BaseX 7.3: unexpected Stack Overflow

> declare namespace map = "http://db.inf.uni-tuebingen.de/map"; > > declare function map:entry($map, $k, $v) { > function($x) { if ($x eq $k) then $v else $map($x) } > }; > > declare function map:empty() > { > function($x) { () } > }; > > > let $map := map:empty(), > $map1 := map:entry($map, 1, ("one", "eins", "uno")), > $map2 := map:entry($map1, 2, ("two", "zwei", "due")) > return $map2(1)

On Tue, Sep 18, 2012 at 10:02 AM, Torsten Grust <torsten.grust at gmail.com> wrote: > Dear all, > > I have been playing with the following toy implementation > of a super-simple associative map (it's mainly an exercise > in demonstrating the use of h-o functions in XQuery 3.0): > >> declare namespace map = "http://db.inf.uni-tuebingen.de/map"; >> >> declare function map:entry($map, $k, $v) { >> function($x) { if ($x eq $k) then $v else $map($x) } >> }; >> >> declare function map:empty() >> { >> function($x) { () } >> }; >> >> >> let $map := map:empty(), >> $map1 := map:entry($map, 1, ("one", "eins", "uno")), >> $map2 := map:entry($map1, 2, ("two", "zwei", "due")) >> return $map2(1) > > The execution of this script with BaseX 7.3 unexpectedly yields > > Stack Overflow: circular variable declaration? > > Note that replacing $map2(1) by $map1(1) in the last line returns > the expected result ("one", "eins", "uno"). > > I'd be grateful for any comment/insight. > > Cheers and keep up the good work, > --Torsten > > -- > | Prof. Dr. Torsten Grust > | Database Systems — Universität Tübingen (Germany) > | torsten.grust at uni-tuebingen.de > | db.inf.uni-tuebingen.de > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk

On 18 Sep 2012, at 12:39, Christian Grün wrote: > Dear Torsten, > > thanks for the bug report, always welcome. The issue is related to the > "Info View" in the GUI or, more exactly, the generation of the query > plan, which was triggering a recursive loop. It was running fine when > the Info View was deactivated (which was the reason why I first > couldn't reproduce the issue locally). > > We haven't implemented yet a general solution to the core issue (which > is discussed in [1] in more detail). Instead, I have just uploaded a > latest stable snapshot, which will simply skip some details in the > serialized query plan, and won't raise any errors anymore.

> On Tue, Sep 18, 2012 at 10:02 AM, Torsten Grust > <torsten.grust at gmail.com> wrote: >> Dear all, >> >> I have been playing with the following toy implementation >> of a super-simple associative map (it's mainly an exercise >> in demonstrating the use of h-o functions in XQuery 3.0): >> >>> declare namespace map = "http://db.inf.uni-tuebingen.de/map"; >>> >>> declare function map:entry($map, $k, $v) { >>> function($x) { if ($x eq $k) then $v else $map($x) } >>> }; >>> >>> declare function map:empty() >>> { >>> function($x) { () } >>> }; >>> >>> >>> let $map := map:empty(), >>> $map1 := map:entry($map, 1, ("one", "eins", "uno")), >>> $map2 := map:entry($map1, 2, ("two", "zwei", "due")) >>> return $map2(1) >> >> The execution of this script with BaseX 7.3 unexpectedly yields >> >> Stack Overflow: circular variable declaration? >> >> Note that replacing $map2(1) by $map1(1) in the last line returns >> the expected result ("one", "eins", "uno"). >> >> I'd be grateful for any comment/insight. >> >> Cheers and keep up the good work, >> --Torsten >> >> -- >> | Prof. Dr. Torsten Grust >> | Database Systems — Universität Tübingen (Germany) >> | torsten.grust at uni-tuebingen.de >> | db.inf.uni-tuebingen.de >> _______________________________________________ >> BaseX-Talk mailing list >> BaseX-Talk at mailman.uni-konstanz.de >> https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk