anchor.diff:       :while rules
        :collect (let ((rule (pop rules)))
                   (destructuring-bind (nt rhs) rule
  +                  (assert rhs (rule) "Invalid rule, missing right-hand-side: ~S" rule)
                     (labels ((new-rule (nt rhs)
                                (push nt non-terminals)
                                (push (list nt rhs) rules))
  
positive.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;; THE END ;;;;
  
  
negative.code:                        :scanner scanner
                         :skip-spaces skip-spaces))
           (*linenum* 0))
      (register-grammar grammar)
  
      `(let ((*eof-symbol* ',*eof-symbol*))
  