Recognizer for a true list of standard characters
(standard-char-listp x) is true if and only if x is a nil-terminated list all of whose members are standard characters. See standard-char-p.
Standard-char-listp has a guard of t.
Function: standard-char-listp
(defun standard-char-listp (l) (declare (xargs :guard t)) (cond ((consp l) (and (characterp (car l)) (standard-char-p (car l)) (standard-char-listp (cdr l)))) (t (equal l nil))))
