But isn't hiding implementation details best done by using an interface (like the Integer superclass) rather than some flag somewhere with branching logic? Fixn

But isn't hiding implementation details best done by using an interface (like the Integer superclass) rather than some flag somewhere with branching logic? Fixnum _is_ useful for C extensions to quickly convert to `int`, but now I suppose you don't know whether an Integer is cast-able to an `int` unless you inspect this flag in a new custom way.