summaryrefslogtreecommitdiff
path: root/pretyping/typeclasses.ml
blob: 0344ebcc335b9e286f6909449e0f70c73eaaf131 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
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
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
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
368
369
370
371
372
373
374
375
376
377
378
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
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2012     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(*i*)
open Names
open Libnames
open Decl_kinds
open Term
open Sign
open Evd
open Environ
open Nametab
open Mod_subst
open Util
open Typeclasses_errors
open Libobject
(*i*)


let add_instance_hint_ref = ref (fun id local pri -> assert false)
let register_add_instance_hint =
  (:=) add_instance_hint_ref
let add_instance_hint id = !add_instance_hint_ref id

let remove_instance_hint_ref = ref (fun id -> assert false)
let register_remove_instance_hint =
  (:=) remove_instance_hint_ref
let remove_instance_hint id = !remove_instance_hint_ref id

let set_typeclass_transparency_ref = ref (fun id local c -> assert false)
let register_set_typeclass_transparency =
  (:=) set_typeclass_transparency_ref
let set_typeclass_transparency gr local c = !set_typeclass_transparency_ref gr local c

let classes_transparent_state_ref = ref (fun () -> assert false)
let register_classes_transparent_state = (:=) classes_transparent_state_ref
let classes_transparent_state () = !classes_transparent_state_ref ()

let solve_instanciation_problem = ref (fun _ _ _ -> assert false)

let resolve_one_typeclass env evm t =
  !solve_instanciation_problem env evm t

type rels = constr list
type direction = Forward | Backward

(* This module defines type-classes *)
type typeclass = {
  (* The class implementation *)
  cl_impl : global_reference;

  (* Context in which the definitions are typed. Includes both typeclass parameters and superclasses. *)
  cl_context : (global_reference * bool) option list * rel_context;

  (* Context of definitions and properties on defs, will not be shared *)
  cl_props : rel_context;

  (* The method implementaions as projections. *)
  cl_projs : (name * (direction * int option) option * constant option) list;
}

module Gmap = Fmap.Make(RefOrdered)

type typeclasses = typeclass Gmap.t

type instance = {
  is_class: global_reference;
  is_pri: int option;
  (* Sections where the instance should be redeclared,
     -1 for discard, 0 for none, mutable to avoid redeclarations
     when multiple rebuild_object happen. *)
  is_global: int;
  is_impl: global_reference;
}

type instances = (instance Gmap.t) Gmap.t

let instance_impl is = is.is_impl

let new_instance cl pri glob impl =
  let global =
    if glob then Lib.sections_depth ()
    else -1
  in
    { is_class = cl.cl_impl;
      is_pri = pri ;
      is_global = global ;
      is_impl = impl }

(*
 * states management
 *)

let classes : typeclasses ref = ref Gmap.empty

let instances : instances ref = ref Gmap.empty

let freeze () = !classes, !instances

let unfreeze (cl,is) =
  classes:=cl;
  instances:=is

let init () =
  classes:= Gmap.empty;
  instances:= Gmap.empty

let _ =
  Summary.declare_summary "classes_and_instances"
    { Summary.freeze_function = freeze;
      Summary.unfreeze_function = unfreeze;
      Summary.init_function = init }

let class_info c =
  try Gmap.find c !classes
  with Not_found -> not_a_class (Global.env()) (constr_of_global c)

let global_class_of_constr env c =
  try class_info (global_of_constr c)
  with Not_found -> not_a_class env c

let dest_class_app env c =
  let cl, args = decompose_app c in
    global_class_of_constr env cl, args

let dest_class_arity env c =
  let rels, c = Term.decompose_prod_assum c in
    rels, dest_class_app env c

let class_of_constr c =
  try Some (dest_class_arity (Global.env ()) c)
  with e when Errors.noncritical e -> None

let rec is_class_type evd c =
  match kind_of_term c with
  | Prod (_, _, t) -> is_class_type evd t
  | Evar (e, _) when is_defined evd e -> is_class_type evd (Evarutil.nf_evar evd c)
  | _ -> class_of_constr c <> None

let is_class_evar evd evi =
  is_class_type evd evi.Evd.evar_concl

(*
 * classes persistent object
 *)

let load_class (_, cl) =
  classes := Gmap.add cl.cl_impl cl !classes

let cache_class = load_class

let subst_class (subst,cl) =
  let do_subst_con c = fst (Mod_subst.subst_con subst c)
  and do_subst c = Mod_subst.subst_mps subst c
  and do_subst_gr gr = fst (subst_global subst gr) in
  let do_subst_ctx ctx = list_smartmap
    (fun (na, b, t) -> (na, Option.smartmap do_subst b, do_subst t))
    ctx in
  let do_subst_context (grs,ctx) =
    list_smartmap (Option.smartmap (fun (gr,b) -> do_subst_gr gr, b)) grs,
    do_subst_ctx ctx in
  let do_subst_projs projs = list_smartmap (fun (x, y, z) -> (x, y, Option.smartmap do_subst_con z)) projs in
  { cl_impl = do_subst_gr cl.cl_impl;
    cl_context = do_subst_context cl.cl_context;
    cl_props = do_subst_ctx cl.cl_props;
    cl_projs = do_subst_projs cl.cl_projs; }

let discharge_class (_,cl) =
  let repl = Lib.replacement_context () in
  let rel_of_variable_context ctx = List.fold_right
    ( fun (n,_,b,t) (ctx', subst) ->
	let decl = (Name n, Option.map (substn_vars 1 subst) b, substn_vars 1 subst t) in
	(decl :: ctx', n :: subst)
    ) ctx ([], []) in
  let discharge_rel_context subst n rel =
    let rel = map_rel_context (Cooking.expmod_constr repl) rel in
    let ctx, _ =
      List.fold_right
	(fun (id, b, t) (ctx, k) ->
	   (id, Option.smartmap (substn_vars k subst) b, substn_vars k subst t) :: ctx, succ k)
	rel ([], n)
    in ctx
  in
  let abs_context cl =
    match cl.cl_impl with
      | VarRef _ | ConstructRef _ -> assert false
      | ConstRef cst -> Lib.section_segment_of_constant cst
      | IndRef (ind,_) -> Lib.section_segment_of_mutual_inductive ind in
  let discharge_context ctx' subst (grs, ctx) =
    let grs' = 
      let newgrs = List.map (fun (_, _, t) -> 
	match class_of_constr t with
	| None -> None
	| Some (_, (tc, _)) -> Some (tc.cl_impl, true))
	ctx' 
      in
	list_smartmap (Option.smartmap (fun (gr, b) -> Lib.discharge_global gr, b)) grs
	  @ newgrs
    in grs', discharge_rel_context subst 1 ctx @ ctx' in
  let cl_impl' = Lib.discharge_global cl.cl_impl in
  if cl_impl' == cl.cl_impl then cl else
    let ctx = abs_context cl in
    let ctx, subst = rel_of_variable_context ctx in
    let context = discharge_context ctx subst cl.cl_context in
    let props = discharge_rel_context subst (succ (List.length (fst cl.cl_context))) cl.cl_props in
    { cl_impl = cl_impl';
      cl_context = context;
      cl_props = props;
      cl_projs = list_smartmap (fun (x, y, z) -> x, y, Option.smartmap Lib.discharge_con z) cl.cl_projs }

let rebuild_class cl = 
  try 
    let cst = Tacred.evaluable_of_global_reference (Global.env ()) cl.cl_impl in
      set_typeclass_transparency cst false false; cl
  with e when Errors.noncritical e -> cl

let class_input : typeclass -> obj =
  declare_object
    { (default_object "type classes state") with
      cache_function = cache_class;
      load_function = (fun _ -> load_class);
      open_function = (fun _ -> load_class);
      classify_function = (fun x -> Substitute x);
      discharge_function = (fun a -> Some (discharge_class a));
      rebuild_function = rebuild_class;
      subst_function = subst_class }

let add_class cl =
  Lib.add_anonymous_leaf (class_input cl)

(** Build the subinstances hints. *)

let check_instance env sigma c =
  try 
    let (evd, c) = resolve_one_typeclass env sigma
      (Retyping.get_type_of env sigma c) in
      Evd.is_empty (Evd.undefined_evars evd)
  with e when Errors.noncritical e -> false

let build_subclasses ~check env sigma glob pri =
  let rec aux pri c =
    let ty = Evarutil.nf_evar sigma (Retyping.get_type_of env sigma c) in
      match class_of_constr ty with
      | None -> []
      | Some (rels, (tc, args)) ->
	let instapp = Reductionops.whd_beta sigma (appvectc c (Termops.extended_rel_vect 0 rels)) in
	let projargs = Array.of_list (args @ [instapp]) in
	let projs = list_map_filter 
	  (fun (n, b, proj) ->
	   match b with 
	   | None -> None
	   | Some (Backward, _) -> None
	   | Some (Forward, pri') ->
	     let proj = Option.get proj in
	     let body = it_mkLambda_or_LetIn (mkApp (mkConst proj, projargs)) rels in
	       if check && check_instance env sigma body then None
	       else 
		 let pri = 
		   match pri, pri' with
		   | Some p, Some p' -> Some (p + p')
		   | Some p, None -> Some (p + 1)
		   | _, _ -> None
		 in
		   Some (ConstRef proj, pri, body)) tc.cl_projs 
	in
	let declare_proj hints (cref, pri, body) =
	  let rest = aux pri body in
	    hints @ (pri, body) :: rest
	in List.fold_left declare_proj [] projs 
  in aux pri (constr_of_global glob)

(*
 * instances persistent object
 *)

type instance_action = 
  | AddInstance
  | RemoveInstance

let load_instance inst = 
  let insts = 
    try Gmap.find inst.is_class !instances 
    with Not_found -> Gmap.empty in
  let insts = Gmap.add inst.is_impl inst insts in
  instances := Gmap.add inst.is_class insts !instances

let remove_instance inst =
  let insts = 
    try Gmap.find inst.is_class !instances 
    with Not_found -> assert false in
  let insts = Gmap.remove inst.is_impl insts in
  instances := Gmap.add inst.is_class insts !instances

let cache_instance (_, (action, i)) =
  match action with 
  | AddInstance -> load_instance i
  | RemoveInstance -> remove_instance i      

let subst_instance (subst, (action, inst)) = action,
  { inst with 
      is_class = fst (subst_global subst inst.is_class);
      is_impl = fst (subst_global subst inst.is_impl) }

let discharge_instance (_, (action, inst)) =
  if inst.is_global <= 0 then None
  else Some (action,
    { inst with 
      is_global = pred inst.is_global;
      is_class = Lib.discharge_global inst.is_class;
      is_impl = Lib.discharge_global inst.is_impl })
    

let is_local i = i.is_global = -1

let add_instance check inst =
  add_instance_hint (constr_of_global inst.is_impl) (is_local inst) inst.is_pri;
  List.iter (fun (pri, c) -> add_instance_hint c (is_local inst) pri) 
    (build_subclasses ~check:(check && not (isVarRef inst.is_impl))
       (Global.env ()) Evd.empty inst.is_impl inst.is_pri)

let rebuild_instance (action, inst) =
  if action = AddInstance then add_instance true inst;
  (action, inst)

let classify_instance (action, inst) =
  if is_local inst then Dispose
  else Substitute (action, inst)

let load_instance (_, (action, inst) as ai) =
  cache_instance ai;
  if action = AddInstance then
    add_instance_hint (constr_of_global inst.is_impl) (is_local inst) inst.is_pri

let instance_input : instance_action * instance -> obj =
  declare_object
    { (default_object "type classes instances state") with
      cache_function = cache_instance;
      load_function = (fun _ x -> cache_instance x);
      open_function = (fun _ x -> cache_instance x);
      classify_function = classify_instance;
      discharge_function = discharge_instance;
      rebuild_function = rebuild_instance;
      subst_function = subst_instance }

let add_instance i =
  Lib.add_anonymous_leaf (instance_input (AddInstance, i));
  add_instance true i

let remove_instance i =
  Lib.add_anonymous_leaf (instance_input (RemoveInstance, i));
  remove_instance_hint i.is_impl

let declare_instance pri local glob =
  let c = constr_of_global glob in
  let ty = Retyping.get_type_of (Global.env ()) Evd.empty c in
    match class_of_constr ty with
    | Some (rels, (tc, args) as _cl) ->
      add_instance (new_instance tc pri (not local) glob)
(*       let path, hints = build_subclasses (not local) (Global.env ()) Evd.empty glob in *)
(*       let entries = List.map (fun (path, pri, c) -> (pri, local, path, c)) hints in *)
(* 	Auto.add_hints local [typeclasses_db] (Auto.HintsResolveEntry entries); *)
(* 	Auto.add_hints local [typeclasses_db]  *)
(* 	(Auto.HintsCutEntry (PathSeq (PathStar (PathAtom PathAny), path))) *)
    | None -> ()

let add_class cl =
  add_class cl;
  List.iter (fun (n, inst, body) ->
	     match inst with
	     | Some (Backward, pri) ->
	       declare_instance pri false (ConstRef (Option.get body))
	     | _ -> ())
  cl.cl_projs


open Declarations

let add_constant_class cst =
  let ty = Typeops.type_of_constant (Global.env ()) cst in
  let ctx, arity = decompose_prod_assum ty in
  let tc = 
    { cl_impl = ConstRef cst;
      cl_context = (List.map (const None) ctx, ctx);
      cl_props = [(Anonymous, None, arity)];
      cl_projs = []
    }
  in add_class tc;
    set_typeclass_transparency (EvalConstRef cst) false false
      
let add_inductive_class ind =
  let mind, oneind = Global.lookup_inductive ind in
  let k =
    let ctx = oneind.mind_arity_ctxt in
    let ty = Inductive.type_of_inductive_knowing_parameters
      (push_rel_context ctx (Global.env ()))
	  oneind (Termops.extended_rel_vect 0 ctx)
    in
      { cl_impl = IndRef ind;
	cl_context = List.map (const None) ctx, ctx;
	cl_props = [Anonymous, None, ty];
	cl_projs = [] }
  in add_class k
      
(*
 * interface functions
 *)

let instance_constructor cl args =
  let lenpars = List.length (List.filter (fun (na, b, t) -> b = None) (snd cl.cl_context)) in
  let pars = fst (list_chop lenpars args) in
    match cl.cl_impl with
      | IndRef ind -> Some (applistc (mkConstruct (ind, 1)) args),
	  applistc (mkInd ind) pars
      | ConstRef cst -> 
	let term = if args = [] then None else Some (list_last args) in
	  term, applistc (mkConst cst) pars
      | _ -> assert false

let typeclasses () = Gmap.fold (fun _ l c -> l :: c) !classes []

let cmap_elements c = Gmap.fold (fun k v acc -> v :: acc) c []

let instances_of c =
  try cmap_elements (Gmap.find c.cl_impl !instances) with Not_found -> []

let all_instances () = 
  Gmap.fold (fun k v acc -> 
    Gmap.fold (fun k v acc -> v :: acc) v acc)
    !instances []

let instances r = 
  let cl = class_info r in instances_of cl    
      
let is_class gr = 
  Gmap.fold (fun k v acc -> acc || v.cl_impl = gr) !classes false

let is_instance = function
  | ConstRef c ->
      (match Decls.constant_kind c with
      | IsDefinition Instance -> true
      | _ -> false)
  | VarRef v ->
      (match Decls.variable_kind v with
      | IsDefinition Instance -> true
      | _ -> false)
  | ConstructRef (ind,_) -> 
      is_class (IndRef ind)
  | _ -> false


(* To embed a boolean for resolvability status.
   This is essentially a hack to mark which evars correspond to
   goals and do not need to be resolved when we have nested [resolve_all_evars]
   calls (e.g. when doing apply in an External hint in typeclass_instances).
   Would be solved by having real evars-as-goals.

   Nota: we will only check the resolvability status of undefined evars.
 *)

let resolvable = Store.field ()
open Store.Field

let is_resolvable evi =
  assert (evi.evar_body = Evar_empty);
  Option.default true (resolvable.get evi.evar_extra)

let mark_resolvability_undef b evi =
  let t = resolvable.set b evi.evar_extra in
  { evi with evar_extra = t }

let mark_resolvability b evi =
  assert (evi.evar_body = Evar_empty);
  mark_resolvability_undef b evi

let mark_unresolvable evi = mark_resolvability false evi
let mark_resolvable evi = mark_resolvability true evi

let mark_resolvability b sigma =
  Evd.fold_undefined (fun ev evi evs ->
    Evd.add evs ev (mark_resolvability_undef b evi))
    sigma (Evd.defined_evars sigma)

let mark_unresolvables sigma = mark_resolvability false sigma

let has_typeclasses evd =
  Evd.fold_undefined (fun ev evi has -> has ||
    (is_resolvable evi && is_class_evar evd evi))
    evd false

let solve_instanciations_problem = ref (fun _ _ _ _ _ -> assert false)

type evar_filter = hole_kind -> bool

let no_goals = function GoalEvar -> false | _ -> true
let all_evars _ = true

let resolve_typeclasses ?(filter=no_goals) ?(split=true) ?(fail=true) env evd =
  if not (has_typeclasses evd) then evd
  else !solve_instanciations_problem env evd filter split fail