anchor.diff:  
   (defmacro decf (place &optional (delta #'1))
     #`(setf ,place (- ,place ,delta)))
  +
  +;;;; Stuff
  +
  +(defun nil? (x)
  +  (if (eq nil x) #t #f))
   
   (defmacro assert (test &optional (msg #'"assertion failed"))
     #`(let ((result ,test))
  
positive.code: (defmethod = ((a object) (b object))
    (eq a b))
  
  ;;;; Numbers
  
  (defmacro define-jsnums-binop (name jsnums-name)
    #`(progn
        (defgeneric ,name (a b))
        (defmethod ,name ((a number) (b number))
          #{ jsnums.~(native-snippet ,jsnums-name)(~a, ~b) #})))
  
  (define-jsnums-binop = "equals")
  (define-jsnums-binop > "greaterThan")
  (define-jsnums-binop < "lessThan")
  (define-jsnums-binop / "divide")
  (define-jsnums-binop * "multiply")
  (define-jsnums-binop + "add")
  (define-jsnums-binop - "subtract")
  
  ;;;; Printing
  
  (defmethod show ((a object))
    #{ JSON.stringify(~a) #})
  
negative.code: (defun not (x)
    (if x #f #t))
  
  ;;;; (Slightly) Generalized references
  
  (eval-when-compile
    (defun setter-name (getter-name)
  