core::ops::Try - Rust
Description: API documentation for the Rust `Try` trait in crate `core`.
Keywords: rust, rustlang, rust-lang, Try

# 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

- [src]
  `impl<T> Try for Option<T> type Ok = T; type Error = NoneError;`
- [src]
  `impl<T, E> Try for Result<T, E> type Ok = T; type Error = E;`

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