anchor.diff:              (t (if (eq x y) *true* *false*)))
         *false*))
   
  +(defprimfun "intern" (string)
  +  (clutter-symbol string))
  +
   (defprimfun "symbol?" (x)
     (if (clutter-symbol-p x) *true* *false*))
   (defprimfun "keyword?" (x)
  
positive.code:   (if (clutter-function-p x) *true* *false*))
  (defprimfun "vau?" (x)
    (if (clutter-operator-p x) *true* *false*))
  
  (defprimfun "vau-name" (v)
    (clutter-operator-name v))
  
negative.code: ;;; Primitive functions
  ;;;
  
  (defvar *primitives* (list))
  
  (defmacro defprimitive (name value)
    (once-only (name value)
     `(progn
        (push ,value *primitives*)
        (extend *global-env* (clutter-symbol ,name) ,value))))
  
  (defmacro defprimop (name vau-list &body body)
    `(defprimitive ,name
  