119 lines
3.7 KiB
Markdown
119 lines
3.7 KiB
Markdown
# rustfmt [](https://travis-ci.org/rust-lang-nursery/rustfmt)
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A tool for formatting Rust code according to style guidelines.
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If you'd like to help out (and you should, it's a fun project!), see
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[Contributing.md](Contributing.md).
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## Quick start
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To install:
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```
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cargo install rustfmt
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```
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to run on a cargo project in the current working directory:
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```
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cargo fmt
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```
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## Installation
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> **Note:** this method currently requires you to be running cargo 0.6.0 or
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> newer.
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```
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cargo install rustfmt
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```
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or if you're using [`multirust`](https://github.com/brson/multirust)
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```
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multirust run nightly cargo install rustfmt
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```
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Usually cargo-fmt, which enables usage of Cargo subcommand `cargo fmt`, is
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installed alongside rustfmt. To only install rustfmt run
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```
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cargo install --no-default-features rustfmt
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```
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## Running
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You can run Rustfmt by just typing `rustfmt filename` if you used `cargo
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install`. This runs rustfmt on the given file, if the file includes out of line
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modules, then we reformat those too. So to run on a whole module or crate, you
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just need to run on the root file (usually mod.rs or lib.rs). Rustfmt can also
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read data from stdin. Alternatively, you can use `cargo fmt` to format all
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binary and library targets of your crate.
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You'll probably want to specify the write mode. Currently, there are modes for
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replace, overwrite, display, and coverage. The replace mode is the default
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and overwrites the original files after renaming them. In overwrite mode,
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rustfmt does not backup the source files. To print the output to stdout, use the
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display mode. The write mode can be set by passing the `--write-mode` flag on
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the command line.
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`rustfmt filename --write-mode=display` prints the output of rustfmt to the
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screen, for example.
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You can run `rustfmt --help` for more information.
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`cargo fmt` uses `--write-mode=replace` by default.
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## Running Rustfmt from your editor
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* [Vim](http://johannh.me/blog/rustfmt-vim.html)
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* [Emacs](https://github.com/fbergroth/emacs-rustfmt)
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* [Sublime Text 3](https://packagecontrol.io/packages/BeautifyRust)
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* [Atom](atom.md)
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## How to build and test
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First make sure you've got Rust **1.4.0** or greater available, then:
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`cargo build` to build.
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`cargo test` to run all tests.
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To run rustfmt after this, use `cargo run --bin rustfmt -- filename`. See the
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notes above on running rustfmt.
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## What style does Rustfmt use?
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Rustfmt is designed to be very configurable. You can create a TOML file called
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rustfmt.toml, place it in the project directory and it will apply the options
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in that file. See `cargo run -- --config-help` for the options which are available,
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or if you prefer to see source code, [src/config.rs].
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By default, Rustfmt uses a style which (mostly) conforms to the
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[Rust style guidelines](https://github.com/rust-lang/rust/tree/master/src/doc/style).
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There are many details which the style guidelines do not cover, and in these
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cases we try to adhere to a style similar to that used in the
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[Rust repo](https://github.com/rust-lang/rust). Once Rustfmt is more complete, and
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able to re-format large repositories like Rust, we intend to go through the Rust
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RFC process to nail down the default style in detail.
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If there are styling choices you don't agree with, we are usually happy to add
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options covering different styles. File an issue, or even better, submit a PR.
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## Gotchas
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* For things you do not want rustfmt to mangle, use one of
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```rust
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#[rustfmt_skip]
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#[cfg_attr(rustfmt, rustfmt_skip)]
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```
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* When you run rustfmt, place a file named rustfmt.toml in target file
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directory or its parents to override the default settings of rustfmt.
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* After successful compilation, a `rustfmt` executable can be found in the
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target directory.
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