`module T : Identifiable.Thing with type t = t`

`include Identifiable.Thing with type t := T.t`

`include Stdlib.Hashtbl.HashedType with type t := T.t`

`val hash : T.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).

`include Stdlib.Map.OrderedType with type t := T.t`

A total ordering function over the keys. This is a two-argument function `f`

such that `f e1 e2`

is zero if the keys `e1`

and `e2`

are equal, `f e1 e2`

is strictly negative if `e1`

is smaller than `e2`

, and `f e1 e2`

is strictly positive if `e1`

is greater than `e2`

. Example: a suitable ordering function is the generic structural comparison function `Stdlib.compare`

.

`val output : Stdlib.out_channel -> T.t -> unit`

`val print : Stdlib.Format.formatter -> T.t -> unit`

`module Set : Identifiable.Set with module T := T`

`module Map : Identifiable.Map with module T := T`

`module Tbl : Identifiable.Tbl with module T := T`