1 # rustfmt [![Build Status](https://travis-ci.org/rust-lang-nursery/rustfmt.svg)](https://travis-ci.org/rust-lang-nursery/rustfmt) [![Build Status](https://ci.appveyor.com/api/projects/status/github/rust-lang-nursery/rustfmt?svg=true)](https://ci.appveyor.com/api/projects/status/github/rust-lang-nursery/rustfmt)
3 A tool for formatting Rust code according to style guidelines.
5 If you'd like to help out (and you should, it's a fun project!), see
6 [Contributing.md](Contributing.md).
16 to run on a cargo project in the current working directory:
24 > **Note:** this method currently requires you to be running cargo 0.6.0 or
31 or if you're using [`rustup.rs`](https://www.rustup.rs/)
34 rustup run nightly cargo install rustfmt
37 Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
38 installed alongside rustfmt. To only install rustfmt run
41 cargo install --no-default-features rustfmt
43 ## Installing from source
45 To install from source, first checkout to the tag or branch you want to install, then issue
47 cargo install --path .
49 This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
54 You can run Rustfmt by just typing `rustfmt filename` if you used `cargo
55 install`. This runs rustfmt on the given file, if the file includes out of line
56 modules, then we reformat those too. So to run on a whole module or crate, you
57 just need to run on the root file (usually mod.rs or lib.rs). Rustfmt can also
58 read data from stdin. Alternatively, you can use `cargo fmt` to format all
59 binary and library targets of your crate.
61 You'll probably want to specify the write mode. Currently, there are modes for
62 diff, replace, overwrite, display, coverage, and checkstyle.
64 * `replace` Is the default and overwrites the original files after creating backups of the files.
65 * `overwrite` Overwrites the original files _without_ creating backups.
66 * `display` Will print the formatted files to stdout.
67 * `diff` Will print a diff between the original files and formatted files to stdout.
68 * `checkstyle` Will output the lines that need to be corrected as a checkstyle XML file,
69 that can be used by tools like Jenkins.
71 The write mode can be set by passing the `--write-mode` flag on
72 the command line. For example `rustfmt --write-mode=display src/filename.rs`
74 `cargo fmt` uses `--write-mode=replace` by default.
76 If you want to restrict reformatting to specific sets of lines, you can
77 use the `--file-lines` option. Its argument is a JSON array of objects
78 with `file` and `range` properties, where `file` is a file name, and
79 `range` is an array representing a range of lines like `[7,13]`. Ranges
80 are 1-based and inclusive of both end points. Specifying an empty array
81 will result in no files being formatted. For example,
84 rustfmt --file-lines '[
85 {"file":"src/lib.rs","range":[7,13]},
86 {"file":"src/lib.rs","range":[21,29]},
87 {"file":"src/foo.rs","range":[10,11]},
88 {"file":"src/foo.rs","range":[15,15]}]'
91 would format lines `7-13` and `21-29` of `src/lib.rs`, and lines `10-11`,
92 and `15` of `src/foo.rs`. No other files would be formatted, even if they
93 are included as out of line modules from `src/lib.rs`.
95 If `rustfmt` successfully reformatted the code it will exit with `0` exit
96 status. Exit status `1` signals some unexpected error, like an unknown option or
97 a failure to read a file. Exit status `2` is returned if there are syntax errors
98 in the input files. `rustfmt` can't format syntatically invalid code. Finally,
99 exit status `3` is returned if there are some issues which can't be resolved
100 automatically. For example, if you have a very long comment line `rustfmt`
101 doesn't split it. Instead it prints a warning and exits with `3`.
103 You can run `rustfmt --help` for more information.
106 ## Running Rustfmt from your editor
108 * [Vim](https://github.com/rust-lang/rust.vim#enabling-autoformat)
109 * [Emacs](https://github.com/fbergroth/emacs-rustfmt)
110 * [Sublime Text 3](https://packagecontrol.io/packages/BeautifyRust)
112 * Visual Studio Code using [RustyCode](https://github.com/saviorisdead/RustyCode) or [vsc-rustfmt](https://github.com/Connorcpu/vsc-rustfmt)
114 ## How to build and test
116 `cargo build` to build.
118 `cargo test` to run all tests.
120 To run rustfmt after this, use `cargo run --bin rustfmt -- filename`. See the
121 notes above on running rustfmt.
124 ## Configuring Rustfmt
126 Rustfmt is designed to be very configurable. You can create a TOML file called
127 `rustfmt.toml` or `.rustfmt.toml`, place it in the project or any other parent
128 directory and it will apply the options in that file. See `rustfmt
129 --config-help` for the options which are available, or if you prefer to see
130 source code, [src/config.rs](src/config.rs).
132 By default, Rustfmt uses a style which (mostly) conforms to the
133 [Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
134 There are many details which the style guidelines do not cover, and in these
135 cases we try to adhere to a style similar to that used in the
136 [Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
137 able to re-format large repositories like Rust, we intend to go through the Rust
138 RFC process to nail down the default style in detail.
140 If there are styling choices you don't agree with, we are usually happy to add
141 options covering different styles. File an issue, or even better, submit a PR.
146 * For things you do not want rustfmt to mangle, use one of
149 #[rustfmt_skip] // requires nightly and #![feature(custom_attribute)] in crate root
150 #[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
152 * When you run rustfmt, place a file named `rustfmt.toml` or `.rustfmt.toml` in
153 target file directory or its parents to override the default settings of
155 * After successful compilation, a `rustfmt` executable can be found in the
157 * If you're having issues compiling Rustfmt (or compile errors when trying to
158 install), make sure you have the most recent version of Rust installed.
163 Rustfmt is distributed under the terms of both the MIT license and the
164 Apache License (Version 2.0).
166 See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.