Implementing `current()`

[Hipska]

I'm wondering why the current() function hasn't been implemented, and if it would make much time to do so.

I'm currently in the situation where I would need a query like //cd[@title=current()/@ref]. The node navigator used for the expression evaluate isn't the document root, but a previously selected node.

[Hipska]

@zhengchun?

[zhengchun]

current() is only supported by XSLT. You can try this //cd[@title=@ref]

[Hipska]

Doesn't that only select cd nodes of which title attribute equals their ref attribute?

Edit: wow that actually worked.. Thanks man!

[Hipska]

Scrap that, it seems it didn't work, it always picks the first one in this case: ../../measType[@p=@p] (as I would expect)

[zhengchun]

Hello, Need a sample document to test.

or try this ../../measType[@p]

[Hipska]

That gives the same result. Its strange, as I was really under the impression your solution first worked..

Anyway, this is a simplified version of the file:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="MeasDataCollection.xsl"?>
<measCollecFile xmlns="http://www.3gpp.org/ftp/specs/archive/32_series/32.435#measCollec">
	<measData>
		<managedElement localDn="foobar.example.com" />
		<measInfo measInfoId="metric_name">
			<measType p="1">field1</measType>
			<measType p="2">field2</measType>
			<measValue measObjLdn="identifier">
				<r p="1">31854</r>
				<r p="2">159773</r>
			</measValue>
		</measInfo>
		<measInfo measInfoId="metric_name2">
			<measType p="1">field3</measType>
			<measType p="2">field4</measType>
			<measValue measObjLdn="identifier">
				<r p="1">1234</r>
				<r p="2">567</r>
			</measValue>
		</measInfo>
	</measData>
</measCollecFile>

And the selected node is each time r, so I need an xpath to find out the field name of it.

[zhengchun]

like this //r[@p]/ancestor::measInfo/measType[@p]

//r[@p]/../../measType[@p]

[Hipska]

That's even worse, now all metrics have field name field1.

The Path is run on each r node. So I think only ../../measType[@p=current()/@p] would work..

[zhengchun]

using the nested query to solve. like this

for _,n:=range xmlquery.Find(doc,"//r[@p]")
{
    for _,nn:=range xmlquery.Find(n,`../../measType[@p='`+n.SelectAttr("p")+`']`){}
}

[Hipska]

Well, yeah. I can't change the code. I'm using telegraf: https://github.com/influxdata/telegraf/blob/6dc2b99549b3fc4684295ebcd2975cee96a1fa28/plugins/parsers/xpath/parser.go#L419-L447

[zhengchun]

I tested //r[@p=../../measType/@p] and it only return the first one node(expected matched 4 node but only gave 2), this is a bug.

[Hipska]

Indeed, see GO playground vs XPather. Can I help with trying to fix it?

Edit: And what should be the correct path be after the fix? ../../measType[@p] or ../../measType[@p=@p]?