Re: [Yap-users] Strange tabling behavior with dif/2

[Edward S. <esc...@ce...>]

Hi Eyal,

Thank you -- this seems to explain the behavior I'm seeing.  Do you have
any suggested alternative?  A version of dif/2 that doesn't use
co-routining maybe?  Does such a thing exist?

Thanks,

Ed

On 02/16/2016 01:29 PM, Eyal Dechter wrote:
> Hi Ed, 
> 
> I think that this is because dif/2 is part of the co-routining extension
> and the tabling extension (YAPTab) doesn't support the co-routining
> extension. According to the manual (section 18) this should through an
> error; that it doesn't is likely a bug. 
> 
> I think the reason it is not supported is because tabling in YAP depends
> on being able to ask when one term is a variant of another. But in the
> presence of constraints like dif/2, two terms that are syntactic
> variants are no longer necessarily unifiable. 
> 
> Best,
> Eyal