Trait ErrSpan

pub trait ErrSpan {
    type Result;

    // Required method
    fn err_span(self, span: Span) -> Self::Result;
}

An extension trait for Result, which adds a span to the error type.

Required Associated Types

type Result

Required Methods

fn err_span(self, span: Span) -> Self::Result

Add the given span to the error type E, turning it into a Spanned<E>.

Some auto-conversion methods to ShellError from other error types are available on spanned errors, to give users better information about where an error came from. For example, it is preferred when working with std::io::Error:

use nu_protocol::{ErrSpan, ShellError, Span};
use std::io::Read;

fn read_from(mut reader: impl Read, span: Span) -> Result<Vec<u8>, ShellError> {
    let mut vec = vec![];
    reader.read_to_end(&mut vec).err_span(span)?;
    Ok(vec)
}

Implementations on Foreign Types

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

type Result = Result<T, Spanned<E>>

fn err_span(self, span: Span) -> <Result<T, E> as ErrSpan>::Result

Implementors