+let rec find_in_ctx i name = function
+ | [] -> raise (ProofEngineTypes.Fail (lazy ("Hypothesis not found: " ^ name)))
+ | Some (Cic.Name name', _)::tl when name = name' -> i
+ | _::tl -> find_in_ctx (i+1) name tl
+;;
+
+let rec position_of i x = function
+ | [] -> assert false
+ | j::tl when j <> x -> position_of (i+1) x tl
+ | _ -> i
+;;
+
+let superposition_tac ~what ~other ~subterms_only ~demodulate status =
+ reset_refs();
+ let proof,goalno = status in
+ let curi,metasenv,pbo,pty = proof in
+ let metano,context,ty = CicUtil.lookup_meta goalno metasenv in
+ let eq_uri,tty = eq_and_ty_of_goal ty in
+ let env = (metasenv, context, CicUniv.empty_ugraph) in
+ let names = names_of_context context in
+ let eq_index, equalities, maxm = find_equalities context proof in
+ let what = find_in_ctx 1 what context in
+ let other = find_in_ctx 1 other context in
+ let eq_what = List.nth equalities (position_of 0 what eq_index) in
+ let eq_other = List.nth equalities (position_of 0 other eq_index) in
+ let index = Indexing.index Indexing.empty eq_other in
+ let maxm, eql =
+ Indexing.superposition_right
+ ~subterms_only eq_uri maxm env index eq_what
+ in
+ prerr_endline ("Superposition right:");
+ prerr_endline ("\n eq: " ^ Equality.string_of_equality eq_what ~env);
+ prerr_endline ("\n table: " ^ Equality.string_of_equality eq_other ~env);
+ prerr_endline ("\n result: ");
+ List.iter (fun e -> prerr_endline (Equality.string_of_equality e ~env)) eql;
+ prerr_endline ("\n result (cut&paste): ");
+ List.iter
+ (fun e ->
+ let t = Equality.term_of_equality eq_uri e in
+ prerr_endline (CicPp.pp t names))
+ eql;
+ if demodulate then
+ begin
+ let table = List.fold_left Indexing.index Indexing.empty equalities in
+ let maxm,eql =
+ List.fold_left
+ (fun (maxm,acc) e ->
+ let maxm,eq =
+ Indexing.demodulation_equality
+ eq_uri maxm env table Utils.Positive e
+ in
+ maxm,eq::acc)
+ (maxm,[]) eql
+ in
+ let eql = List.rev eql in
+ prerr_endline ("\n result [demod]: ");
+ List.iter
+ (fun e -> prerr_endline (Equality.string_of_equality e ~env)) eql;
+ prerr_endline ("\n result [demod] (cut&paste): ");
+ List.iter
+ (fun e ->
+ let t = Equality.term_of_equality eq_uri e in
+ prerr_endline (CicPp.pp t names))
+ eql;
+ end;
+ proof,[goalno]
+;;
+