For convenience the same operations can be applied to arrays as well as to lists. However, size affecting operations are more costly when using arrays. L is treated as the right hand side of an assignment. If L is empty, the NULL expression is returned.
L is treated as the right hand side of an assignment.
A subrange can be extracted from a given list. The index can be any expression that evaluates to an integer value. See also the less and sort commands of the user module. None of the above commands have expressions as results. Therefore they cannot be used to build up expressions or on the right hand side of an assignment.