Re: support for ill-typed literal terms should remain a requirement

On 01/11/2024 20:27, Gregory Williams wrote:
> On Nov 1, 2024, at 1:15 PM, Gregg Kellogg <gregg@greggkellogg.net> wrote:
>>
>> Ill formed literals from recognized datatypes can’t have an associated value by definition, and literals from un-recognized datatypes can’t have a value as the datatype is unrecognized anyway. The question is: is it reasonable for an implementation to drop triples containing ill formed literals with recognized datatypes. I don’t see the harm in requiring that they be retained in a graph even though there is no derived value, but I can see the argument for giving implementations allowance to drop them, and the expense of interoperabiity.
> 
> I think the potential harm is in systems that have specialized storage for recognized datatypes (likely for performance reasons). Requiring such systems to have a secondary storage location for ill-formed literals adds complexity not just in the storage system, but then also potentially in the query system as what was an optimized codepath to access those values turns into a more complex union of the optimized codepath and a fallback codepath to collect all the ill-formed literals.
> 
> I don’t mind systems that want to support such a design, but think it adds a pretty big burden on systems that want only the optimized codepath. It seems strange to me to write a spec that depends on other standards, and then force implementations to ignore the specifics of those other standards.

The only use of "recognized datatypes" [1] in SPARQL 1.2 is in function 
RDFterm-equal. RDFterm-equal is used when there isn't another defined 
function mapping for "=" and "!=" in the spec defined-mapping [3].

This is a SPARQL 1.2 change for clarity in response to a community 
report [4]. It makes clear what happens when additional datatypes are 
provided by a SPARQL implementation.

SPARQL 1.1 makes no mention of "recognized datatypes".

     Andy

[1]
https://www.w3.org/TR/rdf12-concepts/#dfn-recognized-datatype-iri

[2]
https://www.w3.org/TR/sparql12-query/#func-RDFterm-equal

[3]
https://www.w3.org/TR/sparql12-query/#OperatorMapping

[4]
https://github.com/w3c/sparql-query/issues/7
https://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2018Aug/0000.html

Received on Friday, 1 November 2024 21:16:53 UTC