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9rx • last Tuesday at 5:25 PM • 2 replies • view on HN

> I dont see why the Rust style isnt just adopted.

Mostly because it is not entirely clear what the Rust-style equivalent in Go might be. What would Rust's "From" look like, for example?

Replies

masklinn • last Tuesday at 5:30 PM

> What would Rust's "From" look like, for example?

Idiomatic Go type-erases error types into `error`, when there is even a known type in the first place.

Thus `From` is not a consideration, because the only `From` you need is

    impl<'a, E> From<E> for Box<dyn Error + 'a>
    where
        E: Error + 'a,
and that means you can just build that in and nothing else (and it's really already built-in by the implicit upcasting of values into interfaces).
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JamesSwift • last Tuesday at 5:28 PM

Sorry, I wasnt specific in that part. When I say 'rust style' Im really just referring to a union type of `result | error`, with a way to check the state (eg isError and isResult) along with a way to get the state (eg getResult and getError). Optionally '?' and '!' as sugar.

That said, the other responder points out why the sum type approach is not favored (which is news to me, since like I said I havent followed the discussion)

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