lispdoc - results for y-or-n-p

(y-or-n-p &optional format-string &rest arguments)
Function: Y-OR-N-P prints the message, if any, and reads characters from *QUERY-IO* until the user enters y or Y as an affirmative, or either n or N as a negative answer. It asks again if you enter any other characters.
Example:
(defun add-cds ()
  (loop (add-record (prompt-for-cd))
        (if (not (y-or-n-p "Another? [y/n]: "))
            (return))))
Mentioned in:
CLtL2 - 22.4. Querying the User
HyperSpec - Function Y-OR-N-P, YES-OR-NO-P
PCL - improving the user interaction