Trait core::ops::Try

pub trait Try {
    type Ok;
    type Error;
    fn into_result(self) -> Result<Self::Ok, Self::Error>;
    fn from_error(v: Self::Error) -> Self;
    fn from_ok(v: Self::Ok) -> Self;
}

🔬 This is a nightly-only experimental API. (try_trait #42327)

A trait for customizing the behavior of the ? operator.

A type implementing Try is one that has a canonical way to view it in terms of a success/failure dichotomy. This trait allows both extracting those success or failure values from an existing instance and creating a new instance from a success or failure value.

Associated Types

type Ok

🔬 This is a nightly-only experimental API. (try_trait #42327)

The type of this value when viewed as successful.

type Error

🔬 This is a nightly-only experimental API. (try_trait #42327)

The type of this value when viewed as failed.

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Required methods

fn into_result(self) -> Result<Self::Ok, Self::Error>

🔬 This is a nightly-only experimental API. (try_trait #42327)

Applies the "?" operator. A return of Ok(t) means that the execution should continue normally, and the result of ? is the value t. A return of Err(e) means that execution should branch to the innermost enclosing catch, or return from the function.

If an Err(e) result is returned, the value e will be "wrapped" in the return type of the enclosing scope (which must itself implement Try). Specifically, the value X::from_error(From::from(e)) is returned, where X is the return type of the enclosing function.

fn from_error(v: Self::Error) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

Wrap an error value to construct the composite result. For example, Result::Err(x) and Result::from_error(x) are equivalent.

fn from_ok(v: Self::Ok) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

Wrap an OK value to construct the composite result. For example, Result::Ok(x) and Result::from_ok(x) are equivalent.

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Implementors

impl<T> Try for Option<T>

type Ok = T

🔬 This is a nightly-only experimental API. (try_trait #42327)

type Error = NoneError

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn into_result(self) -> Result<T, NoneError>

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_ok(v: T) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_error(_: NoneError) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

impl<T, E> Try for Result<T, E>

type Ok = T

🔬 This is a nightly-only experimental API. (try_trait #42327)

type Error = E

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn into_result(self) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_ok(v: T) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_error(v: E) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

impl<T, E> Try for Poll<Option<Result<T, E>>>

type Ok = Poll<Option<T>>

🔬 This is a nightly-only experimental API. (try_trait #42327)

type Error = E

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn into_result(self) -> Result<Self::Ok, Self::Error>

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_error(e: Self::Error) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_ok(x: Self::Ok) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

impl<T, E> Try for Poll<Result<T, E>>

type Ok = Poll<T>

🔬 This is a nightly-only experimental API. (try_trait #42327)

type Error = E

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn into_result(self) -> Result<Self::Ok, Self::Error>

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_error(e: Self::Error) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

fn from_ok(x: Self::Ok) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

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