[semidet]ord_selectchk(+Item,
?Set1, ?Set2)select(Item, Set1, Set2) and Set1, Set2
are both sorted lists without duplicates. This implementation is only
expected to work for Item ground and either Set1
or Set2 ground. The "chk" suffix is meant to remind you of memberchk/2,
which also expects its first argument to be ground. ord_selectchk(X, S, T) =>
ord_memberchk(X, S) & \+ ord_memberchk(X, T).