ORDKEY signature defines a key type which is totally
ordered. Note that anything ascribing to
EQKEY as well.
type t val equal : t * t → bool val compare : t * t → order val toString : t → string
val equal : t * t → bool
val compare : t * t → order
GREATERas appropriate for the argument pair. This operation is transitive. The comparison must be consistent, that is
compare (x, y) = EQUALif and only if
equal (x, y), and
compare (x, y) = LESSif and only if
compare (y, x) = GREATER.
val toString : t → string