20170617_3.rs

impl FromStr for Lang {
    type Err = Error;
    fn from_str(s:&str) -> Result<Self> {
        match s {
            "nl" => Ok(Lang::Nl),
            "en" => Ok(Lang::En),
            o => Err(format!("Unsupported language: {}", o).into()),
        }
    }
}