-# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt)
+# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt) [](https://ci.appveyor.com/api/projects/status/github/rust-lang-nursery/rustfmt)
A tool for formatting Rust code according to style guidelines.
If you'd like to help out (and you should, it's a fun project!), see
[Contributing.md](Contributing.md).
+If you want latest and greatest, you should use the [libsyntax](https://github.com/rust-lang-nursery/rustfmt/tree/libsyntax)
+branch. It supports some newer Rust syntax which is missing from master and
+fixes some bugs. However, it links against libsyntax from the Rust compiler, so
+you must be using a nightly version of Rust to use it.
+
## Quick start
To install:
cargo install rustfmt
```
-or if you're using [`multirust`](https://github.com/brson/multirust)
+or if you're using [`rustup.rs`](https://www.rustup.rs/)
```
-multirust run nightly cargo install rustfmt
+rustup run nightly cargo install rustfmt
```
Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
```
cargo install --no-default-features rustfmt
```
+## Installing from source
+
+To install from source, first checkout to the tag or branch you want to install, then issue
+```
+cargo install --path .
+```
+This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
+your PATH variable.
## Running
* `overwrite` Overwrites the original files _without_ creating backups.
* `display` Will print the formatted files to stdout.
* `diff` Will print a diff between the original files and formatted files to stdout.
+ Will also exit with an error code if there are any differences.
* `checkstyle` Will output the lines that need to be corrected as a checkstyle XML file,
that can be used by tools like Jenkins.
`cargo fmt` uses `--write-mode=replace` by default.
+If you want to restrict reformatting to specific sets of lines, you can
+use the `--file-lines` option. Its argument is a JSON array of objects
+with `file` and `range` properties, where `file` is a file name, and
+`range` is an array representing a range of lines like `[7,13]`. Ranges
+are 1-based and inclusive of both end points. Specifying an empty array
+will result in no files being formatted. For example,
+
+```
+rustfmt --file-lines '[
+ {"file":"src/lib.rs","range":[7,13]},
+ {"file":"src/lib.rs","range":[21,29]},
+ {"file":"src/foo.rs","range":[10,11]},
+ {"file":"src/foo.rs","range":[15,15]}]'
+```
+
+would format lines `7-13` and `21-29` of `src/lib.rs`, and lines `10-11`,
+and `15` of `src/foo.rs`. No other files would be formatted, even if they
+are included as out of line modules from `src/lib.rs`.
+
If `rustfmt` successfully reformatted the code it will exit with `0` exit
status. Exit status `1` signals some unexpected error, like an unknown option or
a failure to read a file. Exit status `2` is returned if there are syntax errors
## Running Rustfmt from your editor
-* [Vim](http://johannh.me/blog/rustfmt-vim.html)
-* [Emacs](https://github.com/fbergroth/emacs-rustfmt)
+* [Vim](https://github.com/rust-lang/rust.vim#formatting-with-rustfmt)
+* [Emacs](https://github.com/rust-lang/rust-mode)
* [Sublime Text 3](https://packagecontrol.io/packages/BeautifyRust)
* [Atom](atom.md)
-* Visual Studio Code using [RustyCode](https://github.com/saviorisdead/RustyCode) or [vsc-rustfmt](https://github.com/Connorcpu/vsc-rustfmt)
+* 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.
+
+## Checking style on a CI server
+
+To keep your code base consistently formatted, it can be helpful to fail the CI build
+when a pull request contains unformatted code. Using `--write-mode=diff` instructs
+rustfmt to exit with an error code if the input is not formatted correctly.
+It will also print any found differences.
+
+A minimal Travis setup could look like this:
+
+```yaml
+language: rust
+cache: cargo
+before_script:
+- export PATH="$PATH:$HOME/.cargo/bin"
+- which rustfmt || cargo install rustfmt
+script:
+- cargo fmt -- --write-mode=diff
+- cargo build
+- cargo test
+```
+
+Note that using `cache: cargo` is optional but highly recommended to speed up the installation.
## How to build and test
## Configuring Rustfmt
Rustfmt is designed to be very configurable. You can create a TOML file called
-rustfmt.toml, place it in the project directory and it will apply the options
-in that file. See `rustfmt --config-help` for the options which are available,
-or if you prefer to see source code, [src/config.rs](src/config.rs).
+`rustfmt.toml` or `.rustfmt.toml`, place it in the project or any other parent
+directory and it will apply the options in that file. See `rustfmt
+--config-help` for the options which are available, or if you prefer to see
+visual style previews, [Configurations.md](Configurations.md).
By default, Rustfmt uses a style which (mostly) conforms to the
-[Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
+[Rust style guidelines](https://doc.rust-lang.org/1.12.0/style/README.html).
There are many details which the style guidelines do not cover, and in these
cases we try to adhere to a style similar to that used in the
[Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
#[rustfmt_skip] // requires nightly and #![feature(custom_attribute)] in crate root
#[cfg_attr(rustfmt, rustfmt_skip)] // works in stable
```
-* When you run rustfmt, place a file named rustfmt.toml in target file
- directory or its parents to override the default settings of rustfmt.
+* When you run rustfmt, place a file named `rustfmt.toml` or `.rustfmt.toml` in
+ target file directory or its parents to override the default settings of
+ rustfmt.
* After successful compilation, a `rustfmt` executable can be found in the
target directory.
* If you're having issues compiling Rustfmt (or compile errors when trying to
projects / rust.git / blobdiff