Macro immutable_seq::digit

macro_rules! digit {
    ($e0: expr) => { ... };
    ($e0: expr, $e1: expr) => { ... };
    ($e0: expr, $e1: expr, $e2: expr) => { ... };
    ($e0: expr, $e1: expr, $e2: expr, $e3: expr) => { ... };
}