rustidy

A rust source code formatter

Features

• Full support for all stable syntax (except for non-derive macros, which are only parsed, not formatted).

• Support for some nightly-only syntax (such as try blocks, do yeet expressions, and more).

• Formatting derive macro attributes (formats expressions inside of attributes)

• Ability to change the configuration for a block with attributes (both outer and inner attributes are supported):

// Change the threshold for splitting an array into multi-line.
#[rustidy::config(max_array_expr_len = 100)]
const ARRAY: [u32; 25] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25];
#[rustidy::config(max_array_expr_len = 0)]
const ARRAY: [u32; 2] = [
	1,
	2,
];

// Format an array with columns
#[rustidy::config(array_expr_cols = 3)]
const ARRAY: [u32; 8] = [
	1, 2, 3,
	4, 5, 6,
	7, 8,
]

// Change the indentation on a part of the code
#[rustidy::config(indent = "  ")]
fn main() {
  println!("Hello world!");
}
#[rustidy::config(indent = "\t\t")]
fn main() {
		println!("Hello world!");
}

// And of course, you can skip formatting altogether
#[rustidy::skip]
fn main() {
	1      +      6      +
	9      +      9;
}

Installation

From source

You can install rustidy using cargo install on a nightly toolchain:

cargo +nightly install --locked rustidy

This will also install the cargo-rustidy cargo subcommand to allow you to use cargo rustidy.

From binaries

• Binaries are distributed through github releases

Usage

Using cargo rustidy

The most common way to use rustidy is to use it to format all files in a cargo package or workspace using cargo rustidy:

cargo rustidy

This will try to use the rustidy binary in your $PATH. You can also directly specify the binary to use using the RUSTIDY environment variable:

RUSTIDY=.../rustidy cargo rustidy

For pre-commit hooks or CI servers, you can also check that code is formatted properly using the --check flag:

# Exits with 0 if all files are formatted properly, and 1 otherwise
cargo rustidy --check

Using rustidy directly

You can directly format a file in-place (and all of it's modules) using rustidy directly:

rustidy file1.rs file2.rs ...

rustidy also has the ability to read input from stdin and output it to stdout. This is the default mode when no arguments are passed:

printf "fn main() {}" | rustidy > output.rs

Similarly to cargo rustidy, rustidy has a --check argument to ensure that the specified files are all formatted properly:

rustidy --check file1.rs file2.rs ...

Editors

To run rustidy in your editors, you can typically specify it as a replacement for rustfmt.

In VSCode using rust-analyzer, you can achieve this with the following settings:

"rust-analyzer.rustfmt.overrideCommand": ["rustidy"]

Configuration

Rustidy can be configured using a .rustidy.toml file in any parent directory from where it was invoked. Only the first file found will be used as the configuration.

See an example configuration file.

Currently the configuration options are not documented, but you can check a list of them, including their default values, on the source.

License

This project is dual-licensed under either of the following licenses:

• Apache license Version 2.0
• MIT license