Refactor the game event system to be based on Lua at the core

data/campaigns/World_Conquest/lua/campaign_main.lua

@@ -1,7 +1,7 @@
 -- the main file for the WC2 mp campaign
 
 T = wml.tag
-on_event = wesnoth.require("on_event")
+on_event = wesnoth.game_events.add_repeating
 
 
 wesnoth.dofile("./game_mechanics/_load.lua")

data/lua/core/interface.lua

@@ -64,7 +64,41 @@ if wesnoth.kernel_type() == "Game Lua Kernel" then
 	wesnoth.print = wesnoth.deprecate_api('wesnoth.print', 'wesnoth.interface.add_overlay_text', 1, nil, function(cfg)
 		wesnoth.wml_actions.print(cfg)
 	end)
-	-- No deprecation for these since since they're not actually public API yet
-	wesnoth.set_menu_item = wesnoth.interface.set_menu_item
+	wesnoth.set_menu_item = wesnoth.deprecate_api('wesnoth.set_menu_item', 'wesnoth.interface.set_menu_item', 1, nil, function(id, cfg)
+		-- wesnoth.set_menu_item added both the menu item and the event that it triggers
+		-- wesnoth.interface.set_menu_item only adds the menu item
+		wesnoth.interface.set_menu_item(id, cfg)
+		wesnoth.game_events.add_menu(cfg.id, wesnoth.wml_actions.command)
+	end)
 	wesnoth.clear_menu_item = wesnoth.interface.clear_menu_item
+	-- Event handlers don't have a separate module Lua file so dump those here
+	wesnoth.add_event_handler = wesnoth.deprecate_api('wesnoth.add_event_hander', 'wesnoth.game_events.add', 1, nil, function(cfg) wesnoth.wml_actions.event(cfg) end)
+	wesnoth.remove_event_handler = wesnoth.deprecate_api('wesnoth.remove_event_handler', 'wesnoth.game_events.remove', 1, nil, wesnoth.game_events.remove)
+
+	local function old_fire_event(fcn)
+		return function(...)
+			local id = select(1, ...)
+			local loc1, n1 = wesnoth.map.read_location(select(2, ...))
+			local loc2, n2 = wesnoth.map.read_location(select(2 + n1, ...))
+			local weap1, weap2 = select(2 + n1 + n2)
+			local data = {}
+			if weap1 ~= nil then
+				table.insert(data, wml.tag.first(weap1))
+			end
+			if weap2 ~= nil then
+				table.insert(data, wml.tag.second(weap2))
+			end
+			if n1 > 0 then
+				if n2 > 0 then
+					fcn(id, loc1, loc2, data)
+				else
+					fcn(id, loc1, data)
+				end
+			else
+				fcn(id, data)
+			end
+		end
+	end
+	wesnoth.fire_event = wesnoth.deprecate_api('wesnoth.fire_event', 'wesnoth.game_events.fire', 1, nil, old_fire_event(wesnoth.game_events.fire))
+	wesnoth.fire_event_by_id = wesnoth.deprecate_api('wesnoth.fire_event_by_id', 'wesnoth.game_events.fire_by_id', 1, nil, old_fire_event(wesnoth.game_events.fire_by_id))
 end

data/lua/diversion.lua

@@ -1,7 +1,6 @@
 
 local _ = wesnoth.textdomain 'wesnoth-help'
 local T = wml.tag
-local on_event = wesnoth.require("on_event")
 
 local u_pos_filter = function(u_id)
 
@@ -100,7 +99,7 @@ function wesnoth.wml_actions.on_undo_diversion(cfg)
 	status_anim_update(true)
 end
 
-on_event("moveto, die, recruit, recall", function()
+wesnoth.game_events.add_repeating("moveto, die, recruit, recall", function()
         status_anim_update()
 
 end)

data/lua/feeding.lua

@@ -1,10 +1,9 @@
 
 local _ = wesnoth.textdomain 'wesnoth-help'
 local T = wml.tag
-local on_event = wesnoth.require("on_event")
 
 -- The feeding event code
-on_event("die", function()
+wesnoth.game_events.add_repeating("die", function()
 	local ec = wesnoth.current.event_context
 
 	if not ec.x1 or not ec.y1 or not ec.x2 or not ec.y2 then

data/lua/on_event.lua

@@ -51,5 +51,5 @@ local function on_event(eventname, priority, fcn)
 	end
 end
 
-core_on_event = on_event
-return on_event
+core_on_event = wesnoth.deprecate_api("on_event", "wesnoth.game_events.add_repeating", 1, nil, on_event)
+return core_on_event

data/lua/wml-tags.lua

@@ -146,10 +146,12 @@ function wml_actions.fire_event(cfg)
 
 	local w1 = wml.get_child(cfg, "primary_attack")
 	local w2 = wml.get_child(cfg, "secondary_attack")
-	if w2 then w1 = w1 or {} end
+	local data = wml.get_child(cfg, "data") or {}
+	if w1 then table.insert(data, wml.tag.first(w1)) end
+	if w2 then table.insert(data, wml.tag.second(w2)) end
 
-	if cfg.id and cfg.id ~= "" then wesnoth.fire_event_by_id(cfg.id, x1, y1, x2, y2, w1, w2)
-	elseif cfg.name and cfg.name ~= "" then wesnoth.fire_event(cfg.name, x1, y1, x2, y2, w1, w2)
+	if cfg.id and cfg.id ~= "" then wesnoth.game_events.fire_by_id(cfg.id, x1, y1, x2, y2, data)
+	elseif cfg.name and cfg.name ~= "" then wesnoth.game_events.fire(cfg.name, x1, y1, x2, y2, data)
 	end
 end
 
@@ -663,6 +665,7 @@ end
 
 function wml_actions.set_menu_item(cfg)
 	wesnoth.interface.set_menu_item(cfg.id, cfg)
+	wesnoth.game_events.add_menu(cfg.id, wml_actions.command)
 end
 
 function wml_actions.place_shroud(cfg)
@@ -727,15 +730,15 @@ function wml_actions.event(cfg)
 		wesnoth.deprecated_message("[event]remove=yes", 2, "1.17.0", "Use [remove_event] instead of [event]remove=yes")
 		wml_actions.remove_event(cfg)
 	else
-		wesnoth.add_event_handler(cfg)
+		wesnoth.game_events.add_wml(cfg)
 	end
 end
 
 function wml_actions.remove_event(cfg)
 	local id = cfg.id or wml.error("[remove_event] missing required id= key")
 
 	for _,w in ipairs(id:split()) do
-		wesnoth.remove_event_handler(w)
+		wesnoth.game_events.remove(w)
 	end
 end
 

data/modifications/pick_advance/main.lua

@@ -1,6 +1,6 @@
 -- << pick_advance/main.lua
 
-local on_event = wesnoth.require "on_event"
+local on_event = wesnoth.game_events.add_repeating
 local F = wesnoth.require "functional"
 local T = wml.tag
 local _ = wesnoth.textdomain "wesnoth"

data/multiplayer/scenarios/2p_Dark_Forecast.lua

@@ -1,7 +1,7 @@
 
 local _ = wesnoth.textdomain 'wesnoth-multiplayer'
 local T = wml.tag
-local on_event = wesnoth.require("on_event")
+local on_event = wesnoth.game_events.add_repeating
 
 local random_spawns = {
 	{

data/multiplayer/scenarios/2p_Isle_of_Mists.lua

@@ -1,6 +1,6 @@
 local _ = wesnoth.textdomain 'wesnoth-multiplayer'
 local T = wml.tag
-local on_event = wesnoth.require("on_event")
+local on_event = wesnoth.game_events.add_repeating
 
 local random_spawns = {
 	{

data/schema/core/addons.cfg

@@ -124,6 +124,7 @@
 	super="$action_wml"
 	{SIMPLE_KEY name string}
 	{SIMPLE_KEY id string}
+	{SIMPLE_KEY filter_formula string}
 	{DEFAULT_KEY first_time_only bool yes}
 	{DEFAULT_KEY delayed_variable_substitution bool no}
 

data/test/scenarios/events-test_actions.cfg

@@ -0,0 +1,99 @@
+
+# This is kinda a duplicate of a basic unit test system sanity test, but... it seems to fit here as well...
+{GENERIC_UNIT_TEST "event_test_action_wml" (
+    [event]
+        name=start
+        {SUCCEED}
+    [/event]
+)}
+
+# Test that dynamically adding an event from Lua works
+# There's two different ways of adding events, so test both
+{GENERIC_UNIT_TEST "event_test_lua" (
+    [event]
+        name=preload
+        [lua]
+            code=<<
+                wesnoth.game_events.add_repeating('new turn', function()
+                    unit_test.succeed()
+                end)
+            >>
+        [/lua]
+    [/event]
+)}
+{GENERIC_UNIT_TEST "event_test_lua_advanced" (
+    [event]
+        name=preload
+        [lua]
+            code=<<
+                wesnoth.game_events.add{
+                    name = 'new turn',
+                    action = function()
+                        unit_test.succeed()
+                    end
+                }
+            >>
+        [/lua]
+    [/event]
+)}
+
+# Test that first_time_only works correctly in Lua events
+{GENERIC_UNIT_TEST "event_test_lua_repeat" (
+    [event]
+        name=preload
+        [lua]
+            code=<<
+                wml.variables.only_once = 0
+                wml.variables.should_repeat = 0
+                wesnoth.game_events.add{
+                    name = 'new turn',
+                    first_time_only = true,
+                    action = function()
+                        wml.variables.only_once = wml.variables.only_once + 1
+                    end
+                }
+                wesnoth.game_events.add{
+                    name = 'new turn',
+                    first_time_only = false,
+                    action = function()
+                        wml.variables.should_repeat = wml.variables.should_repeat + 1
+                    end
+                }
+            >>
+        [/lua]
+    [/event]
+    [event]
+        name=side 1 turn 1
+        [end_turn][/end_turn]
+    [/event]
+    [event]
+        name=side 2 turn 1
+        [end_turn][/end_turn]
+    [/event]
+    [event]
+        name=side 1 turn 2
+        [end_turn][/end_turn]
+    [/event]
+    [event]
+        name=side 2 turn 2
+        {ASSERT ({VARIABLE_CONDITIONAL only_once equals 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL should_repeat equals 2})}
+        {SUCCEED}
+    [/event]
+)}
+
+# Verify that a warning is produced if adding an event that would break saved games
+{GENERIC_UNIT_TEST "event_test_lua_break_save" (
+    [event]
+        name=start
+        [lua]
+            code=<<
+                wesnoth.game_events.add{
+                    name = 'new turn',
+                    action = function() end
+                }
+                unit_test.succeed()
+            >>
+        [/lua]
+    [/event]
+)}

data/test/scenarios/events-test_filters.cfg

@@ -230,3 +230,119 @@
         {RETURN ({VARIABLE_CONDITIONAL triggers equals 4})}
     [/event]
 )}
+
+{GENERIC_UNIT_TEST event_test_filter_wfl (
+    [event]
+        name=start
+        {VARIABLE triggers 0}
+    [/event]
+    [event]
+        name=side turn
+        first_time_only=no
+        filter_formula="turn_number = side_number"
+        {VARIABLE_OP triggers add 1}
+        {ASSERT ({VARIABLE_CONDITIONAL side_number equals $turn_number})}
+    [/event]
+    [event]
+        name=turn 3
+        {RETURN ({VARIABLE_CONDITIONAL triggers equals 2})}
+    [/event]
+    [event]
+        name=side turn
+        first_time_only=no
+        [end_turn][/end_turn]
+    [/event]
+)}
+
+{GENERIC_UNIT_TEST event_test_filter_wfl2 (
+    [event]
+        name=start
+        {VARIABLE triggers 0}
+        [do_command]
+            [move]
+                x=7,7,6,5,4,3,3,3
+                y=3,4,4,5,4,4,3,2
+            [/move]
+        [/do_command]
+        {RETURN ({VARIABLE_CONDITIONAL triggers equals 3})}
+    [/event]
+    [event]
+        name=enter hex
+        first_time_only=no
+        filter_formula="loc.x = loc.y"
+        {VARIABLE_OP triggers add 1}
+    [/event]
+)}
+
+{GENERIC_UNIT_TEST event_test_filter_lua_serializable (
+    [event]
+        name=start
+        {VARIABLE triggers 0}
+    [/event]
+    [event]
+        name=side turn
+        first_time_only=no
+        [filter_condition]
+            [lua]
+                code=<<return wesnoth.current.turn == wesnoth.current.side>>
+            [/lua]
+        [/filter_condition]
+        {VARIABLE_OP triggers add 1}
+        {ASSERT ({VARIABLE_CONDITIONAL side_number equals $turn_number})}
+    [/event]
+    [event]
+        name=turn 3
+        {RETURN ({VARIABLE_CONDITIONAL triggers equals 2})}
+    [/event]
+    [event]
+        name=side turn
+        first_time_only=no
+        [end_turn][/end_turn]
+    [/event]
+)}
+
+{GENERIC_UNIT_TEST event_test_filter_lua_dynamic (
+    [event]
+        name=preload
+        [lua]
+            code=<<
+                wml.variables.triggers = 0
+                wesnoth.game_events.add{
+                    name = 'side turn',
+                    first_time_only = false,
+                    filter = function()
+                        return wesnoth.current.turn == wesnoth.current.side
+                    end,
+                    action = function()
+                        wml.variables.triggers = wml.variables.triggers + 1
+                        unit_test.assert_equal(wesnoth.current.turn, wesnoth.current.side, 'filter correctly passed')
+                    end
+                }
+            >>
+        [/lua]
+    [/event]
+    [event]
+        name=side 2 turn 3
+        {RETURN ({VARIABLE_CONDITIONAL triggers equals 2})}
+    [/event]
+    [event]
+        name=side turn
+        first_time_only=no
+        [end_turn][/end_turn]
+    [/event]
+)}
+
+{GENERIC_UNIT_TEST event_test_filter_lua_dynamic_break_save (
+    [event]
+        name=start
+        [lua]
+            code=<<
+                wesnoth.game_events.add{
+                    name = 'new turn',
+                    filter = function() end
+                }
+                unit_test.succeed()
+            >>
+        [/lua]
+    [/event]
+)}