typer.ml 33 KB
Newer Older
1
(* TODO:
2
 - rewrite type-checking of operators to propagate constraint
3
4
 - optimize computation of pattern free variables
 - check whether it is worth using recursive hash-consing internally
5
6
*)

7

8
9
10
11
12
13
let warning loc msg =
  Format.fprintf !Location.warning_ppf "Warning %a:@\n%a%s@\n" 
    Location.print_loc loc
    Location.html_hilight loc
    msg

14
15
(* I. Transform the abstract syntax of types and patterns into
      the internal form *)
16
17
18

open Location
open Ast
19
open Ident
20

21
module S = struct type t = string let compare = compare end
22
module StringSet = Set.Make(S)
23
module TypeEnv = Map.Make(S)
24
module Env = Map.Make(Id)
25

26

27
28
exception NonExhaustive of Types.descr
exception Constraint of Types.descr * Types.descr * string
29
exception ShouldHave of Types.descr * string
30
exception WrongLabel of Types.descr * label
31
exception UnboundId of string
32
33

let raise_loc loc exn = raise (Location (loc,exn))
34
35


36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
(* Eliminate Recursion, propagate Sequence Capture Variables *)

let rec seq_vars accu = function
  | Epsilon | Elem _ -> accu
  | Seq (r1,r2) | Alt (r1,r2) -> seq_vars (seq_vars accu r1) r2
  | Star r | WeakStar r -> seq_vars accu r
  | SeqCapture (v,r) -> seq_vars (IdSet.add v accu) r

type derecurs_slot = {
  ploc : Location.loc;
  pid  : int;
  mutable ploop : bool;
  mutable pdescr : derecurs option
} and derecurs =
  | PAlias of derecurs_slot
  | PType of Types.descr
  | POr of derecurs * derecurs
  | PAnd of derecurs * derecurs
  | PDiff of derecurs * derecurs
  | PTimes of derecurs * derecurs
  | PXml of derecurs * derecurs
  | PArrow of derecurs * derecurs
  | POptional of derecurs
  | PRecord of bool * derecurs label_map
  | PCapture of id
  | PConstant of id * Types.const
  | PRegexp of derecurs_regexp * derecurs
and derecurs_regexp =
  | PEpsilon
  | PElem of derecurs
  | PSeq of derecurs_regexp * derecurs_regexp
  | PAlt of derecurs_regexp * derecurs_regexp
  | PStar of derecurs_regexp
  | PWeakStar of derecurs_regexp

let rec hash_derecurs = function
  | PAlias s -> s.pid
  | PType t -> 1 + 17 * (Types.hash_descr t)
  | POr (p1,p2) -> 2 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PAnd (p1,p2) -> 3 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PDiff (p1,p2) -> 4 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PTimes (p1,p2) -> 5 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PXml (p1,p2) -> 6 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PArrow (p1,p2) -> 7 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | POptional p -> 8 + 17 * (hash_derecurs p)
  | PRecord (o,r) -> (if o then 9 else 10) + 17 * (LabelMap.hash hash_derecurs r)
  | PCapture x -> 11 + 17 * (Id.hash x)
  | PConstant (x,c) -> 12 + 17 * (Id.hash x) + 257 * (Types.hash_const c)
  | PRegexp (p,q) -> 13 + 17 * (hash_derecurs_regexp p) + 257 * (hash_derecurs q)
and hash_derecurs_regexp = function
  | PEpsilon -> 1
  | PElem p -> 2 + 17 * (hash_derecurs p)
  | PSeq (p1,p2) -> 3 + 17 * (hash_derecurs_regexp p1) + 257 * (hash_derecurs_regexp p2)
  | PAlt (p1,p2) -> 4 + 17 * (hash_derecurs_regexp p1) + 257 * (hash_derecurs_regexp p2)
  | PStar p -> 5 + 17 * (hash_derecurs_regexp p)
  | PWeakStar p -> 6 + 17 * (hash_derecurs_regexp p)

let rec equal_derecurs p1 p2 = (p1 == p2) || match p1,p2 with
  | PAlias s1, PAlias s2 -> s1 == s2
  | PType t1, PType t2 -> Types.equal_descr t1 t2
  | POr (p1,q1), POr (p2,q2)
  | PAnd (p1,q1), PAnd (p2,q2)
  | PDiff (p1,q1), PDiff (p2,q2)
  | PTimes (p1,q1), PTimes (p2,q2)
  | PXml (p1,q1), PXml (p2,q2)
  | PArrow (p1,q1), PArrow (p2,q2) -> (equal_derecurs p1 p2) && (equal_derecurs q1 q2)
  | POptional p1, POptional p2 -> equal_derecurs p1 p2
  | PRecord (o1,r1), PRecord (o2,r2) -> (o1 == o2) && (LabelMap.equal equal_derecurs r1 r2)
  | PCapture x1, PCapture x2 -> Id.equal x1 x2
  | PConstant (x1,c1), PConstant (x2,c2) -> (Id.equal x1 x2) && (Types.equal_const c1 c2)
  | PRegexp (p1,q1), PRegexp (p2,q2) -> (equal_derecurs_regexp p1 p2) && (equal_derecurs q1 q2)
  | _ -> false
and equal_derecurs_regexp r1 r2 = match r1,r2 with
  | PEpsilon, PEpsilon -> true
  | PElem p1, PElem p2 -> equal_derecurs p1 p2
  | PSeq (p1,q1), PSeq (p2,q2) 
  | PAlt (p1,q1), PAlt (p2,q2) -> (equal_derecurs_regexp p1 p2) && (equal_derecurs_regexp q1 q2)
  | PStar p1, PStar p2
  | PWeakStar p1, PWeakStar p2 -> equal_derecurs_regexp p1 p2
  | _ -> false
116

117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
module DerecursTable = Hashtbl.Make(
  struct 
    type t = derecurs 
    let hash = hash_derecurs
    let equal = equal_derecurs
  end
)

module RE = Hashtbl.Make(
  struct 
    type t = derecurs_regexp * derecurs 
    let hash (p,q) = (hash_derecurs_regexp p) + 17 * (hash_derecurs q)
    let equal (p1,q1) (p2,q2) = (equal_derecurs_regexp p1 p2) && (equal_derecurs q1 q2)
  end
)
132

133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
  
let counter = State.ref "Typer.counter - derecurs" 0
let mk_slot loc = 
  incr counter; 
  { ploop = false; ploc = loc; pid = !counter; pdescr = None }
  
let rec derecurs env p = match p.descr with
  | PatVar v ->
      (try PAlias (TypeEnv.find v env)
       with Not_found -> raise_loc_generic p.loc ("Undefined type/pattern " ^ v))
  | Recurs (p,b) -> derecurs (derecurs_def env b) p
  | Internal t -> PType t
  | Or (p1,p2) -> POr (derecurs env p1, derecurs env p2)
  | And (p1,p2) -> PAnd (derecurs env p1, derecurs env p2)
  | Diff (p1,p2) -> PDiff (derecurs env p1, derecurs env p2)
  | Prod (p1,p2) -> PTimes (derecurs env p1, derecurs env p2)
  | XmlT (p1,p2) -> PXml (derecurs env p1, derecurs env p2)
  | Arrow (p1,p2) -> PArrow (derecurs env p1, derecurs env p2)
  | Optional p -> POptional (derecurs env p)
  | Record (o,r) -> PRecord (o, LabelMap.map (derecurs env) r)
  | Capture x -> PCapture x
  | Constant (x,c) -> PConstant (x,c)
  | Regexp (r,q) -> 
      let constant_nil t v = PAnd (t, PConstant (v, Types.Atom Sequence.nil_atom)) in
      let vars = seq_vars IdSet.empty r in
      let q = IdSet.fold constant_nil (derecurs env q) vars in
      let r = derecurs_regexp (fun p -> p) env r in
      PRegexp (r, q)
and derecurs_regexp vars env = function
  | Epsilon -> PEpsilon
  | Elem p -> PElem (vars (derecurs env p))
  | Seq (p1,p2) -> PSeq (derecurs_regexp vars env p1, derecurs_regexp vars env p2)
  | Alt (p1,p2) -> PAlt (derecurs_regexp vars env p1, derecurs_regexp vars env p2)
  | Star p -> PStar (derecurs_regexp vars env p)
  | WeakStar p -> PStar (derecurs_regexp vars env p)
  | SeqCapture (x,p) -> derecurs_regexp (fun p -> PAnd (vars p, PCapture x)) env p


and derecurs_def env b =
  let b = List.map (fun (v,p) -> (v,p,mk_slot p.loc)) b in
  let env = List.fold_left (fun env (v,p,s) -> TypeEnv.add v s env) env b in
  List.iter (fun (v,p,s) -> s.pdescr <- Some (derecurs env p)) b;
  env
176

177
(* Stratification and recursive hash-consing *)
178
179
180
181
182
183
184
185
186

type descr = 
  | IType of Types.descr
  | IOr of descr * descr
  | IAnd of descr * descr
  | IDiff of descr * descr
  | ITimes of slot * slot
  | IXml of slot * slot
  | IArrow of slot * slot
187
  | IOptional of descr
188
189
190
191
192
193
194
195
  | IRecord of bool * slot label_map
  | ICapture of id
  | IConstant of id * Types.const
and slot = {
  mutable fv : fv option;
  mutable hash : int option;
  mutable rank1: int; mutable rank2: int;
  mutable gen1 : int; mutable gen2: int;
196
  mutable d    : descr option
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
}
    
let descr s = 
  match s.d with
    | Some d -> d
    | None -> assert false
	
let gen = ref 0
let rank = ref 0
	     
let rec hash_descr = function
  | IType x -> Types.hash_descr x
  | IOr (d1,d2) -> 1 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IAnd (d1,d2) -> 2 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IDiff (d1,d2) -> 3 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IOptional d -> 4 + 17 * (hash_descr d)
  | ITimes (s1,s2) -> 5 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IXml (s1,s2) -> 6 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IArrow (s1,s2) -> 7 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IRecord (o,r) -> (if o then 8 else 9) + 17 * (LabelMap.hash hash_slot r)
  | ICapture x -> 10 + 17 * (Id.hash x)
  | IConstant (x,y) -> 11 + 17 * (Id.hash x) + 257 * (Types.hash_const y)
and hash_slot s =
  if s.gen1 = !gen then 13 * s.rank1
  else (
    incr rank;
    s.rank1 <- !rank; s.gen1 <- !gen;
    hash_descr (descr s)
  )
    
let rec equal_descr d1 d2 = 
  match (d1,d2) with
  | IType x1, IType x2 -> Types.equal_descr x1 x2
  | IOr (x1,y1), IOr (x2,y2) 
  | IAnd (x1,y1), IAnd (x2,y2) 
  | IDiff (x1,y1), IDiff (x2,y2) -> (equal_descr x1 x2) && (equal_descr y1 y2)
  | IOptional x1, IOptional x2 -> equal_descr x1 x2
  | ITimes (x1,y1), ITimes (x2,y2) 
  | IXml (x1,y1), IXml (x2,y2) 
  | IArrow (x1,y1), IArrow (x2,y2) -> (equal_slot x1 x2) && (equal_slot y1 y2)
  | IRecord (o1,r1), IRecord (o2,r2) -> (o1 = o2) && (LabelMap.equal equal_slot r1 r2)
  | ICapture x1, ICapture x2 -> Id.equal x1 x2
  | IConstant (x1,y1), IConstant (x2,y2) -> (Id.equal x1 x2) && (Types.equal_const y1 y2)
  | _ -> false
and equal_slot s1 s2 =
  ((s1.gen1 = !gen) && (s2.gen2 = !gen) && (s1.rank1 = s2.rank2))
  ||
  ((s1.gen1 <> !gen) && (s2.gen2 <> !gen) && (
     incr rank;
     s1.rank1 <- !rank; s1.gen1 <- !gen;
     s2.rank2 <- !rank; s2.gen2 <- !gen;
     equal_descr (descr s1) (descr s2)
   ))
  
module Arg = struct
  type t = slot
      
  let hash s =
    match s.hash with
      | Some h -> h
      | None ->
	  incr gen; rank := 0; 
	  let h = hash_slot s in
	  s.hash <- Some h;
	  h
	    
263
264
265
266
267
268
  let equal s1 s2 = 
    (s1 == s2) || 
    (incr gen; rank := 0; 
     let e = equal_slot s1 s2 in
(*     if e then Printf.eprintf "Equal\n"; *)
     e)
269
end
270
271
272
273
274
275
276
277
278
module SlotTable = Hashtbl.Make(Arg)
  
let rec fv_slot s =
  match s.fv with
    | Some x -> x
    | None ->
	if s.gen1 = !gen then IdSet.empty 
	else (s.gen1 <- !gen; fv_descr (descr s))
and fv_descr = function
279
  | IType _ -> IdSet.empty
280
281
282
283
284
285
286
287
288
  | IOr (d1,d2)
  | IAnd (d1,d2)  
  | IDiff (d1,d2) -> IdSet.cup (fv_descr d1) (fv_descr d2)
  | IOptional d -> fv_descr d
  | ITimes (s1,s2)  
  | IXml (s1,s2)  
  | IArrow (s1,s2) -> IdSet.cup (fv_slot s1) (fv_slot s2)
  | IRecord (o,r) -> List.fold_left IdSet.cup IdSet.empty (LabelMap.map_to_list fv_slot r)
  | ICapture x | IConstant (x,_) -> IdSet.singleton x
289

290
291
292
293
294
295
296
297
298
      
let compute_fv s =
  match s.fv with
    | Some x -> ()
    | None ->
	incr gen;
	let x = fv_slot s in
	s.fv <- Some x
	  
299
300

let todo_fv = ref []
301
302
303
304
305
306
307
308
	  
let mk () =   
  let s = 
    { d = None;
      fv = None;
      hash = None;
      rank1 = 0; rank2 = 0;
      gen1 = 0; gen2 = 0 } in
309
  todo_fv := s :: !todo_fv;
310
  s
311
312
313
314

let flush_fv () =
  List.iter compute_fv !todo_fv;
  todo_fv := []
315
    
316
317
318
let compile_slot_hash = DerecursTable.create 67
let compile_hash = DerecursTable.create 67

319
let defs = ref []
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367

let rec compile p =
  try DerecursTable.find compile_hash p
  with Not_found ->
    let c = real_compile p in
    DerecursTable.replace compile_hash p c;
    c
and real_compile = function
  | PAlias v ->
      if v.ploop then
	raise_loc_generic v.ploc ("Unguarded recursion on type/pattern");
      v.ploop <- true;
      let r = match v.pdescr with Some x -> compile x | _ -> assert false in
      v.ploop <- false;
      r
  | PType t -> IType t
  | POr (t1,t2) -> IOr (compile t1, compile t2)
  | PAnd (t1,t2) -> IAnd (compile t1, compile t2)
  | PDiff (t1,t2) -> IDiff (compile t1, compile t2)
  | PTimes (t1,t2) -> ITimes (compile_slot t1, compile_slot t2)
  | PXml (t1,t2) -> IXml (compile_slot t1, compile_slot t2)
  | PArrow (t1,t2) -> IArrow (compile_slot t1, compile_slot t2)
  | POptional t -> IOptional (compile t)
  | PRecord (o,r) ->  IRecord (o, LabelMap.map compile_slot r)
  | PConstant (x,v) -> IConstant (x,v)
  | PCapture x -> ICapture x
  | PRegexp (r,q) -> compile_regexp r q
and compile_regexp r q =
  let memo = RE.create 17 in
  let rec aux accu r q =
    if RE.mem memo (r,q) then accu
    else (
      RE.add memo (r,q) ();
      match r with
	| PEpsilon -> (match q with PRegexp (r,q) -> aux accu r q | _ -> (compile q) :: accu)
	| PElem p -> ITimes (compile_slot p, compile_slot q) :: accu
	| PSeq (r1,r2) -> aux accu r1 (PRegexp (r2,q))
	| PAlt (r1,r2) -> aux (aux accu r1 q) r2 q
	| PStar r1 -> aux (aux accu r1 (PRegexp (r,q))) PEpsilon q
	| PWeakStar r1 -> aux (aux accu PEpsilon q) r1 (PRegexp (r,q))
    )
  in
  let accu = aux [] r q in
  match accu with
    | [] -> assert false
    | p::l -> List.fold_left (fun acc p -> IOr (p,acc)) p l
and compile_slot p =
  try DerecursTable.find compile_slot_hash p
368
369
  with Not_found ->
    let s = mk () in
370
371
    defs := (s,p) :: !defs;
    DerecursTable.add compile_slot_hash p s;
372
    s
373

374
375
376
377
      
let rec flush_defs () = 
  match !defs with
    | [] -> ()
378
    | (s,p)::t -> defs := t; s.d <- Some (compile p); flush_defs ()
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
	
let typ_nodes = SlotTable.create 67
let pat_nodes = SlotTable.create 67
		  
let rec typ = function
  | IType t -> t
  | IOr (s1,s2) -> Types.cup (typ s1) (typ s2)
  | IAnd (s1,s2) ->  Types.cap (typ s1) (typ s2)
  | IDiff (s1,s2) -> Types.diff (typ s1) (typ s2)
  | ITimes (s1,s2) -> Types.times (typ_node s1) (typ_node s2)
  | IXml (s1,s2) -> Types.xml (typ_node s1) (typ_node s2)
  | IArrow (s1,s2) -> Types.arrow (typ_node s1) (typ_node s2)
  | IOptional s -> Types.Record.or_absent (typ s)
  | IRecord (o,r) -> Types.record' (o, LabelMap.map typ_node r)
  | ICapture x | IConstant (x,_) -> assert false
      
and typ_node s : Types.node =
  try SlotTable.find typ_nodes s
  with Not_found ->
    let x = Types.make () in
    SlotTable.add typ_nodes s x;
    Types.define x (typ (descr s));
    x
      
let rec pat d : Patterns.descr =
  if IdSet.is_empty (fv_descr d)
  then Patterns.constr (typ d)
  else pat_aux d
    
    
and pat_aux = function
  | IOr (s1,s2) -> Patterns.cup (pat s1) (pat s2)
  | IAnd (s1,s2) -> Patterns.cap (pat s1) (pat s2)
  | IDiff (s1,s2) when IdSet.is_empty (fv_descr s2) ->
      let s2 = Types.neg (typ s2) in
      Patterns.cap (pat s1) (Patterns.constr s2)
  | IDiff _ ->
      raise (Patterns.Error "Difference not allowed in patterns")
  | ITimes (s1,s2) -> Patterns.times (pat_node s1) (pat_node s2)
  | IXml (s1,s2) -> Patterns.xml (pat_node s1) (pat_node s2)
  | IOptional _ -> 
      raise (Patterns.Error "Optional field not allowed in record patterns")
  | IRecord (o,r) ->
      let pats = ref [] in
      let aux l s = 
	if IdSet.is_empty (fv_slot s) then typ_node s
	else
	  ( pats := Patterns.record l (pat_node s) :: !pats;
	    Types.any_node )
      in
      let constr = Types.record' (o,LabelMap.mapi aux r) in
      List.fold_left Patterns.cap (Patterns.constr constr) !pats
	(* TODO: can avoid constr when o=true, and all fields have fv *)
  | ICapture x -> Patterns.capture x
  | IConstant (x,c) -> Patterns.constant x c
  | IArrow _ ->
      raise (Patterns.Error "Arrow not allowed in patterns")
  | IType _ -> assert false
      
and pat_node s : Patterns.node =
  try SlotTable.find pat_nodes s
  with Not_found ->
    let x = Patterns.make (fv_slot s) in
    SlotTable.add pat_nodes s x;
    Patterns.define x (pat (descr s));
    x
      
let glb = State.ref "Typer.glb_env" TypeEnv.empty
	    
	    
let register_global_types b =
450
451
452
453
454
455
456
  List.iter 
    (fun (v,p) ->
       if TypeEnv.mem v !glb
       then raise_loc_generic p.loc ("Multiple definition for type " ^ v)
    ) b;
  glb := derecurs_def !glb b;
  let b = List.map (fun (v,p) -> (v,p,compile (derecurs !glb p))) b in
457
458
  flush_defs ();
  flush_fv ();
459
460
461
462
463
464
  List.iter 
    (fun (v,p,s) -> 
       if not (IdSet.is_empty (fv_descr s)) then
	 raise_loc_generic p.loc "Capture variables are not allowed in types";
       let t = typ s in
       if (p.loc <> noloc) && (Types.is_empty t) then
465
	 warning p.loc ("This definition yields an empty type for " ^ v);
466
       Types.Print.register_global v t) b
467
468
469

let dump_global_types ppf =
  TypeEnv.iter (fun v _ -> Format.fprintf ppf " %s" v) !glb
470
471
472
    
    
let typ p =
473
  let s = compile_slot (derecurs !glb p) in
474
475
476
477
478
479
  flush_defs ();
  flush_fv ();
  if IdSet.is_empty (fv_slot s) then typ_node s
  else raise_loc_generic p.loc "Capture variables are not allowed in types"
    
let pat p = 
480
  let s = compile_slot (derecurs !glb p) in
481
482
483
484
485
  flush_defs ();
  flush_fv ();
  try pat_node s
  with Patterns.Error e -> raise_loc_generic p.loc e
    | Location (loc,exn) when loc = noloc -> raise (Location (p.loc, exn))
486
487


488
489
(* II. Build skeleton *)

490
module Fv = IdSet
491

492
493
let all_branches = ref []

494
495
496
(* IDEA: introduce a node Loc in the AST to override nolocs
   in sub-expressions *)
   
497
let exp loc fv e =
498
499
  fv,
  { Typed.exp_loc = loc;
500
    Typed.exp_typ = Types.empty;
501
    Typed.exp_descr = e;
502
  }
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581


let rec expr loc = function
  | LocatedExpr (loc,e) -> expr loc e
  | Forget (e,t) ->
      let (fv,e) = expr loc e and t = typ t in
      exp loc fv (Typed.Forget (e,t))
  | Var s -> 
      exp loc (Fv.singleton s) (Typed.Var s)
  | Apply (e1,e2) -> 
      let (fv1,e1) = expr loc e1 and (fv2,e2) = expr loc e2 in
      exp loc (Fv.cup fv1 fv2) (Typed.Apply (e1,e2))
  | Abstraction a ->
      let iface = List.map (fun (t1,t2) -> (typ t1, typ t2)) 
		    a.fun_iface in
      let t = List.fold_left 
		(fun accu (t1,t2) -> Types.cap accu (Types.arrow t1 t2)) 
		Types.any iface in
      let iface = List.map 
		    (fun (t1,t2) -> (Types.descr t1, Types.descr t2)) 
		    iface in
      let (fv0,body) = branches a.fun_body in
      let fv = match a.fun_name with
	| None -> fv0
	| Some f -> Fv.remove f fv0 in
      let e = Typed.Abstraction 
		{ Typed.fun_name = a.fun_name;
		  Typed.fun_iface = iface;
		  Typed.fun_body = body;
		  Typed.fun_typ = t;
		  Typed.fun_fv = fv
		} in
      exp loc fv e
  | Cst c -> 
      exp loc Fv.empty (Typed.Cst c)
  | Pair (e1,e2) ->
      let (fv1,e1) = expr loc e1 and (fv2,e2) = expr loc e2 in
      exp loc (Fv.cup fv1 fv2) (Typed.Pair (e1,e2))
  | Xml (e1,e2) ->
      let (fv1,e1) = expr loc e1 and (fv2,e2) = expr loc e2 in
      exp loc (Fv.cup fv1 fv2) (Typed.Xml (e1,e2))
  | Dot (e,l) ->
      let (fv,e) = expr loc e in
      exp loc fv (Typed.Dot (e,l))
  | RemoveField (e,l) ->
      let (fv,e) = expr loc e in
      exp loc fv (Typed.RemoveField (e,l))
  | RecordLitt r -> 
      let fv = ref Fv.empty in
      let r = LabelMap.map 
		(fun e -> 
		   let (fv2,e) = expr loc e 
		   in fv := Fv.cup !fv fv2; e)
		r in
      exp loc !fv (Typed.RecordLitt r)
  | Op (op,le) ->
      let (fvs,ltes) = List.split (List.map (expr loc) le) in
      let fv = List.fold_left Fv.cup Fv.empty fvs in
      exp loc fv (Typed.Op (op,ltes))
  | Match (e,b) -> 
      let (fv1,e) = expr loc e
      and (fv2,b) = branches b in
      exp loc (Fv.cup fv1 fv2) (Typed.Match (e, b))
  | Map (e,b) ->
      let (fv1,e) = expr loc e
      and (fv2,b) = branches b in
      exp loc (Fv.cup fv1 fv2) (Typed.Map (e, b))
  | Ttree (e,b) ->
      let b = b @ [ mknoloc (Internal Types.any), MatchFail ] in
      let (fv1,e) = expr loc e
      and (fv2,b) = branches b in
      exp loc (Fv.cup fv1 fv2) (Typed.Ttree (e, b))
  | MatchFail -> 
      exp loc (Fv.empty) Typed.MatchFail
  | Try (e,b) ->
      let (fv1,e) = expr loc e
      and (fv2,b) = branches b in
      exp loc (Fv.cup fv1 fv2) (Typed.Try (e, b))

582
	      
583
  and branches b = 
584
    let fv = ref Fv.empty in
585
    let accept = ref Types.empty in
586
    let branch (p,e) = 
587
588
      let (fv2,e) = expr noloc e in
      let br_loc = merge_loc p.loc e.Typed.exp_loc in
589
590
591
592
593
594
595
596
597
598
599
600
601
      let p = pat p in
      let fv2 = Fv.diff fv2 (Patterns.fv p) in
      fv := Fv.cup !fv fv2;
      accept := Types.cup !accept (Types.descr (Patterns.accept p));
      let br = 
	{ 
	  Typed.br_loc = br_loc;
	  Typed.br_used = br_loc = noloc;
	  Typed.br_pat = p;
	  Typed.br_body = e } in
      all_branches := br :: !all_branches;
      br in
    let b = List.map branch b in
602
603
604
605
    (!fv, 
     { 
       Typed.br_typ = Types.empty; 
       Typed.br_branches = b; 
606
607
       Typed.br_accept = !accept;
       Typed.br_compiled = None;
608
609
     } 
    )
610

611
612
let expr = expr noloc

613
614
615
let let_decl p e =
  let (_,e) = expr e in
  { Typed.let_pat = pat p;
616
617
618
619
620
    Typed.let_body = e;
    Typed.let_compiled = None }

(* III. Type-checks *)

621
622
623
let int_cup_record = Types.cup Types.Int.any Types.Record.any


624
type env = Types.descr Env.t
625

626
627
let match_fail = ref Types.empty

628
629
open Typed

630
631
632
633

let check loc t s msg =
  if not (Types.subtype t s) then raise_loc loc (Constraint (t, s, msg))

634
let rec type_check env e constr precise = 
635
(*  Format.fprintf Format.std_formatter "constr=%a precise=%b@\n"
636
637
    Types.Print.print_descr constr precise; 
*)
638
  let d = type_check' e.exp_loc env e.exp_descr constr precise in
639
640
641
  e.exp_typ <- Types.cup e.exp_typ d;
  d

642
and type_check' loc env e constr precise = match e with
643
644
645
646
  | Forget (e,t) ->
      let t = Types.descr t in
      ignore (type_check env e t false);
      t
647
  | Abstraction a ->
648
649
650
651
652
653
654
      let t =
	try Types.Arrow.check_strenghten a.fun_typ constr 
	with Not_found -> 
	  raise_loc loc 
	  (ShouldHave
	     (constr, "but the interface of the abstraction is not compatible"))
      in
655
656
657
      let env = match a.fun_name with
	| None -> env
	| Some f -> Env.add f a.fun_typ env in
658
659
      List.iter 
	(fun (t1,t2) ->
660
	   ignore (type_check_branches loc env t1 a.fun_body t2 false)
661
662
	) a.fun_iface;
      t
663

664
665
  | Match (e,b) ->
      let t = type_check env e b.br_accept true in
666
      type_check_branches loc env t b constr precise
667
668
669

  | Try (e,b) ->
      let te = type_check env e constr precise in
670
      let tb = type_check_branches loc env Types.any b constr precise in
671
      Types.cup te tb
672

673
674
675
676
  | Pair (e1,e2) ->
      type_check_pair loc env e1 e2 constr precise
  | Xml (e1,e2) ->
      type_check_pair ~kind:`XML loc env e1 e2 constr precise
677

678
  | RecordLitt r ->
679
(* try to get rid of precise = true for values of fields *)
680
      if not (Types.Record.has_record constr) then
681
682
	raise_loc loc (ShouldHave (constr,"but it is a record."));
      let (rconstr,res) = 
683
	List.fold_left
684
	  (fun (rconstr,res) (l,e) ->
685
686
687
	     (* could compute (split l e) once... *)
	     let pi = Types.Record.project_opt rconstr l in
	     if Types.is_empty pi then 
688
689
690
	       raise_loc loc 
		 (ShouldHave (constr,(Printf.sprintf 
					"Field %s is not allowed here."
691
					(LabelPool.value l)
692
693
694
				     )
			     ));
	     let t = type_check env e pi true in
695
696
	     let rconstr = Types.Record.condition rconstr l t in
	     let res = if precise then (l,Types.cons t) :: res else res in
697
	     (rconstr,res)
698
	  ) (constr, []) (LabelMap.get r)
699
      in
700
701
702
703
704
705
      if not (Types.Record.has_empty_record rconstr) then
	raise_loc loc 
	  (ShouldHave (constr,"More field should be present"));
      if precise then
	Types.record' (false, LabelMap.from_list (fun _ _ -> assert false) res)
      else constr
706
707
708
709
710
  | Map (e,b) ->
      let t = type_check env e (Sequence.star b.br_accept) true in

      let constr' = Sequence.approx (Types.cap Sequence.any constr) in
      let exact = Types.subtype (Sequence.star constr') constr in
711
712
713
714
715
716
717
      (* Note: 
	 - could be more precise by integrating the decomposition
	 of constr inside Sequence.map.
      *)
      let res = 
	Sequence.map 
	  (fun t -> 
718
	     type_check_branches loc env t b constr' (precise || (not exact)))
719
720
721
	  t in
      if not exact then check loc res constr "";
      if precise then res else constr
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
  | Op ("@", [e1;e2]) ->
      let constr' = Sequence.star 
		      (Sequence.approx (Types.cap Sequence.any constr)) in
      let exact = Types.subtype constr' constr in
      if exact then
	let t1 = type_check env e1 constr' precise
	and t2 = type_check env e2 constr' precise in
	if precise then Sequence.concat t1 t2 else constr
      else
	(* Note:
	   the knownledge of t1 may makes it useless to
	   check t2 with 'precise' ... *)
	let t1 = type_check env e1 constr' true
	and t2 = type_check env e2 constr' true in
	let res = Sequence.concat t1 t2 in
	check loc res constr "";
	if precise then res else constr
739
  | Apply (e1,e2) ->
740
(*
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
      let constr' = Sequence.star 
		      (Sequence.approx (Types.cap Sequence.any constr)) in
      let t1 = type_check env e1 (Types.cup Types.Arrow.any constr') true in
      let t1_fun = Types.Arrow.get t1 in

      let has_fun = not (Types.Arrow.is_empty t1_fun)
      and has_seq = not (Types.subtype t1 Types.Arrow.any) in

      let constr' =
	Types.cap 
	  (if has_fun then Types.Arrow.domain t1_fun else Types.any)
	  (if has_seq then constr' else Types.any)
      in
      let need_arg = has_fun && Types.Arrow.need_arg t1_fun in
      let precise  = need_arg || has_seq in
      let t2 = type_check env e2 constr' precise in
      let res = Types.cup 
		  (if has_fun then 
		     if need_arg then Types.Arrow.apply t1_fun t2
		     else Types.Arrow.apply_noarg t1_fun
		   else Types.empty)
		  (if has_seq then Sequence.concat t1 t2
		   else Types.empty)
      in
      check loc res constr "";
      res
767
*)
768
769
770
      let t1 = type_check env e1 Types.Arrow.any true in
      let t1 = Types.Arrow.get t1 in
      let dom = Types.Arrow.domain t1 in
771
772
773
774
775
776
777
778
779
      let res =
	if Types.Arrow.need_arg t1 then
	  let t2 = type_check env e2 dom true in
	  Types.Arrow.apply t1 t2
	else
	  (ignore (type_check env e2 dom false); Types.Arrow.apply_noarg t1)
      in
      check loc res constr "";
      res
780
781
782
783
784
785
786
787
788
789
790
791
792
  | Op ("flatten", [e]) ->
      let constr' = Sequence.star 
		      (Sequence.approx (Types.cap Sequence.any constr)) in
      let sconstr' = Sequence.star constr' in
      let exact = Types.subtype constr' constr in
      if exact then
	let t = type_check env e sconstr' precise in
	if precise then Sequence.flatten t else constr
      else
	let t = type_check env e sconstr' true in
	let res = Sequence.flatten t in
	check loc res constr "";
	if precise then res else constr
793
794
795
  | Op ("atom_of", [e]) ->
      let t = type_check env e Sequence.string false in
      Types.atom Atoms.any
796
797
798
799
800
  | _ -> 
      let t : Types.descr = compute_type' loc env e in
      check loc t constr "";
      t

801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
and type_check_pair ?(kind=`Normal) loc env e1 e2 constr precise =
  let rects = Types.Product.get ~kind constr in
  if Types.Product.is_empty rects then 
    (match kind with
      | `Normal -> raise_loc loc (ShouldHave (constr,"but it is a pair."))
      | `XML -> raise_loc loc (ShouldHave (constr,"but it is an XML element.")));
  let pi1 = Types.Product.pi1 rects in
  
  let t1 = type_check env e1 (Types.Product.pi1 rects) 
	     (precise || (Types.Product.need_second rects))in
  let rects = Types.Product.restrict_1 rects t1 in
  let t2 = type_check env e2 (Types.Product.pi2 rects) precise in
  if precise then 
    match kind with
      | `Normal -> Types.times (Types.cons t1) (Types.cons t2)
      | `XML -> Types.xml (Types.cons t1) (Types.cons t2)
  else
    constr


821
822
823
824
and compute_type env e =
  type_check env e Types.any true

and compute_type' loc env = function
825
826
  | Var s -> 
      (try Env.find s env 
827
       with Not_found -> raise_loc loc (UnboundId (Id.value s))
828
      )
829
  | Cst c -> Types.constant c
830
831
832
833
  | Dot (e,l) ->
      let t = type_check env e Types.Record.any true in
         (try (Types.Record.project t l) 
          with Not_found -> raise_loc loc (WrongLabel(t,l)))
834
835
836
  | RemoveField (e,l) ->
      let t = type_check env e Types.Record.any true in
      Types.Record.remove_field t l
837
838
839
  | Op (op, el) ->
      let args = List.map (fun e -> (e.exp_loc, compute_type env e)) el in
      type_op loc op args
840
841
842
843
844
845
846
847
848
849
850
851
  | Ttree (e,b) ->
      let t = type_check env e Sequence.any true in
      let r = 
	Sequence.map_tree 
	  (fun t -> 
	     let res = type_check_branches loc env t b Sequence.any true in
	     let resid = !match_fail in
	     match_fail := Types.empty;
	     (res,resid)
	  ) t
      in
      r
852
853
854
855
856

(* We keep these cases here to allow comparison and benchmarking ...
   Just comment the corresponding cases in type_check' to
   activate these ones.
*)
857
858
859
  | Map (e,b) ->
      let t = compute_type env e in
      Sequence.map (fun t -> type_check_branches loc env t b Types.any true) t
860
861
862
863
864
  | Pair (e1,e2) -> 
      let t1 = compute_type env e1 
      and t2 = compute_type env e2 in
      Types.times (Types.cons t1) (Types.cons t2)
  | RecordLitt r ->
865
      let r = LabelMap.map (fun e -> Types.cons (compute_type env e)) r in
866
      Types.record' (false,r)
867
  | _ -> assert false
868

869
and type_check_branches loc env targ brs constr precise =
870
  if Types.is_empty targ then Types.empty 
871
872
  else (
    brs.br_typ <- Types.cup brs.br_typ targ;
873
    branches_aux loc env targ 
874
875
      (if precise then Types.empty else constr) 
      constr precise brs.br_branches
876
  )
877
    
878
879
and branches_aux loc env targ tres constr precise = function
  | [] -> raise_loc loc (NonExhaustive targ)
880
881
882
  | { br_body = { exp_descr = MatchFail } } :: _ ->
      match_fail := Types.cup !match_fail targ;
      tres
883
884
885
886
887
888
  | b :: rem ->
      let p = b.br_pat in
      let acc = Types.descr (Patterns.accept p) in

      let targ' = Types.cap targ acc in
      if Types.is_empty targ' 
889
      then branches_aux loc env targ tres constr precise rem
890
891
892
893
894
895
      else 
	( b.br_used <- true;
	  let res = Patterns.filter targ' p in
	  let env' = List.fold_left 
		       (fun env (x,t) -> Env.add x (Types.descr t) env) 
		       env res in
896
897
	  let t = type_check env' b.br_body constr precise in
	  let tres = if precise then Types.cup t tres else tres in
898
899
	  let targ'' = Types.diff targ acc in
	  if (Types.non_empty targ'') then 
900
	    branches_aux loc env targ'' tres constr precise rem 
901
902
	  else
	    tres
903
	)
904

905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
and type_let_decl env l =
  let acc = Types.descr (Patterns.accept l.let_pat) in
  let t = type_check env l.let_body acc true in
  let res = Patterns.filter t l.let_pat in
  List.map (fun (x,t) -> (x, Types.descr t)) res

and type_rec_funs env l =
  let types = 
    List.fold_left
      (fun accu -> function  {let_body={exp_descr=Abstraction a}} as l ->
	 let t = a.fun_typ in
	 let acc = Types.descr (Patterns.accept l.let_pat) in
	 if not (Types.subtype t acc) then
	   raise_loc l.let_body.exp_loc (NonExhaustive (Types.diff t acc));
	 let res = Patterns.filter t l.let_pat in
	 List.fold_left (fun accu (x,t) -> (x, Types.descr t)::accu) accu res
	 | _ -> assert false) [] l
  in
  let env' = List.fold_left (fun env (x,t) -> Env.add x t env) env types in
  List.iter 
    (function  { let_body = { exp_descr = Abstraction a } } as l ->
       ignore (type_check env' l.let_body Types.any false)
       | _ -> assert false) l;
  types


931
932
and type_op loc op args =
  match (op,args) with
933
    | "+", [loc1,t1; loc2,t2] ->
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
	check loc1 t1 int_cup_record
	"The first argument of + must be an integer or a record";
	let int = Types.Int.get t1 in
	let int = if Intervals.is_empty int then None else Some int in
	let r = if Types.Record.has_record t1 then Some t1 else None in
	(match (int,r) with
	   | Some t1, None ->
	       if not (Types.Int.is_int t2) then
		 raise_loc loc2
		   (Constraint 
		      (t2,Types.Int.any,
		       "The second argument of + must be an integer"));
	       Types.Int.put
		 (Intervals.add t1 (Types.Int.get t2));
	   | None, Some r1 ->
	       check loc2 t2 Types.Record.any 
	       "The second argument of + must be a record";
	       Types.Record.merge r1 t2
	   | None, None ->
	       Types.empty
	   | Some t1, Some r1 ->
	       check loc2 t2 int_cup_record
	       "The second argument of + must be an integer or a record";
	       Types.cup 
		 (Types.Int.put (Intervals.add t1 (Types.Int.get t2)))
		 (Types.Record.merge r1 t2)
	)
961
962
    | "-", [loc1,t1; loc2,t2] ->
	type_int_binop Intervals.sub loc1 t1 loc2 t2
963
    | ("*" | "/" | "mod"), [loc1,t1; loc2,t2] ->
964
	type_int_binop (fun i1 i2 -> Intervals.any) loc1 t1 loc2 t2
965
    | "@", [loc1,t1; loc2,t2] ->
966
967
968
	check loc1 t1 Sequence.any
	  "The first argument of @ must be a sequence";
	Sequence.concat t1 t2
969
    | "flatten", [loc1,t1] ->
970
971
972
	check loc1 t1 Sequence.seqseq 
	  "The argument of flatten must be a sequence of sequences";
	Sequence.flatten t1
973
974
975
976
    | "load_xml", [loc1,t1] ->
	check loc1 t1 Sequence.string
	  "The argument of load_xml must be a string (filename)";
	Types.any
977
978
979
980
    | "load_file", [loc1,t1] ->
	check loc1 t1 Sequence.string
	  "The argument of load_file must be a string (filename)";
	Sequence.string
981
982
983
984
    | "load_html", [loc1,t1] ->
	check loc1 t1 Sequence.string
	  "The argument of load_html must be a string (filename)";
	Types.any
985
986
    | "raise", [loc1,t1] ->
	Types.empty
987
988
    | "print_xml", [loc1,t1] ->
	Sequence.string
989
990
    | "print", [loc1,t1] ->
	check loc1 t1 Sequence.string
991
992
993
994
995
996
997
998
	  "The argument of print must be a string";
	Sequence.nil_type
    | "dump_to_file", [loc1,t1; loc2,t2] ->
	check loc1 t1 Sequence.string
	  "The argument of dump_to_file must be a string (filename)";
	check loc2 t2 Sequence.string
	  "The argument of dump_to_file must be a string (value to dump)";
	Sequence.nil_type
999
1000
    | "int_of", [loc1,t1] ->
	check loc1 t1 Sequence.string
1001
	  "The argument of int_of must be a string";
1002
1003
1004
	if not (Types.subtype t1 Builtin.intstr) then
	  warning loc "This application of int_of may fail";
	Types.interval Intervals.any
1005
1006
    | "string_of", [loc1,t1] ->
	Sequence.string
1007
    | "=", [loc1,t1; loc2,t2] ->
1008
1009
1010
1011
1012
1013
1014
	(* could prevent comparision of functional value here... *)
	(* could also handle the case when t1 and t2 are the same 
	   singleton type *)
	if Types.is_empty (Types.cap t1 t2) then
	  Builtin.false_type
	else 
	  Builtin.bool
1015
1016
1017
    | ("<=" | "<" | ">" | ">=" ), [loc1,t1; loc2,t2] ->
	(* could prevent comparision of functional value here... *)
	Builtin.bool
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
    | _ -> assert false

and type_int_binop f loc1 t1 loc2 t2 =
  if not (Types.Int.is_int t1) then
    raise_loc loc1 
      (Constraint 
	 (t1,Types.Int.any,
	  "The first argument must be an integer"));
  if not (Types.Int.is_int t2) then
    raise_loc loc2
      (Constraint 
1029
	       (t2,Types.Int.any,
1030
1031
		"The second argument must be an integer"));
  Types.Int.put
1032
    (f (Types.Int.get t1) (Types.Int.get t2))
1033
1034
  

1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045


let report_unused_branches () =
  List.iter
    (fun b ->
       if not b.br_used then
	 warning b.br_loc "This branch is not used"
    )
    !all_branches;
  all_branches := []