Been using Crystal on a project that would've been written in basic Ruby.. productivity is amazing. And it has generics! :D https://play.crystal-lang.org/#/r/6r3e
How to get Crystal 0.28.0 on macOS right now! :
brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/ca8f21cd49a936bf154235b365fa23929f9f688d/Formula/crystal.rb
# or: brew upgrade https://raw.githubusercontent.com/Homebrew/homebrew-core/ca8f21cd49a936bf154235b365fa23929f9f688d/Formula/crystal.rb
# start the local playground
crystal play &; open http://127.0.0.1:8080