85 lines
3.6 KiB
Markdown
85 lines
3.6 KiB
Markdown
# Style Guide
|
|
|
|
The style guide can be summed up as 'clang-format with the Google style set'.
|
|
In addition, the [Google Style Guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml)
|
|
is followed and cpplint is the source of truth. When in doubt, defer to what
|
|
code in the project already does.
|
|
|
|
Base rules:
|
|
|
|
* 80 column line length max
|
|
* LF (Unix-style) line endings
|
|
* 2-space soft tabs, no TABs!
|
|
* [Google Style Guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml) for naming/casing/etc
|
|
* Sort includes according to the [style guide rules](http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Names_and_Order_of_Includes)
|
|
* Comments are properly punctuated (that means capitalization and periods, etc)
|
|
* TODO's must be attributed like `// TODO(yourgithubname): foo.`
|
|
|
|
Code that really breaks from the formatting rules will not be accepted, as then
|
|
no one else can use clang-format on the code without also touching all your
|
|
lines.
|
|
|
|
### Why?
|
|
|
|
To quote the [Google Style Guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml):
|
|
|
|
```
|
|
One way in which we keep the code base manageable is by enforcing consistency.
|
|
It is very important that any programmer be able to look at another's code and
|
|
quickly understand it. Maintaining a uniform style and following conventions
|
|
means that we can more easily use "pattern-matching" to infer what various
|
|
symbols are and what invariants are true about them. Creating common, required
|
|
idioms and patterns makes code much easier to understand. In some cases there
|
|
might be good arguments for changing certain style rules, but we nonetheless
|
|
keep things as they are in order to preserve consistency.
|
|
```
|
|
|
|
## Buildbot Verification
|
|
|
|
The buildbot runs `xb lint --all` on the master branch, and will run
|
|
`xb lint --origin` on pull requests. Run `xb format` before you commit each
|
|
local change so that you are consistently clean, otherwise you may have to
|
|
rebase. If you forget, run `xb format --origin` and rebase your changes (so you
|
|
don't end up with 5 changes and then a 6th 'whoops' one - that's nasty).
|
|
|
|
The buildbot is running LLVM 3.8.0. If you are noticing style differences
|
|
between your local lint/format and the buildbot, ensure you are running that
|
|
version.
|
|
|
|
## Tools
|
|
|
|
### clang-format
|
|
|
|
clang-format with the Google style is used to format all files. I recommend
|
|
installing/wiring it up to your editor of choice so that you don't even have to
|
|
think about tabs and wrapping and such.
|
|
|
|
#### Command Line
|
|
|
|
To use the `xb format` auto-formatter, you need to have a `clang-format` on your
|
|
PATH. If you're on Windows you can do this by installing an LLVM binary package
|
|
from [the LLVM downloads page](http://llvm.org/releases/download.html). If you
|
|
install it to the default location the `xb format` command will find it
|
|
automatically even if you don't choose to put all of LLVM onto your PATH.
|
|
|
|
#### Visual Studio
|
|
|
|
Grab the official [experimental Visual Studio plugin](http://llvm.org/builds/).
|
|
To switch to the Google style go Tools -> Options -> LLVM/Clang -> ClangFormat
|
|
and set Style to Google. Then use ctrl-r/ctrl-f to trigger the formatting.
|
|
Unfortunately it only does the cursor by default, so you'll have to select the
|
|
whole doc and invoke it to get it all done.
|
|
|
|
If you have a better option, let me know!
|
|
|
|
#### Xcode
|
|
|
|
Install [Alcatraz](http://alcatraz.io/) to get the [ClangFormat](https://github.com/travisjeffery/ClangFormat-Xcode)
|
|
package. Set it to use the Google style and format on save. Never think about
|
|
tabs or linefeeds or whatever again.
|
|
|
|
### cpplint
|
|
|
|
TODO(benvanik): write a cool script to do this/editor plugins.
|
|
In the future, the linter will run as a git commit hook and on travis.
|