the problem i want to solve is the dynamic creation of a hashed tree from the result of a database query. i tried to solve it with arrays only the success was minor. what i need is a tree of the following scheme:

root
    => node1
    => node2
        => node2.1
        => node2.2
    => node3
[download]

the problem is that the structure has no defined depth. and btw, though it looks like another forum aproach it isn't. :)

here is what i tried:

    for (my $i=0; $i < $counter; $i++)
    {
        my $result = $sth->fetchrow_hashref ();
        # root node
        if (scalar @path == 0)
        {
            $offset = $result->{'lvl'} - 1;
            push @path, $result->{'payload'};
            push @tree, $result->{'payload'};
            next;
        }   
        # child node
        else
        {
            # going down (one step only)
            if (($result->{'lvl'} - $offset) > scalar @path)
            {
                my $last = $path[$#path];
                push @path, $result->{'payload'};
                push @{$tree[$#path][0]}, $result->{'payload'};
                $a_counter = 0;
            }
            # same level
            elsif (($result->{'lvl'} - $offset) == scalar @path)
            {
                my $last = $path[$#path -1];
                push @{$tree[$#path][$a_counter]}, $result->{'payload'
+};
                $a_counter++;
            }
            # going up
            else
            {
                my $steps = scalar @path - $result->{'lvl'} + ($offset
+ -1);
                $#path = $steps;
                push @path, $result->{'payload'};
                my $last = $path[$#path];
                push @{$tree[$#path][0]}, $result->{'payload'};
                $a_counter = 0;
            }
        }
[download]

the result as you may figure out is a array with tree arrays in it without assotiation to the parent.
the database structure is a nested set as found at celko's "sql for smarties", just modified to have more smaller trees instead of one giant one to speed up inserts.