Module String.Map

String maps.

String maps

include Stdlib.Map.S with type key := string and type 'a t := 'a map
val empty : 'a map

The empty map.

val is_empty : 'a map -> bool

Test whether a map is empty or not.

val mem : string -> 'a map -> bool

mem x m returns true if m contains a binding for x, and false otherwise.

val add : string -> 'a -> 'a map -> 'a map

add 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.

before 4.03

Physical equality was not ensured.

val update : string -> ('a option -> 'a option) -> 'a map -> 'a map

update x f m returns a map containing the same bindings as m, except for the binding of x. Depending on the value of y where y is f (find_opt x m), the binding of x is added, removed or updated. If y is None, the binding is removed if it exists; otherwise, if y is Some z then x is associated to z in the resulting map. If x was already bound in m to a value that is physically equal to z, m is returned unchanged (the result of the function is then physically equal to m).

since
4.06.0
val singleton : string -> 'a -> 'a map

singleton x y returns the one-element map that contains a binding y for x.

since
3.12.0
val remove : string -> 'a map -> 'a map

remove 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).

before 4.03

Physical equality was not ensured.

val merge : (string -> 'a option -> 'b option -> 'c option) -> 'a map -> 'a map -> 'a map

merge 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.

since
3.12.0
val union : (string -> 'a -> 'a -> 'a option) -> 'a map -> 'a map -> 'a map

union 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, where

  • f' _key None None = None
  • f' _key (Some v) None = Some v
  • f' _key None (Some v) = Some v
  • f' key (Some v1) (Some v2) = f key v1 v2
since
4.03.0
val compare : ('a -> 'a -> int) -> 'a map -> 'a map -> int

Total ordering between maps. The first argument is a total ordering used to compare data associated with equal keys in the two maps.

val equal : ('a -> 'a -> bool) -> 'a map -> 'a map -> bool

equal 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 : (string -> 'a -> unit) -> 'a map -> unit

iter 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 : (string -> 'a -> 'b -> 'b) -> 'a map -> 'b -> 'b

fold 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 : (string -> 'a -> bool) -> 'a map -> bool

for_all p m checks if all the bindings of the map satisfy the predicate p.

since
3.12.0
val exists : (string -> 'a -> bool) -> 'a map -> bool

exists p m checks if at least one binding of the map satisfies the predicate p.

since
3.12.0
val filter : (string -> 'a -> bool) -> 'a map -> 'a map

filter 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)

since
3.12.0
before 4.03

Physical equality was not ensured.

val partition : (string -> 'a -> bool) -> 'a map -> 'a map * 'a map

partition 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.

since
3.12.0
val cardinal : 'a map -> int

Return the number of bindings of a map.

since
3.12.0
val bindings : 'a map -> (string * 'a) list

Return the list of all bindings of the given map. The returned list is sorted in increasing order of keys with respect to the ordering Ord.compare, where Ord is the argument given to Map.Make.

since
3.12.0
val min_binding : 'a map -> string * 'a

Return the binding with the smallest key in a given map (with respect to the Ord.compare ordering), or raise Not_found if the map is empty.

since
3.12.0
val min_binding_opt : 'a map -> (string * 'a) option

Return the binding with the smallest key in the given map (with respect to the Ord.compare ordering), or None if the map is empty.

since
4.05
val max_binding : 'a map -> string * 'a

Same as Map.S.min_binding, but returns the binding with the largest key in the given map.

since
3.12.0
val max_binding_opt : 'a map -> (string * 'a) option

Same as Map.S.min_binding_opt, but returns the binding with the largest key in the given map.

since
4.05
val choose : 'a map -> string * 'a

Return one binding of the given map, or raise Not_found if the map is empty. Which binding is chosen is unspecified, but equal bindings will be chosen for equal maps.

since
3.12.0
val choose_opt : 'a map -> (string * 'a) option

Return one binding of the given map, or None if the map is empty. Which binding is chosen is unspecified, but equal bindings will be chosen for equal maps.

since
4.05
val split : string -> 'a map -> 'a map * 'a option * 'a map

split 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.

since
3.12.0
val find : string -> 'a map -> 'a

find x m returns the current binding of x in m, or raises Not_found if no such binding exists.

val find_opt : string -> 'a map -> 'a option

find_opt x m returns Some v if the current binding of x in m is v, or None if no such binding exists.

since
4.05
val find_first : (string -> bool) -> 'a map -> string * 'a

find_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 : (string -> bool) -> 'a map -> (string * 'a) option

find_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.

since
4.05
val find_last : (string -> bool) -> 'a map -> string * 'a

find_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.

since
4.05
val find_last_opt : (string -> bool) -> 'a map -> (string * 'a) option

find_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.

since
4.05
val map : ('a -> 'b) -> 'a map -> 'a map

map 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 : (string -> 'a -> 'b) -> 'a map -> 'a map

Same as Map.S.map, but the function receives as arguments both the key and the associated value for each binding of the map.

Iterators

val to_seq : 'a map -> (string * 'a) Stdlib.Seq.t

Iterate on the whole map, in ascending order of keys

since
4.07
val to_seq_from : string -> 'a map -> (string * 'a) Stdlib.Seq.t

to_seq_from k m iterates on a subset of the bindings of m, in ascending order of keys, from key k or above.

since
4.07
val add_seq : (string * 'a) Stdlib.Seq.t -> 'a map -> 'a map

Add the given bindings to the map, in order.

since
4.07
val of_seq : (string * 'a) Stdlib.Seq.t -> 'a map

Build a map from the given bindings

since
4.07
type 'a t = 'a map
val min_binding : 'a map -> (string * 'a) option

Exception safe Map.S.min_binding.

val get_min_binding : 'a map -> string * 'a

get_min_binding is like min_binding but

raises Invalid_argument

on the empty map.

val max_binding : 'a map -> (string * 'a) option

Exception safe Map.S.max_binding.

val get_max_binding : 'a map -> string * 'a

get_max_binding is like max_binding but

raises Invalid_argument

on the empty map.

val choose : 'a map -> (string * 'a) option

Exception safe Map.S.choose.

val get_any_binding : 'a map -> string * 'a

get_any_binding is like choose but

raises Invalid_argument

on the empty map.

val find : string -> 'a map -> 'a option

Exception safe Map.S.find.

val get : string -> 'a map -> 'a

get k m is like Map.S.find but raises Invalid_argument if k is not bound in m.

val dom : 'a map -> set

dom m is the domain of m.

val of_list : (string * 'a) list -> 'a map

of_list bs is List.fold_left (fun m (k, v) -> add k v m) empty bs.

val of_stdlib_map : 'a Stdlib.Map.Make(Stdlib.String).t -> 'a map

of_stdlib_map m is a map from the stdlib-compatible map m.

val to_stdlib_map : 'a map -> 'a Stdlib.Map.Make(Stdlib.String).t

to_stdlib_map m is the stdlib-compatible map equivalent to m.

val pp : ?⁠sep:(Stdlib.Format.formatter -> unit -> unit) -> (Stdlib.Format.formatter -> (string * 'a) -> unit) -> Stdlib.Format.formatter -> 'a map -> unit

pp ~sep pp_binding ppf m formats the bindings of m on ppf. Each binding is formatted with pp_binding and bindings are separated by sep (defaults to Format.pp_print_cut). If the map is empty leaves ppf untouched.

val dump : (Stdlib.Format.formatter -> 'a -> unit) -> Stdlib.Format.formatter -> 'a map -> unit

dump pp_v ppf m prints an unspecified representation of m on ppf using pp_v to print the map codomain elements.

val dump_string_map : Stdlib.Format.formatter -> string map -> unit

dump_string_map ppf m prints an unspecified representation of the string map m on ppf.