anchor.diff:      [(empty? vars) `((lambda () ,@body))]
       [else `((lambda ,(make-vars (caar vars))
                 (cond
  -                [,(make-test (caar vars)) (when-let* ,(cdr vars) ,@body)]
  +                [,(make-var (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 ,(make-vars (car var)) (when ,(make-test (car var)) ,@body)) ,(cadr var)))
  
  (defun make-setting (var) :hidden
    (if (= (n var) 2)
  
negative.code:      (when (and ,@(cars vars)) ,@body))
      ,@(map make-let-binding vars)))
  
  (defmacro when-let* (vars &body)
    "Bind each pair of `(name value)` of VARS, checking if the value is
     truthy before binding the next, and finally evaluating BODY. As with
  