# Functor BatHashtbl.Make

    module Make: functor (H : HashedType) -> S  with type key = H.t

Functor building an implementation of the hashtable structure. The functor `Hashtbl.Make` returns a structure containing a type `key` of keys and a type `'a t` of hash tables associating data of type `'a` to keys of type `key`. The operations perform similarly to those of the generic interface, but use the hashing and equality functions specified in the functor argument `H` instead of generic equality and hashing.

Parameters:

`H` | : | `HashedType`

    type key

    type 'a t

    val create : int -> 'a t

    val length : 'a t -> int

    val is_empty : 'a t -> bool

    val clear : 'a t -> unit

    val copy : 'a t -> 'a t

    val add : 'a t -> key -> 'a -> unit

    val remove : 'a t -> key -> unit

    val remove_all : 'a t -> key -> unit

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

    val find_all : 'a t -> key -> 'a list

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

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

    val replace : 'a t -> key -> 'a -> unit

    val mem : 'a t -> key -> bool

    val iter : (key -> 'a -> unit) -> 'a t -> unit

    val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b

    val map : (key -> 'b -> 'c) -> 'b t -> 'c t

    val map_inplace : (key -> 'a -> 'a) -> 'a t -> unit

    val filter : ('a -> bool) -> 'a t -> 'a t

    val filter_inplace : ('a -> bool) -> 'a t -> unit

    val filteri : (key -> 'a -> bool) -> 'a t -> 'a t

    val filteri_inplace : (key -> 'a -> bool) -> 'a t -> unit

    val filter_map : (key -> 'a -> 'b option) ->
           'a t -> 'b t

    val filter_map_inplace : (key -> 'a -> 'a option) -> 'a t -> unit

    val modify : key -> ('a -> 'a) -> 'a t -> unit

    val modify_def : 'a -> key -> ('a -> 'a) -> 'a t -> unit

    val modify_opt : key -> ('a option -> 'a option) -> 'a t -> unit

    val keys : 'a t -> key BatEnum.t

    val values : 'a t -> 'a BatEnum.t

    val enum : 'a t -> (key * 'a) BatEnum.t

    val of_enum : (key * 'a) BatEnum.t -> 'a t

    val print : ?first:string ->
           ?last:string ->
           ?sep:string ->
           ('a BatInnerIO.output -> key -> unit) ->
           ('a BatInnerIO.output -> 'b -> unit) ->
           'a BatInnerIO.output -> 'b t -> unit

###### Override modules

The following modules replace functions defined in `Hashtbl` with functions behaving slightly differently but having the same name. This is by design: the functions meant to override the corresponding functions of `Hashtbl`.

    module Exceptionless: sig .. end

Operations on `Hashtbl` without exceptions.

    module Infix: sig .. end

Infix operators over a `BatHashtbl`

    module Labels: sig .. end

Operations on `Hashtbl` with labels.