I agree that rust, with Option and Default, is the only right choice - at least from what I've tried. Elm for example has Option but nothing like Default, so so

I agree that rust, with Option and Default, is the only right choice - at least from what I've tried. Elm for example has Option but nothing like Default, so sometimes it's tedious that you have to repeat a lot of handmade defaults, or you're forced to use constructor functions everywhere. But at least the program is correct! Go is like PHP in regards to pushing errors forward. You simply cannot validate everything at every step. Decoding with invariants is the right alternative.