serialization.rs

#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub enum Scope {
    Any,
    Account,
    Edit,
    // ...
}

impl fmt::Display for Scope {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Scope::Any => write!(f, "*"),
            Scope::Account => write!(f, "account"),
            Scope::Edit => write!(f, "edit"),
            // ...
        }
    }
}

#[derive(Debug, Default)]
pub struct Scopes(HashSet<Scope>);

impl Serialize for Scopes {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let scope_string = self.0.iter().fold(String::new(), |mut accumulator, scope| {
            if !accumulator.is_empty() {
                accumulator.push(' ');
            }

            accumulator + scope.to_string().as_str()
        });
        serializer.serialize_str(scope_string.as_str())
    }
}