+let type_of_aux' metasenv context term ugraph =
+ try
+ type_of_aux' metasenv context term ugraph
+ with
+ CicUniv.UniverseInconsistency msg -> raise (RefineFailure msg)
+
+(*CSC: this is a very very rough approximation; to be finished *)
+let are_all_occurrences_positive uri =
+ let rec aux =
+ (*CSC: here we should do a whd; but can we do that? *)
+ function
+ Cic.Appl (Cic.MutInd (uri',_,_)::_) when uri = uri' -> ()
+ | Cic.MutInd (uri',_,_) when uri = uri' -> ()
+ | Cic.Prod (_,_,t) -> aux t
+ | _ -> raise (RefineFailure "not well formed constructor type")
+ in
+ aux
+
+let typecheck metasenv uri obj =
+ let ugraph = CicUniv.empty_ugraph in
+ match obj with
+ Cic.Constant (name,Some bo,ty,args,attrs) ->
+ let bo',boty,metasenv,ugraph = type_of_aux' metasenv [] bo ugraph in
+ let ty',_,metasenv,ugraph = type_of_aux' metasenv [] ty ugraph in
+ let subst,metasenv,ugraph = fo_unif_subst [] [] metasenv boty ty' ugraph in
+ let bo' = CicMetaSubst.apply_subst subst bo' in
+ let ty' = CicMetaSubst.apply_subst subst ty' in
+ let metasenv = CicMetaSubst.apply_subst_metasenv subst metasenv in
+ Cic.Constant (name,Some bo',ty',args,attrs),metasenv,ugraph
+ | Cic.Constant (name,None,ty,args,attrs) ->
+ let ty',_,metasenv,ugraph = type_of_aux' metasenv [] ty ugraph in
+ Cic.Constant (name,None,ty',args,attrs),metasenv,ugraph
+ | Cic.CurrentProof (name,metasenv',bo,ty,args,attrs) ->
+ assert (metasenv' = metasenv);
+ (* Here we do not check the metasenv for correctness *)
+ let bo',boty,metasenv,ugraph = type_of_aux' metasenv [] bo ugraph in
+ let ty',sort,metasenv,ugraph = type_of_aux' metasenv [] ty ugraph in
+ begin
+ match sort with
+ Cic.Sort _
+ (* instead of raising Uncertain, let's hope that the meta will become
+ a sort *)
+ | Cic.Meta _ -> ()
+ | _ -> raise (RefineFailure "The term provided is not a type")
+ end;
+ let subst,metasenv,ugraph = fo_unif_subst [] [] metasenv boty ty' ugraph in
+ let bo' = CicMetaSubst.apply_subst subst bo' in
+ let ty' = CicMetaSubst.apply_subst subst ty' in
+ let metasenv = CicMetaSubst.apply_subst_metasenv subst metasenv in
+ Cic.CurrentProof (name,metasenv,bo',ty',args,attrs),metasenv,ugraph
+ | Cic.Variable _ -> assert false (* not implemented *)
+ | Cic.InductiveDefinition (tys,args,paramsno,attrs) ->
+ (*CSC: this code is greately simplified and many many checks are missing *)
+ (*CSC: e.g. the constructors are not required to build their own types, *)
+ (*CSC: the arities are not required to have as type a sort, etc. *)
+ let uri = match uri with Some uri -> uri | None -> assert false in
+ let typesno = List.length tys in
+ (* first phase: we fix only the types *)
+ let metasenv,ugraph,tys =
+ List.fold_right
+ (fun (name,b,ty,cl) (metasenv,ugraph,res) ->
+ let ty',_,metasenv,ugraph = type_of_aux' metasenv [] ty ugraph in
+ metasenv,ugraph,(name,b,ty',cl)::res
+ ) tys (metasenv,ugraph,[]) in
+ let con_context =
+ List.rev_map (fun (name,_,ty,_)-> Some (Cic.Name name,Cic.Decl ty)) tys in
+ (* second phase: we fix only the constructors *)
+ let metasenv,ugraph,tys =
+ List.fold_right
+ (fun (name,b,ty,cl) (metasenv,ugraph,res) ->
+ let metasenv,ugraph,cl' =
+ List.fold_right
+ (fun (name,ty) (metasenv,ugraph,res) ->
+ let ty = CicTypeChecker.debrujin_constructor uri typesno ty in
+ let ty',_,metasenv,ugraph =
+ type_of_aux' metasenv con_context ty ugraph in
+ let undebrujin t =
+ snd
+ (List.fold_right
+ (fun (name,_,_,_) (i,t) ->
+ (* here the explicit_named_substituion is assumed to be *)
+ (* of length 0 *)
+ let t' = Cic.MutInd (uri,i,[]) in
+ let t = CicSubstitution.subst t' t in
+ i - 1,t
+ ) tys (typesno - 1,t)) in
+ let ty' = undebrujin ty' in
+ metasenv,ugraph,(name,ty')::res
+ ) cl (metasenv,ugraph,[])
+ in
+ metasenv,ugraph,(name,b,ty,cl')::res
+ ) tys (metasenv,ugraph,[]) in
+ (* third phase: we check the positivity condition *)
+ List.iter
+ (fun (_,_,_,cl) ->
+ List.iter (fun (_,ty) -> are_all_occurrences_positive uri ty) cl
+ ) tys ;
+ Cic.InductiveDefinition (tys,args,paramsno,attrs),metasenv,ugraph
+