Media types for RDF languages N3 and Turtle

[Garret Wilson]

There exists serious concern regarding the use of a text top-level type 
for N3. See the recent discussion on www-rdf-comments.

Garret

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
>   http://www.dajobe.org/2004/01/turtle/#sec-mime
>   http://www.w3.org/DesignIssues/Notation3
>
> 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
> with
> [[
> 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.
>