Re: RDF 2.0 Wishlist - Legal RDF which I can't SPARQL

  On 7/29/2010 4:20 AM, Mischa Tuffield wrote:
> The issue arises because turtle doesn't forbid the use of certain 
> characters, for example the backtick " ` " (%60), where as SPARQL does 
> forbid it. Which means that I can write legal turtle, import it into 
> my triplestore, but I wont be able to ever query that data via SPARQL.

Late to this party, I have very little sympathy with Mischa's issue.

First I would draw attention to the small print in RDF Concepts ...

[[
*Note:* this section anticipates an RFC on Internationalized Resource 
Identifiers. Implementations may issue warnings concerning the use of 
RDF URI References that do not conform with [IRI draft 
<http://www.w3.org/TR/rdf-concepts/#ref-iri>] or its successors.
]]
we knew there may be changes - like the space issue, and this small 
print was intended to (somewhat naughtily) include changes made 
elsewhere in the future in the 2004 document.

If I have understood Mischa correctly, the problem is that it is 
possible to enter illegal IRIs into a triple store in some fashion (e.g. 
turtle, and then stuff doesn't work. Surprise, surprise: garbage in, 
garbage out.
Solution: use a triple store that validates its input and rejects 
garbage; tackle the problem at source.
If the turtle spec permits illegal IRIs then that is a bug with the spec.
If a turtle implementation allows illegal IRIs then that may be a 
feature, but one that needs to be used with care.

Dogmatically

Jeremy