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package containers
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Set of Heterogeneous Values

let k1 : int key = newkey () in
let k2 : int key = newkey () in
let k3 : string key = newkey () in
let set =
  empty
  |> set ~key:k1 1
  |> set ~key:k2 2
  |> set ~key:k3 "3"
in
assert (get ~key:k1 set = Some 1);
assert (get ~key:k2 set = Some 2);
assert (get ~key:k3 set = Some "3");
()
  • since 0.11
type t

A set of values of heterogeneous types

type 'a key

A unique "key" to access a value of type 'a in a set

val newkey : unit -> 'a key

newkey () creates a new unique key that can be used to access a 'a value in a set. Each key created with newkey is distinct from any other key, even if they have the same type.

Not thread-safe.

val empty : t

Empty set.

val set : key:'a key -> 'a -> t -> t

set ~key v set maps key to v in set. It means that for every set, get ~key (set ~key v set) = Some v.

val get : key:'a key -> t -> 'a option

get ~key set obtains the value for key in set, if any.

val get_exn : key:'a key -> t -> 'a

Same as get, but can fail.

  • raises Not_found

    if the key is not present.

val cardinal : t -> int

Number of mappings.