Merge pull request #3133 from otavio/rework-readme

[rust.git] / README.md

diff --git a/README.md b/README.md
index 69f4d800dfc841a77d3cf8e95e70ff0fdb3280e1..f811123f72a128cdc250ecdf7a34fe844f1e7b22 100644 (file)
--- a/README.md
+++ b/README.md
@@ -3,30 +3,17 @@
 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
 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).
-
-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-to be a bit out of date).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.
+[Contributing.md](Contributing.md) and our [Code of
+Conduct](CODE_OF_CONDUCT.md).

 
 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.
 
 
 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
 
 ## Quick start
 

-You can use `rustfmt` on Rust 1.24 and above.
+You can run `rustfmt` with Rust 1.24 and above.

 
 To install:
 
 
 To install:
 


@@ -40,6 +27,44 @@ to run on a cargo project in the current working directory:
 cargo fmt
 ```
 
 cargo fmt
 ```
 

+For the latest and greatest `rustfmt` (nightly required):
+```
+rustup component add rustfmt-preview --toolchain nightly
+```
+To run:
+```
+cargo +nightly 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
 
 ```
 ## Installation
 
 ```


@@ -48,9 +73,10 @@ rustup component add rustfmt-preview
 
 ## Installing from source
 
 
 ## Installing from source
 

-To install from source, first checkout to the tag or branch you want to install, then issue
+To install from source (nightly required), first checkout to the tag or branch you want to install, then issue
+

 ```
 ```

-cargo install --path  .
+cargo install --path .

 ```
 
 This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to
 ```
 
 This will install `rustfmt` in your `~/.cargo/bin`. Make sure to add `~/.cargo/bin` directory to


@@ -66,51 +92,14 @@ 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.
 
 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.
+You can run `rustfmt --help` for information about argument.

 
 

-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,
+When running with `--check`, Rustfmt will exit with `0` if Rustfmt would not
+make any formatting changes to the input, and `1` if Rustfmt would make changes.
+In other modes, Rustfmt will exit with `1` if there was some error during
+formatting (for example a parsing or internal error) and `0` if formatting
+completed without error (whether or not changes were made).

 
 

-```
-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
 
 
 ## Running Rustfmt from your editor


@@ -120,28 +109,32 @@ You can run `rustfmt --help` for more information.
 * [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.
 * [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.

+* [IntelliJ or CLion](intellij.md)
+

 
 ## Checking style on a CI server
 
 To keep your code base consistently formatted, it can be helpful to fail the CI build
 
 ## 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
+when a pull request contains unformatted code. Using `--check` instructs

 rustfmt to exit with an error code if the input is not formatted correctly.
 rustfmt to exit with an error code if the input is not formatted correctly.

-It will also print any found differences.
+It will also print any found differences. (Older versions of Rustfmt don't
+support `--check`, use `--write-mode diff`).

 
 

-A minimal Travis setup could look like this:
+A minimal Travis setup could look like this (requires Rust 1.24.0 or greater):

 
 ```yaml
 language: rust
 before_script:
 
 ```yaml
 language: rust
 before_script:

-- rustup toolchain install nightly
-- rustup component add --toolchain nightly rustfmt-preview
-- which rustfmt || cargo install --force rustfmt-nightly
+- rustup component add rustfmt-preview

 script:
 script:

-- cargo +nightly fmt --all -- --write-mode=diff
+- cargo fmt --all -- --check

 - cargo build
 - cargo test
 ```
 
 - cargo build
 - cargo test
 ```
 

+See [this blog post](https://medium.com/@ag_dubs/enforcing-style-in-ci-for-rust-projects-18f6b09ec69d)
+for more info.
+

 ## How to build and test
 
 `cargo build` to build.
 ## How to build and test
 
 `cargo build` to build.


@@ -157,7 +150,7 @@ notes above on running rustfmt.
 Rustfmt is designed to be very configurable. You can create a TOML file called
 `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
 Rustfmt is designed to be very configurable. You can create a TOML file called
 `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
+--help=config` 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 conforms to the [Rust style guide][style
 visual style previews, [Configurations.md](Configurations.md).
 
 By default, Rustfmt uses a style which conforms to the [Rust style guide][style


@@ -174,40 +167,34 @@ See [Configurations.md](Configurations.md) for details.
 * For things you do not want rustfmt to mangle, use one of
 
     ```rust
 * For things you do not want rustfmt to mangle, use one of
 
     ```rust

-    #[rustfmt_skip]  // requires nightly and #![feature(custom_attribute)] in crate root
+    #[rustfmt::skip]  // requires nightly Rust and #![feature(tool_attributes)] in crate root

     #[cfg_attr(rustfmt, rustfmt_skip)]  // works in stable
     ```
 * 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
     #[cfg_attr(rustfmt, rustfmt_skip)]  // works in stable
     ```
 * 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.
+  `rustfmt --print-config default 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.
 
 * 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:
+* You can change the way rustfmt emits the changes with the --emit flag:

 
 

-  On Linux:
+  Example:

 
   ```
 
   ```

-  export LD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$LD_LIBRARY_PATH
+  cargo fmt -- --emit files

   ```
 
   ```
 

-  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
-  ```
+  Options:

 
 

-  (Substitute `x86_64` by `i686` and `gnu` by `msvc` depending on which version of rustc was used to install rustfmt).
+  | Flag |Description| Nightly Only |
+  |:---:|:---:|:---:|
+  | files | overwrites output to files | No |
+  | stdout | writes output to stdout | No |
+  | coverage | displays how much of the input file was processed | Yes |
+  | checkstyle | emits in a checkstyle format | Yes |

 
 ## License
 
 
 ## License