--- /dev/null
+(* Copyright (C) 2000, HELM Team.
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+exception CicReductionInternalError;;
+exception WrongUriToInductiveDefinition;;
+
+let fdebug = ref 1;;
+let debug t env s =
+ let rec debug_aux t i =
+ let module C = Cic in
+ let module U = UriManager in
+ CicPp.ppobj (C.Variable ("DEBUG", None, t)) ^ "\n" ^ i
+ in
+ if !fdebug = 0 then
+ begin
+ print_endline (s ^ "\n" ^ List.fold_right debug_aux (t::env) "") ;
+ flush stdout
+ end
+;;
+
+exception Impossible of int;;
+exception ReferenceToDefinition;;
+exception ReferenceToAxiom;;
+exception ReferenceToVariable;;
+exception ReferenceToCurrentProof;;
+exception ReferenceToInductiveDefinition;;
+
+(* takes a well-typed term *)
+let whd =
+ let rec whdaux l =
+ let module C = Cic in
+ let module S = CicSubstitution in
+ function
+ C.Rel _ as t -> if l = [] then t else C.Appl (t::l)
+ | C.Var uri as t ->
+ (match CicEnvironment.get_cooked_obj uri 0 with
+ C.Definition _ -> raise ReferenceToDefinition
+ | C.Axiom _ -> raise ReferenceToAxiom
+ | C.CurrentProof _ -> raise ReferenceToCurrentProof
+ | C.InductiveDefinition _ -> raise ReferenceToInductiveDefinition
+ | C.Variable (_,None,_) -> if l = [] then t else C.Appl (t::l)
+ | C.Variable (_,Some body,_) -> whdaux l body
+ )
+ | C.Meta _ as t -> if l = [] then t else C.Appl (t::l)
+ | C.Sort _ as t -> t (* l should be empty *)
+ | C.Implicit as t -> t
+ | C.Cast (te,ty) -> whdaux l te (*CSC E' GIUSTO BUTTARE IL CAST? *)
+ | C.Prod _ as t -> t (* l should be empty *)
+ | C.Lambda (name,s,t) as t' ->
+ (match l with
+ [] -> t'
+ | he::tl -> whdaux tl (S.subst he t)
+ (* when name is Anonimous the substitution should be superfluous *)
+ )
+ | C.LetIn (n,s,t) -> whdaux l (S.subst (whdaux [] s) t)
+ | C.Appl (he::tl) -> whdaux (tl@l) he
+ | C.Appl [] -> raise (Impossible 1)
+ | C.Const (uri,cookingsno) as t ->
+ (match CicEnvironment.get_cooked_obj uri cookingsno with
+ C.Definition (_,body,_,_) -> whdaux l body
+ | C.Axiom _ -> if l = [] then t else C.Appl (t::l)
+ | C.Variable _ -> raise ReferenceToVariable
+ | C.CurrentProof (_,_,body,_) -> whdaux l body
+ | C.InductiveDefinition _ -> raise ReferenceToInductiveDefinition
+ )
+ | C.Abst _ as t -> t (*CSC l should be empty ????? *)
+ | C.MutInd (uri,_,_) as t -> if l = [] then t else C.Appl (t::l)
+ | C.MutConstruct (uri,_,_,_) as t -> if l = [] then t else C.Appl (t::l)
+ | C.MutCase (mutind,cookingsno,i,_,term,pl) as t ->
+ let decofix =
+ function
+ C.CoFix (i,fl) as t ->
+ let (_,_,body) = List.nth fl i in
+ let body' =
+ let counter = ref (List.length fl) in
+ List.fold_right
+ (fun _ -> decr counter ; S.subst (C.CoFix (!counter,fl)))
+ fl
+ body
+ in
+ whdaux [] body'
+ | C.Appl (C.CoFix (i,fl) :: tl) ->
+ let (_,_,body) = List.nth fl i in
+ let body' =
+ let counter = ref (List.length fl) in
+ List.fold_right
+ (fun _ -> decr counter ; S.subst (C.CoFix (!counter,fl)))
+ fl
+ body
+ in
+ whdaux tl body'
+ | t -> t
+ in
+ (match decofix (whdaux [] term) with
+ C.MutConstruct (_,_,_,j) -> whdaux l (List.nth pl (j-1))
+ | C.Appl (C.MutConstruct (_,_,_,j) :: tl) ->
+ let (arity, r, num_ingredients) =
+ match CicEnvironment.get_obj mutind with
+ C.InductiveDefinition (tl,ingredients,r) ->
+ let (_,_,arity,_) = List.nth tl i
+ and num_ingredients =
+ List.fold_right
+ (fun (k,l) i ->
+ if k < cookingsno then i + List.length l else i
+ ) ingredients 0
+ in
+ (arity,r,num_ingredients)
+ | _ -> raise WrongUriToInductiveDefinition
+ in
+ let ts =
+ let num_to_eat = r + num_ingredients in
+ let rec eat_first =
+ function
+ (0,l) -> l
+ | (n,he::tl) when n > 0 -> eat_first (n - 1, tl)
+ | _ -> raise (Impossible 5)
+ in
+ eat_first (num_to_eat,tl)
+ in
+ whdaux (ts@l) (List.nth pl (j-1))
+ | C.Abst _| C.Cast _ | C.Implicit ->
+ raise (Impossible 2) (* we don't trust our whd ;-) *)
+ | _ -> t
+ )
+ | C.Fix (i,fl) as t ->
+ let (_,recindex,_,body) = List.nth fl i in
+ let recparam =
+ try
+ Some (List.nth l recindex)
+ with
+ _ -> None
+ in
+ (match recparam with
+ Some recparam ->
+ (match whdaux [] recparam with
+ C.MutConstruct _
+ | C.Appl ((C.MutConstruct _)::_) ->
+ let body' =
+ let counter = ref (List.length fl) in
+ List.fold_right
+ (fun _ -> decr counter ; S.subst (C.Fix (!counter,fl)))
+ fl
+ body
+ in
+ (* Possible optimization: substituting whd recparam in l *)
+ whdaux l body'
+ | _ -> if l = [] then t else C.Appl (t::l)
+ )
+ | None -> if l = [] then t else C.Appl (t::l)
+ )
+ | C.CoFix (i,fl) as t ->
+ (*CSC vecchio codice
+ let (_,_,body) = List.nth fl i in
+ let body' =
+ let counter = ref (List.length fl) in
+ List.fold_right
+ (fun _ -> decr counter ; S.subst (C.CoFix (!counter,fl)))
+ fl
+ body
+ in
+ whdaux l body'
+ *)
+ if l = [] then t else C.Appl (t::l)
+ in
+ whdaux []
+;;
+
+(* t1, t2 must be well-typed *)
+let are_convertible t1 t2 =
+ let module U = UriManager in
+ let rec aux t1 t2 =
+ debug t1 [t2] "PREWHD";
+ (* this trivial euristic cuts down the total time of about five times ;-) *)
+ (* this because most of the time t1 and t2 are "sintactically" the same *)
+ if t1 = t2 then
+ true
+ else
+ begin
+ let module C = Cic in
+ let t1' = whd t1
+ and t2' = whd t2 in
+ debug t1' [t2'] "POSTWHD";
+ (*if !fdebug = 0 then ignore(Unix.system "read" );*)
+ match (t1',t2') with
+ (C.Rel n1, C.Rel n2) -> n1 = n2
+ | (C.Var uri1, C.Var uri2) -> U.eq uri1 uri2
+ | (C.Meta n1, C.Meta n2) -> n1 = n2
+ | (C.Sort s1, C.Sort s2) -> true (*CSC da finire con gli universi *)
+ | (C.Prod (_,s1,t1), C.Prod(_,s2,t2)) ->
+ aux s1 s2 && aux t1 t2
+ | (C.Lambda (_,s1,t1), C.Lambda(_,s2,t2)) ->
+ aux s1 s2 && aux t1 t2
+ | (C.Appl l1, C.Appl l2) ->
+ (try
+ List.fold_right2 (fun x y b -> aux x y && b) l1 l2 true
+ with
+ Invalid_argument _ -> false
+ )
+ | (C.Const (uri1,_), C.Const (uri2,_)) ->
+ (*CSC: questo commento e' chiaro o delirante? Io lo sto scrivendo *)
+ (*CSC: mentre sono delirante, quindi ... *)
+ (* WARNING: it is really important that the two cookingsno are not *)
+ (* checked for equality. This allows not to cook an object with no *)
+ (* ingredients only to update the cookingsno. E.g: if a term t has *)
+ (* a reference to a term t1 which does not depend on any variable *)
+ (* and t1 depends on a term t2 (that can't depend on any variable *)
+ (* because of t1), then t1 cooked at every level could be the same *)
+ (* as t1 cooked at level 0. Doing so, t2 will be extended in t *)
+ (* with cookingsno 0 and not 2. But this will not cause any trouble*)
+ (* if here we don't check that the two cookingsno are equal. *)
+ U.eq uri1 uri2
+ | (C.MutInd (uri1,k1,i1), C.MutInd (uri2,k2,i2)) ->
+ (* WARNIG: see the previous warning *)
+ U.eq uri1 uri2 && i1 = i2
+ | (C.MutConstruct (uri1,_,i1,j1), C.MutConstruct (uri2,_,i2,j2)) ->
+ (* WARNIG: see the previous warning *)
+ U.eq uri1 uri2 && i1 = i2 && j1 = j2
+ | (C.MutCase (uri1,_,i1,outtype1,term1,pl1),
+ C.MutCase (uri2,_,i2,outtype2,term2,pl2)) ->
+ (* WARNIG: see the previous warning *)
+ (* aux outtype1 outtype2 should be true if aux pl1 pl2 *)
+ U.eq uri1 uri2 && i1 = i2 && aux outtype1 outtype2 &&
+ aux term1 term2 &&
+ List.fold_right2 (fun x y b -> b && aux x y) pl1 pl2 true
+ | (C.Fix (i1,fl1), C.Fix (i2,fl2)) ->
+ i1 = i2 &&
+ List.fold_right2
+ (fun (_,recindex1,ty1,bo1) (_,recindex2,ty2,bo2) b ->
+ b && recindex1 = recindex2 && aux ty1 ty2 && aux bo1 bo2)
+ fl1 fl2 true
+ | (C.CoFix (i1,fl1), C.CoFix (i2,fl2)) ->
+ i1 = i2 &&
+ List.fold_right2
+ (fun (_,ty1,bo1) (_,ty2,bo2) b ->
+ b && aux ty1 ty2 && aux bo1 bo2)
+ fl1 fl2 true
+ | (C.Abst _, _) | (_, C.Abst _) | (C.Cast _, _) | (_, C.Cast _)
+ | (C.Implicit, _) | (_, C.Implicit) ->
+ raise (Impossible 3) (* we don't trust our whd ;-) *)
+ | (_,_) ->
+ debug t1' [t2'] "NOT-CONVERTIBLE" ;
+ false
+ end
+ in
+ aux t1 t2
+;;
projects / helm.git / blobdiff