5 ms·

Various prominent people have said years after that .await was the correct choice after all

• steveklabnik 5mo ago
  I was initially very against postfix await and I was wrong. It's great.
• staticassertion 5mo ago
  I'm not prominent but I disagreed with it at the time and I was wrong.
  • adastra22 5mo ago
    I’m curious - why were you wrong? It still seems like a wart to me, all these years later. What am I missing?
    • staticassertion 4mo ago
      I was a proponent of the postfix macro solution. `.await!` or `.await!()`, essentially. The idea was that this could be generalized, it was closer to existing syntax, etc. I was worried about features that I still don't love like `.match` etc (I'm more open to these now). Post-fix macros would have been very complex. Scoping alone is complex. `.await` kinda just works. It does everything you want and the one cost is that it looks like a property access but it isn't. A trivial cost in retrospect that I was a huge baby about, and I'll always feel bad about that.
      • adastra22 4mo ago
        The postfix macro does sound like a better solution tbh. Did you write the static assertions crate? If so, thank you. I’m a daily user.
        • staticassertion 4mo ago
          Ha, no, I did not write that crate. I think my use of this username probably predates rust, certainly that crate. Postfix macros had some very tricky issues and it would have delayed things a lot to figure out the right resolution.
    • tracker1 5mo ago
      Contrast it with async in JS/ES as an example... now combine it with the using statement for disposeAsync instances. await using db = await sqlite.connect(await ctx.getConfig("DB_CONN")); It's not so bad when you have one `await foo` vs `foo.await`, it's when you have several of them on a line in different scopes/contexts. Another one I've seen a lot is... const v = await (await fetch(...)).json(); Though that could also be... const v = await fetch(...).then(r => r.json()); In any case, it still gets ugly very quickly.
      • adastra22 5mo ago
        I’ve never in my life used JS, so I’ll have to take your word for it.
        • tracker1 5mo ago
          It's a language I'm familiar with that uses the `await foo` syntax and often will see more than one in a line, per the examples given. C# is the most prominent language that has similar semantics that I know well, but is usually less of an issue there.
    • fluffybucktsnek 5mo ago
      I'll give my two cents here. I work with Dart daily, and it also uses the `await future` syntax. I can cite a number of ergonomic issues: ```dart (await taskA()).doSomething() (await taskB()) + 1 (await taskC()) as int ``` vs. ```rust taskA().await.doSomething() taskB().await + 1 taskC().await as i32 ``` It gets worse if you try to compose: ```dart (await taskA( (await taskB( (await taskC()) as int )) + 1) ).doSomething() ``` This often leads to trading the await syntax for `then`: ```dart await taskC() .then((r) => r as i32) .then(taskB) .then((r) => r + 1) .then(taskA) .then((r) => r.doSomething()) ``` But this is effectively trading the await structured syntax for a callback one. In Rust, we can write it as this: ```rust taskA(taskB(taskC().await as i32).await + 1).await.doSomething() ```
      • Jtsummers 5mo ago
        Two spaces before a line make it a code block literal This is a code block HN has never used markdown so the triple-tick does nothing but create noise here.
        • fluffybucktsnek 4mo ago
          Thnaks for heads up, I'll keep this in mind in the future.