Interesting.
I thought the Ruby community generally prefers shorter code, e.g. `to_s` instead of `to_string`, and yet that type signature is very verbose: `sig {params(x: Integer).returns(String)}`
The type signature in (secure) ruby [1] - an alternative ruby (subset) with type (optional) annotation - is `sig Integer => String` or `sig [Integer] => [String]. Since the sig is just ruby you can create an alias for types e.g. I = Integer, S = String and than use sig I=>S, for example. [1]: https://github.com/s6ruby