this post was submitted on 27 Sep 2023
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The ???? operator (programming.dev)
submitted 2 years ago* (last edited 2 years ago) by snaggen@programming.dev to c/rust@programming.dev
 

I found this funny.

The context is as explained by @laund@hachyderm.io

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 @antonok@fosstodon.org

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@programming.dev 31 points 2 years ago (4 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 ;)

[–] 1984@lemmy.today 14 points 2 years ago (3 children)

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

[–] aloso@programming.dev 6 points 2 years ago* (last edited 2 years ago)

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(...)?.

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