Let's install Crystal first so we have the language on our machine. Keep in mind that you can also omit --with-llvm
on the installation if you do not plan to do any contributing to the Crystal Lang.
brew update
brew install crystal-lang --with-llvm
If you run in to any errors, it could be because you don't have xcode installed and using its command line tools.
xcode-select --install
xcode-select --switch /Librar...