extern mod std; trait methods { fn to_bytes() -> ~[u8]; } impl (): methods { fn to_bytes() -> ~[u8] { vec::from_elem(0, 0) } } // the position of this function is significant! - if it comes before methods // then it works, if it comes after it then it doesnt! fn to_bools(bitv: {storage: ~[u64]}) -> ~[bool] { vec::from_fn(8, |i| { let w = i / 64; let b = i % 64; let x = 1u64 & (bitv.storage[w] >> b); x == 1u64 }) } fn main() { let bools = ~[false, false, true, false, false, true, true, false]; let bools2 = to_bools({storage: ~[0b01100100]}); for uint::range(0, 8) |i| { io::println(fmt!("%u => %u vs %u", i, bools[i] as uint, bools2[i] as uint)); } assert bools == bools2; }