minecraft-datapack-language 4.3.0

Compile a tiny MDL language or Python API into a Minecraft datapack (1.21+ ready).

Minecraft Datapack Language (MDL)

A tiny compiler that lets you write Minecraft datapacks in a simple language (.mdl) or via a clean Python API, and then compiles to the correct 1.21+ datapack folder layout (singular directories) automatically.

• ✅ Handles the directory renames from snapshots 24w19a (tag subfolders) and 24w21a (core registry folders) for you.
• ✅ Easy hooks into minecraft:tick and minecraft:load via function tags.
• ✅ Creates tags for function, item, block, entity_type, fluid, and game_event.
• ✅ VS Code extension for syntax highlighting, linting, and quick compile.

Default pack_format is 48 (Java 1.21). Set --pack-format 47 to emit the legacy plural layout for older versions.

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Install

Option A — from PyPI (recommended for users)

Global, isolated CLI via pipx:

python3 -m pip install --user pipx
python3 -m pipx ensurepath    # reopen terminal
pipx install minecraft-datapack-language

mdl --help

Virtualenv (if you prefer):

python3 -m venv .venv
source .venv/bin/activate      # Windows: .\.venv\Scripts\Activate.ps1
pip install minecraft-datapack-language

Option B — from source (for contributors)

# inside the repo
python -m pip install -e .

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Update

• pipx: pipx upgrade minecraft-datapack-language
• pip (venv): pip install -U minecraft-datapack-language
• Pin a version: pipx install "minecraft-datapack-language==1.1.0"

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CLI

mdl new my_pack --name "My Pack" --pack-format 48
mdl check my_pack/mypack.mdl
mdl build --mdl my_pack/mypack.mdl -o dist --wrapper mypack --pack-format 48
# → dist/mypack/... and dist/mypack.zip

Build a whole folder of .mdl files

mdl build --mdl src/ -o dist
# Recursively parses src/**/*.mdl, merges into one pack (errors on duplicate functions).

Validate a folder (JSON diagnostics)

mdl check --json src/

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The .mdl language

Grammar you can rely on (based on the parser)

• pack header (required once):

  pack "Name" [description "Desc"] [pack_format N]
  

• namespace (selects a namespace for following blocks):

  namespace "example"
  

• function (colon + indented commands, 4-space indents only):

  function "hello":
      say hi
      tellraw @a {"text":"ok","color":"green"}
  

• function calls (one function invoking another with fully qualified ID):

  function "outer":
      say I will call another function
      function example:hello
  

• hooks (namespaced ids required):

  on_load "example:hello"
  on_tick "example:hello"
  

• tags (supported registries: function, item, block, entity_type, fluid, game_event):

  tag function "minecraft:tick":
      add "example:hello"
  

  The parser accepts an optional replace flag on the header (e.g. tag function "minecraft:tick" replace:) but replacement behavior is controlled by the pack writer.
• comments start with #. Hashes inside quoted strings are preserved.
• whitespace: empty lines are ignored; indentation must be multiples of four spaces (tabs are invalid).

Inside a function block, every non-empty line is emitted verbatim as a Minecraft command—no extra parsing.

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FULL example (nested calls + multi-namespace)

# mypack.mdl — nested and multi-namespace demo
pack "Minecraft Datapack Language" description "Nested + Namespaces" pack_format 48

# === First namespace ===
namespace "example"

function "inner":
    say [example:inner] This is the inner function
    tellraw @a {"text":"Running inner","color":"yellow"}

function "outer":
    say [example:outer] This is the outer function
    # "nested" call into inner (composition)
    function example:inner
    tellraw @a {"text":"Back in outer","color":"aqua"}

# Run outer once on pack load
on_load "example:outer"

# === Second namespace ===
namespace "util"

function "helper":
    say [util:helper] Helping out...
    tellraw @a {"text":"Util helper called","color":"green"}

function "boss":
    say [util:boss] Calling outer, then helper
    # cross-namespace calls with fully-qualified IDs
    function example:outer
    function util:helper
    tellraw @a {"text":"Boss finished!","color":"red"}

# Run boss every tick
on_tick "util:boss"

# Tag example for demonstration (tick also includes boss)
tag function "minecraft:tick":
    add "util:boss"

What this demonstrates

• Nested-like function composition via the function <ns:id> command.
• Multiple namespaces (example, util) calling each other with fully-qualified IDs.
• Lifecycle hooks (on_load, on_tick) using namespaced function IDs.
• Function tagging to participate in vanilla tags (minecraft:tick).

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Python API equivalent

from minecraft_datapack_language import Pack

def build_pack():
    p = Pack(name="Minecraft Datapack Language",
             description="Nested + Namespaces",
             pack_format=48)

    ex = p.namespace("example")
    ex.function("inner",
        'say [example:inner] This is the inner function',
        'tellraw @a {"text":"Running inner","color":"yellow"}'
    )
    ex.function("outer",
        'say [example:outer] This is the outer function',
        'function example:inner',
        'tellraw @a {"text":"Back in outer","color":"aqua"}'
    )

    # Hooks
    p.on_load("example:outer")

    util = p.namespace("util")
    util.function("helper",
        'say [util:helper] Helping out...',
        'tellraw @a {"text":"Util helper called","color":"green"}'
    )
    util.function("boss",
        'say [util:boss] Calling outer, then helper',
        'function example:outer',
        'function util:helper',
        'tellraw @a {"text":"Boss finished!","color":"red"}'
    )

    # Tick hook + a function tag example
    p.on_tick("util:boss")
    p.tag("function", "minecraft:tick", values=["util:boss"])

    return p

Build it:

python - <<'PY'
from my_pack_module import build_pack
from minecraft_datapack_language.cli import main as M
# write to dist/ with a wrapper folder name 'mypack'
p = build_pack()
M(['build', '--py-object', 'my_pack_module:build_pack', '-o', 'dist', '--wrapper', 'mypack', '--pack-format', '48'])
PY

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VS Code

Open vscode-extension/, then:

npm i
# Press F5 to launch the Extension Dev Host

• Highlights .mdl
• Runs mdl check on save and shows inline diagnostics
• MDL: Build current file prompts for output folder and optional wrapper
• MDL: Check Workspace validates the whole workspace

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CI & Releases

• CI runs on push/PR across Linux/macOS/Windows and uploads artifacts.
• Release is triggered by pushing a tag like v1.0.0 or via the Release workflow manually.
• Versions are derived from git tags via setuptools-scm; tag vX.Y.Z → package version X.Y.Z.

Local release helper

# requires GitHub CLI: gh auth login
./scripts/release.sh patch  "Fixes"
./scripts/release.sh minor  "Features"
./scripts/release.sh major  "Breaking"
./scripts/release.sh v1.2.3 "Exact version"