Applying Google C++ styling using clang-format in pre-commit hook

[drewoldag]

I've applied the Google C++ style guide to all the .cpp and .h files in .../src/lib using clang-format.
I checked that the code still compiled using make directly. There were a small number of files that needed some additional changes:

• cosmology.h
• ext.h
• omp.h

As needed in each of those files, I added one or more of the following lines:

using std::ostream
using std::vector
using std::string

Given how common these are, I don't think there will be any namespace collisions, but please cross check this.

Additionally, I've added a pre-commit hook that will check and apply C++ style formatting for each commit. The file that defines the style rules is in .../.clang-format. Currently the only non-default rule is specifying that clang-format use the Google style rules as the default. Note that you can override those rules as desired.

[johannct]

Let's go with that. Does that mean that any push imperatively needs to be followed by a pull to be exactly equivalent to remote?

[drewoldag]

@johannct there's no need to push and then pull to keep your local branch up to date with main. The pre-commit hooks should do that for you. I saw your email about pre-commit getting in the way. I'll create another PR that removes most of the pre-commit hooks (but leaves the hook that will auto format your c++ code for you) and we can reintroduce them as we finish filling out this repository.

The typical workflow would then become:

1. Add/edit c++ code
2. Call git commit -m <message>
3. pre-commit will run clang-format to clean up the formatting of the c++ code and report "FAILED" if it made changes.
4. You review the changes and git add the files that were modified by clang-format
5. Call git commit -m <message> again, this time clang-format will pass and the git commit is completed
6. Call git push