W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > April 2003

Issue jsr-118 (global datatyping)

From: Graham Klyne <gk@ninebynine.org>
Date: Wed, 02 Apr 2003 16:25:39 +0100
Message-Id: <5.1.0.14.2.20030402160604.00ba7908@127.0.0.1>
To: w3c-rdfcore-wg@w3.org

Er, how did this issue end up being assigned to concepts?

Anyway, here's a proposed resolution for discussion:

Rejected, or maybe postponed.

[[
We have much sympathy with this request.  But the working group spent much 
time exploring options to allow global datatyping of the kind requested 
here, and were unable to find a solution that allowed this and also 
preserved other strongly-desired features of RDF.  It might be possible to 
devise an alternative syntax-based approach to global datatyping, but I 
think even that would not fully capture the goals of CC/PP here, to express 
capability profile feature types in a schema separately from on-the-wire 
profiles.

The current version of CC/PP formally treats all attributes as textual 
values (i.e. plain literals in RDFcore parlance).  The global datatyping 
could be achieved for CC/PP applications by continuing to formally treat 
all CC/PP attributes as textual values and:
(a) using range constraints to limit the allowed lexical values, and
(b) building the lexical-to-value mapping into the semantics of the CC/PP 
attribute properties.

(a) would require some URIs to be designated to denote classes for the 
lexical space of the datatypes used.  Currently, CC/PP uses its own URIs 
for datatypes, so this would be easily accommodated.  In practical terms, I 
see no changes to current CC/PP applications required by this change:  what 
is described above is a formal device to make CC/PP as currently defined be 
consistent with the current semantic framework.

The downside of this approach is that it is a non-standard approach to 
using literals to indicate datatype values, and it may add some complexity 
if and when future developments of CC/PP require to express comparisons 
between CC/PP attribute values and datatype values from other RDF descriptions.
]]

Note to WG:  the suggested CC/PP approach is basically a strategy for 
implementing CC/PP under the old datatyping proposal 'S', ignoring the new 
datatyping facilities.

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Wednesday, 2 April 2003 11:49:57 EST

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