## table of contents

- bullseye 4.11.1-4
- testing 4.11.1-5
- unstable 4.11.1-5
- experimental 4.13.1-2

Hashtbl.HashedType(3o) | OCaml library | Hashtbl.HashedType(3o) |

# NAME¶

Hashtbl.HashedType - The input signature of the functor Hashtbl.Make.

# Module type¶

Module type Hashtbl.HashedType

# Documentation¶

Module type **HashedType**

= **sig end**

The input signature of the functor **Hashtbl.Make** .

*type t*

The type of the hashtable keys.

*val equal* : **t -> t -> bool**

The equality predicate used to compare keys.

*val hash* : **t -> int**

A hashing function on keys. It must be such that if two keys are
equal according to **equal** , then they have identical hash values as
computed by **hash** . Examples: suitable ( **equal** , **hash** )
pairs for arbitrary key types include

- ( **(=)** , **Hashtbl.HashedType.hash** ) for comparing
objects by structure (provided objects do not contain floats)

- ( **(fun x y -> compare x y = 0)** ,
**Hashtbl.HashedType.hash** ) for comparing objects by structure and
handling **nan** correctly

- ( **(==)** , **Hashtbl.HashedType.hash** ) for comparing
objects by physical equality (e.g. for mutable or cyclic objects).

2021-12-22 | OCamldoc |