Re: [Ocaml-lib-devel] BitSet

[Nicolas C. <war...@fr...>]

> > Concerning the usage of int, OCaml runtime representation is 31 bits.
They
> > are unboxed and shifted by 1 and the lowest bit is set to 1 so it can't
be
> > mistaken with an address since all addresses are always aligned on 2
bytes
> > (even 4 on most of 32-bits architectures) . So we could use ints as 31
bits
> > but we would then need to div/mod to get the correct integer. Another
nice
> > thing about strings is that their contents are not scanned by the GC
while
> > Array of ints are.
> >
>
> Having looked at implementing bitset myself, I came to the following
> conclusions:
>
> 1) bitset and big int support should be combined, much like an int can be
> viewed both as a small integer and as a small bitset, depending.
>
> 2) Both should be built on top of gmp.
>
> 3) GMP doesn't do everything I want bitset to be able to do yet.  Most
> everything, but not everything (bitblit doesn't exist).
>
> 4) I'm on-again off-again trying to get gmp to accept patches to let it
> do what I want it to, but I'm getting push-back.
>
> I'm tempted to just provide the wrappers for the existing gmp
> functionality, and support the rest when it shows up.  Thoughts?

GMP is C, ExtLib is OCaml
If you want to provide a 3rd party library having very efficient bitsets and
big ints based on GMP, then I think it's nice idea. But since we agreed in
the beginning that ExtLib will not have C parts (since with that comes a lot
of compability, compilation, and installation problems) then I can't see
that being put into ExtLib. Current bitsets are useful and enough efficient
for the average user.

Regards,
Nicolas Cannasse