On Mon, Aug 13, 2007 at 03:21:54PM -0700, John Meacham wrote:
On Sat, Aug 11, 2007 at 12:09:44PM -0300, Isaac Dupree wrote:
BTW: I estimate that it took me about two solid weeks of time, more than I had originally intended to spend :)
I think using CPP will prove important, but makes it harder to test in Hugs... should I use Cabal if I want to use Hugs with haskell+cpp code?
I think if you were willing to use what is provided by the FFI extension, you could make some signifigant improvements without resorting to CPP. mainly, you could use unsigned arithmetic and have access to bit operations.
I was thinking a representation like
data Integer = Integer !Bool Rest data Rest = Digit !Word Rest | End
where the Bool indicates the sign, and the rest are the base-wordsize digits. It would also be possible to just use a sign bit in the number of course. that unboxed strict Word should make a big difference.
You might also try data Integer = Pos !Word | Neg !Word | Big !Word Integer since the incremental penalty of 3 constructors is quite small, and it eliminates a few indirections. (Note: You have to actually specify -funbox-strict-fields for the ! to do much good.) Stefan