gistfile1.rs

Without macros:
pub fn from_bytes_common<T: Num Zero One Copy>(buf: &[u8], radix: uint,
        fractional: bool, exponent: ExponentFormat,
        special: bool, empty_zero: bool) -> Option<T> {
    match exponent {
        ExpDec if radix > DIGIT_E
          => fail fmt!("from_bytes_common: radix %? incompatible with decimal exponent format", radix),
        ExpBin if radix > DIGIT_P
          => fail fmt!("from_bytes_common: radix %? incompatible with binary exponent format", radix),
        _ if special && radix > DIGIT_I // lowest first digit in "inf" and "NaN"
          => fail fmt!("from_bytes_common: radix %? incompatible with special values", radix),
        _ if radix < 2
          => fail fmt!("from_bytes_common: radix %? to low, must lie in the range [2, 36]", radix),
        _ if radix > 36
          => fail fmt!("from_bytes_common: radix %? to high, must lie in the range [2, 36]", radix),
        _ => () // ICE if missing
    }

...
}

With macros:
pub fn from_bytes_common<T: Num Zero One Copy>(buf: &[u8], radix: uint,
        fractional: bool, exponent: ExponentFormat,
        special: bool, empty_zero: bool) -> Option<T> {
    arg_fail!( in ~"from_bytes_common"
        if matches!(exponent: ExpDec) && radix > DIGIT_E:
            "radix %? incompatible with use of 'e' as decimal exponent", radix;
        if matches!(exponent: ExpBin) && radix > DIGIT_P: 
            "radix %? incompatible with use of 'p' as binary exponent", radix;
        if special && radix > DIGIT_I: //lowest first digit in "inf" and "NaN"
            "radix %? incompatible with special values", radix;
        if radix as int <  2: 
            "radix %? too low, must lie in the range [2, 36]", radix;
        if radix as int > 36:
            "radix %? too high, must lie in the range [2, 36]", radix;
    );

  ...
}