Can someone tell me why the following cannot find the string "pciReg" but can find the strings in the other two calls that are commented out. 
#!/usr/bin/perl
use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump pp);
use XML::Simple;

my @list;
my $x = XMLin(<<'END', KeyAttr=>['declaration_name', 'name']);
  <classes name="Panoply::BAR">
    <public_methods>
      <members name="BAR" const="no" kind="function" protection="publi
+c" 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" stat
+ic="no" virtualness="non_virtual">
        <values name="NEW">
        </values>
        <values name="REFRESHED">
        </values>
        <values name="DIRTY">
        </values>
      </members>
    </enums>
  </classes>
END

sub r($$$;$);
sub r($$$;$)
 {my ($r, $l, $e, $a) = @_;
  $a = [] unless $a;
  return unless $l and ref($l); 
  if (ref($l) =~ /HASH/)
   {for(sort keys %$l)
     {unless (/$e/)
       {push @$a,  $_;
        r($r, $l->{$_}, $e, $a);
        pop @$a;
       }
      else
       {&$r(@$a);
       }
     } 
   } 
  elsif (ref($l) =~ /ARRAY/)
   {for(1..@$l)
     {unless ($l->[$_-1] =~ /$e/)
       {push @$a,  $_;
        r($r, $l->[$_-1], $e, $a);
        pop @$a;
       }
      else
       {&$r(@$a);
       }
     } 
   } 
 }

# r sub {push (@list, join(" => ", @_))}, $x, "parameters";
r sub {push (@list, join(" => ", @_))}, $x, "pciReg";
# r sub {push (@list, join(" => ", @_))}, $x, "DIRTY";
my $elist = join("\n", @list);
print "$elist\n";

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In reply to sub that finds ancestor elements by jccunning

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