Example to install and use a specific version of clang-format:
brew tap Ashton-W/homebrew-clang-format-versions-tap
brew install clang-format@3.8
# to run, call:
/usr/local/Cellar/clang-format@3.8/3.8.0/bin/clang-format
# or replace `clang-format`
brew link clang-format@3.8