Question concerning querying cyclic network xml-structure.
Tuesday, 17 July 2012 · 12 messages · last reply 20 Jul 2012
R
Rob17 Jul 2012 15:01 #
Hi,
Can you please help me solving a challenge I have with a specific type XML-query?
Ive a bunch of XML-files that are referencing each other.
So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic.
Actually an m:n relationship between XML-files with possible cyclic structure.
The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of file-in-process-buffer, if the XML-file isnt already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files.
A structure like this (not real code (at all)):
==============================================================
INSTANTIATE Guard FROM COLLECTION
PROCESS-RECURSIVELY( XML-fileName) { PROCESS( XML-fileName)
ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { IF NOT ( Guard.EXISTS( Called-XML-file.NAME) {
Guard.ADD(
Called-XML-file.NAME)
PROCESS-RESURSIVELY(Called-XML-file.NAME)
}
}
}
PROCESS-RESURSIVELY(start-file)
=============================================================
I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) cant handle this situation because of their declarative nature.
Recursiveness is possible with these tools but only in a linear way not in an iterative way.
That is why Im looking for alternatives. Hopefully BaseX can help me out here.
Ive BaseX and the JAVA-examples in eclipse running.
Im b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed.
My question: What is the best way to approach this challenge?
Can you give me some tips?
Kind regards,
Rob Stapper
Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-)
_____
I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> .
SPAMfighter has removed 501 of my spam emails to date.
Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen> Try free scan!
HV
Huib Verweij17 Jul 2012 20:33 #
Hi Rob,
I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is.
In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence.
declare function local:refs($node, $refs) {
if ($node/@ref)
then
if (empty(index-of($refs, $node/@ref))
then let $processedNode := <do something with $node>
return local:refs($processedNode, (@ref, $refs))
else ...
else <process all children of $node>
}Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it.
If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool.
Regards,
Huib Verweij.
Verstuurd vanaf mijn iPad
Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven:
Quoted text · Rob · 56 lines
> Hi, > > Can you please help me solving a challenge I have with a specific type XML-query? > > I’ve a bunch of XML-files that are referencing each other. > So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. > Actually an m:n relationship between XML-files with possible cyclic structure. > > The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of “file-in-process”-buffer, if the XML-file isn’t already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. > > A structure like this (not real code (at all)): > ============================================================== > INSTANTIATE Guard FROM COLLECTION > > PROCESS-RECURSIVELY( XML-fileName) { > PROCESS( XML-fileName) > > ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { > IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { > Guard.ADD( Called-XML-file.NAME) > > PROCESS-RESURSIVELY(Called-XML-file.NAME) > } > } > } > > PROCESS-RESURSIVELY(“start-file”) > ============================================================= > > I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because of their declarative nature. > Recursiveness is possible with these tools but only in a linear way not in an iterative way. > > That is why I’m looking for alternatives. Hopefully BaseX can help me out here. > I’ve BaseX and the JAVA-examples in eclipse running. > I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. > > My question: What is the best way to approach this challenge? > Can you give me some tips? > > > Kind regards, > > Rob Stapper > > Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) > > > > I am using the Free version of SPAMfighter. > SPAMfighter has removed 501 of my spam emails to date. > > Do you have a slow PC? Try free scan! > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
R
Rob18 Jul 2012 08:48 #
Hi Huib,
Thanx for the reply.
I’ve seen this kind of solution before on the internet but this does not work in my case.
I don’t have a single @ref-attribute in $node-element. Instead I have several ref-child-elements within a $node-element. (that is what a meant with linear versus iterative)
In that case I would have an iteration through the ref-child-elements within my function. So there will be an iteration of recursive calls.
But every time I come back from a recursive call my ref-collection won’t be updated with the processed $nodes from this call but will be reset to its original value.
This because of the declarative nature of the XML-tools.
So now I started programming in JAVA in eclipse and stored my XML-files in a BaseX-database.
I can connect to the database but I was wondering what the best approach would be from there.
Any suggestions would be welcome.
Quoted text · Huib Verweij · 60 lines
Van: Huib Verweij [mailto:hhv at home.nl] Verzonden: dinsdag 17 juli 2012 20:33 Aan: Rob CC: basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is. In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence. declare function local:refs($node, $refs) { if ($node/@ref) then if (empty(index-of($refs, $node/@ref)) then let $processedNode := <do something with $node> return local:refs($processedNode, (@ref, $refs)) else ... else <process all children of $node> } Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it. If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool. Regards, Huib Verweij. Verstuurd vanaf mijn iPad Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven: Hi, Can you please help me solving a challenge I have with a specific type XML-query? I’ve a bunch of XML-files that are referencing each other. So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. Actually an m:n relationship between XML-files with possible cyclic structure. The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of “file-in-process”-buffer, if the XML-file isn’t already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. A structure like this (not real code (at all)): ============================================================== INSTANTIATE Guard FROM COLLECTION PROCESS-RECURSIVELY( XML-fileName) { PROCESS( XML-fileName) ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { Guard.ADD( Called-XML-file.NAME) PROCESS-RESURSIVELY(Called-XML-file.NAME) } } } PROCESS-RESURSIVELY(“start-file”) ============================================================= I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because of their declarative nature. Recursiveness is possible with these tools but only in a linear way not in an iterative way. That is why I’m looking for alternatives. Hopefully BaseX can help me out here. I’ve BaseX and the JAVA-examples in eclipse running. I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. My question: What is the best way to approach this challenge? Can you give me some tips? Kind regards, Rob Stapper Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) _____ I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> . SPAMfighter has removed 501 of my spam emails to date. Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen> Try free scan! BaseX-Talk mailing list BaseX-Talk at mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
HV
Huib Verweij18 Jul 2012 09:16 #
Hi Rob,
I think I see how your documents are structured. Depending on the use case, you could try collecting all refs first, throw away the duplicates and then process them. As in:
for $ref in distinct-values(collection('c')//ref/@link)
return local:process(@ref)Hartelijke groet,
Huib.
Verstuurd vanaf mijn iPad
Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende geschreven:
Quoted text · Rob · 104 lines
> Hi Huib, > > Thanx for the reply. > > I’ve seen this kind of solution before on the internet but this does not work in my case. > I don’t have a single @ref-attribute in $node-element. Instead I have several ref-child-elements within a $node-element. (that is what a meant with linear versus iterative) > In that case I would have an iteration through the ref-child-elements within my function. So there will be an iteration of recursive calls. > But every time I come back from a recursive call my ref-collection won’t be updated with the processed $nodes from this call but will be reset to its original value. > This because of the declarative nature of the XML-tools. > > So now I started programming in JAVA in eclipse and stored my XML-files in a BaseX-database. > I can connect to the database but I was wondering what the best approach would be from there. > > Any suggestions would be welcome. > Van: Huib Verweij [mailto:hhv at home.nl] > Verzonden: dinsdag 17 juli 2012 20:33 > Aan: Rob > CC: basex-talk at mailman.uni-konstanz.de > Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. > > Hi Rob, > > I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is. > > In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence. > > declare function local:refs($node, $refs) { > if ($node/@ref) > then > if (empty(index-of($refs, $node/@ref)) > then let $processedNode := <do something with $node> > return local:refs($processedNode, (@ref, $refs)) > else ... > else <process all children of $node> > } > > Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it. > > If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool. > > Regards, > > Huib Verweij. > > Verstuurd vanaf mijn iPad > > Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven: > > Hi, > > Can you please help me solving a challenge I have with a specific type XML-query? > > I’ve a bunch of XML-files that are referencing each other. > So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. > Actually an m:n relationship between XML-files with possible cyclic structure. > > The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of “file-in-process”-buffer, if the XML-file isn’t already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. > > A structure like this (not real code (at all)): > ============================================================== > INSTANTIATE Guard FROM COLLECTION > > PROCESS-RECURSIVELY( XML-fileName) { > PROCESS( XML-fileName) > > ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { > IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { > Guard.ADD( Called-XML-file.NAME) > > PROCESS-RESURSIVELY(Called-XML-file.NAME) > } > } > } > > PROCESS-RESURSIVELY(“start-file”) > ============================================================= > > I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because of their declarative nature. > Recursiveness is possible with these tools but only in a linear way not in an iterative way. > > That is why I’m looking for alternatives. Hopefully BaseX can help me out here. > I’ve BaseX and the JAVA-examples in eclipse running. > I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. > > My question: What is the best way to approach this challenge? > Can you give me some tips? > > > Kind regards, > > Rob Stapper > > Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) > > > > I am using the Free version of SPAMfighter. > SPAMfighter has removed 501 of my spam emails to date. > > Do you have a slow PC? Try free scan! > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
DK
Dirk Kirsten18 Jul 2012 10:35 #
Hi Rob,
Another possibility would be to return the processed ref-child-elements from the recursive function and to update the sequence of already processed nodes. Therefore you could immediately update the sequence and take this into account for the next iterative step.
Cheers,
Dirk
Quoted text · Huib Verweij · 262 lines
On Wed, Jul 18, 2012 at 9:16 AM, Huib Verweij <hhv at home.nl> wrote: > Hi Rob, > > I think I see how your documents are structured. Depending on the use > case, you could try collecting all refs first, throw away the duplicates > and then process them. As in: > > for $ref in distinct-values(collection('c')//ref/@link) > return local:process(@ref) > > Hartelijke groet, > > Huib. > > Verstuurd vanaf mijn iPad > > Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende > geschreven: > > Hi Huib,**** > > ** ** > > Thanx for the reply. **** > > ** ** > > I’ve seen this kind of solution before on the internet but this does not > work in my case.**** > > I don’t have a single @ref-attribute in $node-element. Instead I have > several ref-child-elements within a $node-element. (that is what a meant > with linear versus iterative)**** > > In that case I would have an iteration through the ref-child-elements > within my function. So there will be an iteration of recursive calls.**** > > But every time I come back from a recursive call my ref-collection won’t > be updated with the processed $nodes from this call but will be reset to > its original value.**** > > This because of the declarative nature of the XML-tools. **** > > ** ** > > So now I started programming in JAVA in eclipse and stored my XML-files in > a BaseX-database.**** > > I can connect to the database but I was wondering what the best approach > would be from there.**** > > ** ** > > Any suggestions would be welcome.**** > > **** > > *Van:* Huib Verweij [mailto:hhv at home.nl] > *Verzonden:* dinsdag 17 juli 2012 20:33 > *Aan:* Rob > *CC:* basex-talk at mailman.uni-konstanz.de > *Onderwerp:* Re: [basex-talk] Question concerning querying cyclic network > xml-structure.**** > > ** ** > > Hi Rob,**** > > ** ** > > I think XQuery and XSLT are very much capable of handling your example. If > I understand it correctly, I do not know what linear or iterative recursion > is. > > In fact I programmed something similar to the algorithm you describe in > XQuery recently. I was processing nodes from the BaseX database though, not > XML files. Starting with the first node and an empty sequence as the two > arguments to the function I process only references that are NOT in the > sequence.**** > > ** ** > > declare function local:refs($node, $refs) {**** > > if ($node/@ref)**** > > then**** > > if (empty(index-of($refs, $node/@ref))**** > > then let $processedNode := <do something with $node>**** > > return local:refs($processedNode, (@ref, $refs))**** > > else ...**** > > else <process all children of $node>**** > > }**** > > ** ** > > Well, it looked something like that. You get the idea I hope. Just add > every processed reference to $refs and check that the current @ref is not > in $refs before you process it.**** > > ** ** > > If storing your XML inside BaseX is not an option you might try out Nux ( > http://acs.lbl.gov/software/nux/), I have used it successfully to process > XML files in the past, simply using the fire-xquery command line tool.**** > > ** ** > > Regards,**** > > ** ** > > Huib Verweij.**** > > > Verstuurd vanaf mijn iPad**** > > > Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende > geschreven:**** > > Hi,**** > > **** > > Can you please help me solving a challenge I have with a specific type > XML-query?**** > > **** > > I’ve a bunch of XML-files that are referencing each other. **** > > So, a XML-file can reference to multiple XML-files and a XML-file can be > referenced to by multiple XML-files. This whole reference-structure could > be cyclic.**** > > Actually an m:n relationship between XML-files with possible cyclic > structure.**** > > **** > > The standard solution would be to build a recursive-routine for processing > an XML-file that, before actually processing the XML-file, checks in some > way, for example with some sort of “file-in-process”-buffer, if the > XML-file isn’t already being processed. If not store the name in this > buffer, processes the XML-file and initiate the recursive routine for the > referenced XML-files.**** > > **** > > A structure like this (not real code (at all)):**** > > ==============================================================**** > > INSTANTIATE Guard FROM COLLECTION**** > > **** > > PROCESS-RECURSIVELY( XML-fileName) {**** > > PROCESS( XML-fileName)**** > > **** > > ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT {** > ** > > IF NOT ( Guard.EXISTS( > Called-XML-file.NAME) {**** > > Guard.ADD( > Called-XML-file.NAME)**** > > **** > > > PROCESS-RESURSIVELY(Called-XML-file.NAME)**** > > }**** > > }**** > > }**** > > **** > > PROCESS-RESURSIVELY(“start-file”)**** > > =============================================================**** > > **** > > I found out that, but I could be mistaken, that the standard > W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because > of their declarative nature.**** > > Recursiveness is possible with these tools but only in a linear way not in > an iterative way.**** > > **** > > That is why I’m looking for alternatives. Hopefully BaseX can help me out > here.**** > > I’ve BaseX and the JAVA-examples in eclipse running. **** > > I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a > struggle, but I managed.**** > > **** > > My question: What is the best way to approach this challenge?**** > > Can you give me some tips?**** > > **** > > **** > > Kind regards,**** > > **** > > Rob Stapper**** > > **** > > Meine frage ist in English weil mein Deutsch nicht so gut is wie mein > Englisch. Enschuldigung dafür. ;-)**** > > **** > > **** > > ** ** > ------------------------------ > > I am using the Free version of SPAMfighter<http://www.spamfighter.com/len> > . > SPAMfighter has removed 501 of my spam emails to date. > > Do you have a slow PC?<http://www.spamfighter.com/SLOW-PCfighter?cid=sigen>Try free scan! > **** > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk**** > > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > >
R
Rob18 Jul 2012 11:37 #
Hi Dirk,
Thought about that one too.
But for some reason it doesnt seem to be possible integrating two independent processors; an iterative recursive node-processor and a sequence of already processed nodes-processor, in one and the same query-session.
Anyway, I couldnt make it happen, but then again Im pretty fresh here.
I cant help it, but Im get more and more convinced that is simply isnt possible because to the declarative nature of the XML-tooling.
Thnx for the reply.
Quoted text · Dirk Kirsten · 137 lines
Van: Dirk Kirsten [mailto:dk at basex.org] Verzonden: woensdag 18 juli 2012 10:35 Aan: Huib Verweij CC: Rob; basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, Another possibility would be to return the processed ref-child-elements from the recursive function and to update the sequence of already processed nodes. Therefore you could immediately update the sequence and take this into account for the next iterative step. Cheers, Dirk On Wed, Jul 18, 2012 at 9:16 AM, Huib Verweij <hhv at home.nl> wrote: Hi Rob, I think I see how your documents are structured. Depending on the use case, you could try collecting all refs first, throw away the duplicates and then process them. As in: for $ref in distinct-values(collection('c')//ref/@link) return local:process(@ref) Hartelijke groet, Huib. Verstuurd vanaf mijn iPad Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende geschreven: Hi Huib, Thanx for the reply. Ive seen this kind of solution before on the internet but this does not work in my case. I dont have a single @ref-attribute in $node-element. Instead I have several ref-child-elements within a $node-element. (that is what a meant with linear versus iterative) In that case I would have an iteration through the ref-child-elements within my function. So there will be an iteration of recursive calls. But every time I come back from a recursive call my ref-collection wont be updated with the processed $nodes from this call but will be reset to its original value. This because of the declarative nature of the XML-tools. So now I started programming in JAVA in eclipse and stored my XML-files in a BaseX-database. I can connect to the database but I was wondering what the best approach would be from there. Any suggestions would be welcome. Van: Huib Verweij [mailto:hhv at home.nl] Verzonden: dinsdag 17 juli 2012 20:33 Aan: Rob CC: basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is. In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence. declare function local:refs($node, $refs) { if ($node/@ref) then if (empty(index-of($refs, $node/@ref)) then let $processedNode := <do something with $node> return local:refs($processedNode, (@ref, $refs)) else ... else <process all children of $node> } Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it. If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool. Regards, Huib Verweij. Verstuurd vanaf mijn iPad Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven: Hi, Can you please help me solving a challenge I have with a specific type XML-query? Ive a bunch of XML-files that are referencing each other. So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. Actually an m:n relationship between XML-files with possible cyclic structure. The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of file-in-process-buffer, if the XML-file isnt already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. A structure like this (not real code (at all)): ============================================================== INSTANTIATE Guard FROM COLLECTION PROCESS-RECURSIVELY( XML-fileName) { PROCESS( XML-fileName) ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { Guard.ADD( Called-XML-file.NAME) PROCESS-RESURSIVELY(Called-XML-file.NAME) } } } PROCESS-RESURSIVELY(start-file) ============================================================= I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) cant handle this situation because of their declarative nature. Recursiveness is possible with these tools but only in a linear way not in an iterative way. That is why Im looking for alternatives. Hopefully BaseX can help me out here. Ive BaseX and the JAVA-examples in eclipse running. Im b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. My question: What is the best way to approach this challenge? Can you give me some tips? Kind regards, Rob Stapper Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) _____ I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> . SPAMfighter has removed 501 of my spam emails to date. Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen> Try free scan! BaseX-Talk mailing list BaseX-Talk at mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk BaseX-Talk mailing list BaseX-Talk at mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
R
Huib,
“Hmm, iets anders” like wibi said! (joke for the Dutch readers)
Maybe I could (should) attempt an other approach.
Thnx for the inspiration.
Quoted text · Huib Verweij · 83 lines
Van: Huib Verweij [mailto:hhv at home.nl] Verzonden: woensdag 18 juli 2012 9:17 Aan: Rob CC: basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, I think I see how your documents are structured. Depending on the use case, you could try collecting all refs first, throw away the duplicates and then process them. As in: for $ref in distinct-values(collection('c')//ref/@link) return local:process(@ref) Hartelijke groet, Huib. Verstuurd vanaf mijn iPad Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende geschreven: Hi Huib, Thanx for the reply. I’ve seen this kind of solution before on the internet but this does not work in my case. I don’t have a single @ref-attribute in $node-element. Instead I have several ref-child-elements within a $node-element. (that is what a meant with linear versus iterative) In that case I would have an iteration through the ref-child-elements within my function. So there will be an iteration of recursive calls. But every time I come back from a recursive call my ref-collection won’t be updated with the processed $nodes from this call but will be reset to its original value. This because of the declarative nature of the XML-tools. So now I started programming in JAVA in eclipse and stored my XML-files in a BaseX-database. I can connect to the database but I was wondering what the best approach would be from there. Any suggestions would be welcome. Van: Huib Verweij [mailto:hhv at home.nl] Verzonden: dinsdag 17 juli 2012 20:33 Aan: Rob CC: basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is. In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence. declare function local:refs($node, $refs) { if ($node/@ref) then if (empty(index-of($refs, $node/@ref)) then let $processedNode := <do something with $node> return local:refs($processedNode, (@ref, $refs)) else ... else <process all children of $node> } Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it. If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool. Regards, Huib Verweij. Verstuurd vanaf mijn iPad Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven: Hi, Can you please help me solving a challenge I have with a specific type XML-query? I’ve a bunch of XML-files that are referencing each other. So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. Actually an m:n relationship between XML-files with possible cyclic structure. The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of “file-in-process”-buffer, if the XML-file isn’t already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. A structure like this (not real code (at all)): ============================================================== INSTANTIATE Guard FROM COLLECTION PROCESS-RECURSIVELY( XML-fileName) { PROCESS( XML-fileName) ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { Guard.ADD( Called-XML-file.NAME) PROCESS-RESURSIVELY(Called-XML-file.NAME) } } } PROCESS-RESURSIVELY(“start-file”) ============================================================= I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because of their declarative nature. Recursiveness is possible with these tools but only in a linear way not in an iterative way. That is why I’m looking for alternatives. Hopefully BaseX can help me out here. I’ve BaseX and the JAVA-examples in eclipse running. I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. My question: What is the best way to approach this challenge? Can you give me some tips? Kind regards, Rob Stapper Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) _____ I am using the Free version of SPAMfighter <http://www.spamfighter.com/len> . SPAMfighter has removed 501 of my spam emails to date. Do you have a slow PC? <http://www.spamfighter.com/SLOW-PCfighter?cid=sigen> Try free scan! BaseX-Talk mailing list BaseX-Talk at mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
CG
Hi Rob,
Quoted text · Rob · 2 lines
> I can’t help it, but I’m get more and more convinced that is simply isn’t > possible because to the declarative nature of the XML-tooling.
I'm frequently surprised that you can do nearly everything in a functional language (and in particular XQuery) what you can do in an imperative way, but I agree that it often takes a while to find out what's the most elegant approach. You could have a look at the higher order features of XQuery [1,2], or the map module [3], which can be used to create sets of sequences (something that cannot be done in pure XQuery 3.0). If you decide to spend some more time in getting to know the full range of language features, you may eventually prefer to write all your XML code in XQuery, as we do.
Christian
[1] http://docs.basex.org/wiki/Higher-Order_Functions
[2] http://docs.basex.org/wiki/Higher-Order_Functions_Module [3] http://docs.basex.org/wiki/Map_Module
Quoted text · Rob · 291 lines
> Onderwerp: Re: [basex-talk] Question concerning querying cyclic network > xml-structure. > > > > Hi Rob, > > Another possibility would be to return the processed ref-child-elements from > the recursive function and to update the sequence of already processed > nodes. Therefore you could immediately update the sequence and take this > into account for the next iterative step. > > Cheers, > Dirk > > On Wed, Jul 18, 2012 at 9:16 AM, Huib Verweij <hhv at home.nl> wrote: > > Hi Rob, > > > > I think I see how your documents are structured. Depending on the use case, > you could try collecting all refs first, throw away the duplicates and then > process them. As in: > > > > for $ref in distinct-values(collection('c')//ref/@link) > > return local:process(@ref) > > > > Hartelijke groet, > > > > Huib. > > Verstuurd vanaf mijn iPad > > > Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende > geschreven: > > Hi Huib, > > > > Thanx for the reply. > > > > I’ve seen this kind of solution before on the internet but this does not > work in my case. > > I don’t have a single @ref-attribute in $node-element. Instead I have > several ref-child-elements within a $node-element. (that is what a meant > with linear versus iterative) > > In that case I would have an iteration through the ref-child-elements within > my function. So there will be an iteration of recursive calls. > > But every time I come back from a recursive call my ref-collection won’t be > updated with the processed $nodes from this call but will be reset to its > original value. > > This because of the declarative nature of the XML-tools. > > > > So now I started programming in JAVA in eclipse and stored my XML-files in a > BaseX-database. > > I can connect to the database but I was wondering what the best approach > would be from there. > > > > Any suggestions would be welcome. > > Van: Huib Verweij [mailto:hhv at home.nl] > Verzonden: dinsdag 17 juli 2012 20:33 > Aan: Rob > CC: basex-talk at mailman.uni-konstanz.de > Onderwerp: Re: [basex-talk] Question concerning querying cyclic network > xml-structure. > > > > Hi Rob, > > > > I think XQuery and XSLT are very much capable of handling your example. If I > understand it correctly, I do not know what linear or iterative recursion > is. > > In fact I programmed something similar to the algorithm you describe in > XQuery recently. I was processing nodes from the BaseX database though, not > XML files. Starting with the first node and an empty sequence as the two > arguments to the function I process only references that are NOT in the > sequence. > > > > declare function local:refs($node, $refs) { > > if ($node/@ref) > > then > > if (empty(index-of($refs, $node/@ref)) > > then let $processedNode := <do something with $node> > > return local:refs($processedNode, (@ref, $refs)) > > else ... > > else <process all children of $node> > > } > > > > Well, it looked something like that. You get the idea I hope. Just add every > processed reference to $refs and check that the current @ref is not in $refs > before you process it. > > > > If storing your XML inside BaseX is not an option you might try out Nux > (http://acs.lbl.gov/software/nux/), I have used it successfully to process > XML files in the past, simply using the fire-xquery command line tool. > > > > Regards, > > > > Huib Verweij. > > > Verstuurd vanaf mijn iPad > > > Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende > geschreven: > > Hi, > > > > Can you please help me solving a challenge I have with a specific type > XML-query? > > > > I’ve a bunch of XML-files that are referencing each other. > > So, a XML-file can reference to multiple XML-files and a XML-file can be > referenced to by multiple XML-files. This whole reference-structure could be > cyclic. > > Actually an m:n relationship between XML-files with possible cyclic > structure. > > > > The standard solution would be to build a recursive-routine for processing > an XML-file that, before actually processing the XML-file, checks in some > way, for example with some sort of “file-in-process”-buffer, if the XML-file > isn’t already being processed. If not store the name in this buffer, > processes the XML-file and initiate the recursive routine for the referenced > XML-files. > > > > A structure like this (not real code (at all)): > > ============================================================== > > INSTANTIATE Guard FROM COLLECTION > > > > PROCESS-RECURSIVELY( XML-fileName) { > > PROCESS( XML-fileName) > > > > ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { > > IF NOT ( Guard.EXISTS( Called-XML-file.NAME) > { > > Guard.ADD( > Called-XML-file.NAME) > > > > > PROCESS-RESURSIVELY(Called-XML-file.NAME) > > } > > } > > } > > > > PROCESS-RESURSIVELY(“start-file”) > > ============================================================= > > > > I found out that, but I could be mistaken, that the standard W3C-XML-tooling > (XPATH, XQUERY, XLST) can’t handle this situation because of their > declarative nature. > > Recursiveness is possible with these tools but only in a linear way not in > an iterative way. > > > > That is why I’m looking for alternatives. Hopefully BaseX can help me out > here. > > I’ve BaseX and the JAVA-examples in eclipse running. > > I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, > but I managed. > > > > My question: What is the best way to approach this challenge? > > Can you give me some tips? > > > > > > Kind regards, > > > > Rob Stapper > > > > Meine frage ist in English weil mein Deutsch nicht so gut is wie mein > Englisch. Enschuldigung dafür. ;-) > > > > > > > > ________________________________ > > I am using the Free version of SPAMfighter. > SPAMfighter has removed 501 of my spam emails to date. > > Do you have a slow PC? Try free scan! > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > > > > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >
HV
Hi Rob,
as Dirk said, returning the list of processed references is probably what you're after I think. You could implement two functions then, one for recursive processing and one for iterative processing as you say, calling each other as necessary. The last function would require passing the number of refs that still need to be processed to the function, counting down to zero.
function process-node($node, $refs, $refPos){
$currentRef := $node/ref[position() eq $refPos] if ($refPos gt 0) process-node($node, ($currentRef, $refs), $refPos - 1)
I guess it's the recursive way of iterating :-).
XQuery is a functional programming language, which sometimes requires to think differently about algorithms, perhaps that's what tripping you up? It's certainly not less powerful than imperative programming languages!
Hope this helps.
Huib.
Verstuurd vanaf mijn iPad
Op 18 jul. 2012 om 09:16 heeft Huib Verweij <hhv at home.nl> het volgende geschreven:
Quoted text · Huib Verweij · 123 lines
> Hi Rob, > > I think I see how your documents are structured. Depending on the use case, you could try collecting all refs first, throw away the duplicates and then process them. As in: > > for $ref in distinct-values(collection('c')//ref/@link) > return local:process(@ref) > > Hartelijke groet, > > Huib. > > Verstuurd vanaf mijn iPad > > Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende geschreven: > >> Hi Huib, >> >> Thanx for the reply. >> >> I’ve seen this kind of solution before on the internet but this does not work in my case. >> I don’t have a single @ref-attribute in $node-element. Instead I have several ref-child-elements within a $node-element. (that is what a meant with linear versus iterative) >> In that case I would have an iteration through the ref-child-elements within my function. So there will be an iteration of recursive calls. >> But every time I come back from a recursive call my ref-collection won’t be updated with the processed $nodes from this call but will be reset to its original value. >> This because of the declarative nature of the XML-tools. >> >> So now I started programming in JAVA in eclipse and stored my XML-files in a BaseX-database. >> I can connect to the database but I was wondering what the best approach would be from there. >> >> Any suggestions would be welcome. >> Van: Huib Verweij [mailto:hhv at home.nl] >> Verzonden: dinsdag 17 juli 2012 20:33 >> Aan: Rob >> CC: basex-talk at mailman.uni-konstanz.de >> Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. >> >> Hi Rob, >> >> I think XQuery and XSLT are very much capable of handling your example. If I understand it correctly, I do not know what linear or iterative recursion is. >> >> In fact I programmed something similar to the algorithm you describe in XQuery recently. I was processing nodes from the BaseX database though, not XML files. Starting with the first node and an empty sequence as the two arguments to the function I process only references that are NOT in the sequence. >> >> declare function local:refs($node, $refs) { >> if ($node/@ref) >> then >> if (empty(index-of($refs, $node/@ref)) >> then let $processedNode := <do something with $node> >> return local:refs($processedNode, (@ref, $refs)) >> else ... >> else <process all children of $node> >> } >> >> Well, it looked something like that. You get the idea I hope. Just add every processed reference to $refs and check that the current @ref is not in $refs before you process it. >> >> If storing your XML inside BaseX is not an option you might try out Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to process XML files in the past, simply using the fire-xquery command line tool. >> >> Regards, >> >> Huib Verweij. >> >> Verstuurd vanaf mijn iPad >> >> Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende geschreven: >> >> Hi, >> >> Can you please help me solving a challenge I have with a specific type XML-query? >> >> I’ve a bunch of XML-files that are referencing each other. >> So, a XML-file can reference to multiple XML-files and a XML-file can be referenced to by multiple XML-files. This whole reference-structure could be cyclic. >> Actually an m:n relationship between XML-files with possible cyclic structure. >> >> The standard solution would be to build a recursive-routine for processing an XML-file that, before actually processing the XML-file, checks in some way, for example with some sort of “file-in-process”-buffer, if the XML-file isn’t already being processed. If not store the name in this buffer, processes the XML-file and initiate the recursive routine for the referenced XML-files. >> >> A structure like this (not real code (at all)): >> ============================================================== >> INSTANTIATE Guard FROM COLLECTION >> >> PROCESS-RECURSIVELY( XML-fileName) { >> PROCESS( XML-fileName) >> >> ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT { >> IF NOT ( Guard.EXISTS( Called-XML-file.NAME) { >> Guard.ADD( Called-XML-file.NAME) >> >> PROCESS-RESURSIVELY(Called-XML-file.NAME) >> } >> } >> } >> >> PROCESS-RESURSIVELY(“start-file”) >> ============================================================= >> >> I found out that, but I could be mistaken, that the standard W3C-XML-tooling (XPATH, XQUERY, XLST) can’t handle this situation because of their declarative nature. >> Recursiveness is possible with these tools but only in a linear way not in an iterative way. >> >> That is why I’m looking for alternatives. Hopefully BaseX can help me out here. >> I’ve BaseX and the JAVA-examples in eclipse running. >> I’m b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a struggle, but I managed. >> >> My question: What is the best way to approach this challenge? >> Can you give me some tips? >> >> >> Kind regards, >> >> Rob Stapper >> >> Meine frage ist in English weil mein Deutsch nicht so gut is wie mein Englisch. Enschuldigung dafür. ;-) >> >> >> >> I am using the Free version of SPAMfighter. >> SPAMfighter has removed 501 of my spam emails to date. >> >> Do you have a slow PC? Try free scan! >> _______________________________________________ >> BaseX-Talk mailing list >> BaseX-Talk at mailman.uni-konstanz.de >> https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
R
Hi Christian,
You're probably right. I hoped to find a working example somewhere. But, I still haven't found what I was looking for (this would make a good song title) and that worries me somehow.
I'll have a look at the links and do some more digging.
Rob
-----Oorspronkelijk bericht-----
Quoted text · Christian Grün · 315 lines
Van: Christian Grün [mailto:christian.gruen at gmail.com] Verzonden: woensdag 18 juli 2012 13:50 Aan: Rob CC: Dirk Kirsten; Huib Verweij; basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Hi Rob, > I cant help it, but Im get more and more convinced that is simply > isnt possible because to the declarative nature of the XML-tooling. I'm frequently surprised that you can do nearly everything in a functional language (and in particular XQuery) what you can do in an imperative way, but I agree that it often takes a while to find out what's the most elegant approach. You could have a look at the higher order features of XQuery [1,2], or the map module [3], which can be used to create sets of sequences (something that cannot be done in pure XQuery 3.0). If you decide to spend some more time in getting to know the full range of language features, you may eventually prefer to write all your XML code in XQuery, as we do. Christian [1] http://docs.basex.org/wiki/Higher-Order_Functions [2] http://docs.basex.org/wiki/Higher-Order_Functions_Module [3] http://docs.basex.org/wiki/Map_Module > Onderwerp: Re: [basex-talk] Question concerning querying cyclic > network xml-structure. > > > > Hi Rob, > > Another possibility would be to return the processed > ref-child-elements from the recursive function and to update the > sequence of already processed nodes. Therefore you could immediately > update the sequence and take this into account for the next iterative step. > > Cheers, > Dirk > > On Wed, Jul 18, 2012 at 9:16 AM, Huib Verweij <hhv at home.nl> wrote: > > Hi Rob, > > > > I think I see how your documents are structured. Depending on the use > case, you could try collecting all refs first, throw away the > duplicates and then process them. As in: > > > > for $ref in distinct-values(collection('c')//ref/@link) > > return local:process(@ref) > > > > Hartelijke groet, > > > > Huib. > > Verstuurd vanaf mijn iPad > > > Op 18 jul. 2012 om 08:48 heeft Rob <r.stapper at home.nl> het volgende > geschreven: > > Hi Huib, > > > > Thanx for the reply. > > > > Ive seen this kind of solution before on the internet but this does > not work in my case. > > I dont have a single @ref-attribute in $node-element. Instead I have > several ref-child-elements within a $node-element. (that is what a > meant with linear versus iterative) > > In that case I would have an iteration through the ref-child-elements > within my function. So there will be an iteration of recursive calls. > > But every time I come back from a recursive call my ref-collection > wont be updated with the processed $nodes from this call but will be > reset to its original value. > > This because of the declarative nature of the XML-tools. > > > > So now I started programming in JAVA in eclipse and stored my > XML-files in a BaseX-database. > > I can connect to the database but I was wondering what the best > approach would be from there. > > > > Any suggestions would be welcome. > > Van: Huib Verweij [mailto:hhv at home.nl] > Verzonden: dinsdag 17 juli 2012 20:33 > Aan: Rob > CC: basex-talk at mailman.uni-konstanz.de > Onderwerp: Re: [basex-talk] Question concerning querying cyclic > network xml-structure. > > > > Hi Rob, > > > > I think XQuery and XSLT are very much capable of handling your > example. If I understand it correctly, I do not know what linear or > iterative recursion is. > > In fact I programmed something similar to the algorithm you describe > in XQuery recently. I was processing nodes from the BaseX database > though, not XML files. Starting with the first node and an empty > sequence as the two arguments to the function I process only > references that are NOT in the sequence. > > > > declare function local:refs($node, $refs) { > > if ($node/@ref) > > then > > if (empty(index-of($refs, $node/@ref)) > > then let $processedNode := <do something with $node> > > return local:refs($processedNode, (@ref, $refs)) > > else ... > > else <process all children of $node> > > } > > > > Well, it looked something like that. You get the idea I hope. Just add > every processed reference to $refs and check that the current @ref is > not in $refs before you process it. > > > > If storing your XML inside BaseX is not an option you might try out > Nux (http://acs.lbl.gov/software/nux/), I have used it successfully to > process XML files in the past, simply using the fire-xquery command line tool. > > > > Regards, > > > > Huib Verweij. > > > Verstuurd vanaf mijn iPad > > > Op 17 jul. 2012 om 15:01 heeft Rob <r.stapper at home.nl> het volgende > geschreven: > > Hi, > > > > Can you please help me solving a challenge I have with a specific type > XML-query? > > > > Ive a bunch of XML-files that are referencing each other. > > So, a XML-file can reference to multiple XML-files and a XML-file can > be referenced to by multiple XML-files. This whole reference-structure > could be cyclic. > > Actually an m:n relationship between XML-files with possible cyclic > structure. > > > > The standard solution would be to build a recursive-routine for > processing an XML-file that, before actually processing the XML-file, > checks in some way, for example with some sort of > file-in-process-buffer, if the XML-file isnt already being > processed. If not store the name in this buffer, processes the > XML-file and initiate the recursive routine for the referenced XML-files. > > > > A structure like this (not real code (at all)): > > ============================================================== > > INSTANTIATE Guard FROM COLLECTION > > > > PROCESS-RECURSIVELY( XML-fileName) { > > PROCESS( XML-fileName) > > > > ITERATE Called-XML-file THROUGH XML-file//call-ELEMENT > { > > IF NOT ( Guard.EXISTS( > Called-XML-file.NAME) { > > Guard.ADD( > Called-XML-file.NAME) > > > > > PROCESS-RESURSIVELY(Called-XML-file.NAME) > > } > > } > > } > > > > PROCESS-RESURSIVELY(start-file) > > ============================================================= > > > > I found out that, but I could be mistaken, that the standard > W3C-XML-tooling (XPATH, XQUERY, XLST) cant handle this situation > because of their declarative nature. > > Recursiveness is possible with these tools but only in a linear way > not in an iterative way. > > > > That is why Im looking for alternatives. Hopefully BaseX can help me > out here. > > Ive BaseX and the JAVA-examples in eclipse running. > > Im b.t.w. nor a JAVA- nor an eclipse-expert so it was a bit of a > struggle, but I managed. > > > > My question: What is the best way to approach this challenge? > > Can you give me some tips? > > > > > > Kind regards, > > > > Rob Stapper > > > > Meine frage ist in English weil mein Deutsch nicht so gut is wie mein > Englisch. Enschuldigung dafür. ;-) > > > > > > > > ________________________________ > > I am using the Free version of SPAMfighter. > SPAMfighter has removed 501 of my spam emails to date. > > Do you have a slow PC? Try free scan! > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > > > > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk at mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >
LW
Leonard Wörteler19 Jul 2012 17:28 #
Dear Rob,
Quoted text · Rob · 5 lines
Am 19.07.2012 07:24, schrieb Rob: > You're probably right. I hoped to find a working example somewhere. But, I > still haven't found what I was looking for (this would make a good song > title) and that worries me somehow. > I'll have a look at the links and do some more digging.
it sounds to as if you want to implement a depth-first search over your documents. That's actually pretty easy in XQuery.
The trick is to simulate the mutable state (in your case the global variable
Guard) by threading it through all resursive function calls.
In the attached example I used an example graph from Wikipedia [1]. It is encoded as a list of nodes and references to their children: <graph>
<node name='Frankfurt' id='1'>
<child idref='2' />
<child idref='3' />
<child idref='4' />
</node>
...
</graphThe graph obviously has many cycles. the function
local:depth-first($graph, $start) traverses it in depth-first order, visiting every node only once and collecting the node names in order.
I used the Map Module [2] to encapsulate the state and the XQuery 3.0 higher-order function fold-left(..) [3], but you could use your own recursive function instead of the latter to iterate over the child nodes and pass the state along.
Hope this helps,
cheers, Leo
__________
[1] http://en.wikipedia.org/wiki/File:MapGermanyGraph.svg
[2] http://docs.basex.org/wiki/Map_Module
[3] http://docs.basex.org/wiki/Higher-Order_Functions#Folds
R
Rob20 Jul 2012 10:46 #
Leo,
;-) Ausgezeichnet (briljant)
Exactly what I was looking for.
I don't know if I had been able to figure this out on my own, not within reasonable time. Not even with Christian's tips. For me it's a whole new concept.
Danke,
Rob
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Quoted text · Leonard Wörteler · 30 lines
Van: Leonard Wörteler [mailto:leo at woerteler.de] Verzonden: donderdag 19 juli 2012 17:28 Aan: Rob CC: basex-talk at mailman.uni-konstanz.de Onderwerp: Re: [basex-talk] Question concerning querying cyclic network xml-structure. Dear Rob, Am 19.07.2012 07:24, schrieb Rob: > You're probably right. I hoped to find a working example somewhere. > But, I still haven't found what I was looking for (this would make a > good song > title) and that worries me somehow. > I'll have a look at the links and do some more digging. it sounds to as if you want to implement a depth-first search over your documents. That's actually pretty easy in XQuery. The trick is to simulate the mutable state (in your case the global variable `Guard`) by threading it through all resursive function calls. In the attached example I used an example graph from Wikipedia [1]. It is encoded as a list of nodes and references to their children: <graph> <node name='Frankfurt' id='1'> <child idref='2' /> <child idref='3' /> <child idref='4' /> </node> ... </graph The graph obviously has many cycles. the function `local:depth-first($graph, $start)` traverses it in depth-first order, visiting every node only once and collecting the node names in order. I used the Map Module [2] to encapsulate the state and the XQuery 3.0 higher-order function `fold-left(..)` [3], but you could use your own recursive function instead of the latter to iterate over the child nodes and pass the state along. Hope this helps, cheers, Leo [1] http://en.wikipedia.org/wiki/File:MapGermanyGraph.svg [2] http://docs.basex.org/wiki/Map_Module [3] http://docs.basex.org/wiki/Higher-Order_Functions#Folds
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