Minecraft Commands

A line that starts with / is a Minecraft command. Cobble writes it to the .mcfunction file without the slash:

def setup():
    /scoreboard objectives add deaths deathCount
    /gamerule spawn_mobs false

A # comment after a command is removed from the output.

JSON Text

tellraw, title, and other commands with JSON text work as written:

def announce():
    score = 10
    /tellraw @a {"text":"Game Started!", "color":"gold", "bold":true}
    /title @a title {"text":"Welcome", "color":"aqua"}
    /tellraw @a [{"text":"Score: {score}", "color":"gold"}, {"text":" ready"}]

In tellraw and title, a {variable} inside a JSON text field or a JSON array string becomes a score or NBT text component. The styling of the surrounding text is kept. A /say line with a {variable} becomes a tellraw @a command with the same components. Unlike say, that message has no [name] prefix, and selectors in it such as @s appear as plain text.

Placeholders

{name} inserts a function parameter, a constant, or the variable of a loop that Cobble expands at compile time (see For Loops) into a raw command:

def teleport_player(player, x, y, z):
    /tp {player} {x} {y} {z}
    /tellraw {player} {"text":"Teleported!", "color":"green"}

Function parameters become macro arguments, so that line compiles to a macro line such as $tp $(player) $(x) $(y) $(z). Constants and the values of those loops are substituted at compile time.

A Cobble variable, including the variable of a runtime loop, works as a placeholder only in say, tellraw, and title text, as described under JSON Text. In any other command it is a compile error. To use a variable’s value there, pass it to a function parameter:

count = 3

def give_diamonds(amount):
    /give @a minecraft:diamond {amount}

def reward():
    give_diamonds(count)

Unknown, invalid, and unclosed placeholders are errors. Write {{ and }} for literal braces:

def help():
    /say Type {{name}} to see a placeholder

say Type {name} to see a placeholder

The temp Objective

Raw commands refer to Cobble variables through the objective name temp, which Cobble rewrites to the pack’s <namespace>.vars objective. See The temp Objective In Raw Commands.