`Variable.T`

`type t = t`

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

`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

- (
`(=)`

,`hash`

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

,`hash`

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

correctly - (
`(==)`

,`hash`

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

`include Map.OrderedType with type 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 : out_channel -> t -> unit`

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