You may read again the manual section ncrosby cited, or read tutorial: [https://nim-lang.org/docs/tut2.html#object-oriented-programming-type-conversions](https://nim-lang.org/docs/tut2.html#object-oriented-programming-type-conversions)
In Nim we generally avoid casts, but we may do type conversion:
if obj of Child:
let child = Child(obj)
Run
