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Re: [TTL] Differences between SPARQL and Turtle.

From: Ivan Herman <ivan@w3.org>
Date: Mon, 2 May 2011 15:55:22 +0200
Cc: public-rdf-wg@w3.org
Message-Id: <2BD8F772-7E76-4A2C-B1DC-EC4D01E37D14@w3.org>
To: Andy Seaborne <andy.seaborne@epimorphics.com>

On May 2, 2011, at 15:39 , Andy Seaborne wrote:

<snip/>
>>> 
>>> That was my argument for making \u processing apply before parsing. Then it also applies to comments as well.
>>> 
>>> I don't agree with Richards comments here because if it's done before parsing, so newlines etc are still in the parser input whether they are written as newlines or as \u000A.  It's all unicode codepoint 10 to the parser.
>>> 
>>> 
>>> I think we only have \u because it's needed for N-triples which is US-ASCII.  If it weren't for that, I don't see why we need \u-escapes at all.
>> 
>> That sounds convincing... so if we allow N-triples to be UTF-8, then this would weaken the need for \uXXX, too...
> 
> Yes .. but ...
> We would invalidate N-triples files already out there which I think would be very bad IMHO.

Ouch. Sigh...

Whatever we decide, we should probably put in a warning into Turtle and SPARQL saying: "don't use that stuff!":-) Seriously, I must admit I do not have a strong opinion which way to go, because I do not believe people should really use this; ie, we should take the approach that is the easiest to implement both in Turtle and SPARQL. But I believe the two should be the same.

Ivan 


> 
>> 
>>> 
>>> Computers have other ways of inputting characters not on the keyboard like virtual keyboards or charmap programs.
>>> 
>>> The N-triples doc [*] does actually say that \u can only be used for certain characters (see table).  However, that's fairly impractical to enforce.
>>> 
>>> So removing \u-escapes would be an option except for backwards compatibility for N-triples.
>>> 
>> 
>> If we go for a unicodization of N-triples, then removing \u altogether both from SPARQL and Turtle seems to be a good approach, too.
>> 
>> Would it create lots of problems in SPARQL? Any experience in how widely they are used?
> 
> I've asked the SPARQL-WG for input on the areas of possible change.
> 
> 	Andy
> 
>> 
>> Ivan
>> 
>> 
>>> 
>>> [*] http://www.w3.org/TR/rdf-testcases/#ntrip_strings
>>> 
>>>> If all this is true, then let us go ahead with the proposal...
>>>> 
>>>> Ivan
>>> 
>>> 	Andy
>>> 
>> 
>> 
>> ----
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>> 
>> 
>> 
>> 
>> 
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Monday, 2 May 2011 13:54:10 GMT

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