[PPL-devel] Re: Communicating bignums to/from the C interface

[Vitor Santos Costa]

Hi Roberto

Sorry for the long delay in answering, been a bit busy with another
visit to Wisconsin.

> we now need to communicate bignums to and from the C interface.
> I didn't find provision for this in the current interface.
> What is needed is
> 

I changed the interface to support bignums. Please check the CVS (and
please do report any bugs).

> 1) a predicate to test whether a YAP integer would fit into a long
>     int so that IntOfTerm() can be used;
> 

The interface I wrote now separates integers from bignums, so you
should just use YAP_IsIntTerm vs YAP_IsBigNumTerm. Is that ok for you?


> 2) a sort of NumberCharsOfTerm() to get a char* containing the number
>     chars corresponding to a (possibly big) YAP integer;
> 

You mean like writing a term to a string? I suppose it does make sense
now that I have YAP_ReadBuffer to also have YAP_WriteBuffer. I'll
include that next. Right now, you'd have to use YAP_BigIntFromTerm and
then use the GMP routine to send it out on a string.

> 3) a sort of MkIntFromNumberChars to create a YAP integer out of a char*
>     containing number chars.
> 

The interface now has YAP_ReadBuffer which will do that.

> It would be nice to have these or other equivalent facilities in YAP.
> What do you think?

I do agree, sorry for the delay!

Cheers,

Vitor

PS: Ricardo, you may want to consider including this functionality in
4.4.