use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump pp);
use XML::Simple;

my $x = XMLin(<<'END');
  <files name="Common.h">
    <enums>
      <members kind="enum" name="PermissionLevel" protection="public" static="no" virtualness="non_virtual">
        <values initializer=" 99" name="PERMISSION_PUBLIC"></values>
        <values initializer=" 98" name="PERMISSION_NDA"></values>
      </members>
      <members kind="enum" name="RegisterType" protection="public" static="no" virtualness="non_virtual">
        <values initializer=" 4" name="REGISTER_PCI"></values>
      </members>
    </enums>
    <functions>
      <members const="no" kind="function" name="Compare" protection="public" static="no" type="bool" virtualness="non_virtual" volatile="no">
        <parameters declaration_name="first" type="T"/>
        <parameters declaration_name="second" type="T"/>
      </members>
    </functions>
  </files>
END

pp($x);

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 {say "@_"}, $x, "values";