Sapper, a lightweight web framework written in Rust

Re:Sapper, a lightweight web framework written in Rust by dikaiosune on Wednesday June 01, 2016 @02:12PM (#11816780)

Importantly, it's the Ok variant of the Result<(), SomeError> type, which is richer than a boolean because it carries information about why/where an operation failed, not just whether it succeeded or failed. It's similar to (but not identical to):

    public void someOperation() throws SomeException { ... }

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Re:Sapper, a lightweight web framework written in Rust by cfallin on Wednesday June 01, 2016 @02:23PM (#11816866)

I like to compare it to the "comma error" idiom in Go, i.e., `result, err = doStuff(...)`. The Rust prelude's Result enum is a less ad-hoc version of that.

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Re:Sapper, a lightweight web framework written in Rust by yarper on Wednesday June 01, 2016 @04:24PM (#11817825)

It supports that kind of error handling too,

fn something() -> (String, String) ...

let (result, err) = something()

It's just that Result is preferable because you can pattern match on it

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Re:Sapper, a lightweight web framework written in Rust by kazagistar on Thursday June 02, 2016 @03:52AM (#11820991)

That would be

    fn something() -> (Option<String>, Option<String>)

Because the Rust types aren't nullable by default. But that more clearly demonstrates that Result types are better since they enforce that the error and result are mutually exclusive.

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Re:Sapper, a lightweight web framework written in Rust by yarper on Thursday June 02, 2016 @11:47AM (#11823442)

agreed!

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Re:Sapper, a lightweight web framework written in Rust by dikaiosune on Wednesday June 01, 2016 @02:25PM (#11816881)

Right, and the Rust result also produces a compile-time warning (which can be escalated to an error) if the value isn't checked.

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