LISP: Keyword parameters, supplied-p

Question

At the moment I\'m working through \"Practical Common Lisp\" from Peter Seibel.

In the chapter \"Practical: A Simple Database\" (http://www.gigamonkeys.com/book/pract

Answer 1

It's difficult to tell what you are asking. c-p is bound to T or NIL, depending on whether c is supplied as a parameter. This binding is then available to the body of the function.