The canonical tuple functor: ,
,
Creates a right-nested Tuple out of terms.
Creates a Tuple with left and right as its two direct arguments.
Creates a right-nested Tuple out of first, second, and others.
Wraps terms into a single Term: returns ifEmpty's result if terms is empty, the sole element if terms has exactly one, or a Tuple otherwise. Used, in particular, to fold a Clause's body goals into a single Term.