- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Fri, 07 Sep 2012 19:56:09 +0100
- To: public-rdf-comments@w3.org
On 07/09/12 18:39, Eric Prud'hommeaux wrote: > * Richard Cyganiak <richard@cyganiak.de> [2012-09-07 18:17+0100] >> On 7 Sep 2012, at 17:37, Gavin Carothers wrote: >>>>> It's not clear why the \U form should take eight hex digits when the >>>>> first two are required to be 0. >>>> >>>> Because C++ did it and everybody follows them. It's better if all languages >>>> have the same representation of strings, even if it's not a very good one. >>> >>> Turtle's is inherited from Python, but I believe Python's is from C++ >> >> \uXXXX and \UXXXXXXXX are also in ISO C AFAIK. C# has \u1234 and \U12345678 Java has \u1234 as the UTF-16 value anywhere in the source >> I like the \u{X} form (where X may be 1-6 hex digits) that seems to be under consideration for ECMAScript. I believe Ruby does this too. > > This sounds like a proposal for an addition to the grammar. > -[27] UCHAR ::= '\u' HEX HEX HEX HEX | '\U' HEX HEX HEX HEX HEX HEX HEX HEX > +[27] UCHAR ::= '\u' ('{' HEX* '}' | HEX HEX HEX HEX) | '\U' HEX HEX HEX HEX HEX HEX HEX HEX This also affects N-Triples - more existing data. >> But I feel that Turtle should not add anything new here unless it gets into SPARQL too. > > +1 A SPARQL only issue: {} is common as a template substitution so while not part of the formal SPARQL language systems might be using that to manage templated queries. SPARQL has to be a bit careful introducing it without first checking that the change wasn't making existing practice fragile. Andy > >> I feel that the \uxxxx and \UXXXXXXXX forms cannot be removed at this point due to existing implementations and deployed data. Both forms have been in N-Triples since 2004. N-Triples is defined in a W3C Recommendation [1], and Turtle is designed as a superset of N-Triples. > > I expect that there is exactly 0 real data out there using \UXXXXXXXX. If others presume the same, we could shed \U altogether or reduce it to 6 digits (per I18N-ISSUE-191, bottom of <http://www.w3.org/mid/E1TA0zY-0003XQ-KX@nelson.w3.org>). > > >> Best, >> Richard >> >> [1] http://www.w3.org/TR/rdf-testcases/#ntrip_strings >
Received on Friday, 7 September 2012 18:56:38 UTC