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
|
(***********************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * INRIA-Rocquencourt & LRI-CNRS-Orsay *)
(* \VV/ *************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(***********************************************************************)
(*i $Id$ i*)
open Util
open Formula
open Sequent
open Tacmach
open Term
open Termops
open Reductionops
exception UFAIL of constr*constr
let unif t1 t2= (* Martelli-Montanari style *)
let bige=Queue.create ()
and sigma=ref [] in
let bind i t=
sigma:=(i,t)::
(List.map (function (n,tn)->(n,subst_meta [i,t] tn)) !sigma) in
let rec head_reduce t=
(* forbids non-sigma-normal meta in head position*)
match kind_of_term t with
Meta i->
(try
head_reduce (List.assoc i !sigma)
with Not_found->t)
| _->t in
Queue.add (t1,t2) bige;
try while true do
let t1,t2=Queue.take bige in
let nt1=head_reduce (whd_betaiotazeta t1)
and nt2=head_reduce (whd_betaiotazeta t2) in
match (kind_of_term nt1),(kind_of_term nt2) with
Meta i,Meta j->
if i<>j then
if i<j then bind j nt1
else bind i nt2
| Meta i,_ ->
let t=subst_meta !sigma nt2 in
if Intset.is_empty (free_rels t) &&
not (occur_term (mkMeta i) t) then
bind i t else raise (UFAIL(nt1,nt2))
| _,Meta i ->
let t=subst_meta !sigma nt1 in
if Intset.is_empty (free_rels t) &&
not (occur_term (mkMeta i) t) then
bind i t else raise (UFAIL(nt1,nt2))
| Cast(_,_),_->Queue.add (strip_outer_cast nt1,nt2) bige
| _,Cast(_,_)->Queue.add (nt1,strip_outer_cast nt2) bige
| (Prod(_,a,b),Prod(_,c,d))|(Lambda(_,a,b),Lambda(_,c,d))->
Queue.add (a,c) bige;Queue.add (pop b,pop d) bige
| Case (_,pa,ca,va),Case (_,pb,cb,vb)->
Queue.add (pa,pb) bige;
Queue.add (ca,cb) bige;
let l=Array.length va in
if l<>(Array.length vb) then
raise (UFAIL (nt1,nt2))
else
for i=0 to l-1 do
Queue.add (va.(i),vb.(i)) bige
done
| App(ha,va),App(hb,vb)->
Queue.add (ha,hb) bige;
let l=Array.length va in
if l<>(Array.length vb) then
raise (UFAIL (nt1,nt2))
else
for i=0 to l-1 do
Queue.add (va.(i),vb.(i)) bige
done
| _->if not (eq_constr nt1 nt2) then raise (UFAIL (nt1,nt2))
done;
assert false
(* this place is unreachable but needed for the sake of typing *)
with Queue.Empty-> !sigma
(* collect tries finds ground instantiations for Meta i*)
let is_ground t=(Clenv.collect_metas t)=[]
let collect i l=
try
let t=List.assoc i l in
if is_ground t then Some t else None
with Not_found->None
let unif_atoms_for_meta i (b1,t1) (b2,t2)=
if b1=b2 then None else
try
collect i (unif t1 t2)
with UFAIL(_,_) ->None
module OrderedConstr=
struct
type t=constr
let compare=Pervasives.compare
end
module CS=Set.Make(OrderedConstr)
let match_atom_list i atom l=
let f atom2 accu=
match unif_atoms_for_meta i atom atom2 with
None-> accu
| Some t-> CS.add t accu in
List.fold_right f l CS.empty
let match_lists i l1 l2=
let f atom accu=
CS.union (match_atom_list i atom l2) accu in
List.fold_right f l1 CS.empty
let find_instances i l seq=
let match_hyp f accu=
CS.union (if f.internal then match_lists i l f.atoms else CS.empty) accu in
let match_atom t nam accu=
CS.union (match_atom_list i (false,t) l) accu in
let s1=
match seq.gl with
Atomic t->(match_atom_list i (true,t) l)
| Complex(_,l1)->(match_lists i l l1) in
let s2=CM.fold match_atom seq.hatoms s1 in
let s3=HP.fold match_hyp seq.hyps s2 in
CS.fold (fun x l->x::l) s3 []
|
