anchor.diff:  (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)
  
positive.code:    since `nil` is falsey, evaluation does not continue."
    (cond
      [(empty? vars) `((lambda () ,@body))]
      [else `((lambda (,(caar vars))
                (cond
                  [,(caar vars) (when-let* ,(cdr vars) ,@body)]
                  [else nil]))
              ,(make-binding (cdar vars)))]))
  
  
negative.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 ,(make-vars (car var)) (when ,(make-test (car var)) ,@body)) ,(cadr var)))
  
  (defun make-setting (var) :hidden
    (if (= (n var) 2)
  