1 # rustfmt [![Build Status](https://travis-ci.org/rust-lang-nursery/rustfmt.svg)](https://travis-ci.org/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 [`multirust`](https://github.com/brson/multirust)
34 multirust 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 inclusive of both end points. Specifying an empty array will result in
81 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](http://johannh.me/blog/rustfmt-vim.html)
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, place it in the project directory and it will apply the options
128 in that file. See `rustfmt --config-help` for the options which are available,
129 or if you prefer to see source code, [src/config.rs](src/config.rs).
131 By default, Rustfmt uses a style which (mostly) conforms to the
132 [Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
133 There are many details which the style guidelines do not cover, and in these
134 cases we try to adhere to a style similar to that used in the
135 [Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
136 able to re-format large repositories like Rust, we intend to go through the Rust
137 RFC process to nail down the default style in detail.
139 If there are styling choices you don't agree with, we are usually happy to add
140 options covering different styles. File an issue, or even better, submit a PR.
145 * For things you do not want rustfmt to mangle, use one of
148 #[rustfmt_skip] // requires nightly and #![feature(custom_attribute)] in crate root
149 #[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
151 * When you run rustfmt, place a file named rustfmt.toml in target file
152 directory or its parents to override the default settings of rustfmt.
153 * After successful compilation, a `rustfmt` executable can be found in the
155 * If you're having issues compiling Rustfmt (or compile errors when trying to
156 install), make sure you have the most recent version of Rust installed.
161 Rustfmt is distributed under the terms of both the MIT license and the
162 Apache License (Version 2.0).
164 See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.