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ANSI Common Lisp  14 Conses 14.2 Dictionary of Conses
- Syntax:
-
null
object
 boolean
- Arguments and Values:
-
object - an object.
boolean - a boolean.
- Description:
-
Returns t if object is the empty list; otherwise, returns nil.
- Examples:
-
(null '()) T
(null nil) T
(null t) NIL
(null 1) NIL
- See Also:
-
not
- Notes:
-
null is intended to be used to test for the empty list
whereas not is intended to be used to invert a boolean
(or generalized boolean).
Operationally, null and not compute the same result;
which to use is a matter of style.
(null object) ==(typep object 'null) ==(eq object '())
- Allegro CL Implementation Details:
-
None.
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