#!/usr/bin/perl
use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use XML::LibXML 2;

my $x = XML::LibXML::->load_xml(string => <<'END');
<classes name="Panoply::BAR">
  <public_methods>
	 <members name="BAR" const="no" kind="function" protection="public" static="no" virtualness="non_virtual" volatile="no">
		<parameters declaration_name="pciReg" type="Register::Ptr" />
	 </members>
  </public_methods>
  <enums>
	 <members name="ObjectState" kind="enum" protection="public" static="no" virtualness="non_virtual">
		<values name="NEW">
		</values>
		<values name="REFRESHED">
		</values>
		<values name="DIRTY">
		</values>
	 </members>
  </enums>
</classes>
END

sub _universal_find {
	my $text = shift;
	join '|',
		"//$text",               # Element name
		"//*/\@$text",           # Attribute name
		"//*/text()[.='$text']", # Element contents
		"//*/\@*[.='$text']",    # Attribute value
}

my $coolNodeName = sub { ($_[0]->isa('XML::LibXML::Attr')?'@':'').$_[0]->nodeName };

for my $text (qw[ parameters pciReg DIRTY ])
{
	say "Search for '$text'...";
	for my $node ($x->findnodes( _universal_find($text) ))
	{
		say join ' => ',
			$node->findnodes("ancestor::*")->map(sub { $coolNodeName->($_) }),
			$coolNodeName->($node),
	}
	say "";
}

__END__
Search for 'parameters'...
classes => public_methods => members => parameters

Search for 'pciReg'...
classes => public_methods => members => parameters => @declaration_name

Search for 'DIRTY'...
classes => enums => members => values => @name