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_______________________________________________________________ *)
17 module E = BagEnvironment
18 module S = BagSubstitution
28 | LRef_ of int * B.term option
30 | Bind_ of int * B.id * B.term * B.term
36 (* Internal functions *******************************************************)
38 let term_of_whdr = function
40 | LRef_ (i, _) -> B.LRef i
41 | GRef_ (_, uri, _) -> B.GRef uri
42 | Bind_ (l, id, w, t) -> B.bind_abst l id w t
47 let sc, st = s ^ " in the context", "the term" in
48 L.log O.specs level (L.ct_items1 sc c st t)
50 let log2 s cu u ct t =
51 let s1, s2, s3 = s ^ " in the context", "the term", "and in the context" in
52 L.log O.specs level (L.ct_items2 s1 cu s2 u ~sc2:s3 ~c2:ct s2 t)
54 let empty_machine = {i = 0; c = B.empty_context; s = []}
56 let inc m = {m with i = succ m.i}
58 let unwind_to_term f m t =
59 let map f t (l, id, b) = f (B.Bind (l, id, b, t)) in
60 let f mc = C.list_fold_left f map t mc in
63 let unwind_stack f m =
64 let map f v = unwind_to_term f m v in
70 | None -> assert false
72 let f c = B.get f c i in
75 let push msg f c m l id w =
77 let f w = B.push msg f c l id (B.Abst w) in
82 (* L.warn "entering R.whd"; *)
84 | B.Sort h -> f m (Sort_ h)
86 let f obj = f m (GRef_ obj) in
90 | B.Void -> f m (LRef_ (i, None))
91 | B.Abst t -> f m (LRef_ (i, Some t))
92 | B.Abbr t -> whd f c m t
95 | B.Cast (_, t) -> whd f c m t
96 | B.Appl (v, t) -> whd f c {m with s = v :: m.s} t
97 | B.Bind (l, id, B.Abst w, t) ->
99 | [] -> f m (Bind_ (l, id, w, t))
101 let nl = B.new_location () in
102 let f mc = S.subst (whd f c {m with c = mc; s = tl}) nl l t in
103 B.push "!" f m.c nl id (B.Abbr (B.Cast (w, v)))
105 | B.Bind (l, id, b, t) ->
106 let nl = B.new_location () in
107 let f mc = S.subst (whd f c {m with c = mc}) nl l t in
108 B.push "!" f m.c nl id b
110 (* Interface functions ******************************************************)
112 let rec ho_whd f c m x =
113 (* L.warn "entering R.ho_whd"; *)
115 | Sort_ h -> f (Sort h)
116 | Bind_ (_, _, w, _) ->
117 let f w = f (Abst w) in unwind_to_term f m w
118 | LRef_ (_, Some w) -> ho_whd f c m w
119 | GRef_ (_, _, B.Abst w) -> ho_whd f c m w
120 | GRef_ (_, _, B.Abbr v) -> ho_whd f c m v
121 | LRef_ (_, None) -> assert false
122 | GRef_ (_, _, B.Void) -> assert false
127 let f r = L.unbox level; f r in
128 L.box level; log1 "Now scanning" c t;
129 ho_whd f c empty_machine t
131 let rec are_convertible f ~si a c m1 t1 m2 t2 =
132 (* L.warn "entering R.are_convertible"; *)
133 let rec aux m1 r1 m2 r2 =
134 (* L.warn "entering R.are_convertible_aux"; *)
135 let u, t = term_of_whdr r1, term_of_whdr r2 in
136 log2 "Now really converting" c u c t;
138 | Sort_ h1, Sort_ h2 ->
139 if h1 = h2 then f a else f false
140 | LRef_ (i1, _), LRef_ (i2, _) ->
141 if i1 = i2 then are_convertible_stacks f ~si a c m1 m2 else f false
142 | GRef_ (a1, _, B.Abst _), GRef_ (a2, _, B.Abst _) ->
143 if a1 = a2 then are_convertible_stacks f ~si a c m1 m2 else f false
144 | GRef_ (a1, _, B.Abbr v1), GRef_ (a2, _, B.Abbr v2) ->
147 if a then f a else are_convertible f ~si true c m1 v1 m2 v2
149 are_convertible_stacks f ~si a c m1 m2
151 if a1 < a2 then whd (aux m1 r1) c m2 v2 else
152 whd (aux_rev m2 r2) c m1 v1
153 | _, GRef_ (_, _, B.Abbr v2) ->
154 whd (aux m1 r1) c m2 v2
155 | GRef_ (_, _, B.Abbr v1), _ ->
156 whd (aux_rev m2 r2) c m1 v1
157 | Bind_ (l1, id1, w1, t1), Bind_ (l2, id2, w2, t2) ->
158 let l = B.new_location () in
160 let m1, m2 = inc m1, inc m2 in
161 let f t1 = S.subst (are_convertible f ~si a c m1 t1 m2) l l2 t2 in
164 let f r = if r then push "!" h c m1 l id1 w1 else f false in
165 are_convertible f ~si a c m1 w1 m2 w2
166 (* we detect the AUT-QE reduction rule for type/prop inclusion *)
167 | Sort_ _, Bind_ (l2, id2, w2, t2) when si ->
168 let m1, m2 = inc m1, inc m2 in
169 let f c = are_convertible f ~si a c m1 (term_of_whdr r1) m2 t2 in
170 push "nsi" f c m2 l2 id2 w2
172 and aux_rev m2 r2 m1 r1 = aux m1 r1 m2 r2 in
173 let g m1 r1 = whd (aux m1 r1) c m2 t2 in
174 if a = false then f false else whd g c m1 t1
176 and are_convertible_stacks f ~si a c m1 m2 =
177 (* L.warn "entering R.are_convertible_stacks"; *)
178 let mm1, mm2 = {m1 with s = []}, {m2 with s = []} in
179 let map f a v1 v2 = are_convertible f ~si a c mm1 v1 mm2 v2 in
180 if List.length m1.s <> List.length m2.s then
182 (* L.warn (Printf.sprintf "Different lengths: %u %u"
183 (List.length m1.s) (List.length m2.s)
188 C.list_fold_left2 f map a m1.s m2.s
190 let are_convertible f ?(si=false) c u t =
191 let f b = L.unbox level; f b in
192 L.box level; log2 "Now converting" c u c t;
193 are_convertible f ~si true c empty_machine u empty_machine t