made in gimp, with <3

Context for actual rust programmers

I was having massive beef with the rust compiler yesterday, every cargo check takes 20 seconds.

And then look at the three functions below, only one of them are Send, if you know why, please let me know.

(Note: value that is not Send cannot be held across an await point, and Box<dyn Error> is not Send)

async fn one() {
    let res: Result<(), Box<dyn Error>> = do_stuff();
    if let Err(err) = res {
        let content = err.to_string();
        let _ = do_stuff(content).await;
    }
}

async fn two() {
    let res: Result<(), Box<dyn Error>> = do_stuff();
    let content = if let Err(err) = res {
        Some(err.to_string())
    } else {
        None
    };
    drop(res);
    if let Some(content) = content {
        let _ = do_stuff(content).await;
    }
}

async fn three() {
    let content = {
        let res: Result<(), Box<dyn Error>> = do_stuff();
        if let Err(err) = res {
            Some(err.to_string())
        } else {
            None
        }
    };
    if let Some(content) = content {
        let _ = do_stuff(content).await;
    }
}
  • [object Object]@sh.itjust.worksEnglish
    3·
    2 months ago

    Rust output is bad? I feel like it’s one of the best in terms of telling you where you got things wrong. Nix output when you accidentally get infinite recursion is so bad.

    Come to think of it, Nix fits all three better than Rust.

      • Ethan@programming.devEnglish
        1·
        2 months ago

        Yes, preferring a language that’s easy to read and therefore easy to maintain over a language like Rust is definitely coping 🙄

        • WhyJiffie@sh.itjust.worksEnglish
          1·
          2 months ago

          preferring Rust over Rust? what do you mean?

          do you think loosely typed python is easy to read and maintain?

            • edinbruh@feddit.itEnglish
              1·
              2 months ago

              Yeah, like, who would ever want to

              stuff1()?.map(stuff2);

              It’s much better to just:

              err, value = stuff1();
if err == nil 
    return err, nil;
if value != nil
    stuff2(value);

              And you might even:

              for a in vec {
    vec[a]
}
              • Ethan@programming.devEnglish
                1·
                2 months ago

                I totally agree, that Go snippet is absolutely more maintainable. Though you forgot the curly braces and the semicolons are unnecessary.

                • AeonFelis@lemmy.world
                  2·
                  2 months ago

                  Though you forgot the curly braces and the semicolons are unnecessary.

                  Yup. These are pretty big issues. But there are also some minor, trivial, purely-preference-based issues - like returning an error if err == nil instead of when it isn’t.