Verifies that an item evaluates to nil
(not item)
Typically, the null function is used for lists, and not is used for other data types along with some types of control functions.
Arguments
An AutoLISP expression.
Return Values
T if item evaluates to nil; otherwise nil.
Examples
Command: (setq a 123 b "string" c nil)
nil
Command: (not a)
nil
Command: (not b)
nil
Command: (not c)
T
Command: (not '())
T
The null function.
