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 = BagEnvironment
19 module S = BagSubstitution
21 exception LRefNotFound of B.message
31 | LRef_ of int * B.term option
33 | Bind_ of int * B.id * B.term * B.term
37 | GRef of U.uri * B.term list
40 type ac_result = (int * NUri.uri * Bag.term list) list option
42 type extension = No | NSI
44 (* Internal functions *******************************************************)
46 let term_of_whdr = function
48 | LRef_ (i, _) -> B.LRef i
49 | GRef_ (_, uri, _) -> B.GRef uri
50 | Bind_ (l, id, w, t) -> B.bind_abst l id w t
54 let error i = raise (LRefNotFound (L.items1 (string_of_int i)))
57 let sc, st = s ^ " in the context", "the term" in
58 L.log O.specs level (L.ct_items1 sc c st t)
61 let sc, su, st = s ^ " in the context", "the term", "and the term" in
62 L.log O.specs level (L.ct_items2 sc c su u st t)
64 let empty_machine = {i = 0; c = B.empty_context; s = []}
66 let inc m = {m with i = succ m.i}
68 let unwind_to_term f m t =
69 let map f t (l, id, b) = f (B.Bind (l, id, b, t)) in
70 let f mc = C.list_fold_left f map t mc in
73 let unwind_stack f m =
74 let map f v = unwind_to_term f m v in
82 let f c = B.get f c i in
85 let push f c m l id w =
87 let f w = B.push f c l id (B.Abst w) in
91 let rec whd f c m x = match x with
92 | B.Sort h -> f m (Sort_ h)
94 let f obj = f m (GRef_ obj) in
98 | B.Void -> f m (LRef_ (i, None))
99 | B.Abst t -> f m (LRef_ (i, Some t))
100 | B.Abbr t -> whd f c m t
103 | B.Cast (_, t) -> whd f c m t
104 | B.Appl (v, t) -> whd f c {m with s = v :: m.s} t
105 | B.Bind (l, id, B.Abst w, t) ->
107 | [] -> f m (Bind_ (l, id, w, t))
109 let f mc = whd f c {m with c = mc; s = tl} t in
110 B.push f m.c l id (B.Abbr (B.Cast (w, v)))
112 | B.Bind (l, id, b, t) ->
113 let f mc = whd f c {m with c = mc} t in
116 let insert f i uri vs = function
117 | Some l -> f (Some ((i, uri, vs) :: l))
118 | None -> assert false
120 (* Interface functions ******************************************************)
124 let rec ho_whd f c m x =
126 | Sort_ h -> f (Sort h)
127 | Bind_ (_, _, w, _) ->
128 let f w = f (Abst w) in unwind_to_term f m w
129 | LRef_ (_, Some w) -> ho_whd f c m w
130 | GRef_ (_, uri, B.Abst w) ->
135 let f vs = f (GRef (uri, vs)) in unwind_stack f m
137 if !ext = No then ho_whd h c m w else ho_whd f c m w
138 | GRef_ (_, _, B.Abbr v) -> ho_whd f c m v
139 | LRef_ (_, None) -> assert false
140 | GRef_ (_, _, B.Void) -> assert false
145 let f r = L.unbox level; f r in
146 L.box level; log1 "Now scanning" c t;
147 ho_whd f c empty_machine t
149 let rec are_convertible f xl c m1 t1 m2 t2 =
150 let rec aux m1 r1 m2 r2 =
151 let u, t = term_of_whdr r1, term_of_whdr r2 in
152 log2 "Now really converting" c u t;
154 | Sort_ h1, Sort_ h2 ->
155 if h1 = h2 then f xl else f None
156 | LRef_ (i1, _), LRef_ (i2, _) ->
157 if i1 = i2 then are_convertible_stacks f xl c m1 m2 else f None
158 | GRef_ (a1, _, B.Abst _), GRef_ (a2, _, B.Abst _) ->
159 if a1 = a2 then are_convertible_stacks f xl c m1 m2 else f None
160 | GRef_ (a1, _, B.Abbr v1), GRef_ (a2, _, B.Abbr v2) ->
161 if a1 = a2 then are_convertible_stacks f xl c m1 m2 else
162 if a1 < a2 then whd (aux m1 r1) c m2 v2 else
163 whd (aux_rev m2 r2) c m1 v1
164 | _, GRef_ (_, _, B.Abbr v2) ->
165 whd (aux m1 r1) c m2 v2
166 | GRef_ (_, _, B.Abbr v1), _ ->
167 whd (aux_rev m2 r2) c m1 v1
168 | Bind_ (l1, id1, w1, t1), Bind_ (l2, id2, w2, t2) ->
171 let m1, m2 = inc m1, inc m2 in
172 S.subst (are_convertible f xl c m1 t1 m2) l1 l2 t2
174 if xl = None then f xl else push h c m1 l1 id1 w1
176 are_convertible f xl c m1 w1 m2 w2
177 (* we detect the AUT-QE reduction rule for type/prop inclusion *)
178 | GRef_ (_, uri, B.Abst _), Bind_ (l1, _, _, _) when !ext = No ->
179 let g vs = insert f l1 uri vs xl in
180 if U.eq uri I.imp then unwind_stack g m1 else
181 if U.eq uri I.all then unwind_stack g m1 else
182 begin L.warn (U.string_of_uri uri); f None end
183 | Sort_ _, Bind_ (l2, id2, w2, t2) when !ext = NSI ->
184 let m1, m2 = inc m1, inc m2 in
185 let f c = are_convertible f xl c m1 (term_of_whdr r1) m2 t2 in
186 push f c m2 l2 id2 w2
188 and aux_rev m2 r2 m1 r1 = aux m1 r1 m2 r2 in
189 let f m1 r1 = whd (aux m1 r1) c m2 t2 in
192 and are_convertible_stacks f xl c m1 m2 =
193 let mm1, mm2 = {m1 with s = []}, {m2 with s = []} in
194 let map f xl v1 v2 = are_convertible f xl c mm1 v1 mm2 v2 in
195 if List.length m1.s <> List.length m2.s then f None else
196 C.list_fold_left2 f map xl m1.s m2.s
198 let are_convertible f c u t =
199 let f b = L.unbox level; f b in
200 L.box level; log2 "Now converting" c u t;
201 are_convertible f (Some []) c empty_machine u empty_machine t