`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.hash`

) for comparing objects by structure (provided objects do not contain floats) - (
`(fun x y -> compare x y = 0)`

,`Hashtbl.hash`

) for comparing objects by structure and handling`Stdlib.nan`

correctly - (
`(==)`

,`Hashtbl.hash`

) for comparing objects by physical equality (e.g. for mutable or cyclic objects).