Calculates list length of a true list
(vl-list-length list-or-cons-object)
Arguments
A true or dotted list.
Return Values
An integer containing the list length if the argument is a true list; otherwise nil if list-or-cons-object is a dotted list.
Compatibility note: The vl-list-length function returns nil for a dotted list, while the corresponding Common LISP function issues an error message if the argument is a dotted list.
Examples
_$ (vl-list-length nil)
0
_$ (vl-list-length '(1 2))
2
_$ (vl-list-length '(1 2 . 3))
nil
The listp function.
