Expand description
§Impl Error Macro
§Introduction:
The implementation of trait Error.
P.s.: More useful macros you can find here.
§Examples:
#[derive(Debug, Error)]
struct Error {
source: Option<Box<dyn std::error::Error>>
}
impl ::std::fmt::Display for Error {
fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
write!(f, "it's my custom error")
}
}
let err = Error { source: None };
assert_eq!(format!("{err}"), "it's my custom error");
#[derive(Debug, Error)]
enum Error {
WithAnySource { source: Option<Box<dyn std::error::Error>>, msg: String },
WithCertainSource(#[source] SourceError),
WithoutSource
}
impl ::std::fmt::Display for Error {
fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
match &self {
Self::WithAnySource { source, msg } => write!(f, "the error with a message: '{msg}' and a source: '{src}'", src = if let Some(src) = source.as_deref() { src.to_string() }else { "no source".to_owned() }),
Self::WithCertainSource(src) => write!(f, "the error with the source: '{src}'"),
Self::WithoutSource => write!(f, "the error without a source"),
}
}
}
#[derive(Debug, Error)]
enum SourceError {
Error
}
impl ::std::fmt::Display for SourceError {
fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
match &self {
Self::Error => write!(f, "the source of error"),
}
}
}
let err = Error::WithAnySource { source: Some(Box::new(SourceError::Error)), msg: "the message of error".to_owned() };
let err2 = Error::WithCertainSource( SourceError::Error );
let err3 = Error::WithoutSource;
assert_eq!(format!("{err}"), "the error with a message: 'the message of error' and a source: 'the source of error'");
assert_eq!(format!("{err2}"), "the error with the source: 'the source of error'");
assert_eq!(format!("{err3}"), "the error without a source");
§Licensing:
Distributed under the MIT license.
§Feedback:
You can contact me via GitHub or send a message to my Telegram @fuderis.
This library is constantly evolving, and I welcome your suggestions and feedback. See the documentation here macron documentation