Re: How core is Core?

Hi Hassan,

> Dave Reynolds wrote:
> 
>  > [...]
>  >
>  > (2) We take general function symbols out of Core, dropping back to
>  > function-free horn plus builtin predicates. Perhaps phase 1 should then
>  > be Core plus a first extension which puts the function symbols back in.
>  > That would be a test of the extensibility mechanism and allow us to both
>  > have a really core Core and yet continue to deliver a
>  > Horn-with-function-symbols dialect in phase 1.
> 
> I hate to say "I told you so!" but this was essentially the argument that
> I developed in http://www.w3.org/2005/rules/wg/wiki/B.1.1_CLP_Formulation
> when I proposed RIF Core be based on CLP rather than LP in order to free
> rule systems from implementing term unification if they so desired! This
> seems to have flown over the head of most apparently... :-( So Thank you
> Dave for saying the same thing - albeit apparently unaware that this was
> exactly my point?

Actually I was somewhat aware that's what you were saying at the time 
(and I rather liked the CLP formulation myself).  My apologies for not 
referencing your earlier comments in my message.

However, my message wasn't supposed to be quite:

   "oh look, we seem to have term unification, that's going to be a problem"

it was supposed to more like:

   "why do we continue to talk about all dialects extending Core and 
everyone implementing Core when that seems unlikely given that Core has 
term unification? what does that imply for the extensibility mechanism, 
do we need profiles or something?"

>  > The fact that none of the PR folks seem concerned with the current Core
>  > design is a source of surprise to me and suggests I might be getting my
>  > facts wrong.
> 
> Humph!?!?
> Haven't you read and heard me from the past 16 or so months? Haven't I been
> loud and persistent enough??? :-(

Sorry to upset you, that wasn't my intention :-) and I should have at 
least acknowledged your earlier comments, that para was badly phrased.

However, the reason I started this discussion now was partly the 
discussion on list representation. There we were choosing between lists 
as an opaque ordered sequence data structure and lists as a standard 
explicit algebra of cons/nil either as new syntax or as predefined 
function symbols. I thought I had heard you arguing for the latter 
(though I may have been mistaken) and I couldn't quite square that with 
my assumptions that PR dialects (a) weren't going like having to 
implement term unification but (b) they were going to want a list 
datatype that they could map to (e.g.) Java lists.

Dave
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Received on Saturday, 30 June 2007 16:10:23 UTC