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https://issues.apache.org/jira/browse/JENA-508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14364129#comment-14364129
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Andy Seaborne commented on JENA-508:
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Good spreadsheet.
There are implementations of many XSD operators ("op:") in XSDFuncOp -- they
back the syntax operations like "+". There is no namespace for op: -- the
operations back operators in the language like "+", but making namespace(op) ==
namespace(fn) then it is just wiring needed, the functionality exists.
Anything returning a sequence presents problems in SPARQL and is meaningless
e.g. fn:tokenize and the higher order functions. It may be possible to have
similar functionality but not as functions in teh form XPath3 has them.
Functions in SPARQL take RDF terms as arguments and return RDF terms; an RDF
list isn't a single RDF term.
Aggregate functions (e.g. fn:count) also operate on sequence in XPath/XQuery
but SPARQL has a separate aggregation mechanism somewhat like SQL.
Anything working on XML types, like elements and nodes, don't have a natural
meaning in SPARQL.
xs:yearMonthDuration and xs;dayTimeDuration are now implemented datatypes and
operators shoudl already work on them. xsd:dateTime-xsd:dateTime ->
xsd:duration.
> Add support for XPath 3 Functions
> ---------------------------------
>
> Key: JENA-508
> URL: https://issues.apache.org/jira/browse/JENA-508
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Reporter: Rob Vesse
> Labels: gsoc, gsoc2015
>
> XPath 3 is now a Candidate Recommendation -
> http://www.w3.org/TR/xpath-functions-30/
> It contains many new functions and operators (particularly in the
> mathematical space) which we should consider adding into future versions of
> ARQ.
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