I'm wondering if implementing getfield() / setfield!() for a composite type could be a good design for getters and setters. Say I have a type
type Thing a :: Int b :: int end where I'm requiring the `a` field to be even. It'd be great to be able to type thing = Thing() thing.a = 3 and receive an error. In 0.3.10 and 0.4, I can't implement setfield!(): ERROR: cannot define function setfield!; it already has a value. Is there a way to do this?
