anchor.diff:    (let ((x 0)
           (y 0))
       (double-setf-BAD x y (+ x 100))
  -    (assert-equal x ____)
  -    (assert-equal y ____)))
  +    (assert-equal x 100 )
  +    (assert-equal y 200 )))
   
   ;; sets sym1 and sym2 to val
   (defmacro double-setf-SAFER (sym1 sym2 val)
  
positive.code: (defmacro log-form-with-value (&body body)
    "records the body form, and the form's return value
     to the list *log-with-value* and then evalues the body normally"
    `(let ((logform nil)
           (retval ,@body))
  
       ;; YOUR MACRO COMPLETION CODE GOES HERE.
  
       retval))
  
  
  
  
negative.code:    (repeat-2 (do-something arg1 arg2)))
  
    (assert-expands
     '(progn (setf x (+ 1 x)) (setf x (+ 1 x)))
     (repeat-2 (setf x (+ 1 x)))))
  
  
  