[semidet]cmp_versions(?Cmp,
+V1, +V2)<, =<, =, >=
or >. If
Cmp is unbound we check whether < or >
hold or else bind Cmp to
=.
When comparing for equality (=), the versions are
considered equal if they compare equal up to the detail level of the
least specified. E.g,’9.1.2' is considered equal to’9.1'.