module type S =sig..end
Map.Make.type 
type +'a t 
key to type 'a.val empty : 'a tval is_empty : 'a t -> boolval mem : key -> 'a t -> boolmem x m returns true if m contains a binding for x,
       and false otherwise.val add : key -> 'a -> 'a t -> 'a tadd x y m returns a map containing the same bindings as
       m, plus a binding of x to y. If x was already bound
       in m to a value that is physically equal to y,
       m is returned unchanged (the result of the function is
       then physically equal to m). Otherwise, the previous binding
       of x in m disappears.val singleton : key -> 'a -> 'a tsingleton x y returns the one-element map that contains a binding y
        for x.val remove : key -> 'a t -> 'a tremove x m returns a map containing the same bindings as
       m, except for x which is unbound in the returned map.
       If x was not in m, m is returned unchanged
       (the result of the function is then physically equal to m).val merge : (key -> 'a option -> 'b option -> 'c option) ->
       'a t -> 'b t -> 'c tmerge f m1 m2 computes a map whose keys is a subset of keys of m1
        and of m2. The presence of each such binding, and the corresponding
        value, is determined with the function f.
        In terms of the find_opt operation, we have
        find_opt x (merge f m1 m2) = f (find_opt x m1) (find_opt x m2)
        for any key x, provided that f None None = None.val union : (key -> 'a -> 'a -> 'a option) ->
       'a t -> 'a t -> 'a tunion f m1 m2 computes a map whose keys is the union of keys
        of m1 and of m2.  When the same binding is defined in both
        arguments, the function f is used to combine them.
        This is a special case of merge: union f m1 m2 is equivalent
        to merge f' m1 m2, wheref' None None = Nonef' (Some v) None = Some vf' None (Some v) = Some vf' (Some v1) (Some v2) = f v1 v2val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> intval equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> boolequal cmp m1 m2 tests whether the maps m1 and m2 are
       equal, that is, contain equal keys and associate them with
       equal data.  cmp is the equality predicate used to compare
       the data associated with the keys.val iter : (key -> 'a -> unit) -> 'a t -> unititer f m applies f to all bindings in map m.
       f receives the key as first argument, and the associated value
       as second argument.  The bindings are passed to f in increasing
       order with respect to the ordering over the type of the keys.val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'bfold f m a computes (f kN dN ... (f k1 d1 a)...),
       where k1 ... kN are the keys of all bindings in m
       (in increasing order), and d1 ... dN are the associated data.val for_all : (key -> 'a -> bool) -> 'a t -> boolfor_all p m checks if all the bindings of the map
        satisfy the predicate p.val exists : (key -> 'a -> bool) -> 'a t -> boolexists p m checks if at least one binding of the map
        satisfies the predicate p.val filter : (key -> 'a -> bool) -> 'a t -> 'a tfilter p m returns the map with all the bindings in m
        that satisfy predicate p. If p satisfies every binding in m,
        m is returned unchanged (the result of the function is then
        physically equal to m)val partition : (key -> 'a -> bool) -> 'a t -> 'a t * 'a tpartition p m returns a pair of maps (m1, m2), where
        m1 contains all the bindings of s that satisfy the
        predicate p, and m2 is the map with all the bindings of
        s that do not satisfy p.val cardinal : 'a t -> intval bindings : 'a t -> (key * 'a) listOrd.compare, where Ord is the argument
       given to Map.Make.val min_binding : 'a t -> key * 'aOrd.compare ordering), or raise
       Not_found if the map is empty.val min_binding_opt : 'a t -> (key * 'a) optionOrd.compare ordering), or None
       if the map is empty.val max_binding : 'a t -> key * 'a
val max_binding_opt : 'a t -> (key * 'a) option
val choose : 'a t -> key * 'aNot_found if
       the map is empty. Which binding is chosen is unspecified,
       but equal bindings will be chosen for equal maps.val choose_opt : 'a t -> (key * 'a) optionNone if
       the map is empty. Which binding is chosen is unspecified,
       but equal bindings will be chosen for equal maps.val split : key -> 'a t -> 'a t * 'a option * 'a tsplit x m returns a triple (l, data, r), where
          l is the map with all the bindings of m whose key
        is strictly less than x;
          r is the map with all the bindings of m whose key
        is strictly greater than x;
          data is None if m contains no binding for x,
          or Some v if m binds v to x.val find : key -> 'a t -> 'afind x m returns the current binding of x in m,
       or raises Not_found if no such binding exists.val find_opt : key -> 'a t -> 'a optionfind_opt x m returns Some v if the current binding of x
        in m is v, or None if no such binding exists.val find_first : (key -> bool) -> 'a t -> key * 'afind_first f m, where f is a monotonically increasing function,
       returns the binding of m with the lowest key k such that f k,
       or raises Not_found if no such key exists.
       For example, find_first (fun k -> Ord.compare k x >= 0) m will return
       the first binding k, v of m where Ord.compare k x >= 0
       (intuitively: k >= x), or raise Not_found if x is greater than any
       element of m.
Since 4.05
val find_first_opt : (key -> bool) -> 'a t -> (key * 'a) optionfind_first_opt f m, where f is a monotonically increasing function,
       returns an option containing the binding of m with the lowest key k
       such that f k, or None if no such key exists.val find_last : (key -> bool) -> 'a t -> key * 'afind_last f m, where f is a monotonically decreasing function,
       returns the binding of m with the highest key k such that f k,
       or raises Not_found if no such key exists.val find_last_opt : (key -> bool) -> 'a t -> (key * 'a) optionfind_last_opt f m, where f is a monotonically decreasing function,
       returns an option containing the binding of m with the highest key k
       such that f k, or None if no such key exists.val map : ('a -> 'b) -> 'a t -> 'b tmap f m returns a map with same domain as m, where the
       associated value a of all bindings of m has been
       replaced by the result of the application of f to a.
       The bindings are passed to f in increasing order
       with respect to the ordering over the type of the keys.val mapi : (key -> 'a -> 'b) -> 'a t -> 'b tMap.S.map, but the function receives as arguments both the
       key and the associated value for each binding of the map.