Air

biome_ungrammar is a fork of the rust-analyzer Ungrammar library, maintained by Biome. It provides a grammar specification engine with extended support for specific syntax features not present in the original version.

Key features added in this fork include:

• Double-pipe (||) combinator: Specifies "one or more of the alternatives, in any order."
• Double-amp (&&) combinator: Specifies "all of the alternatives, in any order."
• Documentation comment parsing: Enables parsing documentation comments to attach them to specific nodes and rules within the grammar.

If you do not want to install air globally, you can use uvx to run it as a one-off command. This is useful for temporary formatting tasks.

To run a one-off command using the latest version:

uvx --from air-formatter air format path/to/file.R

To run a specific version of air without installing it:

uvx --from air-formatter@0.8.2 air format path/to/file.R

If you use uv, you can manage Air via the air-formatter package on PyPI. You can either install it as a global tool or run it as a one-off command without a permanent installation.

# Global install
uv tool install air-formatter
air format path/to/my/script.R

# Invoke once without installing
uvx --from air-formatter air format path/to/my/script.R

To run and review tests for the air_r_formatter crate, you must install the cargo-insta tool. This tool is used for snapshot testing.

cargo install cargo-insta

The src/generated.rs file is automatically produced by running the gen-formatter task from the workspace root using just.

just gen-formatter

On macOS, you can install the community-maintained Air formula using Homebrew.

brew install air

You can use Pixi to install Air from the community-maintained conda-forge feedstock. Pixi allows you for adding Air to a specific project, installing it globally, or running it as a one-off command.

# Add to a project
pixi add air
pixi run air format path/to/my/script.R

# Install globally
pixi global install air

# Run one-off command
pixi exec air format path/to/my/script.R

You can install the air command-line tool globally using pip or uv. Installing via these methods adds the air command to your PATH, allowing you to run it directly from your terminal.

To install globally with uv:

uv tool install air-formatter

To install globally with pip:

pip install air-formatter

Once cargo-insta is installed, use the following commands to manage snapshot tests:

• cargo insta test: Runs the tests.
• cargo insta review: Reviews and manages snapshot changes.

If you need to pin your global installation to a specific version of the formatter, use the @version syntax with uv tool install.

Example for version 0.8.2:

uv tool install air-formatter@0.8.2

You can use standard cargo test commands to execute the generated tests. Use the following patterns to filter your test execution:

• Run all tests in all crates.
• Run all tests within a specific crate.
• Run all tests within a specific crate and a specific module.
• Run a single specific test generated by the macro.

# all tests in all crates
cargo test

# all tests of one crate
cargo test -p crate-name

# all tests of one crate and one module
cargo test -p crate-name -- some_mod::

# just one test
cargo test -p crate-name -- some_mod::somefilename