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| ANSI Common Lisp 14 Conses 14.2 Dictionary of Conses
14.2.24 null | Function
  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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