With the help of gitter and @RespiteSage, @watzon, @kai (thank you!), here is what I have so far:
https://play.crystal-lang.org/#/r/74e6
Problem is, we will need to invoke to_i every time we access ["min_value"]. Is there a way to make it permanently an Int32?
Basically, we were thinking of a from_json like method, but for CSV (from_csv). That would be amazeballs.