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character encoding of iso-8859-1 is certainly outdated, and doesn't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.
