Limited tilde expansion, doesn't support ~user

expand.rs

use std::path::{Path, PathBuf};
use std::env;

fn expand<P: AsRef<Path>>(path: P) -> Option<PathBuf> {
    let path = path.as_ref();
    if path.starts_with("~") {
        let mut path = path.iter();
        path.next();
        env::home_dir().map(|home| home.join(path))
    } else {
        Some(path.to_owned())
    }
}

fn main() {
    println!("{:?}, {:?}, {:?}",
             expand("~/code"),
             expand("/home/foo/code"),
             expand("/home/foo/~/foo"));
}