anchor.diff:    (signal c)
     (invoke-debugger c))
   
  -;; 
  +;;;; Printing
   
   (defgeneric show (object))
   
  
positive.code: ;; Bootstrap defmacro
  
  (%%defsyntax defmacro
    (%%lambda (defmacro-form)
  
negative.code: (set-superclass (class function) (class object))
  (set-superclass (class nil) (class object))
  
  ;;;; Numbers
  
  ;;; small-integer, big-integer, rational, and real are defined in JS.
  
  (defclass number)
  (set-superclass (class real) (class number))
  