Minetest Lua Mainmenu API Reference 5.1.0
=========================================

Introduction
-------------
The main menu is defined as a formspec by Lua in builtin/mainmenu/
Description of formspec language to show your menu is in lua_api.txt

Callbacks
---------
core.buttonhandler(fields): called when a button is pressed.
^ fields = {name1 = value1, name2 = value2, ...}
core.event_handler(event)
^ event: "MenuQuit", "KeyEnter", "ExitButton" or "EditBoxEnter"

Gamedata
--------
The "gamedata" table is read when calling core.start(). It should contain:
{
	playername     = <name>,
	password       = <password>,
	address        = <IP/adress>,
	port           = <port>,
	selected_world = <index>, -- 0 for client mode
	singleplayer   = <true/false>,
}

Functions
---------
core.start()
core.close()

Filesystem:
core.get_builtin_path()
^ returns path to builtin root
core.create_dir(absolute_path) (possible in async calls)
^ absolute_path to directory to create (needs to be absolute)
^ returns true/false
core.delete_dir(absolute_path) (possible in async calls)
^ absolute_path to directory to delete (needs to be absolute)
^ returns true/false
core.copy_dir(source,destination,keep_soure) (possible in async calls)
^ source folder
^ destination folder
^ keep_source DEFAULT true --> if set to false source is deleted after copying
^ returns true/false
core.extract_zip(zipfile,destination) [unzip within path required]
^ zipfile to extract
^ destination folder to extract to
^ returns true/false
core.download_file(url,target) (possible in async calls)
^ url to download
^ target to store to
^ returns true/false
core.get_version() (possible in async calls)
^ returns current core version
core.sound_play(spec, looped) -> handle
^ spec = SimpleSoundSpec (see lua-api.txt)
^ looped = bool
core.sound_stop(handle)
core.get_video_drivers()
^ get list of video drivers supported by engine (not all modes are guaranteed to work)
^ returns list of available video drivers' settings name and 'friendly' display name
^ e.g. { {name="opengl", friendly_name="OpenGL"}, {name="software", friendly_name="Software Renderer"} }
^ first element of returned list is guaranteed to be the NULL driver
core.get_mapgen_names([include_hidden=false]) -> table of map generator algorithms
    registered in the core (possible in async calls)
core.get_cache_path() -> path of cache

Formspec:
core.update_formspec(formspec)
core.get_table_index(tablename) -> index
^ can also handle textlists
core.formspec_escape(string) -> string
^ escapes characters [ ] \ , ; that can not be used in formspecs
core.explode_table_event(string) -> table
^ returns e.g. {type="CHG", row=1, column=2}
^ type: "INV" (no row selected), "CHG" (selected) or "DCL" (double-click)
core.explode_textlist_event(string) -> table
^ returns e.g. {type="CHG", index=1}
^ type: "INV" (no row selected), "CHG" (selected) or "DCL" (double-click)
core.set_formspec_prepend(formspec)
^ string to be added to every mainmenu formspec, to be used for theming.

GUI:
core.set_background(type, texturepath,[tile],[minsize])
^ type: "background", "overlay", "header" or "footer"
^ tile: tile the image instead of scaling (background only)
^ minsize: minimum tile size, images are scaled to at least this size prior
^   doing tiling (background only)
core.set_clouds(<true/false>)
core.set_topleft_text(text)
core.show_keys_menu()
core.show_path_select_dialog(formname, caption, is_file_select)
^ shows a path select dialog
^ formname is base name of dialog response returned in fields
^     -if dialog was accepted "_accepted"
^        will be added to fieldname containing the path
^     -if dialog was canceled "_cancelled"
^        will be added to fieldname value is set to formname itself
^ if `is_file_select` is `true`, a file and not a folder will be selected
^ returns nil or selected file/folder
core.get_screen_info()
^ returns {
	density         = <screen density 0.75,1.0,2.0,3.0 ... (dpi)>,
	display_width   = <width of display>,
	display_height  = <height of display>,
	window_width    = <current window width>,
	window_height   = <current window height>
	}

### Content and Packages

Content - an installed mod, modpack, game, or texture pack (txt)
Package - content which is downloadable from the content db, may or may not be installed.

* core.get_modpath() (possible in async calls)
	* returns path to global modpath
* core.get_clientmodpath() (possible in async calls)
	* returns path to global client-side modpath
* core.get_gamepath() (possible in async calls)
	* returns path to global gamepath
* core.get_texturepath() (possible in async calls)
	* returns path to default textures
* core.get_game(index)
	* returns:

		{
			id               = <id>,
			path             = <full path to game>,
			gamemods_path    = <path>,
			name             = <name of game>,
			menuicon_path    = <full path to menuicon>,
			author           = "author",
			DEPRECATED:
			addon_mods_paths = {[1] = <path>,},
		}

* core.get_games() -> table of all games in upper format (possible in async calls)
* core.get_content_info(path)
	* returns

		{
			name             = "name of content",
			type             = "mod" or "modpack" or "game" or "txp",
			description      = "description",
			author           = "author",
			path             = "path/to/content",
			depends          = {"mod", "names"}, -- mods only
			optional_depends = {"mod", "names"}, -- mods only
		}


Favorites:
core.get_favorites(location) -> list of favorites (possible in async calls)
^ location: "local" or "online"
^ returns {
	[1] = {
	clients       = <number of clients/nil>,
	clients_max   = <maximum number of clients/nil>,
	version       = <server version/nil>,
	password      = <true/nil>,
	creative      = <true/nil>,
	damage        = <true/nil>,
	pvp           = <true/nil>,
	description   = <server description/nil>,
	name          = <server name/nil>,
	address       = <address of server/nil>,
	port          = <port>
	},
}
core.delete_favorite(id, location) -> success

Logging:
core.debug(line) (possible in async calls)
^ Always printed to stderr and logfile (print() is redirected here)
core.log(line) (possible in async calls)
core.log(loglevel, line) (possible in async calls)
^ loglevel one of "error", "action", "info", "verbose"

Settings:
core.settings:set(name, value)
core.settings:get(name) -> string or nil (possible in async calls)
core.settings:set_bool(name, value)
core.settings:get_bool(name) -> bool or nil (possible in async calls)
core.settings:save() -> nil, save all settings to config file

For a complete list of methods of the Settings object see
[lua_api.txt](https://github.com/minetest/minetest/blob/master/doc/lua_api.txt)

Worlds:
core.get_worlds() -> list of worlds (possible in async calls)
^ returns {
	[1] = {
	path   = <full path to world>,
	name   = <name of world>,
	gameid = <gameid of world>,
	},
}
core.create_world(worldname, gameid)
core.delete_world(index)

Helpers:
core.get_us_time()
^ returns time with microsecond precision
core.gettext(string) -> string
^ look up the translation of a string in the gettext message catalog
fgettext_ne(string, ...)
^ call core.gettext(string), replace "$1"..."$9" with the given
^ extra arguments and return the result
fgettext(string, ...) -> string
^ same as fgettext_ne(), but calls core.formspec_escape before returning result
core.parse_json(string[, nullvalue]) -> something (possible in async calls)
^ see core.parse_json (lua_api.txt)
dump(obj, dumped={})
^ Return object serialized as a string
string:split(separator)
^ eg. string:split("a,b", ",") == {"a","b"}
string:trim()
^ eg. string.trim("\n \t\tfoo bar\t ") == "foo bar"
core.is_yes(arg) (possible in async calls)
^ returns whether arg can be interpreted as yes
minetest.encode_base64(string) (possible in async calls)
^ Encodes a string in base64.
minetest.decode_base64(string) (possible in async calls)
^ Decodes a string encoded in base64.

Version compat:
core.get_min_supp_proto()
^ returns the minimum supported network protocol version
core.get_max_supp_proto()
^ returns the maximum supported network protocol version

Async:
core.handle_async(async_job,parameters,finished)
^ execute a function asynchronously
^ async_job is a function receiving one parameter and returning one parameter
^ parameters parameter table passed to async_job
^ finished function to be called once async_job has finished
^    the result of async_job is passed to this function

Limitations of Async operations
 -No access to global lua variables, don't even try
 -Limited set of available functions
	e.g. No access to functions modifying menu like core.start,core.close,
	core.show_path_select_dialog
