-# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt)
+# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt) [](https://ci.appveyor.com/project/nrc/rustfmt) [](https://crates.io/crates/rustfmt-nightly) [](https://travis-ci.org/davidalber/rustfmt-travis)
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).
+[Contributing.md](Contributing.md) and our [Code of
+Conduct](CODE_OF_CONDUCT.md).
+
+We are changing the default style used by rustfmt. There is an ongoing [RFC
+process][fmt rfcs]. The last version using the old style was 0.8.6. From 0.9
+onwards, the RFC style is the default. If you want the old style back, you can
+use [legacy-rustfmt.toml](legacy-rustfmt.toml) as your rustfmt.toml.
+
+The current `master` branch uses libsyntax (part of the compiler). It is
+published as `rustfmt-nightly`. The `syntex` branch uses Syntex instead of
+libsyntax, it is published (for now) as `rustfmt`. Most development happens on
+the `master` branch, however, this only supports nightly toolchains. If you use
+stable or beta Rust toolchains, you must use the Syntex version (which is likely
+to be a bit out of date). Version 0.1 of rustfmt-nightly is forked from version
+0.9 of the syntex branch.
+
+You can use rustfmt in Travis CI builds. We provide a minimal Travis CI
+configuration (see [here](#checking-style-on-a-ci-server)) and verify its status
+using another repository. The status of that repository's build is reported by
+the "travis example" badge above.
+
+
+## Quick start
+
+You can use `rustfmt` on Rust 1.24 and above.
+
+To install:
+
+```
+rustup component add rustfmt-preview
+```
+
+to run on a cargo project in the current working directory:
+
+```
+cargo fmt
+```
+
+
+## Limitations
+
+Rustfmt tries to work on as much Rust code as possible, sometimes, the code
+doesn't even need to compile! As we approach a 1.0 release we are also looking
+to limit areas of instability; in particular, post-1.0, the formatting of most
+code should not change as Rustfmt improves. However, there are some things that
+Rustfmt can't do or can't do well (and thus where formatting might change
+significantly, even post-1.0). We would like to reduce the list of limitations
+over time.
+
+The following list enumerates areas where Rustfmt does not work or where the
+stability guarantees do not apply (we don't make a distinction between the two
+because in the future Rustfmt might work on code where it currently does not):
+
+* a program where any part of the program does not parse (parsing is an early
+ stage of compilation and in Rust includes macro expansion).
+* Macro declarations and uses (current status: some macro declarations and uses
+ are formatted).
+* Comments, including any AST node with a comment 'inside' (Rustfmt does not
+ currently attempt to format comments, it does format code with comments inside, but that formatting may change in the future).
+* Rust code in code blocks in comments.
+* Any fragment of a program (i.e., stability guarantees only apply to whole
+ programs, even where fragments of a program can be formatted today).
+* Code containing non-ascii unicode characters (we believe Rustfmt mostly works
+ here, but do not have the test coverage or experience to be 100% sure).
+* Bugs in Rustfmt (like any software, Rustfmt has bugs, we do not consider bug
+ fixes to break our stability guarantees).
## Installation
-> **Note:** this method currently requires you to be running cargo 0.6.0 or
-> newer.
+```
+rustup component add rustfmt-preview
+```
+
+## Installing from source
+To install from source, first checkout to the tag or branch you want to install, then issue
```
-cargo install --git https://github.com/rust-lang-nursery/rustfmt
+cargo install --path .
```
-or if you're using [`multirust`](https://github.com/brson/multirust)
+This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
+your PATH variable.
+
+
+## Running
+
+You can run Rustfmt by just typing `rustfmt filename` if you used `cargo
+install`. This runs rustfmt on the given file, if the file includes out of line
+modules, then we reformat those too. So to run on a whole module or crate, you
+just need to run on the root file (usually mod.rs or lib.rs). Rustfmt can also
+read data from stdin. Alternatively, you can use `cargo fmt` to format all
+binary and library targets of your crate.
+
+You'll probably want to specify the write mode. Currently, there are modes for
+`diff`, `replace`, `overwrite`, `display`, `coverage`, `checkstyle`, and `plain`.
+
+* `overwrite` Is the default and overwrites the original files _without_ creating backups.
+* `replace` Overwrites the original files after creating backups of the files.
+* `display` Will print the formatted files to stdout.
+* `plain` Also writes to stdout, but with no metadata.
+* `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.
+
+The write mode can be set by passing the `--write-mode` flag on
+the command line. For example `rustfmt --write-mode=display src/filename.rs`
+
+`cargo fmt` uses `--write-mode=overwrite` 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,
```
-multirust run nightly cargo install --git https://github.com/rust-lang-nursery/rustfmt
+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
+in the input files. `rustfmt` can't format syntactically invalid code. Finally,
+exit status `3` is returned if there are some issues which can't be resolved
+automatically. For example, if you have a very long comment line `rustfmt`
+doesn't split it. Instead it prints a warning and exits with `3`.
+
+You can run `rustfmt --help` for more information.
+
## 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/RustFmt)
* [Atom](atom.md)
+* 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
-## How to build and test
+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.
-First make sure you've got Rust **1.4.0** or greater available, then:
+A minimal Travis setup could look like this (requires Rust 1.24.0 or greater):
-`cargo build` to build.
+```yaml
+language: rust
+before_script:
+- rustup component add rustfmt-preview
+script:
+- cargo fmt --all -- --write-mode=diff
+- cargo build
+- cargo test
+```
-`cargo test` to run all tests.
+## How to build and test
-`cargo run -- filename` to run on a file, if the file includes out of line
-modules, then we reformat those too. So to run on a whole module or crate, you
-just need to run on the top file.
+`cargo build` to build.
-You'll probably want to specify the write mode. Currently, there are the
-replace, overwrite, display and coverage modes. The replace mode is the default
-and overwrites the original files after renaming them. In overwrite mode,
-rustfmt does not backup the source files. To print the output to stdout, use the
-display mode. The write mode can be set by passing the `--write-mode` flag on
-the command line.
+`cargo test` to run all tests.
-`cargo run -- filename --write-mode=display` prints the output of rustfmt to the
-screen, for example.
+To run rustfmt after this, use `cargo run --bin rustfmt -- filename`. See the
+notes above on running rustfmt.
-## What style does Rustfmt use?
+## 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 `cargo run -- --config-help` for the options which are available,
-or if you prefer to see source code, [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) confirms to the
-[Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
-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
-able to re-format large repositories like Rust, we intend to go through the Rust
-RFC process to nail down the default style in detail.
+By default, Rustfmt uses a style which conforms to the [Rust style guide][style
+guide] that has been formalized through the [style RFC
+process][fmt rfcs].
-If there are styling choices you don't agree with, we are usually happy to add
-options covering different styles. File an issue, or even better, submit a PR.
+Configuration options are either stable or unstable. Stable options can always
+be used, while unstable ones are only available on a nightly toolchain, and opt-in.
+See [Configurations.md](Configurations.md) for details.
-## Gotchas
+## Tips
* For things you do not want rustfmt to mangle, use one of
```rust
- #[rustfmt_skip]
- #[cfg_attr(rustfmt, rustfmt_skip)]
+ #[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. You can generate a file containing the default configuration with
+ `rustfmt --dump-default-config rustfmt.toml` and customize as needed.
* 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
+ install), make sure you have the most recent version of Rust installed.
+
+* If you get an error like `error while loading shared libraries` while starting
+ up rustfmt you should try the following:
+
+ On Linux:
+
+ ```
+ export LD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$LD_LIBRARY_PATH
+ ```
+
+ On MacOS:
+
+ ```
+ export DYLD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$DYLD_LIBRARY_PATH
+ ```
+
+ On Windows (Git Bash/Mingw):
+
+ ```
+ export PATH=$(rustc --print sysroot)/lib/rustlib/x86_64-pc-windows-gnu/lib/:$PATH
+ ```
+
+ (Substitute `x86_64` by `i686` and `gnu` by `msvc` depending on which version of rustc was used to install rustfmt).
+
+## License
+
+Rustfmt is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.
+
+[rust]: https://github.com/rust-lang/rust
+[fmt rfcs]: https://github.com/rust-lang-nursery/fmt-rfcs
+[style guide]: https://github.com/rust-lang-nursery/fmt-rfcs/blob/master/guide/guide.md
projects / rust.git / blobdiff