> Rust's is notable in that they have both Either and Result. I think there's value in that, even if it is mainly for ergonomics and communication.
either isn't in std though, it's a third party crate. Personally, I think the core data structure should be as generic as possible. The reality is that if the Result type was named appropriately, the Either crate would be redundant.
What enum? We're talking about a specific data type, it doesn't make any sense to say 'an enum' is the generic version of Result.
I understand why they chose Result instead of Either. I just disagree with it; what you end up with is 2 data structures with the exact same structure and implementations but that represent different things. If you have Either in std, then Result is redundant, but not the other way around.
> What Result? Result is a generic not a specific type. It's essentially a shorthand instead of manually writing out the enum yourself.
No, it's not 'a generic', but it has generic type parameters. An enum can be any number of variants with any number of type parameters.
A result is:
data Result a b = Err a | Ok b
(or in Rust)
enum Result<T, E> { Err(E), Ok(T) }
> It's essentially a shorthand instead of manually writing out the enum yourself.
I'm not sure which enum you're referring to. You do realise an enum can have any number of variants, not just 2? I could define a sum type with 16 variants. 'enum' is just Rusts keyword for defining sum types.
> Result has semantic meaning that's lost with Either.
> You do realise an enum can have any number of variants, not just 2?
Yes, that's what makes it more generic than Result. Indeed that's the only practical difference except for a few helper functions and a #[must_use] (which only makes sense for Result, not for a more general Either type).
>> Result has semantic meaning that's lost with Either.
>Which is what?
Seriously? Error checking! That's the whole point of it. One side has meaning over the other; it has weight. The "left" is the result you want. The "right" is when something gone wrong.
either isn't in std though, it's a third party crate. Personally, I think the core data structure should be as generic as possible. The reality is that if the Result type was named appropriately, the Either crate would be redundant.