Function select_user_input 

pub fn select_user_input<'rule, T, M, R>(
    t: &T,
    rs: &mut dyn Iterator<Item = (&'rule R, Update<T, M>)>,
) -> Option<(&'rule R, Update<T, M>)>
where
    T: Uniplate + Display,
    R: Rule<T, M> + Display,

Selects a (Rule, Update) based on user input through stdin.

See the module-level documentation for more information.