anchor.diff:  (defmethod add ((list <list>) elt)
     (list-add list elt))
   
  -(defclass <list-iter> (list i))
  +(defclass <list-iter> () 
  +  (list
  +   i))
   
   (defun <list-iter> ((list <list>))
     (let ((iter (make <list-iter>)))
  
positive.code:   "#<function>")
  
  
  ;; Conditions
  
  (defmacro deferror (name &rest slots)
    #`(defclass (,name <error>) ,@slots))
  
  (defclass <exception>)
  (defclass (<error> <exception>))
  (defclass (<warning> <exception>))
  (defclass (<restart> <exception>))
  
  ;; Collections
  
  (defgeneric elt (collection index))
  
negative.code: (defmacro make (class-name)
    #`(make-instance (class ,class-name)))
  
  (defmacro defclass (class-name &optional (supers #'()) (slots #'()))
    (let ((superclass (if (compound-empty? supers) #f (compound-elt supers 0))))
      #`(progn
          (defvar (class ,class-name) (make-class))
          ,(if superclass 
  