The story of Max, a real programmer

> The reason the Go code is so much bigger is because it checks and (kind of) handles errors everywhere (?) they could occur

I’ve said before and will say again: error handling is most of what’s hard about programming (certainly most of what’s hard about distributed systems).

I keep looking for a programming language that makes error handling a central part of the design (rather than focusing on non-error control flow of various kinds), but honestly I don’t even know what would be better than the current options (Java/Python’s exceptions, or Go’s multiple returns, or Rust’s similar-seeming Result<T, E>). I know Linus likes using goto for errors (though I think it just kind of looks like try/catch in C) but I don’t know of much else.

It would need to be the case that code that doesn’t want to handle errors (like Max’s simple website) doesn’t have any error handling code, but it’s easy to add, and common patterns (e.g. “retry this inner operation N times, maybe with back off and jitter, and then fail this outer operation, either exiting the program or leaving unaffected parts running”) are easy to express

In terms of developer ergonomics, try/catch seems among the best we've come up with so far. We want to focus on the success case and leave the error case as a footnote.

That's the simplicity argument here too: sometimes we only want to write the success case, and are happy with platform defaults for error reporting. (Another thing that PHP handled out-of-the-box because its domain was so constrained; it had started with strong default HTML output for error conditions that's fairly readable and useful for debugging. It's also useful for disclosure leaks which is why the defaults and security best practices have shifted so much from the early days of PHP when even php_info() was by default turned on and easy to run to debug some random cgi-bin server you were assigned by the hosting company that week.)

Most of the problems with try/catch aren't even really problems with that form of error handling, but with the types of the errors themselves. In C++/Java/C#/others, when an error happens we want stack traces for debugging and stack walks are expensive and may require pulling symbols data from somewhere else and that can be expensive. But that's not actually inherent to the try/catch pattern. You can throw cheaper error types. (JS you don't have to throw the nice Error family that does stack traces, you could throw a cheap string, for instance. Python has some stack walking tricks that keep its Exceptions somewhat cheaper and a lot lazier, because Python expects try/except to be a common flow control idiom.)

We also know from Haskell do-notation and now async/await in so many languages (and some of Rust's syntax sugar, etc) that you can have the try/catch syntax sugar but still power it with Result/Either monads. You can have that cake and eat it, too. In JS, a Promise is a future Either<ResolvedType, RejectedType> but in an async/await function you are writing your interactions with it as "normal JS" try/catch. Both can and do coexist in the same language together, it's not really a "battle" between the two styles, the simple conceptual model of try/catch "footnotes" and the robust type system affordances of a Result/Either monad type.

(If there is a war, it's with Go doing a worst of both worlds and not using a true flat-mappable Monad for its return type. But then that would make try/catch easy syntax sugar to build on top of it, and that seems to be the big thing they don't want, for reasons that seem as much obstinance as anything to me.)