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.

In reply to dynamic hashed tree by norbu09

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