(null)

(numberp)

(null item)

Determine whether the item is bound to nil.

The null function confirms that your item is bound to nil. If it is nil, a T is returned. If it is not nil, nil is returned.

Examples

Code	Returns
(null "Yes!")	nil
(null (> 5 6))	T

NOTES

The null function is the opposite of the boundp function.
The not and the null functions are very similar. The difference is that not checks whether the item is nil. Null is meant for testing for empty lists.