anchor.diff:                                   x))))
       (if parsed-value
           (call-next-method tmpl
  -                          parsed-value)
  +                          parsed-value
  +                          bindings)
           +fail+)))
                         
                           
  
positive.code: (defun unify (x y &optional (bindings +no-bindings+))
    (if bindings
        (unify/impl x y bindings)))
  
  
  ;;; unify/impl for wildcard
  
negative.code:                        (first b)
                         bindings))))))
  
  ;;; unify/impl for strings
  
  (defmethod unify/impl ((a string) (b string) bindings)
  