anchor.diff:  
   (defclass simple-error (error))
   (defmethod show-object ((s simple-error))
  -  (string-concat (simple-error-message s) (simple-error-arg s)))
  +  (string-concat (simple-error-message s) ": " (simple-error-arg s)))
   
   (defclass control-error (error))
   
  
positive.code: (defmethod show-object ((a number))
    #{ (~a).toString() #})
  
  ;;;; Numbers
  
  (defmacro define-jsnums-binop (name jsnums-name)
  
negative.code: ;;;; Debugger
  
  (defun invoke-debugger ((c condition))
    (print (string-concat "Condition: " (show c)))
    (throw c))
  
  ;;;; Streams
  