Change language on the fly in the advanced settings dialog (#100)

builtin/mainmenu/common.lua

@@ -259,3 +259,44 @@ function menu_worldmt(selected, setting, value)
 		return nil
 	end
 end
+--------------------------------------------------------------------------------
+function get_language_list()
+	-- Get a list of languages and language names
+	local path_locale = core.get_locale_path()
+	local languages = core.get_dir_list(path_locale, true)
+	local language_names = {}
+	for i = #languages, 1, -1 do
+		local language = languages[i]
+		local f = io.open(path_locale .. DIR_DELIM .. language .. DIR_DELIM ..
+						  "LC_MESSAGES" .. DIR_DELIM .. "minetest.mo")
+		if f then
+			-- HACK
+			local name = f:read("*a"):match("\nLanguage%-Team: ([^\\\n\"]+) <https://")
+			language_names[language] = name or language
+			f:close()
+		else
+			table.remove(languages, i)
+		end
+	end
+
+	languages[#languages + 1] = "en"
+	language_names.en = "English"
+
+	-- Sort the languages list based on their human readable name
+	table.sort(languages, function(a, b)
+		return language_names[a] < language_names[b]
+	end)
+
+	local language_name_list = {}
+	for i, language in ipairs(languages) do
+		language_name_list[i] = core.formspec_escape(language_names[language])
+	end
+	local language_dropdown = table.concat(language_name_list, ",")
+
+	local lang_idx = table.indexof(languages, fgettext("LANG_CODE"))
+	if lang_idx < 0 then
+		lang_idx = table.indexof(languages, "en")
+	end
+
+	return languages, language_dropdown, lang_idx, language_name_list
+end

builtin/mainmenu/dlg_settings_advanced.lua

@@ -516,6 +516,7 @@ local full_settings = parse_config_file(false, true)
 local search_string = ""
 local settings = full_settings
 local selected_setting = 1
+local languages, language_dropdown, lang_idx, language_name_list = get_language_list()
 
 local function get_current_value(setting)
 	local value = core.settings:get(setting.name)
@@ -579,7 +580,14 @@ local function create_change_setting_formspec(dialogdata)
 	local formspec = ""
 
 	-- Setting-specific formspec elements
-	if setting.type == "bool" then
+	if setting.name == "language" then
+		-- Special case for the change language setting
+		-- The first option is empty (so lang_idx is offset by 1)
+		formspec = "dropdown[3," .. height .. ";4,1;dd_language;,"
+				.. language_dropdown .. ";" .. lang_idx + 1 .. ";true]"
+		height = height + 1.25
+
+	elseif setting.type == "bool" then
 		local selected_index = 1
 		if core.is_yes(get_current_value(setting)) then
 			selected_index = 2
@@ -830,10 +838,36 @@ local function create_change_setting_formspec(dialogdata)
 	)
 end
 
+-- Reload the main menu so that everything uses the new language
+local function reload_main_menu()
+	dofile(core.get_builtin_path() .. "init.lua")
+
+	-- Open a new advanced settings dialog
+	local maintab = ui.find_by_name("maintab")
+	local adv_settings_dlg = create_adv_settings_dlg(search_string,
+		settings, selected_setting)
+	adv_settings_dlg:set_parent(maintab)
+	maintab:hide()
+	adv_settings_dlg:show()
+end
+
 local function handle_change_setting_buttons(this, fields)
 	local setting = settings[selected_setting]
 	if fields["btn_done"] or fields["key_enter"] then
-		if setting.type == "bool" then
+		if setting.name == "language" then
+			local new_idx = tonumber(fields["dd_language"]) - 1
+			if lang_idx ~= new_idx then
+				if languages[new_idx] then
+					core.settings:set("language", languages[new_idx])
+				else
+					core.settings:remove("language")
+				end
+
+				reload_main_menu()
+				return true
+			end
+
+		elseif setting.type == "bool" then
 			local new_value = fields["dd_setting_value"]
 			-- Note: new_value is the actual (translated) value shown in the dropdown
 			core.settings:set_bool(setting.name, new_value == fgettext("Enabled"))
@@ -1020,6 +1054,10 @@ local function create_settings_formspec(tabview, _, tabdata)
 			formspec = formspec .. "," .. (current_level + 1) .. "," .. core.formspec_escape(name) .. ","
 					.. core.formspec_escape(get_current_np_group_as_string(entry)) .. ","
 
+		elseif entry.name == "language" then
+			formspec = formspec .. "," .. (current_level + 1) .. "," .. core.formspec_escape(name) .. ","
+					.. (language_name_list[lang_idx] or "") .. ","
+
 		else
 			formspec = formspec .. "," .. (current_level + 1) .. "," .. core.formspec_escape(name) .. ","
 					.. core.formspec_escape(get_current_value(entry)) .. ","
@@ -1106,7 +1144,10 @@ local function handle_settings_buttons(this, fields, tabname, tabdata)
 		if setting and setting.type ~= "category" then
 			core.settings:remove(setting.name)
 			core.settings:write()
-			core.update_formspec(this:get_formspec())
+
+			if setting.name == "language" then
+				reload_main_menu()
+			end
 		end
 		return true
 	end
@@ -1126,7 +1167,11 @@ local function handle_settings_buttons(this, fields, tabname, tabdata)
 	return false
 end
 
-function create_adv_settings_dlg()
+function create_adv_settings_dlg(new_search_string, new_settings, new_selected_setting)
+	search_string = new_search_string or search_string
+	settings = new_settings or settings
+	selected_setting = new_selected_setting or selected_setting
+
 	local dlg = dialog_create("settings_advanced",
 				create_settings_formspec,
 				handle_settings_buttons,

builtin/mainmenu/tab_settings_simple.lua

@@ -76,42 +76,7 @@ local getSettingIndex = {
 	end
 }
 
--- Get a list of languages and language names
-local path_locale = core.get_builtin_path() .. ".." .. DIR_DELIM .. "locale"
-local languages = core.get_dir_list(path_locale, true)
-local language_names = {}
-for i = #languages, 1, -1 do
-	local language = languages[i]
-	local f = io.open(path_locale .. DIR_DELIM .. language .. DIR_DELIM ..
-					  "LC_MESSAGES" .. DIR_DELIM .. "minetest.mo")
-	if f then
-		-- HACK
-		local name = f:read("*a"):match("\nLanguage%-Team: ([^\\\n\"]+) <https://")
-		language_names[language] = name or language
-		f:close()
-	else
-		table.remove(languages, i)
-	end
-end
-
-languages[#languages + 1] = "en"
-language_names.en = "English"
-
--- Sort the languages list based on their human readable name
-table.sort(languages, function(a, b)
-	return language_names[a] < language_names[b]
-end)
-
-local language_name_list = {}
-for i, language in ipairs(languages) do
-	language_name_list[i] = core.formspec_escape(language_names[language])
-end
-local language_dropdown = table.concat(language_name_list, ",")
-
-local lang_idx = table.indexof(languages, fgettext("LANG_CODE"))
-if lang_idx < 0 then
-	lang_idx = table.indexof(languages, "en")
-end
+local languages, language_dropdown, lang_idx = get_language_list()
 
 local function formspec(tabview, name, tabdata)
 	local fps = tonumber(core.settings:get("fps_max"))

src/gettext.cpp

@@ -228,6 +228,7 @@ void init_gettext(const char *path, const std::string &configured_language,
 				char lang[3] = {0};
 				strncpy(lang, locale[0].language, 2);
 				setenv("LANG", lang, 1);
+				setenv("LANGUAGE", lang, 1);
 			}
 
 			SDL_free(locale);
@@ -237,6 +238,7 @@ void init_gettext(const char *path, const std::string &configured_language,
 		NSString *syslang = [[NSLocale preferredLanguages] firstObject];
 		[syslang getBytes:lang maxLength:2 usedLength:nil encoding:NSASCIIStringEncoding options:0 range:NSMakeRange(0, 2) remainingRange:nil];
 		setenv("LANG", lang, 1);
+		setenv("LANGUAGE", lang, 1);
 #endif
 		setlocale(LC_ALL, "");
 	}

src/script/lua_api/l_mainmenu.cpp

@@ -555,6 +555,13 @@ int ModApiMainMenu::l_get_texturepath_share(lua_State *L)
 	return 1;
 }
 
+/******************************************************************************/
+int ModApiMainMenu::l_get_locale_path(lua_State *L)
+{
+	lua_pushstring(L, fs::RemoveRelativePathComponents(porting::path_locale).c_str());
+	return 1;
+}
+
 /******************************************************************************/
 int ModApiMainMenu::l_get_cache_path(lua_State *L)
 {
@@ -1000,6 +1007,7 @@ void ModApiMainMenu::Initialize(lua_State *L, int top)
 	API_FCT(get_serverlistpath);
 	API_FCT(get_texturepath);
 	API_FCT(get_texturepath_share);
+	API_FCT(get_locale_path);
 	API_FCT(get_cache_path);
 	API_FCT(get_temp_path);
 	API_FCT(create_dir);

src/script/lua_api/l_mainmenu.h

@@ -122,6 +122,8 @@ private:
 
 	static int l_get_texturepath_share(lua_State *L);
 
+	static int l_get_locale_path(lua_State *L);
+
 	static int l_get_cache_path(lua_State *L);
 
 	static int l_get_temp_path(lua_State *L);