Re: [NTG-context] xml in lua: how to say "ancestor"?

25 Feb 2017


      On 2/25/2017 5:18 PM, Thomas A. Schmitz wrote:
...
Hi all,
no real example, just snippets, sorry: I need to process xml documents
in lua (because I want to collect information in tables). The structure
is a bit irregular:
<document>
  <chapter title="One">
    <section title="One">
      <subsection title="One">
    Text
      </subsection>
    </section>
  </chapter>
  <chapter title="Two">
    <subsection title="One">
      Text
    </subsection>
  </chapter>
</document>
So chapters may or may not have sections. If, on the level of my
subscetions, I want to extract the information of the chapter title, in
a ConTeXt environment, I could say
\xmlattribute{#1}{ancestor::chapter}{title}. How could I do the same in
lua? I have something like
xml.attribute(e, "../../chapter", "title", "")
but that only works for the first case, not the second one. I tried to
understand the lpegs in lxml-lpt.lua, but didn't succeed.
Thanks, and best wishes
\starttext
\startbuffer[test]
<document>
   <chapter title="OneC">
     <section title="OneS">
       <subsection title="OneSS">
     Text
       </subsection>
     </section>
   </chapter>
   <chapter title="TwoC">
     <subsection title="OneSS">
       Text
     </subsection>
   </chapter>
</document>
\stopbuffer

\startxmlsetups xml:test:setups
     \xmlsetsetup{\xmldocument}{*}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:test:setups}

\startxmlsetups xml:document
     \xmlflush{#1}
\stopxmlsetups
\startxmlsetups xml:chapter
     \blank[2*big] CHAPTER: \xmlattribute{#1}{.}{title}\blank
     \xmlflush{#1}
\stopxmlsetups
\startxmlsetups xml:section
     \blank SECTION: \xmlattribute{#1}{.}{title} \blank\relax
     (previous:\xmlattribute{#1}{..[tag()='chapter']}{title})
     \blank
     \xmlflush{#1}
\stopxmlsetups
\startxmlsetups xml:subsection
     \blank SUBSECTION: \xmlattribute{#1}{.}{title} \blank\relax
     \blank
     (previous:\xmlattribute{#1}{..[tag()='section' or 
tag()='chapter']}{title})
     \blank
     \xmlflush{#1}
\stopxmlsetups

\xmlprocessbuffer{main}{test}{}

\stoptext

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