implemented

main.rkt

@@ -7,33 +7,105 @@
          tray-set-icon!
          tray-set-menu!)
 
-(define (unsupported who . _args)
-  (error who "not supported on this operating system: ~a" (system-type 'os*)))
-
-(define mk-tray
-  (λ args
-    (apply unsupported 'mk-tray args)))
-
-(define tray-close
-  (λ args
-    (apply unsupported 'tray-close args)))
-
-(define tray-set-icon!
-  (λ args
-    (apply unsupported 'tray-set-icon! args)))
-
-(define tray-set-menu!
-  (λ args
-    (apply unsupported 'tray-set-menu! args)))
-
+;; The platform implementation is loaded dynamically so that requiring
+;; racket-tray remains possible on platforms that do not yet have a backend.
 (define-runtime-module-path windows-module "private/windows.rkt")
 
+(define platform-mk-tray #f)
+(define platform-tray-close #f)
+(define platform-tray-set-icon! #f)
+(define platform-tray-set-menu! #f)
+
 (when (eq? (system-type 'os*) 'windows)
-  (set! mk-tray
+  (set! platform-mk-tray
         (dynamic-require windows-module 'mk-tray))
-  (set! tray-close
+  (set! platform-tray-close
         (dynamic-require windows-module 'tray-close))
-  (set! tray-set-icon!
+  (set! platform-tray-set-icon!
         (dynamic-require windows-module 'tray-set-icon!))
-  (set! tray-set-menu!
+  (set! platform-tray-set-menu!
         (dynamic-require windows-module 'tray-set-menu!)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Supporting functions
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Report that the current operating system has no tray backend.
+; pre    : who is the name of the public procedure being called.
+; post   : No state is changed.
+; result : Does not return; raises an exception naming the unsupported OS.
+; internals:
+;          The public module remains loadable on every platform; only an
+;          attempted tray operation fails when no backend was loaded.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (unsupported who)
+  (error who "not supported on this operating system: ~a" (system-type 'os*)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Provided functions
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Create a tray icon using the backend for the current platform.
+; pre    : frame, icon-file, on-click-cb and hide-on-minimize? satisfy the
+;          requirements documented for mk-tray.
+; post   : On a supported platform a tray icon is created; otherwise an
+;          unsupported-platform exception is raised.
+; result : The platform tray value accepted by the other public procedures.
+; internals:
+;          This module is a small platform-neutral dispatcher. Windows code is
+;          loaded dynamically only on Windows so requiring racket-tray remains
+;          possible on other operating systems.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (mk-tray frame
+                 icon-file
+                 on-click-cb
+                 #:hide-on-minimize? [hide-on-minimize? #f])
+  (if platform-mk-tray
+      (platform-mk-tray frame
+                        icon-file
+                        on-click-cb
+                        #:hide-on-minimize? hide-on-minimize?)
+      (unsupported 'mk-tray)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Close a tray icon through the active platform backend.
+; pre    : tray is a value previously returned by mk-tray.
+; post   : Platform tray resources are released on supported systems.
+; result : void on success; raises when the platform is unsupported.
+; internals:
+;          All resource ownership and idempotence rules are implemented by the
+;          platform backend.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (tray-close tray)
+  (if platform-tray-close
+      (platform-tray-close tray)
+      (unsupported 'tray-close)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Replace the image of an existing tray icon.
+; pre    : tray is open and icon-file names a format supported by the backend.
+; post   : The active tray image is replaced when the backend succeeds.
+; result : The backend result; the Windows implementation returns void.
+; internals:
+;          The public facade performs no image conversion itself.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (tray-set-icon! tray icon-file)
+  (if platform-tray-set-icon!
+      (platform-tray-set-icon! tray icon-file)
+      (unsupported 'tray-set-icon!)))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Set or remove the context menu of an existing tray icon.
+; pre    : tray is open and menu is accepted by the active backend.
+; post   : The tray uses the supplied menu specification on success.
+; result : void on Windows; raises when the platform is unsupported.
+; internals:
+;          Menu normalization belongs to the platform implementation because
+;          native event integration is platform-specific.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (tray-set-menu! tray menu)
+  (if platform-tray-set-menu!
+      (platform-tray-set-menu! tray menu)
+      (unsupported 'tray-set-menu!)))