(service home-sway-service-type
         (sway-configuration
          (startup-programs
           `(,(with-extensions
               (list
                ((options->transformation
                  '((with-commit . "guile-g-golf=v0.8.0-rc9")))
                 guile-g-golf))
               #~(string-append
                  "guile "
                  #$(scheme-file "launcher.scm"
                     #~(begin
                         (eval-when (expand load eval)
                           (use-modules (oop goops))
                           (default-duplicate-binding-handler
                             '(merge-generics replace
                               warn-override-core warn last))
                           (setenv "GI_TYPELIB_PATH"
                                   #$(file-append
                                      (directory-union
                                       "typelibs"
                                       (let ((ungraft
                                              (package-mapping
                                               (lambda (p)
                                                 (cond
                                                  ;; Ungrafted fails to validate runpath.
                                                  ((string=? (package-name p)
                                                             "gst-plugins-bad")
                                                   (specification->package
                                                    "gst-plugins-bad-minimal"))
                                                  (else
                                                   (let ((old
                                                          (or (package-replacement p) p)))
                                                     (package
                                                      (inherit old)
                                                      (arguments
                                                       (substitute-keyword-arguments
                                                        (package-arguments old)
                                                        ((#:disallowed-references _)  (list))
                                                        ((#:allowed-references _) #f))))))))
                                               #:deep? #t)))
                                         (map ungraft (list gdk-pixbuf
                                                            graphene gtk harfbuzz
                                                            pango))))
                                      "/lib/girepository-1.0"))
                           (use-modules (g-golf))
                           (g-irepository-require
                            "Gtk" #:version "4.0")
                           (for-each (lambda (name)
                                       (gi-import-by-name "Gtk" name))
                                     '("Application"
                                       "ApplicationWindow"
                                       "Builder")))
                         (use-modules (sxml simple))
                         (define ui