anchor.diff:         :return (values data t)
        :finally
          (if error-p
  -           (error "Sorry, No value for ~S of type ~S in environment ~S found."
  +           (error "No value for ~S of type ~S in environment ~S was found."
                     name type environment)
              (values default-value nil))))
   
  -#+(or)
  +#+(or) ;; it's not used for now
   (defun (setf %lookup) (value environment type name &key (error-p nil))
     (loop
  -     for env-piece in environment
  -     when (and (eql (first env-piece)  type)
  -               (eql (second env-piece) name))
  -       do (setf (cddr env-piece) value) and
  -       return value
  -     finally
  +     :for env-piece :in environment
  +     :when (and (eql (first env-piece) type)
  +                (eql (second env-piece) name))
  +       :do (progn
  +             (setf (cddr env-piece) value)
  +             (return value))
  +     :finally
          (when error-p
  -         (error "Sorry, No value for ~S of type ~S in environment ~S found."
  +         (error "No value for ~S of type ~S in environment ~S was found."
                   name type environment))))
   
   ;;;
  
positive.code: (defparameter +atom-marker+ '+atom-marker+)
  
  (defun find-walker-handler (form)
    "Simple function which tells us what handler should deal
    with FORM. Signals an error if we don't have a handler for
    FORM."
    (if (atom form)
        (gethash '+atom-marker+ *walker-handlers*)
        (aif (gethash (car form) *walker-handlers*)
  
negative.code:   (unwalk-form (walk-form form nil (make-walkenv env))))
  
  (defvar *warn-undefined* nil
    "When non-NIL, any references to undefined functions or variables will signal a warning.")
  
  (defun walk-form (form &optional (parent nil) (env (make-walkenv)))
    "Walk FORM and return a CLOS based AST that represents it."
  