result-ext

Introduction

This crate extends Result with additional methods, currently:

• contains
• contains_err
• map_or2 (as a replacement for map_or)
• map_or_else2 (as a replacement for map_or_else)

Its sister crate is option-ext, which extends Option.

Requirements

Rust 1.0 or newer.

Usage

Dependency

Add the library as a dependency to your project by inserting

result-ext = "0.2.0"

into the [dependencies] section of your Cargo.toml file.

Example

use result_ext::ResultExt;

fn example_contains() {
    use result_ext::ResultExt;

    let x: Result<u32, &str> = Ok(2);
    assert_eq!(x.contains(&2), true);

    let x: Result<u32, &str> = Ok(3);
    assert_eq!(x.contains(&2), false);

    let x: Result<u32, &str> = Err("Some error message");
    assert_eq!(x.contains(&2), false);
}

fn example_contains_err() {
    let x: Result<u32, &str> = Ok(2);
    assert_eq!(x.contains_err(&"Some error message"), false);
    
    let x: Result<u32, &str> = Err("Some error message");
    assert_eq!(x.contains_err(&"Some error message"), true);
    
    let x: Result<u32, &str> = Err("Some other error message");
    assert_eq!(x.contains_err(&"Some error message"), false);
}

fn example_map_or2() {
    let x: Result<_, &str> = Ok("foo");
    assert_eq!(x.map_or2(|v| v.len(), 23), 3);
    
    let x: Result<&str, _> = Err("bar");
    assert_eq!(x.map_or2(|v| v.len(), 23), 23);
}

fn example_map_or_else2() {
    let k = 23;
    
    let x : Result<_, &str> = Ok("foo");
    assert_eq!(x.map_or_else2(|v| v.len(), |e| k * 2), 3);
    
    let x : Result<&str, _> = Err("bar");
    assert_eq!(x.map_or_else2(|v| v.len(), |e| k * 2), 46);  
}