Swap transition count and listener order

* Set cowait flag

* Set screen as unregistered

* Do not process screen which have been unregistered

* Java 17

.github/workflows/ci-workflow.yml

@@ -10,7 +10,7 @@ jobs:
           - uses: actions/checkout@v1
           - uses: actions/setup-java@v1
             with:
-                java-version: '11'
+                java-version: '17'
           - name: Run.sh
             env:
                 DEFOLD_USER: bjorn.ritzl@gmail.com

README_API.md

@@ -40,13 +40,18 @@ Clear the stack of screens completely. Any visible screen will be hidden by navi
 * `callback` (function) - Optional function to call when the stack has been cleared.
 
 
-## monarch.back([data], [callback])
+## monarch.back([options], [data], [callback])
 Go back to a previous Monarch screen. This operation will be added to the queue if Monarch is busy.
 
 **PARAMETERS**
+* `options` (table) - Options when showing the new screen (see below).
 * `data` (table) - Optional data to associate with the screen you are going back to.  Retrieve using `monarch.data()`.
 * `callback` (function) - Optional function to call when the previous screen is visible.
 
+The options table can contain the following fields:
+
+* `sequential` (boolean) - If the `sequential` flag is set Monarch will start loading the screen only after the previous screen finished transitioning out.
+
 
 ## monarch.preload(screen_id, [options], [callback])
 Preload a Monarch screen. This will load but not enable the screen. This is useful for content heavy screens that you wish to be able to show without having to wait for it load. This operation will be added to the queue if Monarch is busy.
@@ -177,7 +182,7 @@ Remove a previously added listener.
 
 
 ## monarch.post(screen_id, message_id, [message])
-Post a message to a visible screen. If the screen is created through a collection proxy it must have specified a receiver url. If the screen is created through a collection factory the function will post the message to all game objects within the collection.
+Post a message to a visible screen. The screen must have set a message listener using `monarch.on_post()`.
 
 **PARAMETERS**
 * `screen_id` (string|hash) - Id of the screen to post message to

example/advanced/about.gui_script

@@ -5,11 +5,13 @@ function init(self)
 	msg.post(".", "acquire_input_focus")
 	gui.set_render_order(15)
 
-	self.transition = transitions.create(gui.get_node("root"))
+	local transition = transitions.create(gui.get_node("root"))
 		.show_in(transitions.slide_in_top, gui.EASING_OUTQUAD, 0.6, 0)
 		.show_out(transitions.slide_out_top, gui.EASING_INQUAD, 0.6, 0)
 		.back_in(transitions.slide_in_top, gui.EASING_OUTQUAD, 0.6, 0)
 		.back_out(transitions.slide_out_top, gui.EASING_INQUAD, 0.6, 0)
+
+	monarch.on_transition("about", transition)
 end
 
 function on_input(self, action_id, action)
@@ -27,5 +29,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 end

example/advanced/advanced.collection

@@ -21,16 +21,6 @@ embedded_instances {
   "    value: \"menu\"\n"
   "    type: PROPERTY_TYPE_HASH\n"
   "  }\n"
-  "  properties {\n"
-  "    id: \"transition_id\"\n"
-  "    value: \"/go\"\n"
-  "    type: PROPERTY_TYPE_HASH\n"
-  "  }\n"
-  "  properties {\n"
-  "    id: \"focus_id\"\n"
-  "    value: \"/go\"\n"
-  "    type: PROPERTY_TYPE_HASH\n"
-  "  }\n"
   "  property_decls {\n"
   "  }\n"
   "}\n"
@@ -146,11 +136,6 @@ embedded_instances {
   "    value: \"pregame\"\n"
   "    type: PROPERTY_TYPE_HASH\n"
   "  }\n"
-  "  properties {\n"
-  "    id: \"transition_url\"\n"
-  "    value: \"pregame:/go#pregame\"\n"
-  "    type: PROPERTY_TYPE_URL\n"
-  "  }\n"
   "  property_decls {\n"
   "  }\n"
   "}\n"
@@ -211,11 +196,6 @@ embedded_instances {
   "    value: \"game\"\n"
   "    type: PROPERTY_TYPE_HASH\n"
   "  }\n"
-  "  properties {\n"
-  "    id: \"transition_url\"\n"
-  "    value: \"game:/go#game\"\n"
-  "    type: PROPERTY_TYPE_URL\n"
-  "  }\n"
   "  property_decls {\n"
   "  }\n"
   "}\n"
@@ -287,16 +267,6 @@ embedded_instances {
   "    type: PROPERTY_TYPE_BOOLEAN\n"
   "  }\n"
   "  properties {\n"
-  "    id: \"transition_url\"\n"
-  "    value: \"about:/go#about\"\n"
-  "    type: PROPERTY_TYPE_URL\n"
-  "  }\n"
-  "  properties {\n"
-  "    id: \"focus_url\"\n"
-  "    value: \"about:/go#about\"\n"
-  "    type: PROPERTY_TYPE_URL\n"
-  "  }\n"
-  "  properties {\n"
   "    id: \"preload\"\n"
   "    value: \"true\"\n"
   "    type: PROPERTY_TYPE_BOOLEAN\n"
@@ -376,11 +346,6 @@ embedded_instances {
   "    value: \"true\"\n"
   "    type: PROPERTY_TYPE_BOOLEAN\n"
   "  }\n"
-  "  properties {\n"
-  "    id: \"transition_url\"\n"
-  "    value: \"confirm:/go#confirm\"\n"
-  "    type: PROPERTY_TYPE_URL\n"
-  "  }\n"
   "  property_decls {\n"
   "  }\n"
   "}\n"

example/advanced/confirm.gui_script

@@ -7,11 +7,13 @@ function init(self)
 	self.no = gui.get_node("no_button")
 	gui.set_render_order(15)
 
-	self.transition = transitions.create(gui.get_node("root"))
+	local transition = transitions.create(gui.get_node("root"))
 		.show_in(transitions.scale_in, gui.EASING_OUTBACK, 0.3, 0)
 		.show_out(transitions.scale_out, gui.EASING_INBACK, 0.3, 0)
 		.back_in(transitions.scale_in, gui.EASING_OUTBACK, 0.3, 0)
 		.back_out(transitions.scale_out, gui.EASING_INBACK, 0.3, 0)
+
+	monarch.on_transition("confirm", transition)
 end
 
 function on_input(self, action_id, action)
@@ -35,5 +37,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 end

example/advanced/game.gui_script

@@ -3,11 +3,12 @@ local transitions = require "monarch.transitions.gui"
 
 function init(self)
 	msg.post(".", "acquire_input_focus")
-	
+
 	local data = monarch.data(hash("game"))
 	gui.set_text(gui.get_node("level"), tostring(data.level))
 
-	self.transition = transitions.in_right_out_left(gui.get_node("root"), 0.6, 0)
+	local transition = transitions.in_right_out_left(gui.get_node("root"), 0.6, 0)
+	monarch.on_transition("game", transition)
 end
 
 function on_input(self, action_id, action)
@@ -21,5 +22,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 end

example/advanced/menu.gui_script

@@ -8,7 +8,8 @@ function init(self)
 
 	gui.animate(gui.get_node("spinner"), gui.PROP_ROTATION, vmath.vector3(0, 0, -360), gui.EASING_INOUTQUAD, 2, 0, nil, gui.PLAYBACK_LOOP_FORWARD)
 
-	self.transition = transitions.fade_in_out(gui.get_node("root"), 0.6, 0)
+	local transition = transitions.fade_in_out(gui.get_node("root"), 0.6, 0)
+	monarch.on_transition("menu", transition)
 end
 
 function on_input(self, action_id, action)
@@ -28,7 +29,7 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 	if message_id == monarch.FOCUS.GAINED then
 		gui.set_text(gui.get_node("timestamp"), os.date())
 	end

example/advanced/popup.gui_script

@@ -9,12 +9,13 @@ function init(self)
 	gui.set_render_order(14)
 
 	gui.animate(gui.get_node("spinner"), gui.PROP_ROTATION, vmath.vector3(0, 0, -360), gui.EASING_INOUTQUAD, 2, 0, nil, gui.PLAYBACK_LOOP_FORWARD)
-	
+
-	self.transition = transitions.create(gui.get_node("root"))
+	local transition = transitions.create(gui.get_node("root"))
 		.show_in(transitions.scale_in, gui.EASING_OUTBACK, 0.3, 0)
 		.show_out(transitions.scale_out, gui.EASING_INBACK, 0.3, 0)
 		.back_in(transitions.scale_in, gui.EASING_OUTBACK, 0.3, 0)
 		.back_out(transitions.scale_out, gui.EASING_INBACK, 0.3, 0)
+	monarch.on_transition("popup", transition)
 end
 
 function on_input(self, action_id, action)
@@ -39,5 +40,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 end

example/advanced/pregame.gui_script

@@ -5,8 +5,9 @@ function init(self)
 	msg.post(".", "acquire_input_focus")
 	self.play = gui.get_node("play_button")
 	self.back = gui.get_node("back_button")
-	
+
-	self.transition = transitions.in_right_out_left(gui.get_node("root"), 0.6, 0)
+	local transition = transitions.in_right_out_left(gui.get_node("root"), 0.6, 0)
+	monarch.on_transition("pregame", transition)
 end
 
 function on_input(self, action_id, action)
@@ -26,5 +27,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	self.transition.handle(message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 end

example/slidingwindow/slidingwindow.script

@@ -4,10 +4,25 @@ function init(self)
 	monarch.debug()
 	msg.post("@render:/", "clear_color", { color = vmath.vector4(0.4, 0.6, 0.8,1.0) })
 	msg.post("#", "init_monarch") -- wait until init() has been called for all screen.script instances
+	monarch.add_listener()
+end
+
+function final(self)
+	monarch.remove_listener()
 end
 
 function on_message(self, message_id, message, sender)
 	if message_id == hash("init_monarch") then
 		monarch.show(hash("window1"))
+	elseif message_id == monarch.SCREEN_TRANSITION_IN_STARTED then
+		print("Monarch screen transition in started", message.screen)
+	elseif message_id == monarch.SCREEN_TRANSITION_IN_FINISHED then
+		print("Monarch screen transition in finished", message.screen)
+	elseif message_id == monarch.SCREEN_TRANSITION_OUT_STARTED then
+		print("Monarch screen transition out started", message.screen)
+	elseif message_id == monarch.SCREEN_TRANSITION_OUT_FINISHED then
+		print("Monarch screen transition out finished", message.screen)
+	elseif message_id == monarch.SCREEN_TRANSITION_FAILED then
+		print("Monarch screen transition failed")
 	end
 end

example/slidingwindow/window2.gui_script

@@ -23,6 +23,5 @@ function on_input(self, action_id, action)
 end
 
 function on_message(self, message_id, message, sender)
-	print("window2", message_id, message, sender)
 	monarch.on_message(message_id, message, sender)
 end

game.project

@@ -5,7 +5,7 @@ dependencies#0 = https://github.com/britzl/deftest/archive/2.7.0.zip
 dependencies#1 = https://github.com/defold/lua-language-server/releases/download/v0.0.3/release.zip
 
 [bootstrap]
-main_collection = /example/slidingwindow/slidingwindow.collectionc
+main_collection = /example/advanced/advanced.collectionc
 
 [input]
 game_binding = /input/game.input_bindingc

monarch/monarch.lua

@@ -3,17 +3,25 @@ local async = require "monarch.utils.async"
 
 local M = {}
 
-local CONTEXT = hash("monarch_context")
+local WAITFOR_COWAIT = hash("waitfor_cowait")
-local PROXY_LOADED = hash("proxy_loaded")
+local WAITFOR_CONTEXT = hash("waitfor_monarch_context")
-local PROXY_UNLOADED = hash("proxy_unloaded")
+local WAITFOR_PROXY_LOADED = hash("waitfor_proxy_loaded")
-local LAYOUT_CHANGED = hash("layout_changed")
+local WAITFOR_PROXY_UNLOADED = hash("waitfor_proxy_unloaded")
+local WAITFOR_TRANSITION_DONE = hash("waitfor_transition_done")
 
-local RELEASE_INPUT_FOCUS = hash("release_input_focus")
+local MSG_CONTEXT = hash("monarch_context")
-local ACQUIRE_INPUT_FOCUS = hash("acquire_input_focus")
+local MSG_PROXY_LOADED = hash("proxy_loaded")
-local ASYNC_LOAD = hash("async_load")
+local MSG_PROXY_UNLOADED = hash("proxy_unloaded")
-local UNLOAD = hash("unload")
+local MSG_LAYOUT_CHANGED = hash("layout_changed")
-local ENABLE = hash("enable")
+local MSG_RELEASE_INPUT_FOCUS = hash("release_input_focus")
-local DISABLE = hash("disable")
+local MSG_ACQUIRE_INPUT_FOCUS = hash("acquire_input_focus")
+local MSG_ASYNC_LOAD = hash("async_load")
+local MSG_UNLOAD = hash("unload")
+local MSG_ENABLE = hash("enable")
+local MSG_DISABLE = hash("disable")
+
+
+local DEPRECATED = hash("__DEPRECATED__")
 
 -- transition messages
 M.TRANSITION = {}
@@ -82,10 +90,13 @@ local function assign(to, from)
 	return to
 end
 
-local function cowait(delay)
+local function cowait(screen, delay)
+	log("cowait()", screen.id, delay)
 	local co = coroutine.running()
 	assert(co, "You must run this from within a coroutine")
+	screen.wait_for = WAITFOR_COWAIT
 	timer.delay(delay, false, function()
+		screen.wait_for = nil
 		assert(coroutine.resume(co))
 	end)
 	coroutine.yield()
@@ -261,12 +272,6 @@ end
 --		  keep input focus when below a popup
 --		* others_keep_input_focus_when_below_screen - If screens below this
 --		  screen should keep input focus
--- 		* transition_url - URL to a script that is responsible for the
---		  screen transitions
--- 		* focus_url - URL to a script that is to be notified of focus
---		  lost/gained events
---		* receiver_url - URL to a script that is to receive messages sent
---		  using monarch.send()
 --		* auto_preload - true if the screen should be automatically preloaded
 function M.register_proxy(id, proxy, settings)
 	assert(proxy, "You must provide a collection proxy URL")
@@ -276,6 +281,15 @@ function M.register_proxy(id, proxy, settings)
 	screen.focus_url = settings and settings.focus_url
 	screen.receiver_url = settings and settings.receiver_url
 	screen.auto_preload = settings and settings.auto_preload
+	if screen.transition_url.fragment == DEPRECATED then
+		screen.transition_url = nil
+	end
+	if screen.focus_url.fragment == DEPRECATED then
+		screen.focus_url = nil
+	end
+	if screen.receiver_url.fragment == DEPRECATED then
+		screen.receiver_url = nil
+	end
 	if screen.auto_preload then
 		M.preload(id)
 	end
@@ -298,10 +312,6 @@ M.register = M.register_proxy
 --		  keep input focus when below a popup
 --		* others_keep_input_focus_when_below_screen - If screens below this
 --		  screen should keep input focus
--- 		* transition_id - Id of the game object in the collection that is responsible
---		  for the screen transitions
--- 		* focus_id - Id of the game object in the collection that is to be notified
---		  of focus lost/gained events
 --		* auto_preload - true if the screen should be automatically preloaded
 function M.register_factory(id, factory, settings)
 	assert(factory, "You must provide a collection factory URL")
@@ -310,6 +320,13 @@ function M.register_factory(id, factory, settings)
 	screen.transition_id = settings and settings.transition_id
 	screen.focus_id = settings and settings.focus_id
 	screen.auto_preload = settings and settings.auto_preload
+
+	if screen.transition_id == DEPRECATED then
+		screen.transition_id = nil
+	end
+	if screen.focus_id == DEPRECATED then
+		screen.focus_id = nil
+	end
 	if screen.auto_preload then
 		M.preload(id)
 	end
@@ -323,6 +340,7 @@ function M.unregister(id)
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
 	log("unregister()", id)
+	local screen = screens[id]
 	screens[id] = nil
 	-- remove screen from stack
 	for i = #stack, 1, -1 do
@@ -330,16 +348,20 @@ function M.unregister(id)
 			table.remove(stack, i)
 		end
 	end
+	screen.unregistered = true
+	if screen.wait_for then
+		assert(coroutine.resume(screen.co))
+	end
 end
 
 local function acquire_input(screen)
 	log("acquire_input()", screen.id)
 	if not screen.input then
 		if screen.proxy then
-			msg.post(screen.script, ACQUIRE_INPUT_FOCUS)
+			msg.post(screen.script, MSG_ACQUIRE_INPUT_FOCUS)
 		elseif screen.factory then
 			for id,instance in pairs(screen.factory_ids) do
-				msg.post(instance, ACQUIRE_INPUT_FOCUS)
+				msg.post(instance, MSG_ACQUIRE_INPUT_FOCUS)
 			end
 		end
 		screen.input = true
@@ -357,10 +379,10 @@ local function release_input(screen, next_screen)
 		local release_focus = not keep_if_next_is_popup and not keep_when_below_next
 		if release_focus then
 			if screen.proxy then
-				msg.post(screen.script, RELEASE_INPUT_FOCUS)
+				msg.post(screen.script, MSG_RELEASE_INPUT_FOCUS)
 			elseif screen.factory then
 				for id,instance in pairs(screen.factory_ids) do
-					msg.post(instance, RELEASE_INPUT_FOCUS)
+					msg.post(instance, MSG_RELEASE_INPUT_FOCUS)
 				end
 			end
 			screen.input = false
@@ -370,24 +392,25 @@ end
 
 local function change_context(screen)
 	log("change_context()", screen.id)
-	screen.wait_for = CONTEXT
+	screen.wait_for = WAITFOR_CONTEXT
-	msg.post(screen.script, CONTEXT, { id = screen.id })
+	msg.post(screen.script, MSG_CONTEXT, { id = screen.id })
 	coroutine.yield()
 	screen.wait_for = nil
 end
 
 local function unload(screen, force)
+	if screen.unregistered then return end
 	if screen.proxy then
 		log("unload() proxy", screen.id)
 		if screen.auto_preload and not force then
 			if screen.loaded then
-				msg.post(screen.proxy, DISABLE)
+				msg.post(screen.proxy, MSG_DISABLE)
 				screen.loaded = false
 			end
 			screen.preloaded = true
 		else
-			screen.wait_for = PROXY_UNLOADED
+			screen.wait_for = WAITFOR_PROXY_UNLOADED
-			msg.post(screen.proxy, UNLOAD)
+			msg.post(screen.proxy, MSG_UNLOAD)
 			coroutine.yield()
 			screen.loaded = false
 			screen.preloaded = false
@@ -411,8 +434,8 @@ local function unload(screen, force)
 	-- we need to wait here in case the unloaded screen contained any screens
 	-- if this is the case we need to let these sub-screens have their final()
 	-- functions called so that they have time to call unregister()
-	cowait(0)
+	cowait(screen, 0)
-	cowait(0)
+	cowait(screen, 0)
 end
 
 
@@ -435,9 +458,13 @@ local function preload(screen)
 			screen.preloading = false
 			return false, error_message
 		end
-		screen.wait_for = PROXY_LOADED
+		screen.wait_for = WAITFOR_PROXY_LOADED
-		msg.post(screen.proxy, ASYNC_LOAD)
+		msg.post(screen.proxy, MSG_ASYNC_LOAD)
 		coroutine.yield()
+		screen.wait_for = nil
+		if screen.unregistered then
+			return false, "Screen was unregistered while loading"
+		end
 	elseif screen.factory then
 		log("preload() factory")
 		if collectionfactory.get_status(screen.factory) == collectionfactory.STATUS_UNLOADED then
@@ -445,6 +472,9 @@ local function preload(screen)
 				assert(coroutine.resume(screen.co))
 			end)
 			coroutine.yield()
+			if screen.unregistered then
+				return false, "Screen was unregistered while loading"
+			end
 		end
 
 		if collectionfactory.get_status(screen.factory) ~= collectionfactory.STATUS_LOADED then
@@ -476,7 +506,7 @@ local function load(screen)
 	end
 
 	if screen.proxy then
-		msg.post(screen.proxy, ENABLE)
+		msg.post(screen.proxy, MSG_ENABLE)
 	elseif screen.factory then
 		screen.factory_ids = collectionfactory.create(screen.factory)
 		screen.transition_url = screen.factory_ids[screen.transition_id]
@@ -489,8 +519,9 @@ end
 
 local function transition(screen, message_id, message, wait)
 	log("transition()", screen.id)
+	if screen.unregistered then return end
 	if screen.transition_url then
-		screen.wait_for = M.TRANSITION.DONE
+		screen.wait_for = WAITFOR_TRANSITION_DONE
 		msg.post(screen.transition_url, message_id, message)
 		if wait then
 			coroutine.yield()
@@ -512,14 +543,15 @@ end
 
 local function focus_lost(screen, next_screen)
 	log("focus_lost()", screen.id)
+	if screen.unregistered then return end
 	if screen.focus_url then
 		msg.post(screen.focus_url, M.FOCUS.LOST, { id = next_screen and next_screen.id })
 		-- if there's no transition on the screen losing focus and it gets
 		-- unloaded this will happen before the focus_lost message reaches
 		-- the focus_url
 		-- we add a delay to ensure the message queue has time to be processed
-		cowait(0)
+		cowait(screen, 0)
-		cowait(0)
+		cowait(screen, 0)
 	else
 		log("focus_lost() no focus url - ignoring")
 	end
@@ -640,7 +672,7 @@ local function show_in(screen, previous_screen, reload, add_to_stack, wait_for_t
 			return
 		end
 		-- wait one frame so that the init() of any script have time to run before starting transitions
-		cowait(0)
+		cowait(screen, 0)
 		reset_timestep(screen)
 		transition(screen, M.TRANSITION.SHOW_IN, { previous_screen = previous_screen and previous_screen.id }, wait_for_transition)
 		screen.visible = true
@@ -666,7 +698,7 @@ local function back_in(screen, previous_screen, wait_for_transition, cb)
 			return
 		end
 		-- wait one frame so that the init() of any script have time to run before starting transitions
-		cowait(0)
+		cowait(screen, 0)
 		reset_timestep(screen)
 		if previous_screen and not previous_screen.popup then
 			transition(screen, M.TRANSITION.BACK_IN, { previous_screen = previous_screen.id }, wait_for_transition)
@@ -683,8 +715,8 @@ local function back_out(screen, next_screen, wait_for_transition, cb)
 	log("back_out()", screen.id)
 	assert(wait_for_transition ~= nil)
 	run_coroutine(screen, cb, function()
-		notify_transition_listeners(M.SCREEN_TRANSITION_OUT_STARTED, { screen = screen.id, next_screen = next_screen and next_screen.id })
 		active_transition_count = active_transition_count + 1
+		notify_transition_listeners(M.SCREEN_TRANSITION_OUT_STARTED, { screen = screen.id, next_screen = next_screen and next_screen.id })
 		change_context(screen)
 		release_input(screen, next_screen)
 		focus_lost(screen, next_screen)
@@ -933,21 +965,38 @@ end
 
 
 -- Go back to the previous screen in the stack.
+-- @param options (table) - Table with options when backing out from the screen (can be nil).
+--		Valid values:
+-- 		* sequential - Set to true to wait for the current screen to hide itself out before starting the
+--				   back in transition even when transitioning to a different scene ID.
+
 -- @param data (*) - Optional data to set for the previous screen
 -- @param cb (function) - Optional callback to invoke when the previous screen is visible again
-function M.back(data, cb)
+function M.back(options, data, cb)
 	log("back() queuing action")
+	-- backwards compatibility with old version M.back(data, cb)
+	-- case when back(data, cb)
+	if type(data) == "function" then
+		cb = data
+		data = options
+		options = nil
+	-- case when back(data, nil)
+	elseif options ~= nil and data == nil and cb == nil then
+		data = options
+		options = nil
+	end
 
 	queue_action(function(action_done)
 		local callbacks = callback_tracker()
-		local back_cb = callbacks.track()
 		local screen = table.remove(stack)
 		if screen then
 			log("back()", screen.id)
+			local back_cb = callbacks.track()
 			local top = stack[#stack]
 			-- if we go back to the same screen we need to first hide it
 			-- and wait until it is hidden before we show it again
-			if top and screen.id == top.id then
+			local same_screen = top and top.id == screen.id
+			if same_screen or (options and options.sequential) then
 				back_out(screen, top, WAIT_FOR_TRANSITION, function()
 					if data then
 						top.data = data
@@ -1141,45 +1190,39 @@ function M.post(id, message_id, message)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
 
 	local screen = screens[id]
-	if screen.proxy then
+	if screen.receiver_url then
-		if screen.receiver_url then
+		log("post() sending message to", screen.receiver_url)
-			log("post() sending message to", screen.receiver_url)
+		msg.post(screen.receiver_url, message_id, message)
-			msg.post(screen.receiver_url, message_id, message)
-		else
-			return false, "Unable to post message since screen has no receiver url specified"
-		end
 	else
-		for id,instance in pairs(screen.factory_ids) do
+		return false, "Unable to post message since screen has no receiver url specified. Set one using monarch.on_post()."
-			msg.post(instance, message_id, message)
-		end
 	end
 	return true
 end
 
 
 function M.on_message(message_id, message, sender)
-	if message_id == PROXY_LOADED then
+	if message_id == MSG_PROXY_LOADED then
 		local screen = find_screen(sender)
 		assert(screen, "Unable to find screen for loaded proxy")
-		if screen.wait_for == PROXY_LOADED then
+		if screen.wait_for == WAITFOR_PROXY_LOADED then
 			assert(coroutine.resume(screen.co))
 		end
-	elseif message_id == PROXY_UNLOADED then
+	elseif message_id == MSG_PROXY_UNLOADED then
 		local screen = find_screen(sender)
 		assert(screen, "Unable to find screen for unloaded proxy")
-		if screen.wait_for == PROXY_UNLOADED then
+		if screen.wait_for == WAITFOR_PROXY_UNLOADED then
 			assert(coroutine.resume(screen.co))
 		end
-	elseif message_id == CONTEXT then
+	elseif message_id == MSG_CONTEXT then
 		local screen = find_screen(sender)
 		assert(screen, "Unable to find screen for current script url")
-		if screen.wait_for == CONTEXT then
+		if screen.wait_for == WAITFOR_CONTEXT then
 			assert(coroutine.resume(screen.co))
 		end
 	elseif message_id == M.TRANSITION.DONE then
 		local screen = find_transition_screen(sender)
 		assert(screen, "Unable to find screen for transition")
-		if screen.wait_for == M.TRANSITION.DONE then
+		if screen.wait_for == WAITFOR_TRANSITION_DONE then
 			assert(coroutine.resume(screen.co))
 		end
 	elseif message_id == M.TRANSITION.SHOW_IN
@@ -1192,7 +1235,7 @@ function M.on_message(message_id, message, sender)
 		if screen.transition_fn then
 			screen.transition_fn(message_id, message, sender)
 		end
-	elseif message_id == LAYOUT_CHANGED then
+	elseif message_id == MSG_LAYOUT_CHANGED then
 		local screen = find_screen(sender)
 		if screen and screen.transition_fn then
 			screen.transition_fn(message_id, message, sender)

monarch/screen_factory.script

@@ -6,8 +6,8 @@ go.property("popup", false)
 go.property("popup_on_popup", false)
 go.property("screen_keeps_input_focus_when_below_popup", false)
 go.property("others_keep_input_focus_when_below_screen", false)
-go.property("transition_id", hash(""))
+go.property("transition_id", hash("__DEPRECATED__"))
-go.property("focus_id", hash(""))
+go.property("focus_id", hash("__DEPRECATED__"))
 go.property("preload", false)
 
 
@@ -15,7 +15,7 @@ function init(self)
 	monarch = require "monarch.monarch"
 	assert(not self.popup_on_popup or (self.popup_on_popup and self.popup), "Popup on Popups can only be set if the Popup flag is set")
 	assert(self.screen_factory ~= msg.url(), "You must specify either a factory URL")
-	
+
 	local settings = {
 		popup = self.popup,
 		popup_on_popup = self.popup_on_popup,

monarch/screen_proxy.script

@@ -7,9 +7,9 @@ go.property("popup_on_popup", false)
 go.property("timestep_below_popup", 1)
 go.property("screen_keeps_input_focus_when_below_popup", false)
 go.property("others_keep_input_focus_when_below_screen", false)
-go.property("transition_url", msg.url())
+go.property("transition_url", msg.url("#__DEPRECATED__"))
-go.property("focus_url", msg.url())
+go.property("focus_url", msg.url("#__DEPRECATED__"))
-go.property("receiver_url", msg.url())
+go.property("receiver_url", msg.url("#__DEPRECATED__"))
 go.property("preload", false)
 
 
@@ -19,7 +19,7 @@ function init(self)
 	assert(not self.popup_on_popup or (self.popup_on_popup and self.popup), "Popup on Popups can only be set if the Popup flag is set")
 	assert(self.screen_proxy ~= url, "You must specify either a proxy URL")
 	assert(self.timestep_below_popup >= 0, "Timestep must be positive")
-	
+
 	local settings = {
 		popup = self.popup,
 		popup_on_popup = self.popup_on_popup,

test/data/screen1.gui_script

@@ -1,5 +1,11 @@
+local monarch
+
 function init(self)
-	print("init - screen1")
+	monarch = require "monarch.monarch"
+	print("init - screen1", msg.url())
+	monarch.on_post("screen1", function(message_id, message, sender)
+		_G.screen1_on_post = message or true
+	end)
 end
 
 function final(self)
@@ -7,7 +13,8 @@ function final(self)
 end
 
 function on_message(self, message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 	if message_id == hash("foobar") then
-		_G.screen1_foobar = message or true
+		_G.screen1_on_message = message or true
 	end
 end

test/data/screen2.gui_script

@@ -1,5 +1,11 @@
+local monarch
+
 function init(self)
-	print("init - screen2")
+	monarch = require "monarch.monarch"
+	print("init - screen2", msg.url())
+	monarch.on_post("screen2", function(message_id, message, sender)
+		_G.screen2_on_post = message or true
+	end)
 end
 
 function final(self)
@@ -7,7 +13,8 @@ function final(self)
 end
 
 function on_message(self, message_id, message, sender)
+	monarch.on_message(message_id, message, sender)
 	if message_id == hash("foobar") then
-		_G.screen2_foobar = message or true
+		_G.screen2_on_message = message or true
 	end
 end

test/test_monarch.lua

@@ -12,7 +12,6 @@ local FOCUS1 = hash("focus1")
 local BACKGROUND = hash("background")
 local POPUP1 = hash("popup1")
 local POPUP2 = hash("popup2")
-local FOOBAR = hash("foobar")
 local TRANSITION1 = hash("transition1")
 
 local function check_stack(expected_screens)
@@ -220,7 +219,7 @@ return function()
 			assert(monarch.data(SCREEN2) == data2, "Expected data on screen2 doesn't match actual data")
 
 			local data_back = { going = "back" }
-			monarch.back(data_back)
+			monarch.back(nil, data_back)
 			assert(wait_until_visible(SCREEN1))
 
 			assert(monarch.data(SCREEN1) == data_back, "Expected data on screen1 doesn't match actual data")
@@ -491,49 +490,56 @@ return function()
 
 
 		it("should be able to post messages without message data to visible screens", function()
-			_G.screen1_foobar = nil
+			_G.screen1_on_message = nil
-			_G.screen2_foobar = nil
+			_G.screen1_on_post = nil
+			_G.screen2_on_message = nil
+			_G.screen2_on_post = nil
 
 			-- proxy screen
 			monarch.show(SCREEN1)
 			wait_until_visible(SCREEN1)
 			assert(monarch.post(SCREEN1, "foobar"), "Expected monarch.post() to return true")
 			cowait(0.1)
-			assert(_G.screen1_foobar, "Screen1 never received a message")
+			assert(_G.screen1_on_message, "Screen1 never received a message")
+			assert(_G.screen1_on_post, "Screen1 never received a callback")
 
 			-- factory screen
 			monarch.show(SCREEN2)
 			wait_until_visible(SCREEN2)
 			assert(monarch.post(SCREEN2, "foobar"), "Expected monarch.post() to return true")
 			cowait(0.1)
-			assert(_G.screen2_foobar, "Screen2 never received a message")
+			assert(_G.screen2_on_message, "Screen2 never received a message")
+			assert(_G.screen2_on_post, "Screen2 never received a callback")
 		end)
 
 
 		it("should be able to post messages with message data to visible screens", function()
-			_G.screen1_foobar = nil
+			_G.screen1_on_message = nil
-			_G.screen2_foobar = nil
+			_G.screen1_on_post = nil
+			_G.screen2_on_message = nil
+			_G.screen2_on_post = nil
 
 			-- proxy screen
 			monarch.show(SCREEN1)
 			wait_until_visible(SCREEN1)
 			assert(monarch.post(SCREEN1, "foobar", { foo = "bar" }), "Expected monarch.post() to return true")
 			cowait(0.1)
-			assert(_G.screen1_foobar, "Screen1 never received a message")
+			assert(_G.screen1_on_message, "Screen1 never received a message")
-			assert(_G.screen1_foobar.foo == "bar", "Screen1 never received message data")
+			assert(_G.screen1_on_message.foo == "bar", "Screen1 never received message data")
-			
+
 			-- factory screen
 			monarch.show(SCREEN2)
 			wait_until_visible(SCREEN2)
 			assert(monarch.post(SCREEN2, "foobar", { foo = "bar" }), "Expected monarch.post() to return true")
 			cowait(0.1)
-			assert(_G.screen2_foobar, "Screen2 never received a message")
+			assert(_G.screen2_on_message, "Screen2 never received a message")
-			assert(_G.screen2_foobar.foo == "bar", "Screen2 never received message data")
+			assert(_G.screen2_on_message.foo == "bar", "Screen2 never received message data")
 		end)
 
 
 		it("should not be able to post messages to hidden screens", function()
-			_G.screen1_foobar = nil
+			_G.screen1_on_message = nil
+			_G.screen1_on_post = nil
 
 			monarch.show(SCREEN1)
 			monarch.show(SCREEN2)
@@ -542,7 +548,7 @@ return function()
 			local ok, err = monarch.post(SCREEN1, "foobar")
 			assert(not ok and err, "Expected monarch.post() to return false plus an error message")
 			cowait(0.1)
-			assert(not _G.screen1_foobar, "Screen1 should not have received a message")
+			assert(not _G.screen1_on_message, "Screen1 should not have received a message")
 		end)