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[Exist-open] Strange xquery problem (bug?)
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From: <sju...@ko...> - 2004-05-28 20:44:47
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The following function won't parse one xpath expression in one single
case:
declare function fn:display($hits as node()+)
as element()
{
let $current := item-at($hits, 1),
$top := $current/topicClass/@top,
$mid := $current/topicClass/@mid,
$botm := $current/topicClass/@botm,
$count := count($current/entryref)
return
<entry>
{
for $p in 1 to $count
let $entry := item-at($current/entryref, $p),
$lang := $entry/@xml:lang,
$common := $entry/entry/common <=== This is the problem
return
<entryref xml:lang="{$lang}">
{$common}
</entryref>
}
</entry>
};
The problem is that $common returns _nothing_ as long as I use anything
more than the simple variable $entry on the right hand side of the
asignment. That is:
$common := $entry
returns the expected sequence, whereas
$common := $entry/entry
$common := $entry/entry/common
$common := $entry/@xml:lang
does not return _anything_, even though the same xpath expression does
return the expected result for other variables (e.g. $lang). I believe
I have tried everything, even renaming the variable, but to no avail.
The input data has the following structure in the database:
<entry id="5727">
<topicClass top="F" mid="F0000" botm="FN0010"/>
<entryref xml:lang="sme">
<xi:include href="terms-sme.xml#xpointer(//entry[@id='deatta#S'])" />
</entryref>
<entryref xml:lang="nor">
<xi:include href="terms-nor.xml#xpointer(//entry[@id='trykk#S'])" />
</entryref>
</entry>
which after XInclude expansion becomes:
<entry>
<entryref xml:lang="sme">
<entry id="deatta#S">
<common>
<head pos="S">deatta</head>
...
</common>
<senses>
...
</senses>
</entry>
</entryref>
<entryref xml:lang="nor">
... (same as above)
</entryref>
</entry>
Looking at the log file, there is an xinclude processing difference
relating to the different $common asignments.
$common := $entry
gives log entries:
28 May 2004 23:25:14,914 [Thread-14] DEBUG (XQueryPool.java
[borrowCompiledXQuery]:80) - file:/Library/Tomcat/
webapps/exist/sami/termrequest.xq is invalid
28 May 2004 23:25:14,965 [Thread-14] DEBUG (XQuery.java [compile]:93) -
compilation took 47
28 May 2004 23:25:14,970 [Thread-14] DEBUG (EvalFunction.java
[eval]:99) - eval: for $r in document('/db/ordba
se/terms/SD-terms/termcenter.xml')//entry[@id &= '5727'] return $r
28 May 2004 23:25:15,136 [Thread-14] DEBUG (EvalFunction.java
[eval]:121) - found 1 for for $r in document('/d
b/ordbase/terms/SD-terms/termcenter.xml')//entry[@id &= '5727'] return
$r
28 May 2004 23:25:15,558 [Thread-14] DEBUG (LocalXPathQueryService.java
[execute]:213) - query took 645 ms.
28 May 2004 23:25:15,564 [Thread-14] DEBUG (XIncludeFilter.java
[startElement]:141) - processing include ...
28 May 2004 23:25:15,567 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:159) - found href="terms-sme
.xml#xpointer(//entry[@id='deatta#S'])"
28 May 2004 23:25:15,570 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:167) - found xpointer: xpoin
ter(//entry[@id='deatta#S'])
28 May 2004 23:25:15,582 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:175) - loading /db/ordbase/t
erms/SD-terms/terms-sme.xml
28 May 2004 23:25:15,587 [Thread-14] INFO (XIncludeFilter.java
[processXInclude]:229) - xpointer query: (ROOT
/descendant-or-self::entry[(attribute::id = deatta#S)])
28 May 2004 23:25:16,040 [Thread-14] INFO (XIncludeFilter.java
[processXInclude]:235) - xpointer found: 1
28 May 2004 23:25:16,048 [Thread-14] DEBUG (XIncludeFilter.java
[startElement]:141) - processing include ...
28 May 2004 23:25:16,051 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:159) - found href="terms-nor
.xml#xpointer(//entry[@id='trykk#S'])"
28 May 2004 23:25:16,054 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:167) - found xpointer: xpoin
ter(//entry[@id='trykk#S'])
28 May 2004 23:25:16,057 [Thread-14] DEBUG (XIncludeFilter.java
[processXInclude]:175) - loading /db/ordbase/t
erms/SD-terms/terms-nor.xml
28 May 2004 23:25:16,065 [Thread-14] INFO (XIncludeFilter.java
[processXInclude]:229) - xpointer query: (ROOT
/descendant-or-self::entry[(attribute::id = trykk#S)])
28 May 2004 23:25:16,430 [Thread-14] INFO (XIncludeFilter.java
[processXInclude]:235) - xpointer found: 1
whereas
$common := $entry/entry/common
gives log entries:
28 May 2004 23:20:38,863 [Thread-15] DEBUG (XQueryPool.java
[borrowCompiledXQuery]:80) - file:/Library/Tomcat/
webapps/exist/sami/termrequest.xq is invalid
28 May 2004 23:20:39,072 [Thread-15] DEBUG (XQuery.java [compile]:93) -
compilation took 206
28 May 2004 23:20:39,076 [Thread-15] DEBUG (EvalFunction.java
[eval]:99) - eval: for $r in document('/db/ordba
se/terms/SD-terms/termcenter.xml')//entry[@id &= '5727'] return $r
28 May 2004 23:20:39,370 [Thread-15] DEBUG (EvalFunction.java
[eval]:121) - found 1 for for $r in document('/d
b/ordbase/terms/SD-terms/termcenter.xml')//entry[@id &= '5727'] return
$r
28 May 2004 23:20:39,918 [Thread-15] DEBUG (LocalXPathQueryService.java
[execute]:213) - query took 1056 ms.
(I don't know the cause of the log entry about the xq file being
invalid, but since it's there in both cases, that could not be the
reason, whatever it is)
It seems that the XInclude statements are not processed at all in the
latter case, although the statements themselves are removed. To me it
seems like eXist is shortcutting too much when evaluating/compiling the
xquery, such that the XInclude expansion happens *after* the $common
assignment. If so, the assignment will not succeed, which would explain
this behaviour.
The function is a modified version of the xquery/biblio.xq example in
the distribution, and the above function is used to
"postprocess"/restructure the result set (or so I believed) before
display, which made me assume that the function would have access to
the whole XInclude-expanded structure.
This looks like an eXist bug to me. Or is there anything I have missed?
I am using the latest snapshot of today.
Regards,
Sjur
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