this post was submitted on 27 Sep 2023
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The ???? operator (programming.dev)
submitted 1 year ago* (last edited 1 year ago) by snaggen to c/rust
 

I found this funny.

The context is as explained by @[email protected]

the issue is that you can't return from inside a closure, since the closure might be called later/elsewhere

and this post was the asnwer to the question by @[email protected]

you got me curious what the record for the longest ? operator chain on crates.io is

Original post: https://fosstodon.org/users/antonok/statuses/111134824451525448

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[–] KillTheMule 33 points 1 year ago (5 children)

While funny, this also highlights part of why I like rust's error handling story so much: You can really just read the happy path and understand what's going on. The error handling takes up minimal space, yet with one glance you can see that errors are all handled (bubbled up in this case). The usual caveats still apply, of course ;)

[–] [email protected] 16 points 1 year ago (4 children)

I'm writing my Rust wrong... I have match statements everywhere to the degree that it's cluttering up everything.

[–] aloso 7 points 1 year ago* (last edited 1 year ago) (1 children)

If all you do in the Err(e) => ... match arm is returning the error, then you absolutely should use the ? operator instead.

If the match arm also converts the error type into another error type, implement the From trait for the conversion, then you can use ? as well.

If you want to add more information to the error, you can use .map_err(...)?. Or, if you're using the anyhow crate, .with_context(...)?.

[–] [email protected] 3 points 1 year ago

You can also do map_err, which is a bit cleaner while keeping the mapping obvious. If you really need to do some logic on error, extracting that to the calling function is often better.

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