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).
8 We are changing the default style used by rustfmt. There is an ongoing [RFC process](https://github.com/rust-lang-nursery/fmt-rfcs).
9 The last version using the old style was 0.8.6. From 0.9 onwards, the RFC style
10 is the default. If you want the old style back, you can use [legacy-rustfmt.toml](legacy-rustfmt.toml)
13 The current `master` branch uses libsyntax (part of the compiler). It is
14 published as `rustfmt-nightly`. The `syntex` branch uses Syntex instead of
15 libsyntax, it is published (for now) as `rustfmt`. Most development happens on
16 the `master` branch, however, this only supports nightly toolchains. If you use
17 stable or beta Rust toolchains, you must use the Syntex version (which is likely
18 to be a bit out of date). Version 0.1 of rustfmt-nightly is forked from version
19 0.9 of the syntex branch.
30 to run on a cargo project in the current working directory:
38 > **Note:** this method currently requires you to be running cargo 0.6.0 or
45 or if you're using [`rustup.rs`](https://www.rustup.rs/)
48 rustup run nightly cargo install rustfmt
51 Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
52 installed alongside rustfmt. To only install rustfmt run
55 cargo install --no-default-features rustfmt
57 ## Installing from source
59 To install from source, first checkout to the tag or branch you want to install, then issue
61 cargo install --path .
63 This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
68 You can run Rustfmt by just typing `rustfmt filename` if you used `cargo
69 install`. This runs rustfmt on the given file, if the file includes out of line
70 modules, then we reformat those too. So to run on a whole module or crate, you
71 just need to run on the root file (usually mod.rs or lib.rs). Rustfmt can also
72 read data from stdin. Alternatively, you can use `cargo fmt` to format all
73 binary and library targets of your crate.
75 You'll probably want to specify the write mode. Currently, there are modes for
76 diff, replace, overwrite, display, coverage, and checkstyle.
78 * `replace` Is the default and overwrites the original files after creating backups of the files.
79 * `overwrite` Overwrites the original files _without_ creating backups.
80 * `display` Will print the formatted files to stdout.
81 * `diff` Will print a diff between the original files and formatted files to stdout.
82 Will also exit with an error code if there are any differences.
83 * `checkstyle` Will output the lines that need to be corrected as a checkstyle XML file,
84 that can be used by tools like Jenkins.
86 The write mode can be set by passing the `--write-mode` flag on
87 the command line. For example `rustfmt --write-mode=display src/filename.rs`
89 `cargo fmt` uses `--write-mode=replace` by default.
91 If you want to restrict reformatting to specific sets of lines, you can
92 use the `--file-lines` option. Its argument is a JSON array of objects
93 with `file` and `range` properties, where `file` is a file name, and
94 `range` is an array representing a range of lines like `[7,13]`. Ranges
95 are 1-based and inclusive of both end points. Specifying an empty array
96 will result in no files being formatted. For example,
99 rustfmt --file-lines '[
100 {"file":"src/lib.rs","range":[7,13]},
101 {"file":"src/lib.rs","range":[21,29]},
102 {"file":"src/foo.rs","range":[10,11]},
103 {"file":"src/foo.rs","range":[15,15]}]'
106 would format lines `7-13` and `21-29` of `src/lib.rs`, and lines `10-11`,
107 and `15` of `src/foo.rs`. No other files would be formatted, even if they
108 are included as out of line modules from `src/lib.rs`.
110 If `rustfmt` successfully reformatted the code it will exit with `0` exit
111 status. Exit status `1` signals some unexpected error, like an unknown option or
112 a failure to read a file. Exit status `2` is returned if there are syntax errors
113 in the input files. `rustfmt` can't format syntatically invalid code. Finally,
114 exit status `3` is returned if there are some issues which can't be resolved
115 automatically. For example, if you have a very long comment line `rustfmt`
116 doesn't split it. Instead it prints a warning and exits with `3`.
118 You can run `rustfmt --help` for more information.
121 ## Running Rustfmt from your editor
123 * [Vim](https://github.com/rust-lang/rust.vim#formatting-with-rustfmt)
124 * [Emacs](https://github.com/rust-lang/rust-mode)
125 * [Sublime Text 3](https://packagecontrol.io/packages/BeautifyRust)
127 * Visual Studio Code using [vscode-rust](https://github.com/editor-rs/vscode-rust), [vsc-rustfmt](https://github.com/Connorcpu/vsc-rustfmt) or [rls_vscode](https://github.com/jonathandturner/rls_vscode) through RLS.
129 ## Checking style on a CI server
131 To keep your code base consistently formatted, it can be helpful to fail the CI build
132 when a pull request contains unformatted code. Using `--write-mode=diff` instructs
133 rustfmt to exit with an error code if the input is not formatted correctly.
134 It will also print any found differences.
136 A minimal Travis setup could look like this:
142 - export PATH="$PATH:$HOME/.cargo/bin"
143 - which rustfmt || cargo install rustfmt
145 - cargo fmt -- --write-mode=diff
150 Note that using `cache: cargo` is optional but highly recommended to speed up the installation.
152 ## How to build and test
154 `cargo build` to build.
156 `cargo test` to run all tests.
158 To run rustfmt after this, use `cargo run --bin rustfmt -- filename`. See the
159 notes above on running rustfmt.
162 ## Configuring Rustfmt
164 Rustfmt is designed to be very configurable. You can create a TOML file called
165 `rustfmt.toml` or `.rustfmt.toml`, place it in the project or any other parent
166 directory and it will apply the options in that file. See `rustfmt
167 --config-help` for the options which are available, or if you prefer to see
168 visual style previews, [Configurations.md](Configurations.md).
170 By default, Rustfmt uses a style which (mostly) conforms to the
171 [Rust style guidelines](https://doc.rust-lang.org/1.12.0/style/README.html).
172 There are many details which the style guidelines do not cover, and in these
173 cases we try to adhere to a style similar to that used in the
174 [Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
175 able to re-format large repositories like Rust, we intend to go through the Rust
176 RFC process to nail down the default style in detail.
178 If there are styling choices you don't agree with, we are usually happy to add
179 options covering different styles. File an issue, or even better, submit a PR.
184 * For things you do not want rustfmt to mangle, use one of
187 #[rustfmt_skip] // requires nightly and #![feature(custom_attribute)] in crate root
188 #[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
190 * When you run rustfmt, place a file named `rustfmt.toml` or `.rustfmt.toml` in
191 target file directory or its parents to override the default settings of
193 * After successful compilation, a `rustfmt` executable can be found in the
195 * If you're having issues compiling Rustfmt (or compile errors when trying to
196 install), make sure you have the most recent version of Rust installed.
201 Rustfmt is distributed under the terms of both the MIT license and the
202 Apache License (Version 2.0).
204 See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.