NBT

In Minecraft, NBT is one of the most important data types. NBT is a tree-structured data format that can store a wide variety of data, such as integers, floating-point numbers, strings, arrays, lists, and compound data. In MCFPP, NBT is a built-in data type that can be used directly.

Basic Usage of NBT Data Types

In MCFPP, the type identifier for NBT is nbt. You can create NBT data using the standard SNBT (Stringified NBT) syntax, for example:

var value1 as nbt = "Hello, World!";

var number as nbt = 42;

var list as nbt = [1, 2, 3];

var uuid as nbt = [I; 0, 0, 0, 1];

var itemStack as nbt = {
    "Count": 1,
    "Item": "minecraft:stone",
    "tag": {
        "display": {
            "Name": "Stone"
        }
    }
};

You can use [] indexing to access members of complex NBT data, for example:

var itemStack as nbt = {
    "Count": 1,
    "Item": "minecraft:stone",
    "tag": {
        "display": {
            "Name": "Stone"
        }
    }
};

print(itemStack["tag"]["display"]["Name"]);

var list as nbt = [1, 2, 3];

print(list[0]);

The compiler does not check if the index is valid. Even if the indexed data does not exist, the compiler will still concatenate the NBT path normally. The same principle applies to list, dict, and map types.

There is one exception: when the compiler knows the value of the NBT type. In this case, NBT will attempt to check whether the data is valid. However, it will not throw an error but will issue a warning. The data pack will still be generated as expected.