module type HashedType = sig .. endThe input signature of the functor Hashtbl.Make.
type t;
The type of the hashtable keys.
let equal: (t, t) => bool;
The equality predicate used to compare keys.
let 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).