Media types for RDF languages N3 and Turtle
garret at globalmentor.com
Mon Dec 17 16:22:16 CET 2007
There exists serious concern regarding the use of a text top-level type
for N3. See the recent discussion on www-rdf-comments.
Eric Prud'hommeaux wrote:
> Hi all, there are a couple languages that have been used for a while,
> turtle and n3, and I am trying work out the right media types to
> register for them.
> == Cast of Characters
> ║ name ║ role ║ current media type ║
> ║ RDF │ data model │ N/A ║
> ║ RDFXML │ XML serialization of RDF │ application/rdf+xml ║
> ║ ntriples │ simple serialization of RDF │ text/plain ║
> ║ turtle │ textual serialization of RDF │ application/x+turtle ║
> ║ n3 │ extension¹of turtle language │ text/rdf+n3 (not ║
> ║ │ expressing a superset of RDF │ registered) ║
> ¹ The origins of turtle and n3 are complicated, but this is the
> most practical model for media type consideration.
> These languages will be published under http://www.w3.org/TR/
> (which implies certain persistance and update policy) as soon
> as I work out what to include in the media type registration.
> In the mean time, see
> Neither the turtle nor n3 media types are registered. I seek advice
> from the community on exactly how to register them, as I will have
> to beat out some sort of consensus in order to register them.
> == Issues
> • subsumption relationshop — n3 subsumes turtle in both data model and
> grammar. To that end, text/n3; and text/n3; profile=turtle have been
> suggested. Another suggestion has been text/rdf+n3 and
> text/rdf+turtle , in somewhat the spirit of XML (where the +xml
> indecates the that it's the XML encoding of the preceding datatype).
> • subtree — turtle and n3 are certainly more human-readable than
> ntriples (as they are basically extensions of ntriples, with
> namespace prefixes and abbreviations for some atoms). The default
> character encoding of iso-8859-1 is certainly outdated, and doesn't
> make sense for any of these languages. Garret Wilson (Cc'd) raised
> the question of whether a text/ registration may force the charset
> to be, say, utf-8². Both n3 and turtle, as well as related langs
> like SPARQL, are explcitly utf-8. Can the registration include text
> like "The encoding is always UTF-8"? Would that mean that the
> media type would not need a constant charset parameter?
> ² http://lists.w3.org/Archives/Public/www-rdf-comments/2007OctDec/0017
> == Strawman
> Let me propose:
> n3: text/rdf+n3
> turtle: text/rdf+turtle
> Encoding considerations: The encoding is always UTF-8
> and the expectation that
> Content-type: text/rdf+n3
> (or +turtle) fully specifies the media type and the
> character encoding.
> A plea to all: bear in mind that this consensus bit is a hard job,
> and that the world will be much better off if we can reach a timely
> compromise. We've suffered for five years without these media types
> so let's keep our mission reallistic.
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