(module firstorder mzscheme

  (provide make-first-order
	   first-order->higher-order)

  (define-values (struct:fo make-first-order fo? fo-get fo-set!)
    (make-struct-type 'procedure #f 2 0 #f null (current-inspector) 0))  

  (define fo-proc-id (make-struct-field-accessor fo-get 1))

  (define (first-order->higher-order id)
    (let ([v (syntax-local-value id (lambda () #f))])
      (if (or (fo? v)
              (and (set!-transformer? v)
                   (fo? (set!-transformer-procedure v))))
          (syntax-property
           (syntax-local-introduce 
            (fo-proc-id (if (fo? v) v (set!-transformer-procedure v))))
           'disappeared-use
           (syntax-local-introduce id))
	  id))))