move WML [event] impl to lua, fixup core wml vs lua loading order

This commit moves [event] to be implemented in lua/wml-tags.lua.
It turns out that because of some questionable ordering in
data/core/_main.cfg, none of the tags defined in
data/lua/wml-tags.lua are actually defined at the time that core
is read, instead they are defined right after this. This is broken,
the entire wml library should be defined before core is read. Thus
we reorder some directives in data/core/_main.cfg to ensure this.

This commit adds lua callbacks `wesnoth.add_event_handler`,
`wesnoth.remove_event_handler` as well.

data/core/_main.cfg

@@ -3,6 +3,14 @@
 
 # wmlscope: set export=yes
 
+[lua]
+    code=<<
+wesnoth.dofile 'lua/backwards-compatibility.lua'
+wesnoth.dofile 'lua/wml-tags.lua'
+wesnoth.dofile 'ai/micro_ais/micro_ai_wml_tag.lua'
+>>
+[/lua]
+
 #ifndef NO_TERRAIN_GFX
 {core/terrain-graphics/}
 #endif
@@ -16,11 +24,3 @@
 #endif
 {core/units.cfg}
 {core/editor/}
-
-[lua]
-    code=<<
-wesnoth.dofile 'lua/backwards-compatibility.lua'
-wesnoth.dofile 'lua/wml-tags.lua'
-wesnoth.dofile 'ai/micro_ais/micro_ai_wml_tag.lua'
->>
-[/lua]

data/lua/wml-tags.lua

@@ -1363,6 +1363,15 @@ function wml_actions.end_turn(cfg)
 	wesnoth.end_turn()
 end
 
+function wml_actions.event(cfg)
+	local remove = cfg.remove
+	if remove then
+		wesnoth.remove_event_handler(cfg.id)
+	else
+		wesnoth.add_event_handler(cfg)
+	end
+end
+
 function wml_actions.label(cfg)
 	wesnoth.label(cfg)
 end

src/game_events/action_wml.cpp

@@ -670,19 +670,6 @@ WML_HANDLER_FUNCTION(endlevel, /*event_info*/, cfg)
 	}
 }
 
-/// Adding new events
-WML_HANDLER_FUNCTION(event, /*event_info*/, cfg)
-{
-	assert(resources::game_events);
-	if (cfg["remove"].to_bool(false)) {
-		resources::game_events->remove_event_handler(cfg["id"]);
-	} else if (!cfg["delayed_variable_substitution"].to_bool(true)) {
-		resources::game_events->add_event_handler(cfg.get_parsed_config());
-	} else {
-		resources::game_events->add_event_handler(cfg.get_config());
-	}
-}
-
 /// Experimental data persistence
 /// @todo Finish experimenting.
 WML_HANDLER_FUNCTION(get_global_variable,/**/,pcfg)

src/scripting/game_lua_kernel.cpp

@@ -51,6 +51,7 @@
 #include "game_display.hpp"             // for game_display
 #include "game_errors.hpp"              // for game_error
 #include "game_events/conditional_wml.hpp"  // for conditional_passed
+#include "game_events/manager.hpp"	// for add_event_handler
 #include "game_events/pump.hpp"         // for queued_event
 #include "game_preferences.hpp"         // for encountered_units
 #include "image.hpp"                    // for get_image, locator
@@ -2729,6 +2730,26 @@ int game_lua_kernel::intf_remove_tile_overlay(lua_State *L)
 	return 0;
 }
 
+/// Adding new events
+int game_lua_kernel::intf_add_event(lua_State *L)
+{
+	vconfig cfg(luaW_checkvconfig(L, 1));
+	game_events::manager & man = *game_state_.events_manager_;
+
+	if (!cfg["delayed_variable_substitution"].to_bool(true)) {
+		man.add_event_handler(cfg.get_parsed_config());
+	} else {
+		man.add_event_handler(cfg.get_config());
+	}
+	return 0;
+}
+
+int game_lua_kernel::intf_remove_event(lua_State *L)
+{
+	game_state_.events_manager_->remove_event_handler(luaL_checkstring(L, 1));
+	return 0;
+}
+
 int game_lua_kernel::intf_color_adjust(lua_State *L)
 {
 	if (game_display_) {
@@ -3219,6 +3240,7 @@ game_lua_kernel::game_lua_kernel(const config &cfg, CVideo * video, game_state &
 		{ NULL, NULL }
 	};
 	lua_cpp::Reg const cpp_callbacks[] = {
+		{ "add_event_handler",		boost::bind(&game_lua_kernel::intf_add_event, this, _1)				},
 		{ "add_tile_overlay",		boost::bind(&game_lua_kernel::intf_add_tile_overlay, this, _1)			},
 		{ "allow_end_turn",		boost::bind(&game_lua_kernel::intf_allow_end_turn, this, _1)			},
 		{ "allow_undo",			boost::bind(&game_lua_kernel::intf_allow_undo, this, _1)			},
@@ -3264,6 +3286,7 @@ game_lua_kernel::game_lua_kernel(const config &cfg, CVideo * video, game_state &
 		{ "put_recall_unit",		boost::bind(&game_lua_kernel::intf_put_recall_unit, this, _1)			},
 		{ "put_unit",			boost::bind(&game_lua_kernel::intf_put_unit, this, _1)				},
 		{ "redraw",			boost::bind(&game_lua_kernel::intf_redraw, this, _1)				},
+		{ "remove_event_handler",	boost::bind(&game_lua_kernel::intf_remove_event, this, _1)			},
 		{ "remove_shroud",		boost::bind(&game_lua_kernel::intf_shroud_op, this, _1, false)			},
 		{ "remove_tile_overlay",	boost::bind(&game_lua_kernel::intf_remove_tile_overlay, this, _1)		},
 		{ "replace_schedule",		boost::bind(&game_lua_kernel::intf_replace_schedule, this, _1)			},

src/scripting/game_lua_kernel.hpp

@@ -124,6 +124,8 @@ class game_lua_kernel : public lua_kernel_base
 	int intf_get_sides(lua_State* L);
 	int intf_add_tile_overlay(lua_State *L);
 	int intf_remove_tile_overlay(lua_State *L);
+	int intf_add_event(lua_State *L);
+	int intf_remove_event(lua_State *L);
 	int intf_color_adjust(lua_State *L);
 	int intf_delay(lua_State *L);
 	int intf_label(lua_State *L);