Re: [Chicken-users] 32 bit integers?

[Dan Muresan]

> > Wider integers are promoted to flonums.
>
> Or to bignums with the numbers egg (full numeric tower).

Right, that's why I specified "normal" numbers.

> Especially if you didn't expect it. (It is documented but a tutorial on 
> foreign function interfacing would be nice.)

Actually, I haven't found the 31-bit format documented anywhere (maybe I 
missed it). I thought that at least normal C int's would always fit in a 
fixnum. It was an unpleasant surprise to see an expression like (logior 
flags ...) fail, when "flags" was promoted to a flonum.

> If you use one of integer unsigned-integer integer32 unsigned-integer32 
> integer64 long unsigned-long as a foreign parameter/return type Chicken 
> will automatically convert a flonum integer to/from the native type.

Yes, but flonum's can't be used in some contexts:

* bit ops

* modulo-2^32 arithmetic (i.e. C-like 32-bit wraparound arithmetic)

I don't see a way to hack these using flonums. Bignums would solve the 
problem but they're slow.

> Would the native integers be part of the numeric tower? If so this is a 
> major piece of work. If disjoint from the number type then fairly 
> straightforward to create but of limited utility.

I'm not really sure what "disjoint" means here... They would be 
available without (require-extension numbers). There would be separate 
functions native+, native* etc. OCaml has native integers for this very 
reason.

Best,
Dan