2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department, University of Bologna, Italy.
6 ||T|| HELM is free software; you can redistribute it and/or
7 ||A|| modify it under the terms of the GNU General Public License
8 \ / version 2 or (at your option) any later version.
9 \ / This software is distributed as is, NO WARRANTY.
10 V_______________________________________________________________ *)
18 module E = BrgEnvironment
19 module S = BrgSubstitution
21 exception LRefNotFound of B.message
25 s: (B.term * int) list
28 (* Internal functions *******************************************************)
32 let error i = raise (LRefNotFound (L.items1 (string_of_int i)))
35 let sc, st = s ^ " in the context", "the term" in
36 L.log O.specs level (L.ct_items1 sc c st t)
39 let sc, su, st = s ^ " in the context", "the term", "and the term" in
40 L.log O.specs level (L.ct_items2 sc c su u st t)
43 c = B.empty_context; s = []
48 | Some (_, b) -> f e b
51 let f c = B.get f c i in
55 let map f (v, i) = f (v, succ i) in
58 let unwind_to_term f m t =
59 let map f t (a, b) = f (B.Bind (a, b, t)) in
60 let f mc = C.list_fold_left f map t mc in
66 f {m with c = (a, b) :: m.c}
69 let rec step f ?(delta=false) ?(rt=false) c m x =
70 (* L.warn "entering R.step"; *)
75 | _, _, B.Abbr v when delta ->
77 step f ~delta ~rt c m v
78 | _, _, B.Abst w when rt ->
80 step f ~delta ~rt c m w
82 f m (B.GRef (B.Entry (e, b) :: a, uri))
89 step f ~delta ~rt c m v
92 step f ~delta ~rt c m w
94 f m (B.LRef (B.Entry (e, b) :: a, i))
96 let f e = S.lift_bind (f e) (succ i) (0) in
100 step f ~delta ~rt c m t
101 | B.Appl (_, v, t) ->
102 step f ~delta ~rt c {m with s = (v, 0) :: m.s} t
103 | B.Bind (a, B.Abst w, t) ->
107 P.add ~beta:1 ~upsilon:(List.length tl) ();
108 let f mc sc = step f ~delta ~rt c {c = mc; s = sc} t in
109 let f mc = lift_stack (f mc) tl in
110 let f v = B.push f m.c a (B.Abbr v (* (B.Cast ([], w, v)) *) ) in
113 | B.Bind (a, b, t) ->
114 P.add ~upsilon:(List.length m.s) ();
115 let f sc mc = step f ~delta ~rt c {c = mc; s = sc} t in
116 let f sc = B.push (f sc) m.c a b in
119 (* Interface functions ******************************************************)
122 let f r = L.unbox level; f r in
124 | B.Bind (_, B.Abst w, _) ->
125 let f w = f (Some w) in unwind_to_term f m w
128 L.box level; log1 "Now scanning" c t;
129 step f ~delta:true ~rt:true c empty_machine t
131 let rec ac_nfs f ~si r c m1 u m2 t =
132 (* L.warn "entering R.are_convertible_aux"; *)
133 log2 "Now converting nfs" c u t;
135 | B.Sort (_, h1), B.Sort (_, h2) ->
136 if h1 = h2 then f r else f false
137 | B.LRef (B.Entry (e1, B.Abst _) :: _, i1),
138 B.LRef (B.Entry (e2, B.Abst _) :: _, i2) ->
139 P.add ~zeta:(i1+i2-e1-e2) ();
140 if e1 = e2 then ac_stacks f ~si r c m1 m2 else f false
141 | B.GRef (B.Entry (e1, B.Abst _) :: _, _),
142 B.GRef (B.Entry (e2, B.Abst _) :: _, _) ->
143 if e1 = e2 then ac_stacks f ~si r c m1 m2 else f false
144 | B.GRef (B.Entry (e1, B.Abbr v1) :: _, _),
145 B.GRef (B.Entry (e2, B.Abbr v2) :: _, _) ->
151 ac f ~si true c m1 v1 m2 v2
154 ac_stacks f ~si r c m1 m2
155 else if e1 < e2 then begin
157 step (ac_nfs f ~si r c m1 u) c m2 v2
160 step (ac_nfs_rev f ~si r c m2 t) c m1 v1
162 | _, B.GRef (B.Entry (_, B.Abbr v2) :: _, _) ->
164 step (ac_nfs f ~si r c m1 u) c m2 v2
165 | B.GRef (B.Entry (_, B.Abbr v1) :: _, _), _ ->
167 step (ac_nfs_rev f ~si r c m2 t) c m1 v1
168 | B.Bind (a1, (B.Abst w1 as b1), t1),
169 B.Bind (a2, (B.Abst w2 as b2), t2) ->
170 let g m1 m2 = ac f ~si r c m1 t1 m2 t2 in
171 let g m1 = push (g m1) m2 a2 b2 in
172 let f r = if r then push g m1 a1 b1 else f false in
173 ac f ~si r c m1 w1 m2 w2
174 | B.Sort _, B.Bind (a, b, t) when si ->
176 let f m1 m2 = ac f ~si r c m1 u m2 t in
177 let f m1 = push (f m1) m2 a b in
181 and ac_nfs_rev f ~si r c m2 t m1 u = ac_nfs f ~si r c m1 u m2 t
183 and ac f ~si r c m1 t1 m2 t2 =
184 (* L.warn "entering R.are_convertible"; *)
185 let g m1 t1 = step (ac_nfs f ~si r c m1 t1) c m2 t2 in
186 if r = false then f false else step g c m1 t1
188 and ac_stacks f ~si r c m1 m2 =
189 (* L.warn "entering R.are_convertible_stacks"; *)
190 let mm1, mm2 = {m1 with s = []}, {m2 with s = []} in
191 let map f r (v1, h1) (v2, h2) =
192 let f v1 = S.lift (ac f ~si r c mm1 v1 mm2) h2 (0) v2 in
195 if List.length m1.s <> List.length m2.s then
197 (* L.warn (Printf.sprintf "Different lengths: %u %u"
198 (List.length m1.s) (List.length m2.s)
203 C.list_fold_left2 f map r m1.s m2.s
205 let are_convertible f ?(si=false) c u t =
206 let f b = L.unbox level; f b in
207 L.box level; log2 "Now converting" c u t;
208 ac f ~si true c empty_machine u empty_machine t