use strict;
use warnings;
use Data::Dumper;

# test data
my $data = {
    test  => {
        foo => { bar => 'bar',
                 baz => 'baz',
                 bul => { foo => { bar => 'bul' } } },
        bar => { baz => 'baz' },
    },
    foo => { bar => 'foo' },
};

my $found = rec_data('->{foo}->{bar}', $data);
print Dumper($found);

print "--- array of ref's ---\n";
print "$_\n" for @$found;

# verify by hand
print "--- verify by hand ---\n";
print \$data->{foo}->{bar}, "\n",
      \$data->{test}->{foo}->{bar}, "\n",
      \$data->{test}->{foo}->{bul}->{foo}->{bar}, "\n";



sub rec_data
{
    my ($pattern, $data) = @_;
    return if ref($data) ne 'HASH';

    my @keys = keys %$data; # persist the value of the keys
    return if !@keys;

    my @found;

    # do we see pattern?
    if (eval 'exists $data' . $pattern) {
        push @found, eval '\$data' . $pattern;
    }

    # traverse the 'children'
    # foreach (keys %$data) will not work and will result
    # in deep recursion
    foreach (@keys) {       # get the value of each key
        my $result = rec_data($pattern, $data->{$_});
        next if ! $result;
        push @found, @$result;
    }

    return(\@found);
}
[download]

$VAR1 = [
          \'foo',
          \'bar',
          \'bul'
        ];
--- array of ref's ---
SCALAR(0x167bdc)
SCALAR(0x167b4c)
SCALAR(0xf4a50)
--- verify by hand ---
SCALAR(0x167bdc)
SCALAR(0x167b4c)
SCALAR(0xf4a50)
[download]