+ fprintf fmt "%s"
+ (Pretty.padding (max_pre - Pretty.length s1 - Pretty.length s2));
+ fprintf fmt " %s %s@\n" Pretty.left_arrow s3;
+ ) strs_strings;
+ fprintf fmt "%s@\n" line
+
+
+let get_trans a tag states =
+ StateSet.fold (fun q acc0 ->
+ try
+ let trs = Hashtbl.find a.transitions q in
+ List.fold_left (fun acc1 (labs, phi) ->
+ if QNameSet.mem tag labs then
+ TransList.cons (Transition.make (q, labs, phi)) acc1
+ else acc1) acc0 trs
+ with Not_found -> acc0
+ ) states TransList.nil
+
+
+let get_form a tag q =
+ try
+ let trs = Hashtbl.find a.transitions q in
+ List.fold_left (fun aphi (labs, phi) ->
+ if QNameSet.mem tag labs then Formula.or_ aphi phi else aphi
+ ) Formula.false_ trs
+ with
+ Not_found -> Formula.false_
+
+(*
+ [complete transitions a] ensures that for each state q
+ and each symbols s in the alphabet, a transition q, s exists.
+ (adding q, s -> F when necessary).
+*)
+
+let complete_transitions a =
+ StateSet.iter (fun q ->
+ if StateSet.mem q a.starting_states then ()
+ else
+ let qtrans = Hashtbl.find a.transitions q in
+ let rem =
+ List.fold_left (fun rem (labels, _) ->
+ QNameSet.diff rem labels) QNameSet.any qtrans
+ in
+ let nqtrans =
+ if QNameSet.is_empty rem then qtrans
+ else
+ (rem, Formula.false_) :: qtrans
+ in
+ Hashtbl.replace a.transitions q nqtrans
+ ) a.states
+
+(* [cleanup_states] remove states that do not lead to a
+ selecting states *)
+
+let cleanup_states a =
+ let memo = ref StateSet.empty in
+ let rec loop q =
+ if not (StateSet.mem q !memo) then begin
+ memo := StateSet.add q !memo;
+ let trs = try Hashtbl.find a.transitions q with Not_found -> [] in
+ List.iter (fun (_, phi) ->
+ StateSet.iter loop (Formula.get_states phi)) trs
+ end
+ in
+ StateSet.iter loop a.selecting_states;
+ let unused = StateSet.diff a.states !memo in
+ StateSet.iter (fun q -> Hashtbl.remove a.transitions q) unused;
+ a.states <- !memo
+
+(* [normalize_negations a] removes negative atoms in the formula
+ complementing the sub-automaton in the negative states.
+ [TODO check the meaning of negative upward arrows]
+*)
+
+let normalize_negations auto =
+ let memo_state = Hashtbl.create 17 in
+ let todo = Queue.create () in
+ let rec flip b f =
+ match Formula.expr f with
+ Boolean.True | Boolean.False -> if b then f else Formula.not_ f
+ | Boolean.Or(f1, f2) ->
+ (if b then Formula.or_ else Formula.and_)(flip b f1) (flip b f2)
+ | Boolean.And(f1, f2) ->
+ (if b then Formula.and_ else Formula.or_)(flip b f1) (flip b f2)
+ | Boolean.Atom(a, b') -> begin
+ match a.Atom.node with
+ | Move (m, q) ->
+ if b == b' then begin
+ (* a appears positively, either no negation or double negation *)
+ if not (Hashtbl.mem memo_state (q,b)) then Queue.add (q,true) todo;
+ Formula.mk_atom (Move(m, q))
+ end else begin
+ (* need to reverse the atom
+ either we have a positive state deep below a negation
+ or we have a negative state in a positive formula
+ b' = sign of the state
+ b = sign of the enclosing formula
+ *)
+ let not_q =
+ try
+ (* does the inverted state of q exist ? *)
+ Hashtbl.find memo_state (q, false)
+ with
+ Not_found ->
+ (* create a new state and add it to the todo queue *)
+ let nq = State.next () in
+ auto.states <- StateSet.add nq auto.states;
+ Hashtbl.add memo_state (q, false) nq;
+ Queue.add (q, false) todo; nq
+ in
+ Formula.mk_atom (Move (m,not_q))
+ end
+ | _ -> if b then f else Formula.not_ f
+ end
+ in
+ (* states that are not reachable from a selection stat are not interesting *)
+ StateSet.iter (fun q -> Queue.add (q, true) todo) auto.selecting_states;
+
+ while not (Queue.is_empty todo) do
+ let (q, b) as key = Queue.pop todo in
+ if not (StateSet.mem q auto.starting_states) then
+ let q' =
+ try
+ Hashtbl.find memo_state key
+ with
+ Not_found ->
+ let nq = if b then q else
+ let nq = State.next () in
+ auto.states <- StateSet.add nq auto.states;
+ nq
+ in
+ Hashtbl.add memo_state key nq; nq
+ in
+ let trans = try Hashtbl.find auto.transitions q with Not_found -> [] in
+ let trans' = List.map (fun (lab, f) -> lab, flip b f) trans in
+ Hashtbl.replace auto.transitions q' trans';
+ done;
+ cleanup_states auto
+
+exception Found of State.t * State.t
+
+let simplify_epsilon auto =
+ let rec loop old_states =
+ if old_states != auto.states then begin
+ let old_states = auto.states in
+ try
+ Hashtbl.iter
+ (fun qfrom v -> match v with
+ [ (labels, phi) ] ->
+ if labels == QNameSet.any then begin
+ match (Formula.expr phi) with
+ Boolean.Atom ( {Atom.node = Move(`Stay, qto); _ }, true) -> raise (Found (qfrom, qto))
+ | _ -> ()
+ end
+ | _ -> ()
+ ) auto.transitions
+ with Found (qfrom, qto) ->
+ Hashtbl.remove auto.transitions qfrom;
+ let new_trans = Hashtbl.fold (fun q tr_lst acc ->
+ let new_tr_lst =
+ List.map (fun (lab, phi) ->
+ (lab, Formula.rename_state phi qfrom qto))
+ tr_lst
+ in
+ (q, new_tr_lst) :: acc) auto.transitions []
+ in
+ Hashtbl.reset auto.transitions;
+ List.iter (fun (q, l) -> Hashtbl.add auto.transitions q l) new_trans;
+ auto.states <- StateSet.remove qfrom auto.states;
+ if (StateSet.mem qfrom auto.starting_states) then
+ auto.starting_states <- StateSet.add qto (StateSet.remove qfrom auto.starting_states);
+ if (StateSet.mem qfrom auto.selecting_states) then
+ auto.selecting_states <- StateSet.add qto (StateSet.remove qfrom auto.selecting_states);
+ loop old_states
+ end
+ in
+ loop StateSet.empty
+
+
+
+(* [compute_dependencies auto] returns a hash table storing for each
+ states [q] a Move.table containing the set of states on which [q]
+ depends (loosely). [q] depends on [q'] if there is a transition
+ [q, {...} -> phi], where [q'] occurs in [phi].
+*)
+let compute_dependencies auto =
+ let edges = Hashtbl.create 17 in
+ StateSet.iter
+ (fun q -> Hashtbl.add edges q (Move.create_table StateSet.empty))
+ auto.starting_states;
+ Hashtbl.iter (fun q trans ->
+ let moves = try Hashtbl.find edges q with Not_found ->
+ let m = Move.create_table StateSet.empty in
+ Hashtbl.add edges q m;
+ m
+ in
+ List.iter (fun (_, phi) ->
+ let m_phi = Formula.get_states_by_move phi in
+ Move.iter (fun m set ->
+ Move.set moves m (StateSet.union set (Move.get moves m)))
+ m_phi) trans) auto.transitions;
+
+ edges
+
+let state_prerequisites dir auto q =
+ Hashtbl.fold (fun q' trans acc ->
+ List.fold_left (fun acc (_, phi) ->
+ let m_phi = Formula.get_states_by_move phi in
+ if StateSet.mem q (Move.get m_phi dir)
+ then StateSet.add q' acc else acc)
+ acc trans) auto.transitions StateSet.empty
+
+let compute_rank auto =
+ let dependencies = compute_dependencies auto in
+ let upward = [ `Stay ; `Parent ; `Previous_sibling ] in
+ let downward = [ `Stay; `First_child; `Next_sibling ] in
+ let swap dir = if dir == upward then downward else upward in
+ let is_satisfied dir q t =
+ Move.for_all (fun d set ->
+ if List.mem d dir then
+ StateSet.(is_empty (remove q set))
+ else StateSet.is_empty set) t
+ in
+ let update_dependencies dir initacc =
+ let rec loop acc =
+ let new_acc =
+ Hashtbl.fold (fun q deps acc ->
+ let to_remove = StateSet.union acc initacc in
+ List.iter
+ (fun m ->
+ Move.set deps m (StateSet.diff (Move.get deps m) to_remove)
+ )
+ dir;
+ if is_satisfied dir q deps then StateSet.add q acc else acc
+ ) dependencies acc
+ in
+ if acc == new_acc then new_acc else loop new_acc
+ in
+ let satisfied = loop StateSet.empty in
+ StateSet.iter (fun q ->
+ Hashtbl.remove dependencies q) satisfied;
+ satisfied
+ in
+ let current_states = ref StateSet.empty in
+ let rank_list = ref [] in
+ let rank = ref 0 in
+ let current_dir = ref upward in
+ let detect_cycle = ref 0 in
+ while Hashtbl.length dependencies != 0 do
+ let new_sat = update_dependencies !current_dir !current_states in
+ if StateSet.is_empty new_sat then incr detect_cycle;
+ if !detect_cycle > 2 then assert false;
+ rank_list := (!rank, new_sat) :: !rank_list;
+ rank := !rank + 1;
+ current_dir := swap !current_dir;
+ current_states := StateSet.union new_sat !current_states;
+ done;
+ let by_rank = Hashtbl.create 17 in
+ List.iter (fun (r,s) ->
+ let set = try Hashtbl.find by_rank r with Not_found -> StateSet.empty in
+ Hashtbl.replace by_rank r (StateSet.union s set)) !rank_list;
+ auto.ranked_states <-
+ Array.init (Hashtbl.length by_rank) (fun i -> Hashtbl.find by_rank i)
+
+
+module Builder =
+ struct
+ type auto = t
+ type t = auto
+ let next = Uid.make_maker ()
+
+ let make () =
+ let auto =
+ {
+ id = next ();
+ states = StateSet.empty;
+ starting_states = StateSet.empty;
+ selecting_states = StateSet.empty;
+ transitions = Hashtbl.create MED_H_SIZE;
+ ranked_states = [| |]
+ }
+ in
+ auto
+
+ let add_state a ?(starting=false) ?(selecting=false) q =
+ a.states <- StateSet.add q a.states;
+ if starting then a.starting_states <- StateSet.add q a.starting_states;
+ if selecting then a.selecting_states <- StateSet.add q a.selecting_states
+
+ let add_trans a q s f =
+ if not (StateSet.mem q a.states) then add_state a q;
+ let trs = try Hashtbl.find a.transitions q with Not_found -> [] in
+ let cup, ntrs =
+ List.fold_left (fun (acup, atrs) (labs, phi) ->
+ let lab1 = QNameSet.inter labs s in
+ let lab2 = QNameSet.diff labs s in
+ let tr1 =
+ if QNameSet.is_empty lab1 then []
+ else [ (lab1, Formula.or_ phi f) ]
+ in
+ let tr2 =
+ if QNameSet.is_empty lab2 then []
+ else [ (lab2, Formula.or_ phi f) ]
+ in
+ (QNameSet.union acup labs, tr1@ tr2 @ atrs)
+ ) (QNameSet.empty, []) trs
+ in
+ let rem = QNameSet.diff s cup in
+ let ntrs = if QNameSet.is_empty rem then ntrs
+ else (rem, f) :: ntrs
+ in
+ Hashtbl.replace a.transitions q ntrs
+
+
+
+ let finalize a =
+ complete_transitions a;
+ normalize_negations a;
+ simplify_epsilon a;
+ compute_rank a;
+ a
+ end
+
+
+let map_set f s =
+ StateSet.fold (fun q a -> StateSet.add (f q) a) s StateSet.empty
+
+let map_hash fk fv h =
+ let h' = Hashtbl.create (Hashtbl.length h) in
+ let () = Hashtbl.iter (fun k v -> Hashtbl.add h' (fk k) (fv v)) h in
+ h'
+
+let rec map_form f phi =
+ match Formula.expr phi with
+ | Boolean.Or(phi1, phi2) -> Formula.or_ (map_form f phi1) (map_form f phi2)
+ | Boolean.And(phi1, phi2) -> Formula.and_ (map_form f phi1) (map_form f phi2)
+ | Boolean.Atom({ Atom.node = Move(m,q); _}, b) ->
+ let a = Formula.mk_atom (Move (m,f q)) in
+ if b then a else Formula.not_ a
+ | _ -> phi
+
+let rename_states mapper a =
+ let rename q = try Hashtbl.find mapper q with Not_found -> q in
+ { Builder.make () with
+ states = map_set rename a.states;
+ starting_states = map_set rename a.starting_states;
+ selecting_states = map_set rename a.selecting_states;
+ transitions =
+ map_hash
+ rename
+ (fun l ->
+ (List.map (fun (labels, form) -> (labels, map_form rename form)) l))
+ a.transitions;
+ ranked_states = Array.map (map_set rename) a.ranked_states
+ }
+
+let copy a =
+ let mapper = Hashtbl.create MED_H_SIZE in
+ let () =
+ StateSet.iter (fun q -> Hashtbl.add mapper q (State.next())) a.states
+ in
+ rename_states mapper a
+
+
+let concat a1 a2 =
+ let a1 = copy a1 in
+ let a2 = copy a2 in
+ let link_phi =
+ StateSet.fold
+ (fun q phi -> Formula.(or_ (stay q) phi))
+ a1.selecting_states Formula.false_
+ in
+ Hashtbl.iter (fun q trs -> Hashtbl.add a1.transitions q trs)
+ a2.transitions;
+ StateSet.iter
+ (fun q ->
+ Hashtbl.replace a1.transitions q [(QNameSet.any, link_phi)])
+ a2.starting_states;
+ let a = { a1 with
+ states = StateSet.union a1.states a2.states;
+ selecting_states = a2.selecting_states;
+ transitions = a1.transitions;
+ }
+ in compute_rank a; a
+
+let merge a1 a2 =
+ let a1 = copy a1 in
+ let a2 = copy a2 in
+ let a = { a1 with
+ states = StateSet.union a1.states a2.states;
+ selecting_states = StateSet.union a1.selecting_states a2.selecting_states;
+ starting_states = StateSet.union a1.starting_states a2.starting_states;
+ transitions =
+ let () =
+ Hashtbl.iter (fun k v -> Hashtbl.add a1.transitions k v) a2.transitions
+ in
+ a1.transitions
+ } in
+ compute_rank a ; a
+
+
+let link a1 a2 q link_phi =
+ let a = { a1 with
+ states = StateSet.union a1.states a2.states;
+ selecting_states = StateSet.singleton q;
+ starting_states = StateSet.union a1.starting_states a2.starting_states;
+ transitions =
+ let () =
+ Hashtbl.iter (fun k v -> Hashtbl.add a1.transitions k v) a2.transitions
+ in
+ Hashtbl.add a1.transitions q [(QNameSet.any, link_phi)];
+ a1.transitions
+ }
+ in
+ compute_rank a; a
+
+let union a1 a2 =
+ let a1 = copy a1 in
+ let a2 = copy a2 in
+ let q = State.next () in
+ let link_phi =
+ StateSet.fold
+ (fun q phi -> Formula.(or_ (stay q) phi))
+ (StateSet.union a1.selecting_states a2.selecting_states)
+ Formula.false_
+ in
+ link a1 a2 q link_phi
+
+let inter a1 a2 =
+ let a1 = copy a1 in
+ let a2 = copy a2 in
+ let q = State.next () in
+ let link_phi =
+ StateSet.fold
+ (fun q phi -> Formula.(and_ (stay q) phi))
+ (StateSet.union a1.selecting_states a2.selecting_states)
+ Formula.true_
+ in
+ link a1 a2 q link_phi
+
+let neg a =
+ let a = copy a in
+ let q = State.next () in
+ let link_phi =
+ StateSet.fold
+ (fun q phi -> Formula.(and_ (not_(stay q)) phi))
+ a.selecting_states
+ Formula.true_
+ in
+ let () = Hashtbl.add a.transitions q [(QNameSet.any, link_phi)] in
+ let a =
+ { a with
+ selecting_states = StateSet.singleton q;
+ }
+ in
+ normalize_negations a; compute_rank a; a
+
+let diff a1 a2 = inter a1 (neg a2)