anchor.diff:     since `nil` is falsey, evaluation does not continue."
     (cond
       [(empty? vars) `((lambda () ,@body))]
  -    [else `((lambda (,(caar vars))
  +    [else `((lambda ,(make-vars (caar vars))
                 (cond
  -                [,(caar vars) (when-let* ,(cdr vars) ,@body)]
  +                [,(make-test (caar vars)) (when-let* ,(cdr vars) ,@body)]
                   [else nil]))
               ,(make-binding (cdar vars)))]))
   
  
positive.code: 
     When `bar` has an index `baz`, it will be bound to `foo` and
     printed. If not, the print statement will not be executed."
    `((lambda (,(car var)) (when ,(car var) ,@body)) ,(cadr var)))
  
  (defun make-setting (var) :hidden
    (if (= (n var) 2)
  
negative.code: (defun make-vars (x) :hidden
    (if (list? x) x (list x)))
  
  (defun make-test (x) :hidden
    (if (list? x) (car x) x))
  
  (defun make-binding (xs) :hidden
    (if (= (n xs) 1)
      (car xs)
  