anchor.diff:  	(e (flatten (mapcar #'(lambda (e) (expand-randomly e rules rstate)) e)))
   	((and (listp symb)
   	      (equal (car symb) :!))
  -	 (eval (second symb)))
  +	 (expand-randomly (eval (second symb)) rules rstate))
   	(t symb))))
  +
  +  (defun uniform (&rest list)
  +    (elt list (random (length list))))
     
     (defun double-marked (rules)
       (loop
  
positive.code:   (list :if :while :id :do :id := :num :end :then :else :end :$)
    (list :id := :while :id :do :end :$))
  
  (define-random-accept-test grammar-12-random-accept-test grammar-12-parser 50 :S
    (:S --> :STMTS)
    (:STMTS --> :STMT :STMTS)
    (:STMTS --> :eps)
  
negative.code:   (:S1 --> #\( :S1 #\+ :F #\))
    (:F --> #'integerp))
  
  (define-random-test grammar-10-random-accept-test grammar-10-parser 50 :S t
    (:S --> :S1)
    (:S1 --> :F)
    (:S1 --> #\( :S1 #\+ :F #\))
  