4.3 Logical functions

Besides the special forms and and or (see section 2.6 ), the standard library provides the unary not function, which complements its boolean argument.

(not obj) \(\rightarrow \) boolean

The negation of any non-boolean value is false, as is the negation of true, i.e., any value different from false represents truth in the language:

(not 3) ;; => false
(not {}) ;; => false
(not []) ;; => false
(not [1 2]) ;; => false
(not true) ;; => false
(not false) ;; => true