Recognizer for association lists with symbols as values
(R-symbol-alistp x) is true if and only if x is a list of pairs of the form (cons key val) where val is a symbolp.
Function: r-symbol-alistp
(defun r-symbol-alistp (x) (declare (xargs :guard t)) (cond ((atom x) (equal x nil)) (t (and (consp (car x)) (symbolp (cdr (car x))) (r-symbol-alistp (cdr x))))))
