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"whole reason quads were implemented"

From: Sandro Hawke <sandro@w3.org>
Date: Wed, 09 May 2012 21:04:25 -0400
To: Andy Seaborne <andy.seaborne@epimorphics.com>
Cc: public-rdf-wg@w3.org
Message-ID: <1336611865.2368.83.camel@waldron>
On Wed, 2012-05-09 at 21:03 +0100, Andy Seaborne wrote:
> 
> On 09/05/12 20:02, Sandro Hawke wrote:
> > On Wed, 2012-05-09 at 11:26 -0700, Steve Harris wrote:
> >>
> >> Right. The whole reason quads were implemented was to be able to track
> >> what *triples* appears in what documents (typically found on the web,
> >> but file: is good too).
> >
> > Speak for yourself, please, Steve.   I've seen several implementations
> > of quads that were used for other purposes and it's quite possible they
> > predated yours.
> 
> Which systems?  I'd like to understand the motivations and approaches.

I don't actually think the history is that useful.  I was just clumsily
trying to get Steve to stop generalizing and consider some of the other
perspectives or help me understand why he wouldn't/couldn't.

But since you ask, and now I'm thinking about it....

An i-search for "quad" in my work notes turns up a conversation with
danbri and bwm from March 2001 talking about prolog handling of RDF
using triple/3 vs triple/4 and implementations by Jan Grant and Stefan
Decker.   I have vague memories of Stefan's F-Logic variant at the time
called "Triple", but which used quads.  I think he called the fourth
position the "model"; in this conversation, danbri calls it
"context/layer/etc".

I think cwm switched from formula objects to quads about that time, but
it's not immediately obvious to me in the cvs log.  "RDF quotation" is
first mentioned in Feb 2001 and "quad" is never mentioned.  

There were lots of cwm uses cases; many of them show up in the Semantic
Web tutorial TimBL, DanC, and I gave at WWW 2003 [1].   I don't think I
started using quads (instead of just multiple in-memory triple stores)
in my own programming until 2004 or so, when they showed up in swipl.

I'm not claiming any of this is particularly important or useful
evidence about what works or doesn't work, and most of it doesn't argue
for standards in this field - for that we have to turn the the use cases
we've been elucidating in this group, I think.

    -- Sandro

[1] http://www.w3.org/2000/10/swap/doc/

> 	Andy
> 
> 
Received on Thursday, 10 May 2012 01:04:37 GMT

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