flatten.ml

(* Original OCaml code: *)

let flatten_transitions : StateSet.t CharSetMap.t -> StateSet.t CharMap.t =
  fun char_map ->
    CharSetMap.fold
      (fun char_set state_set char_map ->
         CharSet.fold
           (fun char char_map ->
              let entry = match CharMap.find char char_map with
                | exception Not_found -> StateSet.empty
                | state_set -> state_set in
              CharMap.add char (StateSet.union state_set entry) char_map)
             char_set
             char_map)
      char_map
      CharMap.empty

(* Reason code produced by bsrefmt from OCaml: *)

let flatten_transitions: CharSetMap.t(StateSet.t) => CharMap.t(StateSet.t) =
  char_map =>
    CharSetMap.fold(
      (char_set, state_set, char_map) =>
        CharSet.fold(
          (char, char_map) => {
            let entry =
              switch (CharMap.find(char, char_map)) {
              | exception Not_found => StateSet.empty
              | state_set => state_set
              };
            CharMap.add(char, StateSet.union(state_set, entry), char_map);
          },
          char_set,
          char_map,
        ),
      char_map,
      CharMap.empty,
    );

(* Looks nice! But not so nice when trying to convert back to OCaml from Reason using bsrefmt: *)

let flatten_transitions: StateSet.t CharSetMap.t -> StateSet.t CharMap.t =
  fun char_map  ->
    CharSetMap.fold
      (fun char_set  ->
         fun state_set  ->
           fun char_map  ->
             CharSet.fold
               (fun char  ->
                  fun char_map  ->
                    let entry =
                      match CharMap.find char char_map with
                      | exception Not_found  -> StateSet.empty
                      | state_set -> state_set in
                    CharMap.add char (StateSet.union state_set entry)
                      char_map) char_set char_map) char_map CharMap.empty

(* Which is the same thing, but doesn't look very nice. *)