erroneous - Helper for defining and using errors

erroneous is a crate with two features:

• Its Error trait
• Its Error derive

Example

#[macro_use]
extern crate derive_more;
#[macro_use]
extern crate erroneous;

#[derive(Debug, Display, Error)]
enum ParseError {
	#[display(fmt = "Found an unexpected 'a' in the input")]
	UnexpectedA,
	#[display(fmt = "Found an unexpected 'b' in the input")]
	UnexpectedB,
	#[display(fmt = "Input was empty")]
	Empty,
}

The Error trait

The Error trait is a supertrait of std::error::Error. It is automatically implemented for all implementors of std::error::Error, with some restrictions, particularly, it is Send + Sync + 'static. This means you have more freedom when dealing with them, and can in addition downcast dyn Error to concrete types. In addition, the trait also includes a helper method to iterate the chain of errors called iter.

The Error derive

This feature just implements std::error::Error (and thus also erroneous::Error) for you, You can annotate a field in your input as #[error(source)] to make the source method return that field.

License

erroneous is licensed under the terms of the MIT License or the Apache License 2.0, at your choosing.