Subject: RE: [xsl] Matching a recursive local element structure From: "David Lee" <dlee@xxxxxxxxxxx> Date: Fri, 4 Feb 2011 20:27:51 -0500 |
Everything is checked into sourceforge but its giving me network errors now (under https://xmlsh.svn.sourceforge.net/svnroot/xmlsh/extensions/json, This URl is giving me network errors http://xmlsh.svn.sourceforge.net/viewvc/xmlsh/ But I dont recommend it ... its quite complex and large. I'm not really asking for people read or write this for me ... or analyze the code. (if you did it would be awesome ! but its a challenging task) .. The basic concept is I'm extracting from the XSD using Apache schema API a 'minimal' description of the element structure, then using xquery attempting to produce match expressions for each element (and attribute) declaration and trying to avoid infinite recursion. Its amazingly non-trivial. Which is why I'm asking for is abstract ideas ... and of course willing to accept abstract answers ... or none of course ... I'm not asking for a solution just hoping maybe a suggestion on paths to explore. It just 'seems like its such an obvious problem' that people would have run into it before and just know if off the top of their heads ... I'm hoping there is a 'simple pattern' that match expressions might 'match up' with XSD structures in an 'obvious' way ... But alas I suspect that may be asking too much. My next thought is this might be best solved with a schema-aware xslt expression, but in the general case these may not be types, just recursive references. Recursion is fun ! ---------------------------------------- David A. Lee dlee@xxxxxxxxxxx http://www.xmlsh.org -----Original Message----- From: Brandon Ibach [mailto:brandon.ibach@xxxxxxxxxxxxxxxxxxx] Sent: Friday, February 04, 2011 8:14 PM To: xsl-list Subject: Re: [xsl] Matching a recursive local element structure Can we see the code you have so far? It'd be a lot easier to address specific issues in existing code than to philosophize about an abstract approach. -Brandon :) On Fri, Feb 4, 2011 at 8:06 PM, David Lee <dlee@xxxxxxxxxxx> wrote: > Thanks for the ideas (all!) > Let me restate my question maybe it might lead to another idea (I'm still > floundering !) > > For every element declaration in an XSD I would like to generate a unique > XSLT match expression that matches that element declaration (but no others). > I've got it working quite well for both global and local elements until I > hit a recursive structure then well ... it recurses :) > > Thanks for any suggestions ! > > I *feel* this should be solvable because while the structure are infinitely > recursive, each level of the recursion matches the same element declaration > so shouldnt have to be unrolled ... I just cant yet get my head around a > match expression to catch it right. > > But maybe its not finitely solvable ? > > > > ---------------------------------------- > David A. Lee > dlee@xxxxxxxxxxx > http://www.xmlsh.org > > > -----Original Message----- > From: Brandon Ibach [mailto:brandon.ibach@xxxxxxxxxxxxxxxxxxx] > Sent: Friday, February 04, 2011 7:44 PM > To: xsl-list > Subject: Re: [xsl] Matching a recursive local element structure > > > Perhaps this approach is not as generic as you may have had in mind, > but for this case, I think it would work. > > <template match=section/text//list/item[not(ancestor::subheading)] > > > -Brandon :) > > > On Fri, Feb 4, 2011 at 7:01 PM, David Lee <dlee@xxxxxxxxxxx> wrote: >> Suppose I have a schema which describes a recursive structure as local >> elements. >> Example (pseudo DTD, and pseudo xml I can provide more formal defs if > needed >> ) >> >> Element section (text)* >> Element text ( list | para | bold | #PCDATA )* >> Element list ( item*) >> Element item ( text | subheading ) * >> Element subheading (text)* >> >> So for example doc may look like >> >> <section> >> <text>Text >> <list> >> <item><para>Item Text</para></item> >> <item><para>Item Text2</para></item> >> <item><para>Item Text</para> >> <list><item><para>More text> </item></list></para></item> >> </list> >> </text> >> </section> >> >> >> The key point is that the schema is recursive, so an xpath (or xslt match) >> might be >> >> section/text >> section/text/list/item/para >> >> section/text/list/item/list/item/list/item/list/item/list/item . Can get >> really long here !!!! >> >> >> >> Now suppose I want to avoid an infinite number of XSLT match strings but I >> want to match say list/item but ONLY within section/text >> (presume there may be a different list/item locally defined within say >> subheader) >> >> >> Suggestions on to a good way to do that ? >> >> <template match=section/text//list/item > >> >> But this might match >> section/text/subheading/list/item >> or >> section/text/list/item/subheading/list/item >> >> >> which I dont want. >> >> I only want to match the list/item which is a local element definition >> below section (recursively),. >> so the match should select >> section/text/list/item/list/item/list/item >> but not >> section/text/list/item/subheading/list/item >> >> ( which I would say match with >> subheading/list/item >> subheading/list/item/list/item >> ) >> >> >> Is there an obvious way to do this ? >> Its entirely possible that Im asking an impossible question (that is the >> schemas may simply not allow this restriction in the first place), >> But Im trying to solve a general problem so asking a general question. >> >> This is based on generating match strings from XSD element declarations so >> its really a XSD question as well >> Maybe its impossible to describe a schema such that a descendant > list/item >> is distinguishable if its under section or subheading ? >> >> Thanks for any suggestion ! >> >> >> -David >> >> ---------------------------------------- >> David A. Lee >> dlee@xxxxxxxxxxx >> http://www.xmlsh.org >> >> >> >> ---------------------------------------- >> David A. Lee >> dlee@xxxxxxxxxxx >> http://www.xmlsh.org
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