From: Edi Weitz edi@weitz.de Date: Fri, 14 Jan 2011 17:59:52 +0100 Cc: Sergey Vasilyev sergey@itasoftware.com, Common Lisp Professionals pro@common-lisp.net
There are lots of functions in the standard which are predicates in that they return generalized booleans but on the other hand return something "useful" if the result is not NIL, e.g. MEMBER or STRING<.
And some of them might also end in -p
(digit-char-p)
-nick