#!/usr/bin/perl
# recurse.pl -- Aid to Parse::RecDescent builders
use warnings;
use diagnostics;
use Data::Dumper;

my @data = (
    'level0', ['level1','(',['level2',['level3','line1','line2','line3']]]
);

print Dumper @data,"\n";
recurse (\@data);

sub recurse {
    my $tree        = shift;
    my $indent      = shift;
    my $level_count = shift;
    my $count       = 0;

    unless ( defined($indent) ) {
        $indent = 0;
    }
    unless ( defined($level_count) ) {
        $level_count = "";
    }

    foreach (@$tree) {
        if ( ref eq 'ARRAY' ) {
            printf( "%40s |%s[\n", sprintf( "%s%s", $level_count, $count ),
              '.' x $indent );
            recurse( $_, $indent + 2, $level_count . "$count." );
            $count++;
            printf( "%40s |%s]\n", " ", '.' x $indent );
        }
        else {

            if ( !defined($_) ) {
                printf( "%40s |%s%s\n",
                  sprintf( "%s%s", $level_count, $count++ ), '.' x $indent,
                  "!Undefined!" );
            }
            elsif ( $_ eq "" ) {
                printf( "%40s |%s%s\n",
                  sprintf( "%s%s", $level_count, $count++ ), '.' x $indent,
                  "!NULL!" );
            }
            elsif ( $_ eq "\n" ) {
                printf( "%40s |%s%s\n",
                  sprintf( "%s%s", $level_count, $count++ ), '.' x $indent,
                  '\\n' );
            }
            else {
                printf( "%40s |%s%s\n",
                  sprintf( "%s%s", $level_count, $count++ ), '.' x $indent,
                  $_ );
            }
        }
    }
}

##</code><code>##

$>recurse
$VAR1 = 'level0';
$VAR2 = [
          'level1',
          '(',
          [
            'level2',
            [
              'level3',
              'line1',
              'line2',
              'line3'
            ]
          ]
        ];
$VAR3 = '
';
                                       0 |level0
                                       1 |[
                                     1.0 |..level1
                                     1.1 |..(
                                     1.2 |..[
                                   1.2.0 |....level2
                                   1.2.1 |....[
                                 1.2.1.0 |......level3
                                 1.2.1.1 |......line1
                                 1.2.1.2 |......line2
                                 1.2.1.3 |......line3
                                         |....]
                                         |..]
                                         |]