Miscellaneous LUA functionality

- Created emu.register_before_load_settings(), to allow LUA scripts to
    override default input port values before settings are loaded

  - New ioport_field methods/props ([set_]default_input_seq(), port)

src/emu/machine.cpp

@@ -308,6 +308,7 @@ int running_machine::run(bool quiet)
 		start();
 
 		// load the configuration settings
+		manager().before_load_settings(*this);
 		m_configuration->load_settings();
 
 		// disallow save state registrations starting here.

src/emu/main.h

@@ -85,6 +85,7 @@ public:
 	virtual void create_custom(running_machine& machine) { }
 	virtual void load_cheatfiles(running_machine& machine) { }
 	virtual void ui_initialize(running_machine& machine) { }
+	virtual void before_load_settings(running_machine &machine) { }
 
 	virtual void update_machine() { }
 

src/frontend/mame/luaengine.cpp

@@ -691,6 +691,11 @@ void lua_engine::on_machine_stop()
 	execute_function("LUA_ON_STOP");
 }
 
+void lua_engine::on_machine_before_load_settings()
+{
+	execute_function("LUA_ON_BEFORE_LOAD_SETTINGS");
+}
+
 void lua_engine::on_machine_pause()
 {
 	execute_function("LUA_ON_PAUSE");
@@ -784,6 +789,7 @@ void lua_engine::initialize()
  * emu.register_callback(callback, name) - register callback to be used by MAME via lua_engine::call_plugin()
  * emu.register_menu(event_callback, populate_callback, name) - register callbacks for plugin menu
  * emu.register_mandatory_file_manager_override(callback) - register callback invoked to override mandatory file manager
+ * emu.register_before_load_settings(callback) - register callback to be run before settings are loaded
  * emu.show_menu(menu_name) - show menu by name and pause the machine
  *
  * emu.print_verbose(str) - output to stderr at verbose level
@@ -824,6 +830,7 @@ void lua_engine::initialize()
 	emu["register_frame_done"] = [this](sol::function func){ register_function(func, "LUA_ON_FRAME_DONE"); };
 	emu["register_periodic"] = [this](sol::function func){ register_function(func, "LUA_ON_PERIODIC"); };
 	emu["register_mandatory_file_manager_override"] = [this](sol::function func) { register_function(func, "LUA_ON_MANDATORY_FILE_MANAGER_OVERRIDE"); };
+	emu["register_before_load_settings"] = [this](sol::function func) { register_function(func, "LUA_ON_BEFORE_LOAD_SETTINGS"); };
 	emu["register_menu"] = [this](sol::function cb, sol::function pop, const std::string &name) {
 			std::string cbfield = "menu_cb_" + name;
 			std::string popfield = "menu_pop_" + name;
@@ -1786,10 +1793,12 @@ void lua_engine::initialize()
  * field:set_value(value)
  * field:set_input_seq(seq_type, seq)
  * field:input_seq(seq_type)
+ * field:set_default_input_seq(seq_type, seq)
+ * field:default_input_seq(seq_type)
  *
  * field.device - get associated device_t
+ * field.port - get associated ioport_port
  * field.live - get ioport_field_live
-
  * field.name
  * field.default_name
  * field.player
@@ -1829,7 +1838,16 @@ void lua_engine::initialize()
 				input_seq_type seq_type = parse_seq_type(seq_type_string);
 				return sol::make_user(f.seq(seq_type));
 			},
+			"set_default_input_seq", [](ioport_field &f, const std::string &seq_type_string, sol::user<input_seq> seq) {
+				input_seq_type seq_type = parse_seq_type(seq_type_string);
+				f.set_defseq(seq_type, seq);
+			},
+			"default_input_seq", [](ioport_field &f, const std::string &seq_type_string) {
+				input_seq_type seq_type = parse_seq_type(seq_type_string);
+				return sol::make_user(f.defseq(seq_type));
+			},
 			"device", sol::property(&ioport_field::device),
+			"port", sol::property(&ioport_field::port),
 			"name", sol::property(&ioport_field::name),
 			"default_name", sol::property([](ioport_field &f) {
 					return f.specific_name() ? f.specific_name() : f.manager().type_name(f.type(), f.player());

src/frontend/mame/luaengine.h

@@ -51,6 +51,7 @@ public:
 	void on_frame_done();
 	void on_periodic();
 	bool on_missing_mandatory_image(const std::string &instance_name);
+	void on_machine_before_load_settings();
 
 	template<typename T, typename U>
 	bool call_plugin(const std::string &name, const T in, U &out)

src/frontend/mame/mame.cpp

@@ -323,6 +323,11 @@ void mame_machine_manager::ui_initialize(running_machine& machine)
 	m_ui->display_startup_screens(m_firstrun);
 }
 
+void mame_machine_manager::before_load_settings(running_machine& machine)
+{
+	m_lua->on_machine_before_load_settings();
+}
+
 void mame_machine_manager::create_custom(running_machine& machine)
 {
 	// start the inifile manager

src/frontend/mame/mame.h

@@ -50,6 +50,8 @@ public:
 
 	virtual void ui_initialize(running_machine& machine) override;
 
+	virtual void before_load_settings(running_machine& machine) override;
+
 	std::vector<std::reference_wrapper<const std::string>> missing_mandatory_images();
 
 	/* execute as configured by the OPTION_SYSTEMNAME option on the specified options */