tree-sitter-mojo

This project provides a Tree-sitter grammar for the Mojo programming language. It is based on the grammar for Python, reflecting the similar syntax structures between Python and Mojo.

Project Overview

The Mojo programming language shares a syntax that is nearly identical to Python. To accommodate the specifics of Mojo while leveraging existing robust solutions, this Tree-sitter grammar is derived from the official tree-sitter-python repository. Necessary modifications to the Python grammar to support Mojo-specific elements are integrated automatically on a weekly basis through GitHub Actions.

Automation with GitHub Actions

The primary customization in this project resides in a single GitHub Actions workflow: tree_sitter_maker.yml. This workflow is responsible for periodically updating the Tree-sitter grammar to adapt any changes from the Python grammar and apply Mojo-specific adjustments.

The updated grammar files are automatically generated and maintained through this automated process, ensuring that the Tree-sitter grammar for Mojo is always up-to-date with the latest syntactical standards of both Python and Mojo.

Adding Mojo-Specific Keywords

You can add Mojo-specific keywords like fn to the grammar by including them in the env: section of the tree_sitter_maker.yml. This allows for easy customization and expansion of the grammar to fit the evolving needs of the Mojo language.

Setting Up Helix for Mojo

To use this Tree-sitter grammar with the Helix editor, follow the setup instructions below:

1. Configure Helix

First, create a languages.toml configuration file in your Helix setup located at ~/.config/helix:

use-grammars = { only = [ "mojo" ] }

[language-server]
mojo = { command = "mojo-lsp-server" }

[[language]]
name = "mojo"
scope = "source.mojo"
roots = []
injection-regex = "mojo"
file-types = ["mojo", "🔥"]
comment-token = "#"
indent = { tab-width = 4, unit = "    " }
language-servers = [ "mojo" ]

[[grammar]]
name = "mojo"
source = { git = "https://github.com/garam-kim1/tree-sitter-mojo", rev = "b1cbffe21200732f78bbdd7e3f600d7c0569830a" }

2. Install the Grammar

After configuring, fetch, and build the grammar using the following commands in the Helix terminal:

hx --grammar fetch
cd ~/.config/helix
mkdir -p runtime/queries/mojo/
cp -r runtime/grammars/sources/mojo/runtime/queries/mojo/* runtime/queries/mojo/
hx --grammar build

These steps will integrate the Mojo language support into Helix, enabling syntax highlighting and other language-specific features.