anchor.diff:  ;;;; * Walkers
   
   (deflisp1-walker form ()
  +  ;; By default all forms will stay the same.
     form)
   
   (deflisp1-walker if-form (consequent then else)
  +  ;; Transform the test and branches recursively.
     (new 'if-form
          :consequent (lisp1 consequent)
          :then       (lisp1 then)
          :else       (lisp1 else)))
   
   (deflisp1-walker lambda-function-form (arguments body)
  +  ;; For any function-form (ie lambda), we just transform the body.
  +  ;; We also must add the parameters to the list of bound variables.
     (let1 *bound-vars*
         (append (mapcar #'name arguments) *bound-vars*)
       (new 'lambda-function-form
  
positive.code: 
  (deflisp1-walker multiple-value-call-form (func arguments)
    (new 'multiple-value-call-form
         :func      (lisp1 func)
         :arguments (lisp1s arguments)))
  
  (deflisp1-walker multiple-value-prog1-form (first-form other-forms)
    (new 'multiple-value-prog1-form
         :first-form  (lisp1 first-form)
         :other-forms (lisp1s other-forms)))
  
  (deflisp1-walker symbol-macrolet-form (binds body)
  
negative.code: ;;;; * Entry point
  
  (defgeneric lisp1 (form)
    (:documentation "Translate FORM from Lisp-1 to Lisp-2.
  
  Define methods on this generic function with DEFLISP1-WALKER."))
  
  (defmethod lisp1 (form)
    "If FORM isn't a FORM object, we'll convert it to one, apply
  the transformation and convert it back."
    (unwalk-form (lisp1 (walk-form form))))
  
  (defmacro with-lisp1 (form)
    "Execute FORM as if it were run in a Lisp-1."
    (lisp1 form))
  
  (defmacro deflisp1-walker (class (&rest slots) &body body)
    "Define a Lisp-1 to Lisp-2 walker.
  
  It takes the class of a CL form object, and its slots as
  arguments.  It also captures the variable FORM for convenience."
    `(defmethod lisp1 ((form ,class))
       (with-slots ,slots form
         ,@body)))
  
  ;;;; * Special Variables
  
  (defvar *bound-vars* nil
    "When walking code, this variable contains a list of
  variables (represented by symbols) which have been bound.")
  
  ;;;; * Definers
  
  (defmacro defun1 (name (&rest args) &body body)
    "Define a function with BODY written in Lisp-1 style.
  
  This is just like DEFUN."
    (let1 *bound-vars*
        (append *bound-vars* (extract-argument-names args :allow-specializers nil))
      `(defun ,name ,args
         ,(lisp1 `(block ,name ,@body)))))
  
  (defmacro defmethod1 (name (&rest args) &body body)
    "Define a function with BODY written in Lisp-1 style.
  
  This is just like DEFMETHOD."
    (let1 *bound-vars*
        (append *bound-vars* (extract-argument-names args :allow-specializers t))
      `(defmethod ,name ,args
  