Function parse_number 

pub fn parse_number<I, F, E: FloatLiteralE + IntLiteralE>(
    p: &mut ParserHelper<'_>,
    from_decimal: fn(&str) -> Result<I, E>,
    from_hex: fn(&str) -> Result<I, E>,
    from_binary: fn(&str) -> Result<I, E>,
    from_s: fn(&str) -> Result<F, E>,
    neg_inf: F,
    pos_inf: F,
    nan: F,
) -> Result<Number<I, F>, Error<E>>

Parse number literal.