Sum types: https://go.dev/play/p/R7Bhy2LDmde

Enums: https://go.dev/play/p/MnbmE0B3sSE

Here you go.

That code appears to be using reflection to build up runtime tables?

https://github.com/qlova/tech/blob/c6379c9c32e5b7b2973bc02ba...

https://github.com/qlova/tech/blob/c6379c9c32e5b7b2973bc02ba...

That's a big difference from other languages where this is all handled at compile time.

This is cool, but it doesn't seem like Switch is implemented for Int, and the use of runtime reflection limits the contexts in which this implementation can be used, compared to a language construct that gets compiled into efficient machine code. I wouldn't want this to be endemic in my codebase or my dependencies.

Enum supports an exhaustive Switch as well, here's an example based on the blog post: https://go.dev/play/p/Ef78vLyw33g

Is it just me or is the syntax on these worse than the issues it’s solving?

It's not you, this is a worse version of std::variant, which isn't exactly great in the first place.