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Function NOT

Syntax

  • not xboolean

Arguments and Values

Description

Returns t if x is false; otherwise, returns nil.

Examples

(not nil)

T

(not '())

T

(not (integerp 'sss))

T

(not (integerp 1))

NIL

(not 3.7)

NIL

(not 'apple)

NIL

Side Effects

None.

Affected By

None.

Exceptional Situations

None.

See Also

Notes

not is intended to be used to invert the `truth value' of a boolean (or generalized boolean) whereas null is intended to be used to test for the empty list. Operationally, not and null compute the same result; which to use is a matter of style.

\issue{NOT-AND-NULL-RETURN-VALUE:X3J13-MAR-93}