NULL.html -- ACL2 Version 6.3

### NULL

recognizer for the empty list

    Major Section:  ACL2-BUILT-INS

`Null` is the function that checks whether its argument is `nil`. For recursive definitions it is often preferable to test for the end of a list using `endp` instead of `null`; see endp.

`Null` is a Common Lisp function. See any Common Lisp documentation for more information.

To see the ACL2 definition of this function, see pf.