- From: Gregory Williams <greg@evilfunhouse.com>
- Date: Wed, 21 Nov 2012 12:34:20 -0500
- To: John Snelson <John.Snelson@marklogic.com>
- Cc: "public-rdf-dawg-comments@w3.org" <public-rdf-dawg-comments@w3.org>
On Nov 6, 2012, at 7:29 PM, John Snelson wrote: > The specification for "ORDER BY"[1] contains the following sentence: > > "A plain literal is lower than an RDF literal with type xsd:string of the same lexical form." > > Since the definition of the DATATYPE() function [2] describes the type of a simple literal as xsd:string, this sentence does not make any sense. > > I suggest that the sentence quoted above be removed. In addition, the entries in the "variable bindings in ascending order" table relating to simple literals and literals typed explicitly as xsd:string needs to be revised. John, The values that SPARQL's DATATYPE() function returns are similar to, but not exactly the same as the datatype of a literal. In cases where DATATYPE() is called with a typed literal[1], it returns the datatype of the literal. However, the DATATYPE() function definition also defines two cases in which a value is returned when the literal *isn't* a typed literal: """ * If the literal is a simple literal, return xsd:string * If the literal is literal with a language tag, return rdf:langString """ In both of these cases, the literal in question is a plain literal[2], not a typed literal. With that in mind, hopefully the language used in describing ORDER BY is more clear (that is, "an RDF literal with type xsd:string" is merely one of two possibly argument types for which DATATYPE() may return xsd:string). I hope this clarifies the issue. thanks, gregory williams [1] http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-typed-literal [2] http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-plain-literal
Received on Wednesday, 21 November 2012 17:34:46 UTC