anchor.diff:    (apply #'list* values))
   (defprimfun "length" (seq)
     (length seq))
  -;;; TODO: Does this sideffect?
   (defprimfun "append" (&rest lists)
     (apply #'append lists))
   
  -(defprimfun "set-head" (cons new-car)
  -  (rplaca cons new-car))
  -(defprimfun "set-tail" (cons new-cdr)
  -  (rplacd cons new-cdr))
  -
   (defprimfun "eql?" (x y)
  -  (if (eql x y) *true* *false*))
  +  (if (eql (type-of x) (type-of y))
  +      (cond ((numberp x) (if (= x y) *true* *false*))
  +            ((or (listp x) (stringp x)) (if (equal x y) *true* *false*))
  +            (t (if (eq x y) *true* *false*)))
  +      *false*))
   
   (defprimfun "symbol?" (x)
     (if (clutter-symbol-p x) *true* *false*))
  
positive.code:   (cons x y))
  (defprimfun "cons?" (x)
    (consp x))
  (defprimfun "car" (cons)
    (car cons))
  (defprimfun "cdr" (cons)
  
negative.code: (defprimfun "eval" (expression environment)
    (clutter-eval expression environment))
  
  (defprimfun "make-env" (&rest parents)
    (apply #'make-env parents))
  
  