- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 11 Oct 2005 13:51:57 +0100
- To: Eric Prud'hommeaux <eric@w3.org>
- CC: public-rdf-dawg@w3.org
Eric Prud'hommeaux wrote: > I've changed 11.2.3.9 sop:datatype > Returns a valid [RFC3066] language tag representing the XML schema > language datatype for a variable. > to > Returns the datatype of its argument if that argument is a typed > literal. Otherwise it produces a type error. In the case of a plain literal with no language tag, it would be natural to return "", rather than an error. This is akin to XML and avoids needing a hasLang(..) operation. > and 11.2.3.8 sop:lang > Returns a valid [RFC3066] language tag representing the XML schema > language datatype for a variable. > to > Returns an [RFC3066] language tag representing the XML schema > language datatype of its argument if that argument has a language > tag. Otherwise it produces a type error. If it is going to be an error, then we should have hasDatatype(). [Not sure why the table entry is "SPARQL Casts" for these operations] Andy > > I used the lang change in langMatches: > RFC3066 section 2.5 defines the language range '*' to match any > tag. In SPARQL, the idiom langMatches( lang( ?v ), "*" ) will not > match literals without a language tag as lang( ?v ) will produce a > type error. > > > So basically, the argument for DATATYPE must be a typed literal, and > the argument to LANG must be a langed literal. > > > > > There is still more work to do on errors. For instance, Andy asked > what 1/0 is. XPath F&O has a large number of them[ERR], which we > implicitly use by defining our operators in terms of XPath functions. > > For instance, the Operator Mapping Table[OPS] ties '/' to > op:numeric-divide[DIV]. (This is inspired by XQuery's similar > construct somewhere near [QOP].) > > I think what's needed is some words about "errors" and "type errors" > and "other errors" derived from F&O. > > [ERR] http://www.w3.org/TR/2005/WD-xpath-functions-20050915/#d1e10985 > [DIV] http://www.w3.org/TR/2005/WD-xpath-functions-20050915/#func-numeric-divide > [OPS] http://unagi/2001/sw/DataAccess/rq23/#OperatorMapping > [QOP] http://www.w3.org/TR/xquery/#dt-gregorian
Received on Tuesday, 11 October 2005 12:52:19 UTC