Read scores, NBT, and command results

A game score or NBT path can be absent. tryRead reports whether a value exists and supplies the value to a callback.

Read an entity score

Create test data in the game:

scoreboard objectives add points dummy
scoreboard players set @s points 10

func main() {
    @s.withEntityCtx { ctx ->
        var found = ctx.executor.score["points"].tryRead { points ->
            print(points)
        }
        print(found)
    }
}

When the score exists, tryRead invokes the callback once and returns true. A zero score also counts as a successful read. An absent score produces false.

The callback receives a snapshot. Use the address value's set method to write a value. Read ScoreRef and NBTRef for complete examples.

Read NBT

func main() {
    @s.withEntityCtx { ctx ->
        var found = ctx.executor.dat.air.tryRead { air ->
            print(toInt(air))
        }
        print(found)
    }
}

This example reads the entity's Air field. toInt converts the NBT number to an integer for calculations.

Check a command result

Standard library commands with result support return CommandResult. It contains success: bool and result: int.

func main() {
    var moved = tp(@a, 0 80 0)
    if (moved.success) {
        print(moved.result)
    } else {
        print("No player moved")
    }
}

success reports whether the command succeeded. The Minecraft command determines the meaning of result. For teleportation, it reports the number of affected targets.