (subTyp (xt', xt) |
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373 | handle Unify ue => |
374 | dte (WrongType ("Retrieved environment variable", |
375 | (EVar x, loc), |
376 | xt', |
377 | xt, |
378 | SOME ue)); |
379 | rt)) |
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380 | | (TError, _) => rt |
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381 | | _ => (dte (WrongForm ("Body of environment variable read", |
382 | "action", |
383 | rest, |
384 | rt, |
385 | NONE)); |
386 | (TError, loc)) |
387 | end |
388 | |
389 | | ESeq [] => raise Fail "Empty ESeq" |
390 | | ESeq [e1] => checkExp G e1 |
391 | | ESeq (e1 :: rest) => |
392 | let |
393 | val e2 = (ESeq rest, loc) |
394 | |
395 | val t1 = whnorm (checkExp G e1) |
396 | val t2 = whnorm (checkExp G e2) |
397 | in |
398 | case t1 of |
399 | (TAction (p1, d1, r1), _) => |
400 | (case t2 of |
401 | (TAction (p2, d2, r2), _) => |
402 | let |
403 | val p' = predSimpl (CAnd (p1, p2), loc) |
404 | |
405 | val d' = SM.foldli (fn (name, t, d') => |
406 | case SM.find (r1, name) of |
407 | NONE => |
408 | (case SM.find (d', name) of |
409 | NONE => SM.insert (d', name, t) |
410 | | SOME t' => |
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411 | ((case envVarSetFrom name e1 of |
412 | NONE => subTyp (t, t') |
413 | | SOME e => hasTyp (e, t, t')) |
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414 | handle Unify ue => |
415 | dte (WrongType ("Shared environment variable", |
416 | (EVar name, loc), |
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417 | t', |
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418 | t, |
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419 | SOME ue)); |
420 | d')) |
421 | | SOME t' => |
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422 | ((case envVarSetFrom name e1 of |
423 | NONE => subTyp (t, t') |
424 | | SOME e => hasTyp (e, t, t')) |
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425 | handle Unify ue => |
426 | dte (WrongType ("Shared environment variable", |
427 | (EVar name, loc), |
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428 | t', |
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429 | t, |
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430 | SOME ue)); |
431 | d')) |
432 | d1 d2 |
433 | |
434 | val r' = SM.foldli (fn (name, t, r') => SM.insert (r', name, t)) |
435 | r1 r2 |
436 | in |
437 | (TAction (p', d', r'), loc) |
438 | end |
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439 | | (TError, _) => t2 |
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440 | | _ => (dte (WrongForm ("Action to be sequenced", |
441 | "action", |
442 | e2, |
443 | t2, |
444 | NONE)); |
445 | (TError, loc))) |
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446 | | (TError, _) => t1 |
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447 | | _ => (dte (WrongForm ("Action to be sequenced", |
448 | "action", |
449 | e1, |
450 | t1, |
451 | NONE)); |
452 | (TError, loc)) |
453 | end |
454 | |
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455 | | ELocal (e1, e2) => |
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456 | let |
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457 | val t1 = whnorm (checkExp G e1) |
458 | val t2 = whnorm (checkExp G e2) |
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459 | in |
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460 | case t1 of |
461 | (TAction (p1, d1, r1), _) => |
462 | (case t2 of |
463 | (TAction (p2, d2, r2), _) => |
464 | let |
465 | val p' = predSimpl (CAnd (p1, p2), loc) |
466 | |
467 | val d' = SM.foldli (fn (name, t, d') => |
468 | case SM.find (r1, name) of |
469 | NONE => |
470 | (case SM.find (d', name) of |
471 | NONE => SM.insert (d', name, t) |
472 | | SOME t' => |
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473 | ((case envVarSetFrom name e1 of |
474 | NONE => subTyp (t', t) |
475 | | SOME e => hasTyp (e, t', t)) |
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476 | handle Unify ue => |
477 | dte (WrongType ("Shared environment variable", |
478 | (EVar name, loc), |
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479 | t', |
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480 | t, |
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481 | SOME ue)); |
482 | d')) |
483 | | SOME t' => |
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484 | ((case envVarSetFrom name e1 of |
485 | NONE => subTyp (t', t) |
486 | | SOME e => hasTyp (e, t', t)) |
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487 | handle Unify ue => |
488 | dte (WrongType ("Shared environment variable", |
489 | (EVar name, loc), |
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490 | t', |
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491 | t, |
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492 | SOME ue)); |
493 | d')) |
494 | d1 d2 |
495 | in |
496 | (TAction (p', d', r2), loc) |
497 | end |
498 | | (TError, _) => t2 |
499 | | _ => (dte (WrongForm ("Action to be sequenced", |
500 | "action", |
501 | e2, |
502 | t2, |
503 | NONE)); |
504 | (TError, loc))) |
505 | | (TError, _) => t1 |
506 | | _ => (dte (WrongForm ("Action to be sequenced", |
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507 | "action", |
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508 | e1, |
509 | t1, |
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510 | NONE)); |
511 | (TError, loc)) |
512 | end |
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513 | |
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514 | |
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515 | | EWith (e1, e2) => |
516 | let |
517 | val t1 = whnorm (checkExp G e1) |
518 | val t2 = whnorm (checkExp G e2) |
519 | in |
520 | case t1 of |
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521 | (TNested (pd, (TAction (pr, d1, r1), _)), _) => |
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522 | (case t2 of |
523 | (TAction (p, d, r), _) => |
524 | if predImplies (pd, p) then |
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525 | let |
526 | val combineRecs = |
527 | SM.unionWithi (fn (name, t1, t2) => |
528 | (subTyp (t1, t2) |
529 | handle Unify ue => |
530 | dte (WrongType ("Environment variable", |
531 | (EVar name, loc), |
532 | t1, |
533 | t2, |
534 | SOME ue)); |
535 | t2)) |
536 | in |
537 | (TAction (pr, combineRecs (d, d1), |
538 | combineRecs (r, r1)), loc) |
539 | end |
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540 | else |
541 | (dte (WrongPred ("nested action", |
542 | pd, |
543 | p)); |
544 | (TError, loc)) |
545 | | (TError, _) => t2 |
546 | | _ => |
547 | (dte (WrongForm ("Body of nested action", |
548 | "action", |
549 | e2, |
550 | t2, |
551 | NONE)); |
552 | (TError, loc))) |
553 | | (TError, _) => t1 |
554 | | _ => |
555 | (dte (WrongForm ("Container of nested action", |
556 | "action", |
557 | e1, |
558 | t1, |
559 | NONE)); |
560 | (TError, loc)) |
561 | end |
562 | |
563 | | ESkip => (TAction ((CPrefix (CRoot, loc), loc), |
564 | SM.empty, SM.empty), loc) |
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565 | end |
566 | |
567 | exception Ununif |
568 | |
569 | fun ununif (tAll as (t, loc)) = |
570 | case t of |
571 | TBase _ => tAll |
572 | | TList t => (TList (ununif t), loc) |
573 | | TArrow (d, r) => (TArrow (ununif d, ununif r), loc) |
574 | | TAction (p, d, r) => (TAction (p, SM.map ununif d, SM.map ununif r), loc) |
575 | | TUnif (_, ref (SOME t)) => ununif t |
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576 | | TNested _ => tAll |
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577 | | TError => tAll |
578 | |
579 | | TUnif (_, ref NONE) => raise Ununif |
580 | |
581 | fun hasError (t, _) = |
582 | case t of |
583 | TBase _ => false |
584 | | TList t => hasError t |
585 | | TArrow (d, r) => hasError d orelse hasError r |
586 | | TAction (p, d, r) => List.exists hasError (SM.listItems d) |
587 | orelse List.exists hasError (SM.listItems r) |
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588 | | TNested _ => false |
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589 | | TError => false |
590 | | TUnif (_, ref (SOME t)) => hasError t |
591 | | TUnif (_, ref NONE) => false |
592 | |
593 | |
594 | fun checkUnit G (eAll as (_, loc)) = |
595 | let |
596 | val _ = resetUnif () |
597 | val t = checkExp G eAll |
598 | in |
599 | if hasError t then |
600 | t |
601 | else |
602 | ununif t |
603 | handle Ununif => |
604 | (ErrorMsg.error (SOME loc) "Unification variables remain in type:"; |
a4c53cb2 |
605 | output (p_typ t); |
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606 | t) |
607 | end |
608 | |
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609 | fun checkDecl G (d, _, loc) = |
610 | case d of |
89c9edc9 |
611 | DExternType name => |
612 | if !externFlag then |
613 | bindType G name |
614 | else |
615 | (ErrorMsg.error (SOME loc) "'extern type' not allowed in untrusted code"; |
616 | G) |
617 | | DExternVal (name, t) => |
618 | if !externFlag then |
619 | bindVal G (name, checkTyp G t, NONE) |
620 | else |
621 | (ErrorMsg.error (SOME loc) "'extern val' not allowed in untrusted code"; |
622 | G) |
add6f172 |
623 | | DVal (name, to, e) => |
624 | let |
625 | val to = |
626 | case to of |
627 | NONE => (newUnif (), loc) |
628 | | SOME to => checkTyp G to |
629 | |
630 | val t = checkExp G e |
631 | in |
4264c8ef |
632 | hasTyp (e, t, to) |
add6f172 |
633 | handle Unify ue => |
12ad758b |
634 | Describe.describe_type_error loc |
635 | (WrongType ("Bound value", |
636 | e, |
637 | t, |
638 | to, |
639 | SOME ue)); |
add6f172 |
640 | bindVal G (name, to, SOME e) |
641 | end |
51c32b45 |
642 | | DContext name => bindContext G name |
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643 | |
51c32b45 |
644 | fun checkFile G tInit (_, ds, eo) = |
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645 | let |
646 | val G' = foldl (fn (d, G) => checkDecl G d) G ds |
647 | in |
648 | case eo of |
649 | NONE => () |
650 | | SOME (e as (_, loc)) => |
651 | let |
652 | val t = checkExp G' e |
653 | in |
4264c8ef |
654 | hasTyp (e, t, tInit) |
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655 | handle Unify ue => |
656 | (ErrorMsg.error (SOME loc) "Bad type for final expression of source file."; |
657 | preface ("Actual:", p_typ t); |
658 | preface ("Needed:", p_typ tInit)) |
659 | end; |
660 | G' |
661 | end |
662 | |
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663 | end |