prog/gnu/guile/gtk.scm

(use-modules (gi) (gi repository))

(require "Gio" "2.0")
(require "Gtk" "3.0")

(load-by-name "Gio" "Application") ;; activate, run
(load-by-name "Gtk" "Application")
(load-by-name "Gtk" "ApplicationWindow")
(load-by-name "Gtk" "Button")
(load-by-name "Gtk" "ButtonBox")
(load-by-name "Gtk" "Widget") ;; show-all

(define (print-hello widget)
  (display "Hello World\n"))

(define (activate-callback app)
  (let* ((window (make <GtkApplicationWindow>
                   #:application app
                   #:default-height 200
                   #:default-width 200
                   #:title "Window"))
         (button-box (make <GtkButtonBox> #:parent window))
         (button (make <GtkButton>
                   #:parent button-box
                   #:label "Hello world")))
    (connect button clicked print-hello)
    (connect button clicked (lambda _ (destroy window)))
    (show-all window)))

(define (main)
  (let ((app (make <GtkApplication> #:application-id "org.gtk.example")))
    (connect app activate activate-callback)
    (run app (command-line))))

(main)