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

  • KillTheMule@programming.dev
    1·
    1 year ago

    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
      0·
      1 year ago

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

      • Aloso@programming.dev
        1·
        1 year 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(...)?.

  • BB_C@programming.dev
    1·
    1 year ago

    Is everyone genuinely liking this!

    This is, IMHO, not a good style.

    Isn’t something like this much clearer?

    // Add `as_cstr()` to `NixPath` trait first

let some_or_null_cstr = |v| v.map(NixPath::as_cstr)
  .unwrap_or(Ok(std::ptr::null()));

// `Option::or_null_cstr()` for `OptionᐸTᐳ`
// where `T:  NixPath` would make this even better
let source_cstr = some_or_null_cstr(＆source)?;
let target_cstr = target.as_cstr()?;
let fs_type_cstr = some_or_null_cstr(＆fs_type)?;
let data_cstr = some_or_null_cstr(＆data)?;
let res = unsafe { .. };

    Edit: using alternative chars to circumvent broken Lemmy sanitization.

  • Turun@feddit.de
    0·
    1 year ago

    I never though about chaining ?! This is hilarious and I need to use it somewhere now.

      • Turun@feddit.de
        1·
        1 year ago

        It make total sense, I just never ran into a Result(Result(Result(T, E), E), E) situation

        Edit: Lemmy is so scared of cross site scripting, they simply remove all less than and greater than signs, lmao