Trait core::ops::Try[−][src]

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.

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.

Implementors

impl<T> Try for Option<T> type Ok = T; type Error = NoneError;
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impl<T, E> Try for Result<T, E> type Ok = T; type Error = E;
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