Trait ResultExt

pub trait ResultExt<T>
where
    Self: Sized,
{
    // Required method
    fn with_context<C, D>(self, chain: C) -> Result<T, Error>
       where C: FnOnce(&Error) -> D,
             D: Into<Error>;
}

Extra convenience functions for results based on core errors.

Required Methods

fn with_context<C, D>(self, chain: C) -> Result<T, Error>

where C: FnOnce(&Error) -> D, D: Into<Error>,

Provide a context for the result in case it is an error.

The context callback is expected to return a new error, which will replace the given error and set the replaced error as its source.

Examples

use amethyst_error::{Error, ResultExt};

fn failing_function() -> Result<(), Error> {
    Err(Error::from_string("failing"))
}

fn other_function() -> Result<(), Error> {
    Ok(failing_function().with_context(|_| Error::from_string("other"))?)
}

let e = other_function().expect_err("no error");

assert_eq!("other", e.to_string());
assert_eq!("failing", e.source().expect("no source").to_string());
assert!(e.source().expect("no source").source().is_none());

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

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

where E: Into<Error>,

fn with_context<C, D>(self, chain: C) -> Result<T, Error>

where C: FnOnce(&Error) -> D, D: Into<Error>,

Implementors