Expressions

Expression is a special line of code (or rather mathematical expression) that allows to check for specific conditions. Expressions support full power of McLib's math parser, which supports basic arithmetic operations (+, -, *, /), math functions (abs(), sin(), cos(), sqrt(), etc.) and many other things. For more information check out this page.

Parsed expressions

Parsed expressions are present in events and dialogues. These wrapped in ${...} allow you to substitute an expression inside of a text field, with the result of that expression. For example: if you attach to global Player: chat message trigger (in server settings) to an event, its variable message will be available within expressions (and also in scripts via IScriptEvent.getValue(String)):

Where parsed expressions are supported, which should be in:

• Command's node command text field
• Trigger's node custom data text field
• Reaction's/reply's content text field
• Quest chain's subject text field

Any of the functions described below can be used. Beside that, values that came from trigger node's Custom data and global trigger's Available particles should be accessible via variable name, like ${message} from the chat trigger in the screenshot above.

Special variables

Beside variables mentioned above, there will be also following variables available in the context:

• subject, first entity's UUID (which can be used with for entity <target> selector arguments)
• subject_name, first entity's display name
• object, second entity's UUID
• object_name, second entity's display name
• player, first player's (could be either subject or object) UUID
• player_name, first player's (could be either subject_name or object_name) display_name
• npc, first Mappet NPC's (could be either subject or object) UUID
• npc_name, first Mappet NPC's (could be either subject_name or object_name) display_name

If there are no entity was passed in the context, obviously all of the variables will be empty strings. Obviously, if neither subject or object is a player entity nor an NPC, player* and npc* variables will be empty strings. See also this section on events page.

Mappet's expression functions

Beside that, expressions support special features that allow to connect it with other Mappet's features. Here is a full list of them:

Quest functions

Name and arguments	Return value
quest_present(id, target)	Returns boolean whether one of the players by target selector has a quest by id in progress
quest_completed(id, target)	Returns boolean whether one of the player by target selector has completed a quest by id. Alternatively ~ can be used, for target, to check whether quest was completed globally.
quest_present_or_completed(id)	Returns boolean whether a quest by id was completed or one of the current players has it, this useful if you want to check whether the quest by id wasn't taken before.

Faction functions

Name and arguments	Return value
faction_friendly(id, target)	Returns boolean whether faction score of the faction by id of player by target selector makes it friendly.
faction_neutral(id, target)	Returns boolean whether faction score of the faction by id of player by target selector makes it neutral.
faction_hostile(id, target)	Returns boolean whether faction score of the faction by id of player by target selector makes it hostile.
faction_has(id, target)	Returns boolean whether player by target selector has faction score by id.
faction_score(id, target)	Returns faction score of faction by id of a single player by target selector.

State functions

Name and arguments	Return value
state(id[, target])	Returns value of state by id. If target is omitted, then it would use global state, or current subject's states. If target is specified, then it will try to find by a target selector a player with that state, or ~ for global state.

Player inventory functions

Name and arguments	Return value
inv_has(item_id[, target, all])	Returns boolean whether player(s) by target selector has an item by item_id in the inventory (not in held or equipped slots). all is a boolean that signifies whether (value 1) all players should be checked, or only one (value 0) player should have at least.
inv_holds(item_id[, target, all])	Returns boolean whether player(s) by target selector holds an item by item_id in main or off hands.
inv_armor(item_id[, target, all])	Returns boolean whether player(s) by target selector equipped an item by item_id in any of the armor slots.

Player functions

Name and arguments	Return value
player_xp(target)	Returns target player's current total XP.
player_xp_level(target)"	Returns target player's current XP level.
player_hp(target)	Returns target player's current HP.
player_hunger(target)	Returns target player's hunger.
player_armor(target)	Returns target player's armor.
player_is_alive(target)	Returns whether target player(s).

Dialogue functions

Name and arguments	Return value
dialogue_read(id, target)	Returns whether given target has read dialogue by id.

World functions

Note: [dimension_id] argument is an optional argument in case you're using these expressions where world wasn't provided (like on server start global trigger). 0 is overworld, -1 is nether and 1 is the end.

Name and arguments	Return value
world_time([dimension_id])	Returns world time (i.e. the one that actually is day/night), whether 1000 is day and 13000 is night.
world_total_time([dimension_id])	Returns total world time since the beginning of world's initialization.
world_is_night([dimension_id])	Returns boolean whether it's night time (12000 - 24000).
world_is_day([dimension_id])	Returns boolean whether it's day time (0 - 12000).

Note: boolean is either 1 (true) or 0 (false).