?Var in +DomainVar is an element of Domain. Domain is
one of:
- Integer
- Singleton set consisting only of Integer.
- Lower .. Upper
- All integers I such that Lower
=< I =< Upper.
Lower must be an integer or the atom inf, which
denotes negative infinity. Upper must be an integer or
the atom sup, which denotes positive infinity.
- Domain1
\/ Domain2 - The union of Domain1 and Domain2.
[det]in(+TupleList,
-Tuple)As in/1 but succeeds when any one of
the tuples in TupleList is available. Tuple is
unified with the fetched tuple.