easy-ext

An attribute macro for easily writing extension trait pattern.

Usage

Add this to your Cargo.toml:

[dependencies]
easy-ext = "0.1"

The current easy-ext requires Rust 1.31 or later.

Examples

use easy_ext::ext;

#[ext(ResultExt)]
impl<T, E> Result<T, E> {
    fn err_into<U>(self) -> Result<T, U>
    where
        E: Into<U>,
    {
        self.map_err(Into::into)
    }
}

Code like this will be generated:

trait ResultExt<T, E> {
    fn err_into<U>(self) -> Result<T, U>
    where
        E: Into<U>;
}

impl<T, E> ResultExt<T, E> for Result<T, E> {
    fn err_into<U>(self) -> Result<T, U>
    where
        E: Into<U>,
    {
        self.map_err(Into::into)
    }
}

You can elide the trait name. Note that in this case, #[ext] assigns a random name, so you cannot import/export the generated trait.

use easy_ext::ext;

#[ext]
impl<T, E> Result<T, E> {
    fn err_into<U>(self) -> Result<T, U>
    where
        E: Into<U>,
    {
        self.map_err(Into::into)
    }
}

Supported items

License

Licensed under either of

Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution