Macro yrt::yrt

macro_rules! yrt {
    ($expr:expr) => { ... };
    ($expr:expr,) => { ... };
}

Extracts an error from a Result or propogates its value. This macro operates like the inverse of the try! macro.

In case of the Ok variant, it retrieves the inner value. yrt! then performs conversion using From. This provides automatic conversion for general value propogation. The resulting value is then immediately returned.

Because of the early return, yrt! can only be used in functions that return Result.

Examples

use std::io;
use std::fs::File;
use std::io::prelude::*;
use yrt::yrt;

// The preferred method of quick returning Errors
fn early_return_success() -> Result<File, ()> {
    let _ = yrt!(File::open("my_best_friends.txt"));

    // The unwrap is just for example code
    Ok(File::create("my_best_friends.txt").unwrap())
}

// This is equivalent to:
fn write_to_file_using_match() -> Result<File, ()> {
    let _ = match File::open("my_best_friends.txt") {
        Ok(v) => return Ok(From::from(v)),
        Err(e) => e,
    };

    Ok(File::create("my_best_friends.txt").unwrap())
}