module IntRank: sig .. end
This module describes an ordered type
t equipped with a
distinguished constant
none. The ordering is used during
unification, see
Unifier.
type int
val compare : t -> t -> int
compare x y is a total ordering. It returns a negative integer
if x is less than y, 0 if x and y are equal, and a
positive integer if x is greater than y.
val none : t
none is the special value used to identify the universal
quantifiers of a type scheme in an environment frame. Such
variables are not part of dtv(S), that is, the type
variables currently in scope, which explains why they do not
carry a nonnegative integer rank.
val outermost : t
outermost is the rank assigned to variables that are
existentially bound at the outermost level.