6.1.1 Booleans

The standard boolean objects are #t and #f. Note: the empty list is true.

library procedure: not obj

not returns #t if obj is false, and returns #f otherwise.

(not #t)                               ⇒ #f
(not 3)                                ⇒ #f
(not (list 3))                         ⇒ #f
(not #f)                               ⇒ #t
(not '())                              ⇒ #f
(not (list))                           ⇒ #f
(not 'nil)                             ⇒ #f

library procedure: boolean? obj

Boolean? returns #t if obj is either #t or #f and returns #f otherwise.

(boolean? #f)                          ⇒ #t
(boolean? 0)                           ⇒ #f
(boolean? '())                         ⇒ #f

This document was generated on October 23, 2011 using texi2html 5.0.