←back to thread

611 points LorenDB | 1 comments | | HN request time: 0.001s | source
Show context
dvratil ◴[] No.43908097[source]
The one thing that sold me on Rust (going from C++) was that there is a single way errors are propagated: the Result type. No need to bother with exceptions, functions returning bool, functions returning 0 on success, functions returning 0 on error, functions returning -1 on error, functions returning negative errno on error, functions taking optional pointer to bool to indicate error (optionally), functions taking reference to std::error_code to set an error (and having an overload with the same name that throws an exception on error if you forget to pass the std::error_code)...I understand there's 30 years of history, but it still is annoying, that even the standard library is not consistent (or striving for consistency).

Then you top it on with `?` shortcut and the functional interface of Result and suddenly error handling becomes fun and easy to deal with, rather than just "return false" with a "TODO: figure out error handling".

replies(24): >>43908133 #>>43908158 #>>43908212 #>>43908219 #>>43908294 #>>43908381 #>>43908419 #>>43908540 #>>43908623 #>>43908682 #>>43908981 #>>43909007 #>>43909117 #>>43909521 #>>43910388 #>>43912855 #>>43912904 #>>43913484 #>>43913794 #>>43914062 #>>43914514 #>>43917029 #>>43922951 #>>43924618 #
ryandrake ◴[] No.43909521[source]
Error handling and propagation is one of those things I found the most irritating and struggled[1] with the most as I learned Rust, and to be honest, I'm still not sure I understand or like Rust's way. Decades of C++ and Python has strongly biased me towards the try/except pattern.

1: https://news.ycombinator.com/item?id=41543183

replies(2): >>43909625 #>>43911068 #
zaphar ◴[] No.43911068[source]
Counterpoint: Decades of C++/Python/Java/... has strongly biased me against the try/except pattern.

It's obviously subjective in many ways. However, what I dislike the most is that try/except hides the error path from me when I'm reading code. Decades of trying to figure out why that stacktrace is happening in production suddenly has given me a strong dislike for that path being hidden from me when I'm writing my code.

replies(1): >>43915140 #
sham1 ◴[] No.43915140[source]
There should be a way to have the function/method document what sort of stuff can go wrong, and what kinds of exceptions you can get out of it.

It could be some kind of an exception check thing, where you would either have to make sure that you handle the error locally somehow, or propagate it upwards. Sadly programming is not ready for such ideas yet.

---

I jest, but this is exactly what checked exceptions are for. And the irony of stuff like Rust's use of `Result<T, E>` and similarly ML-ey stuff is that in practice they end up with what are essentially just checked exceptions, except with the error type information being somewhere else.

Of course, people might argue that checked exceptions suck because they've seen the way Java has handled them, but like... that's Java. And I'm sorry, but Java isn't the definition of how checked exceptions can work. But because of Java having "tainted" the idea, it's not explored any further, because we instead just assume that it's bad by construction and then end up doing the same thing anyway, only slightly different.

replies(3): >>43916813 #>>43919889 #>>43922385 #
1. SJMG ◴[] No.43919889{3}[source]
I totally agree with you that Java checked exceptions suck. IME exceptions are far more ergonomic than Result.

Nim has a good take on exception tracking that's elegant, performant, and only on request (unlike Java's attempt).