W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > March 2002

Re: Proposed NTriples changes for literal notation

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Fri, 08 Mar 2002 18:18:47 +0000
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
cc: RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <5470.1015611527@tatooine.ilrt.bris.ac.uk>
>>>Graham Klyne said:
> Dave,
> 
> Generally this looks good.  I have a couple of nits and comments, but don't 
> feel strongly about the resolution:

<snip/>

> It would feel more consistent to me to have:
> 
>    xml("<b>foo</b>"-en)        XML content, language given "en"

Hmm.  Yeah, might be better.

<snip/>

> >   * Provides only one way to encoded the literal-structures
> >     and so in that sense is canonical.
> 
> Also good - simple-minded applications may still do string comparison, right?

That is the case by design - you can use string comparsion to compare
all *terms* in NTriples for equality: literal, uriref, nodeID

<snip/>
> Frpm RFC 3066:
> 
> [[[
> 2.1 Language tag syntax
> 
>     The language tag is composed of one or more parts: A primary language
>     subtag and a (possibly empty) series of subsequent subtags.
> 
>     The syntax of this tag in ABNF [RFC 2234] is:
> 
>      Language-Tag = Primary-subtag *( "-" Subtag )
> 
>      Primary-subtag = 1*8ALPHA
> 
>      Subtag = 1*8(ALPHA / DIGIT)
> ]]]
> 
> so on that basis, quotes are not needed.

OK.  I thought there was more.  I intended to read what XML says
about xml:lang at http://www.w3.org/TR/REC-xml#sec-lang-tag and
follow up the several references, which don't seem to include RFC 3066?


> >   2. Want one way to describe all literal structures:
> >     Solution:
> >       literal(unicode string value, unicode string language, boolean isXML)
> >     and define the abbreviated forms in terms of that
> 
> I don't see any value in this.

Patrick I think said otherwise.  It might be useful for the MT if you
need to talk about all literals.

> >   3. I assume "chat" != "chat"-"" (need to check language RFCs)
> >     Solution if this is needed:
> >       Restrict the language string to always 1+ chars
> 
> According to RFC 3066, a language tag may not be empty so this case 
> shouldn't arise.  I think it would be consistent with suggestions for 
> xml:lang to have a blank tag value mean no language tag.  Then:
> 
>      "chat" == "chat"-""

OK so I would have:
       "chat"      = a unicode string, no language
       "chat"-""   = illegal since xml:lang string can't be empty
       "chat"-"en" = legal string, language
          etc.

Cheers

Dave
Received on Friday, 8 March 2002 14:41:32 EST

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