a little refactoring

imperative-shell/event-loop.sml

@@ -0,0 +1,35 @@
+structure EventLoop =
+struct
+  open CML
+  open InputMessage
+
+  fun update inputMailbox =
+    let
+      val _ =
+        case Mailbox.recv inputMailbox of
+          MOUSE_MOVE {x, y} =>
+            print (String.concat
+              ["x pos: ", Int.toString x, ", y pos: ", Int.toString y, "\n"])
+        | MOUSE_LEFT_CLICK => print "clicked mouse\n"
+        | MOUSE_LEFT_RELEASE => print "released mouse\n"
+    in
+      update inputMailbox
+    end
+
+  fun draw (window, graphDrawObject, buttonDrawObject, buttonDrawLength) =
+    if not (Glfw.windowShouldClose window) then
+      let
+        val _ = Gles3.clearColor (1.0, 1.0, 1.0, 1.0)
+        val _ = Gles3.clear ()
+
+        val _ = AppDraw.drawGraphLines graphDrawObject
+        val _ = AppDraw.drawButton (buttonDrawObject, buttonDrawLength)
+
+        val _ = Glfw.pollEvents ()
+        val _ = Glfw.swapBuffers window
+      in
+        draw (window, graphDrawObject, buttonDrawObject, buttonDrawLength)
+      end
+    else
+      Glfw.terminate ()
+end