Struct Error 

pub struct Error {
    pub message: Cow<'static, str>,
    pub source: Option<Box<dyn StdError + Send + Sync + 'static>>,
    pub location: Option<&'static Location<'static>>,
}

A convenient, ready-to-use error type with built-in context support.

Error can be used directly without defining custom error types. It stores an error message, optional source error, and optional location.

Example

use scoped_error::Error;

fn fallible() -> Result<(), Error> {
    // &str or String can be converted to Error
    Err(Error::new("Something went wrong"))
}

Fields

message: Cow<'static, str>

The error message.

source: Option<Box<dyn StdError + Send + Sync + 'static>>

The underlying error that caused this one.

location: Option<&'static Location<'static>>

The location where this error was created.

Implementations

impl Error

pub fn new(msg: impl Into<Cow<'static, str>>) -> Error

Create a new Error with the given message.

The source and location are initially None.

Examples found in repository

examples/multi.rs (line 20)

fn fetch(url: &str) -> Result<String, scoped_error::Error> {
    let err = || scoped_error::Error::new(format!("failed to fetch {}", url));

    expect_error_fn(err, || {
        connect(url)?;
        Ok("connected".into())
    })
}

fn connect(url: &str) -> Result<String, scoped_error::Error> {
    let err = || scoped_error::Error::new(format!("failed to connect to {}", url));

    expect_error_fn(err, || Err("no network connection")?)
}

Trait Implementations

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats using the error report for human-readable output.

impl Display for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Displays the message with location if available.

impl Error for Error

fn source(&self) -> Option<&(dyn StdError + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<(Cow<'static, str>, Frame)> for Error

fn from(value: (Cow<'static, str>, Frame)) -> Self

Converts to this type from the input type.

impl WithContext for Error

fn with_context(self, context: Frame) -> Self

Attach a context layer to this error.

fn location(&self) -> Option<&'static Location<'static>>

Get the location where this error was created or where context was attached.