Minecraft Datapack Language

This is the parser for the Minecraft Datapack Language. The backend will be rewriten somepoint soon. There is an already existing version of this, the ebnf I came up with a while ago, and I have a simple python parser thing that takes a reduced form of it and makes it into functioning minecraft datapack code. Mainly made for this project.

Examples

The basis of the language is on the use of calling functions with arguments to allow the manipulation of commands directly. This behaviour can be exploited to create a higher level language directly!

Now what do I mean by this? One of the outcomes that is– nearly– impossible to achieve in normal Minecraft command blocks/ datapacks is the concatination of strings. However with function calls it becomes trivial.

In minecraft datapack `mcfunction` code

Concatenate output

cat_and_say.mcfunction

#inputs :
# A : Some literal
# B : Some other literal
$data modify storage example:utils cat_output set value "$(A)$(B)"
$say "$(A)$(B)"

And then the calling code

Call Code

main.mcfunction

data modify storage example:main cat_and_say_args set value {A:"Hello,",B:" World!"}
function example:cat_and_say with storage example:main cat_and_say_args

Which then will output Hello, World! and store it to example:utils cat_output

In mdl

In a direct translation this could be

// utils.mcf
data cat_output := "";

fn cat_and_say(eff A: String, eff B: String) : Void {
    utils.cat_output = "<A><B>";
    $say "<A><B>";
}
// main.mcf
namespace utils = "utils.mcf'
utils/cat_and_say("Hello,"," World!");

Or using inlining

namespace utils = {
    data cat_output := "";
};

// Define an inline function with default values
cat_and_say<data A: string = "Hello,", data B: String = " World!"> {
    utils.cat_output = "<A><B>";
    $say "<A><B>";
}

cat_and_say();
// "Hello, World!"
cat_and_say("Blocky"," Place...");
// "Blocky, Place..."

Or just letting the macro system solve automatically.

namespace utils = {
    data cat_output := "";
};

data A := "Hello,";
data B := " World!";
utils.cat_output = "<A><B>";
$say "<A><B>";

MISC

This is my first time ever using the V programming language, it has been interesting to say the least. There are some qualms that I hold, however, it seems to be a very productive language.

Notes

Namespaces

// a.mcf
namespace a;
namespace b = "b.mcf";
data x := 10;

// b.mcf
namespace b;
namespace a = "a.mcf";

fn addx(data y: Int) : Int {
    return y + a.x;
}

fn add2x(data y: Int) : Int{
    return y + a.b.addx(y);
}

Should ultimately result in

//b.mcf

fn addx(data y : Int) : Int{
    return y + a.x;
}

fn add2x(datay: Int) : Int{
    return y + addx(y);
}