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RE: RDF QLs within a larger language

From: Howard Katz <howardk@fatdog.com>
Date: Mon, 28 Jun 2004 07:10:51 -0700
To: "Eric Prud'hommeaux" <eric@w3.org>, <public-rdf-dawg@w3.org>

> -----Original Message-----
> From: public-rdf-dawg-request@w3.org
> [mailto:public-rdf-dawg-request@w3.org]On Behalf Of Eric Prud'hommeaux
> Sent: Monday, June 28, 2004 12:10 AM
> To: public-rdf-dawg@w3.org
> Subject: RDF QLs within a larger language
> Howard's XSRQL [1] and TimBL's N3QL [2] are good examples of RDF
> functions that fit into a larger QL. In the XSRQL case, it gives us
> an opportunity to lean on some already specified and implemented
> functionality in XQuery that is likely to get very wide
> deployment. I'm curious about how much re-use we get, Howard.

Lots, I think. There's re-use of:

1) re-use of the main XQuery surface syntax.
In broad strokes I think XSQRL syntax is identical to XQuery syntax, except
XSRQL has just if, then, else, for, let, where, return, while XQuery has
(oops, I just ran out of digitial ink ... sorry :-)

2) re-use of the path language. Here tho I've mutated the language somewhat
to make it applicable to traversing RDF

3) more under-the-hood type things, such as

    (a) functional programming style
    (b) heterogeneous result sequences
    (c) query-resolution-as-successive-modification-of-a-data-model-instance
    (d) built-in function library, signatures using typed arguments
    (e) user-defined functions
    (f) concept of query and environmental declarations in a prolog
     more ???


> N3QL constrains itself to be a subset of the N3 syntax which can be
> used for query. This is especially usful if N3 is later adopted as a
> rules language because we would get to take advantage of the fact that
> query goals and rule goals are very similar, both in syntax and in
> semantics. Once we've defined a language that produces some sort of
> variable bindings, it's pretty easy to define how to use those
> bindings to construct new graphs.
> Anybody interested in exploring this with me?
> [1] http://www.fatdog.com/xsrql.html#Examples
> [2] http://www.w3.org/DesignIssues/N3QL
> --
> -eric
> office: +81.466.49.1170 W3C, Keio Research Institute at SFC,
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> (eric@w3.org)
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Received on Monday, 28 June 2004 10:09:58 UTC

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