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LANG: Re: RE: parseType="daml:list" doesn't cut it

From: Jonathan Borden <jonathan@openhealth.org>
Date: Tue, 5 Mar 2002 11:45:36 -0500
Message-ID: <005301c1c465$3119cd00$0301a8c0@ne.mediaone.net>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "www-webont-wg" <www-webont-wg@w3.org>, "Jim Hendler" <hendler@cs.umd.edu>
Jim Hendler wrote:

> At 10:42 AM +0000 3/5/02, Jeremy Carroll wrote:
> >I think there are three issues here and I would like to separate them:
> >
> >1: was rdf:parseType="daml:collection" a good idea? Does it need
blessing?
> >
> >2: how does rdf:parseType="Literal" interact with RDF and OWL?
> >
> >3: is rdf:parseType="foobar" a sensible extensibility mechanism which OWL
> >can live with.
>
> Jeremy/Jonathan (et al) -
>   For the sake of the WebOnt Wkg Group, many of whom haven't been as
> involved in RDF development as you, could you provide some pointers
> to things like rdf:parsetype and etc, and help us understand which is
> in RDF as accepted by the W3C (original rec), which are newer things
> under consideration by RDF Core, etc.  I'm not really aiming this at
> the message above, but generally as this layering and RDF stuff goes
> forward, it is hard for some of us to follow -
>   thanks

rdf:parseType="Literal" indicates that the object of a statement is an XML
literal.

e.g

<rdf:Description rdf:about="#foo">
    <ex:pred rdf:parseType="Literal">
            <this>
                <is>
                    <some>
                            <XML/>
                    </some>
                </is>
            </this>
    </ex:pred>
</rdf:Description>

From RDF M&S http://www.w3.org/TR/REC-rdf-syntax/

[[
7.5. Values Containing Markup
When a property value is a literal that contains XML markup, the following
syntax is used to signal to the RDF interpreter not to interpret the markup
but rather to retain it as part of the value. The precise representation of
the resulting value is not specified here.
]]

RDF M&S 1 states that values of rdf:parseType other than "Literal" and
"Resource" are reserved for future versions of the RDF specification, but
that _other values_ are to be treated by an RDF 1 processor as identical to
"Literal"

[[
The parseType attribute changes the interpretation of the element content.
The parseType attribute should have one of the values 'Literal' or
'Resource'. The value is case-sensitive. The value 'Literal' specifies that
the element content is to be treated as an RDF/XML literal; that is, the
content must not be interpreted by an RDF processor. The value 'Resource'
specifies that the element content must be treated as if it were the content
of a Description element. Other values of parseType are reserved for future
specification by RDF. With RDF 1.0 other values must be treated as identical
to 'Literal'. In all cases, the content of an element having a parseType
attribute must be well-formed XML. The content of an element having a
parseType="Resource" attribute must further match the production for the
content of a Description element.
]]

The bottom line is that RDF 1 treats rdf:parseType="daml:collection" and
rdf:parseType="log:quote" as _identical_ to rdf:parseType="Literal"

DAML uses stuff inside "daml:collection" as other than an XML literal
N3 uses stuff inside "log:quote" as other than an XML literal

hence these so-called syntactic extensions are not properly compatible with
RDF. I am not arguing that these extensions are not useful (to the contrary)
rather that they are not RDF.

Jonathan
Received on Tuesday, 5 March 2002 12:41:42 GMT

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