Function (Java Edition)

Functions allow players to run lists of commands using text files with the extension.

Usage
To utilize functions, the text files must first be placed into the  folder within .minecraft. They can then be run using the several methods detailed below.

Function files must be further divided into subfolders, and are run in-game using the format, where   is the first-level subfolder name of the   folder. For example, running  will refer to the function located at. If the namespace is left out when trying to call a function, it will default to.

Within the text file, one valid command is placed per line (without the usual forward slash). Players can add comments within the function text file by preceding them with a. If a function is added or modified, the command will reload the function files from disk, allowing Minecraft to recognise any changes to the function files. Commands run inside a function will obey.

Commands in functions can be longer than the 32 500 character limit in command blocks. Functions will also run all of their commands in a single tick. Functions called from within other functions will run their commands in the same tick as their parent. Position changes that happen within a function will not affect the relative coordinates used in other commands within that function (or other functions called within the function) till the next iteration regardless of the order of commands, the command circumvents this. For example:

tp @a ~ ~5 ~ setblock ~ ~-1 ~ emerald_block execute @a ~ ~ ~ setblock ~ ~-1 ~ diamond_block

These 3 commands will teleport all players 5 blocks up, place an emerald_block one block below their original position before the teleport and place a diamond block one block below their new position after the teleport. This behavior does not affect position arguments within selectors, which will always test for the current position at the time of execution.

Since they are simply text files, functions are easily modifiable and less likely to induce lag when used in large quantities, compared to command blocks. However, the successful output of a function cannot be measured with a comparator (without the use of complex scoreboard commands).

There are several methods of running a function file in-game:

Commands

 * Allows players to run a function once.
 * The commands in the function are run through the entity or command block that ran the command.
 * The optional arguments  and   will make the function only run when the   was found or not found in the world respectively.
 * Usage:
 * Usage:


 * Runs a function every tick.
 * The commands in the function are run through the server.
 * If multiple functions need to be looped, it is possible to insert function commands into this looped function file, put function commands in those functions, etc.
 * Usage:
 * Usage:

Advancements
Advancements can run a function once as a reward for completing them. The commands in the function are run through the player who completed the advancement.

Reward functions are called within advancement JSON files using the following format:

{    "rewards": { "function": "namespace:path/to/function/file" } }

Issues
Funktion Fonctions 関数 函数