Data templates

data defines named fields, constructors, and methods. It tells the compiler which members an NBT value contains.

data Reward {
    var amount: int
    var label: string

    constructor(amount: int, label: string) {
        this.amount = amount
        this.label = label
    }

    func show() {
        print(this.label)
        print(this.amount)
    }
}

func main() {
    var reward = Reward(10, "Daily reward")
    reward.amount += 5
    reward.show()
}

constructor initializes a new object. this means the current object. Use this.amount inside a method and reward.amount outside it.

Copy an object value

Data templates use value semantics. This changes the copy:

data Reward {
    var amount: int = 10
}

func main() {
    var original = Reward()
    var copy = original
    copy.amount = 20
    print(original.amount)
    print(copy.amount)
}

This prints 10 followed by 20. Constructors initialize fields through explicit, typed parameters.

Continue with nested templates, singleton objects, and inheritance. Use generic templates for configurable field types.