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https://issues.apache.org/jira/browse/JENA-1313?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15993415#comment-15993415
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ASF GitHub Bot commented on JENA-1313:
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Github user afs commented on the issue:
https://github.com/apache/jena/pull/237
Yes - I was agreeing with the approach of a collation function and it being
app-decided not fixed by the nature of the data.
If it can be done without to be hardwired in to `NodeValue.compare` and
overloading themeaning of `NodeValueString` I think we will be better placed
long term.
`NodeValueString` says "// A plain string, with no language tag, or an
xsd:string." and it seems likely this assumption is used elsewhere. I think
sneaking in something to `NodeValueString` may have effects elsewhere as it
violates the assumption of `NodeValueString` (e.g. equality).
`NodeValueSortKey`, and a new value space `VSPACE_SORTKEY`, which only is
useful in `ORDER BY` (and `makeNode` is an exception) means we can say "only
for sorting". `arq:collation` then stops being usable as a general function.
> Language-specific collation in ARQ
> ----------------------------------
>
> Key: JENA-1313
> URL: https://issues.apache.org/jira/browse/JENA-1313
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Affects Versions: Jena 3.2.0
> Reporter: Osma Suominen
>
> As [discussed|http://markmail.org/message/v2bvsnsza5ksl2cv] on the users
> mailing list in October 2016, I would like to change ARQ collation of literal
> values to be language-aware and respect language-specific collation rules.
> This would probably involve changing at least the
> [NodeUtils.compareLiteralsBySyntax|https://github.com/apache/jena/blob/master/jena-arq/src/main/java/org/apache/jena/sparql/util/NodeUtils.java#L199]
> method.
> It currently sorts by lexical value first, then by language tag. Since the
> collation order needs to be stable across all possible literal values, I
> think the safest way would be to sort by language tag first, then by lexical
> value according to the collation rules for that language.
> But what about subtags like {{@en-US}} or {{@pt-BR}}? Can they have different
> collation rules than the main language? It would be a bit strange if all
> {{@en-US}} literals sorted after {{@en}} literals...
> It would be good to check how Dydra does this and possibly take the same
> approach. See the message linked above for further backgound.
> I've been talking with [~kinow] about this and he may be interested in
> implementing it.
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