Decorator

Decorators in Deco are special annotations that provide additional functionality to functions. They are marked with the @ symbol and placed before function definitions. Decorators allow you to bind functions to specific Minecraft events or tags, simplifying datapack development.

Using Decorators

The basic syntax for a decorator is:

@decoratorName(arguments)
func functionName {
    // function code
}

Where:

• @decoratorName: The name of the decorator, starting with @
• (arguments): Optional parameters, some decorators require arguments
• func functionName { ... }: The decorated function

For example, the following code uses the @load decorator to mark a function that will execute when the datapack is loaded:

@load
func initialize {
    tellraw @a {"text":"Datapack loaded!","color":"green"}
}

Multiple Decorators

A single function can have multiple decorators applied to it by listing them before the function definition:

@load
@tag("custom:init")
func setupGame {
    scoreboard objectives add health health
    scoreboard objectives setdisplay sidebar health
}

This function will run both when the datapack is loaded and when you run function #custom:init.

Decorator Arguments

Some decorators need arguments to specify their behavior. Arguments are provided in parentheses after the decorator name:

@tag("minecraft:load")
func onLoad {
    say Datapack loaded!
}

@onPlaceBlock("minecraft:redstone_block")
func powerOn {
    say Power activated!
}

How Decorators Work

During compilation, Deco automatically generates the necessary function tag files and event handling code based on the decorators:

• @load and @tick decorators add your functions to Minecraft's built-in minecraft:load and minecraft:tick tags
• @tag adds your function to the specified custom tag
• @onPlaceBlock creates an advanced detection system using advancements and functions to detect when specific blocks are placed
• ...

This automatic generation saves you from having to manually create these structures, making your datapack development more efficient and your code more readable.

Available Decorators

Deco currently supports the following decorators:

@load

The @load decorator registers a function to run when the datapack is loaded.

@load
func initialize {
    tellraw @a {"text":"Datapack loaded!","color":"green"}
    scoreboard objectives add myScore dummy
}

After compilation, this function will be automatically added to the minecraft:load function tag, causing it to run whenever the datapack is loaded.

@tick

The @tick decorator registers a function to run every game tick.

@tick
func update {
    execute as @a at @s run particle minecraft:end_rod ~ ~1 ~ 0.2 0.2 0.2 0 1
}

After compilation, this function will be automatically added to the minecraft:tick function tag, causing it to run every game tick.

@tag

The @tag decorator allows you to add a function to a specific function tag.

@tag("custom:example")
func myTaggedFunction {
    say This function is in a custom tag!
}

After compilation, this function will be added to the specified function tag, in this case custom:example.

@onPlaceBlock

The @onPlaceBlock decorator binds a function to the event of a player placing a specific block.

@onPlaceBlock("minecraft:diamond_block")
func onDiamondPlaced {
    tellraw @a [{"selector":"@s"},{"text":" placed a diamond block!"}]
    give @s minecraft:diamond 1
}

When a player places a diamond block, the function will be triggered, displaying a message to all players and giving a diamond to the player who placed the block.