;; Load Gtk
(use-modules (g-golf))
(gi-import "Gtk")

;; When the application is launched..
(define (activate app)
  ;; - Create a new window and a new button
  (let ((window (make <gtk-application-window>
                  #:title "Hello"
                  #:application app))
        (button (make <gtk-button>
                  #:label "Hello, World!")))
    ;; - Which closes the window when clicked
    (connect button
             'clicked
             (lambda (b)
               (close window)))
    (set-child window button)
    (show window)))

(let ((app (make <gtk-application>
             #:application-id "com.example.GtkApplication")))
  (connect app 'activate activate)
  (run app 0 '()))