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Re: Proposal

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Fri, 11 Jul 2003 11:10:14 +0300
Message-ID: <003201c34783$e1597510$810fa20a@NOE.Nokia.com>
To: "ext Brian McBride" <bwm@hplb.hpl.hp.com>
Cc: "rdf core" <w3c-rdfcore-wg@w3.org>, <duerst@w3.org>, <w3c-i18n-ig@w3.org>


The simple answer to your questions below are, whatever lexical forms
are now produced for typed literals of rdf:XMLLiteral will simply become
plain literal strings.

So this proposal does not open the floor to any new cases that are not
already addressed in the specs.

Only the representation/semantics of those strings derived from
parseType="Literal"
fragments changes, not the parser behavior in deriving those strings from
the
RDF/XML.

Patrick


----- Original Message -----
From: "ext Brian McBride" <bwm@hplb.hpl.hp.com>
To: <Patrick.Stickler@nokia.com>
Cc: "rdf core" <w3c-rdfcore-wg@w3.org>; <duerst@w3.org>;
<w3c-i18n-ig@w3.org>
Sent: 10 July, 2003 21:20
Subject: Re: Proposal


> Patrick,
>
> Thank you for this suggestion.
>
> A couple of questions:
>
>  - is it necessary to drop the definition of the xml:literal datatype?
>
>  - What triple does
>
> <rdf:Description>
>   <ex:foo rdf:parseType="Literal"><em>&lt;foo&gt;</em></ex:foo>
> </rdf:Description>
>
> generate?
>
>  - What triple does
>
> <rdf:Description>
>   <ex:foo rdf:parseType="Literal"><ex:foo ex:b='b' ex:a='a' /></ex:foo>
> </rdf:Description>
>
> generate?
>
> Some incomplete noodlings that might be relevant can be found at:
>
>   http://esw.w3.org/topic/RdfCoreXmlLiteral
>
> Brian
>
>
>
> On Thu, 2003-07-10 at 16:02, Patrick.Stickler@nokia.com wrote:
> > OK folks,
> >
> > In the interests of satisfying all interested parties,
> > I offer the following proposal for an alternative
> > solution to the present one, based on nothing new,
> > just a partial roll back to a more traditional M&S
> > treatment of XML literals.
> >
> > Changes:
> >
> > 1. The datatype rdf:XMLLiteral is discarded.
> >
> > 2. The attribute+value rdf:parseType="Literal" is
> > strictly syntactic, indicating a plain literal
> > which is serialized in the RDF/XML instance as XML.
> > I.e. a literal constituting text with markup.
> >
> > 3. The attribute rdf:datatype can co-occur with
> > rdf:parseType="Literal". The combination of these two
> > together is similar to the present interpretation of
> > rdf:parseType="Literal" alone, but now requires the
> > explicit specification of a datatype rather than
> > being implicitly taken to be of type rdf:XMLLiteral.
> >
> > --
> >
> > Thus, given a context of
> >
> >    <rdf:RDF ... xml:lang="fi">
> >       ...
> >    </rdf:RDF>
> >
> > all of the following:
> >
> > 1. <rdf:Description rdf:about="#x">
> >       <ex:foo>bar</ex:foo>
> >    </rdf:Description>
> >
> > 2. <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:parseType="Literal">bar</ex:foo>
> >    </rdf:Description>
> >
> > 3. <rdf:Description rdf:about="#x" ex:foo="bar"/>
> >
> > generate the same triple:
> >
> >   <#x> ex:foo "bar"@fi .
> >
> > --
> >
> > All of the following:
> >
> > 4. <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:parseType="Literal"><xhtml:b>bar</xhtml:b></ex:foo>
> >    </rdf:Description>
> >
> > 5. <rdf:Description rdf:about="#x">
> >       <ex:foo>&lt;xhtml:b&gt;bar&lt;/xhtml:b&gt;</ex:foo>
> >    </rdf:Description>
> >
> > 6. <rdf:Description rdf:about="#x"
ex:foo="&lt;xhtml:b&gt;bar&lt;/xhtml:b&gt;"/>
> >
> > generate the same triple:
> >
> >    <#x> ex:foo "<xhtml:b>bar</xhtml:b>"@fi .
> >
> > --
> >
> > Both of the following:
> >
> > 7. <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:datatype="&ex;blargh">bar</ex:foo>
> >    </rdf:Description>
> >
> > 8. <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:datatype="&ex;blargh"
rdf:parseType="Literal">bar</ex:foo>
> >    </rdf:Description>
> >
> > generate the same triple:
> >
> >    <#x> ex:foo "bar"^^ex:blargh .
> >
> > --
> >
> > And both of the following:
> >
> > 9. <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:datatype="&ex;blargh"
rdf:parseType="Literal"><xhtml:b>bar</xhtml:b></ex:foo>
> >    </rdf:Description>
> >
> > 10.<rdf:Description rdf:about="#x">
> >       <ex:foo
rdf:datatype="&ex;blargh">&lt;xhtml:b&gt;bar&lt;/xhtml:b&gt;</ex:foo>
> >    </rdf:Description>
> >
> > generate the same triple:
> >
> >    <#x> ex:foo "<xhtml:b>bar</xhtml:b>"^^ex:blargh .
> >
> > --
> >
> > Users are then free to choose between legacy M&S literals, with lang
> > tag, with no special distinction made in the graph regarding the
> > presence or absence of markup; or alternatively, typed literals
> > with no lang tags and likewise no distinction made in the graph
regarding
> > the presence or absence of markup in the lexical forms.
> >
> > There remains no semantic distinction between a plain literal and
> > an XML literal. An "XML literal" is simply a plain literal with
> > XML markup that is serialized as unescaped XML. Nothing more.
> >
> > RDF continues to have two kinds of literals, plain and typed, and
> > comparison of plain literals, regardless of the presence of markup,
> > is by simple string comparison. All reference to canonicalization
> > is removed from the specs -- hopefully moved to a Note addressing the
> > use of RDF with datatyped literals having XML encoded lexical forms,
> > and including the definition of a datatype equivalent to rdf:XMLLiteral
> > or a similar interpretation of xsd:complexType.
> >
> > Let the market and user community decide which alternative,
> > plain or typed literal, is best for which application.
> >
> > Equivalences between plain literals and typed literals is
> > left to each individual specification of each datatype.
> >
> > Note again, that this alternative proposal introduces nothing
> > substantively new to the mix. And in fact, the minor changes
> > to the RDF/XML syntax represent how most earlier RDF parsers
> > treated rdf:parseType="Literal" to begin with.
> >
> > It also will allow folks to say useful things like
> >
> >    <rdf:Description rdf:about="#x">
> >       <ex:foo rdf:datatype="&xhtml;b" rdf:parseType="Literal">
> >          <xhtml:b>bar</xhtml:b>
> >       </ex:foo>
> >    </rdf:Description>
> >
> > i.e.
> >
> >    <#foo> ex:foo "<xhtml:b>bar</xhtml:b>"^^xhtml:b .
> >
> > and thus take advantage of being able to serialize those typed
> > XML encoded lexical forms without escaping.
> >
> > --
> >
> > Martin, does that meet your expectations and wishes
> > better than the present solution?
> >
> > If so, is the WG favorable to such a proposed change?
> >
> > Regards,
> >
> > Patrick
> >
> > --
> > Patrick Stickler
> > Nokia, Finland
> > patrick.stickler@nokia.com
> >
>
>
Received on Friday, 11 July 2003 04:10:30 EDT

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