[NTG-context] How could I find the 'depth' of an element found with xml.first()?

[Hans Hagen]

On 6/18/2020 3:24 PM, Gerben Wierda wrote:
> Given the following XML snippet
> 
> 	<opa id=“opa">
> 		<Foo name="SubFoo Level One" id="Foo">
> 			<Foo name="SubFoo Level Two" id="Foo_2">
> 				<bar id="Bar" name="A Bar">
> 					<bar name="Bar Level Three" id="Bar_2">
> 						<Foo id="oma">OmaFoo</Foo>
> 					</bar>
> 				</bar>
> 				<Foo name="Fuzz Level Four" id="Fuzz"/>
> 			</Foo>
> 			<Foo name="SubFoo Level Two" id="Foo_3">
> 				<fuzz name="Fuzz" id="Fuzz_2"/>
> 			</Foo>
> 		</Foo>
> 	</opa>
> 
> 
> How would I go about to find the depth of an item found with an LPATH? E.g.
> 
> //[id="Foo_3"] would find a node at depth 2 (assuming <opa> is at level 0) while //[id=“Fuzz_2"] would find a node at depth 3 and in either cases I would like to get that number (2 or 3) as well as the actual node. I can assume the values for ‘id’  are unique.
> 
> I was wondering how I could go about finding the ‘depth’ of an item in the XML when using the LMTX built-in functions to work with XML. I don’t think there is a default function for that, is there?
You don't deserve an answer because this is not a MWE!

\startbuffer[test]
<something>
     <what>
         <what>
             here
         </what>
     </what>
</something>
\stopbuffer

\startxmlsetups xml:mysetups
     \xmlsetsetup{#1}{something|what}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:mysetups}

\startxmlsetups xml:something
     \xmlflush{#1}
\stopxmlsetups

\startluacode
     function xml.finalizers.tex.depth(t)
         local d = 0
         local t = t and t[1]
         while t do
             d = d + 1
             t = xml.parent(t)
             if not t then
                 break
             end
         end
         context(d)
     end
\stopluacode

\startxmlsetups xml:what
     \xmldoifelse {#1} {..[name() == "what"]} {
         YES
     } {
         NOP
     }
     [\xmlflush{#1}]
     (\xmlfilter{#1}{./depth()})
\stopxmlsetups

\starttext
     \xmlprocessbuffer{main}{test}{}
\stoptext

I might add it anyway (a faster variant that is),

Hans


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