+ let is_goal_trivial = function
+ | _, [Terms.Equation (_,_,_,Terms.Eq),_], [], _, _ -> true
+ | _, [Terms.Equation (l,r,_,_),_], [], vl, _ ->
+ (try ignore(Unif.unification (* vl *) [] l r); true
+ with FoUnif.UnificationFailure _ -> false)
+ | _ -> false
+
+ let fold_build_new_clause bag maxvar id rule filter res clause_ctx =
+ debug (lazy (string_of_int (List.length res)));
+ let (bag, maxvar), res =
+ HExtlib.filter_map_acc
+ (fun (bag, maxvar) (t,subst,id2,pos,dir) ->
+ match build_clause ~fresh:true bag maxvar filter
+ rule t subst id id2 pos dir clause_ctx with
+ | None -> None
+ | Some (bag,maxvar,res,_) -> Some ((bag,maxvar),res))
+ (bag, maxvar) res
+ in
+ bag, maxvar, res
+ ;;
+
+ (* Tries to rewrite an equality to identity, using unit equalities in table *)
+ let rewrite_eq ~unify l r ty vl table =
+ let retrieve = if unify then IDX.DT.retrieve_unifiables
+ else IDX.DT.retrieve_generalizations in
+ let lcands = retrieve table l in
+ let rcands = retrieve table r in
+ let f b c =
+ let id, dir, l, r, vl =
+ match c with
+ | (d,_,_, (id,[],[Terms.Equation (l,r,ty,_),_],vl,_))-> id, d, l, r, vl
+ | (d,_,_, (id,[Terms.Equation (l,r,ty,_),_],[],vl,_))-> id, d, l, r, vl
+ |_ -> assert false
+ in
+ let reverse = (dir = Terms.Left2Right) = b in
+ let l, r, proof_rewrite_dir = if reverse then l,r,Terms.Left2Right
+ else r,l, Terms.Right2Left in
+ (id,proof_rewrite_dir,Terms.Node [ Terms.Leaf B.eqP; ty; l; r ], vl)
+ in
+ let cands1 = List.map (f true) (IDX.ClauseSet.elements lcands) in
+ let cands2 = List.map (f false) (IDX.ClauseSet.elements rcands) in
+ let t = Terms.Node [ Terms.Leaf B.eqP; ty; l; r ] in
+ let locked_vars = if unify then [] else vl in
+ let rec aux = function
+ | [] -> None
+ | (id2,dir,c,vl1)::tl ->
+ try
+ let subst = Unif.unification (* (vl@vl1) *) locked_vars c t in
+ Some (id2, dir, subst)
+ with FoUnif.UnificationFailure _ -> aux tl
+ in
+ aux (cands1 @ cands2)
+ ;;
+
+ let is_subsumed ~unify bag maxvar (id, nlit, plit, vl, _) table =
+ match nlit,plit with
+ | [Terms.Equation (l,r,ty,_) ,_],[]
+ | [],[Terms.Equation (l,r,ty,_) ,_]->
+ (match rewrite_eq ~unify l r ty vl table with
+ | None -> None
+ | Some (id2, dir, subst) ->
+ let id_t = Terms.Node [ Terms.Leaf B.eqP; ty; r; r ] in
+ build_clause ~fresh:true bag maxvar (fun _ -> true)
+ Terms.Superposition id_t subst id id2 [2] dir (fun l -> [],[l,true]))
+ | _ -> None (* TODO : implement subsumption for clauses *)
+ ;;
+ let prof_is_subsumed = HExtlib.profile ~enable "is_subsumed";;
+ let is_subsumed ~unify bag maxvar c x =
+ prof_is_subsumed.HExtlib.profile (is_subsumed ~unify bag maxvar c) x
+ ;;
+ (* id refers to a clause proving contextl l = contextr r *)
+
+ let rec deep_eq ~unify l r ty pos contextl contextr table acc =
+ match acc with
+ | None -> None
+ | Some(bag,maxvar,(id,nlit,plit,vl,p as cl),subst) ->
+ let l = Subst.apply_subst subst l in
+ let r = Subst.apply_subst subst r in
+ try
+ let subst1 = Unif.unification (* vl *) [] l r in
+ let lit =
+ match nlit,plit with
+ | [Terms.Equation (l,r,ty,o),_],[] ->
+ Terms.Equation (FoSubst.apply_subst subst1 l,
+ FoSubst.apply_subst subst1 r, ty, o)
+ | _ -> debug (lazy (Pp.pp_clause cl));assert false
+ in
+ Some(bag,maxvar,(id,[lit,true],[],vl,p),Subst.concat subst1 subst)
+ with FoUnif.UnificationFailure _ ->
+ match rewrite_eq ~unify l r ty vl table with
+ | Some (id2, dir, subst1) ->
+ let newsubst = Subst.concat subst1 subst in
+ let id_t =
+ FoSubst.apply_subst newsubst
+ (Terms.Node[Terms.Leaf B.eqP;ty;contextl r;contextr r])
+ in
+ (match
+ build_clause ~fresh:true bag maxvar (fun _ -> true)
+ Terms.Superposition id_t
+ subst1 id id2 (pos@[2]) dir (fun l -> [l,true],[])
+ with
+ | Some (bag, maxvar, c, _) ->
+ Some(bag,maxvar,c,newsubst)
+ | None -> assert false)
+ | None ->
+ match l,r with
+ | Terms.Node (a::la), Terms.Node (b::lb) when
+ a = b && List.length la = List.length lb ->
+ let acc,_,_,_ =
+ List.fold_left2
+ (fun (acc,pre,postl,postr) a b ->
+ let newcl =
+ fun x -> contextl(Terms.Node (pre@(x::postl))) in
+ let newcr =
+ fun x -> contextr(Terms.Node (pre@(x::postr))) in
+ let newpos = List.length pre::pos in
+ let footail l =
+ if l = [] then [] else List.tl l in
+ (deep_eq ~unify a b ty
+ newpos newcl newcr table acc,pre@[b],
+ footail postl, footail postr))
+ (acc,[a],List.tl la,List.tl lb) la lb
+ in acc
+ | _,_ -> None
+ ;;
+ let prof_deep_eq = HExtlib.profile ~enable "deep_eq";;
+ let deep_eq ~unify l r ty pos contextl contextr table x =
+ prof_deep_eq.HExtlib.profile (deep_eq ~unify l r ty pos contextl contextr table) x
+ ;;
+
+ let rec orphan_murder bag acc i =
+ match Terms.get_from_bag i bag with
+ | (_,_,_,_,Terms.Exact _),discarded,_ -> (discarded,acc)
+ | (_,_,_,_,Terms.Step (_,i1,i2,_,_,_)),true,_ -> (true,acc)
+ | (_,_,_,_,Terms.Step (_,i1,i2,_,_,_)),false,_ ->
+ if (List.mem i acc) then (false,acc)
+ else match orphan_murder bag acc i1 with
+ | (true,acc) -> (true,acc)
+ | (false,acc) ->
+ let (res,acc) = orphan_murder bag acc i2 in
+ if res then res,acc else res,i::acc
+ ;;
+
+ let orphan_murder bag actives cl =
+ let (id,_,_,_,_) = cl in
+ let actives = List.map (fun (i,_,_,_,_) -> i) actives in
+ let (res,_) = orphan_murder bag actives id in
+ if res then debug (lazy "Orphan murdered"); res
+ ;;
+ let prof_orphan_murder = HExtlib.profile ~enable "orphan_murder";;
+ let orphan_murder bag actives x =
+ prof_orphan_murder.HExtlib.profile (orphan_murder bag actives) x