extern crate failure;
use failure::ResultExt;
use std::fs::File;

type FailResult<T> = Result<T, failure::Error>;

fn opensome() -> FailResult<()> {
    File::open("/nonexisintg")?;
    Ok(())
}

fn try_open() -> FailResult<()> {
    println!("Trying");
    opensome().context("failed while trying")?;
    Ok(())
}

fn run() -> FailResult<()> {
    try_open()
}

fn main() {
    if let Err(e) = run() {
        eprintln!("error: {}", e);
        let mut cause = e.cause();
        loop {
            eprintln!("caused by: {}", cause);
            cause = match cause.cause() {
                Some(e) => e,
                None => break,
            };
        }
        std::process::exit(1);
    }
}