hierarchy system in mysql with php

[eluser]FutureKing[/eluser]
Thank you very much.

One more thing I want to ask;

Please look at the code below:

Code:

function index()
    {
        $this->load->model('MPTtree');
        $this->MPTtree->set_opts(array( 'table' => 'orgchart',
        'left' => 'lft',
        'right' => 'rgt',
        'id' => 'catid',
        'title' => 'member'));
        $tree = $this->MPTtree->tree2array();    
        $this->doit($tree);
    }
    function doit($tree,$prev_text=''){                
        foreach($tree as $node){                        
            if($prev_text!=''){
                echo $prev_text.$node['member'];                
            }else{
                echo $node['member'];
            }
            echo "<br />";
            //echo $node['lft'].'<br />';
            
            if(isset($node['children'])){
                $prev_text=$prev_text.$node['member'].'--';
                $tree=$node['children'];
                $this->doit($tree,$prev_text);
            }
        }
        $prev_text='';        
    }

The above code generates the following output from tree2array() method:
albert
albert--A child!
albert--bert
albert--chuck
albert--chuck--donna
albert--chuck--eddie
albert--chuck--fred

I just want to ask, I am using $this->doit($tree,$prev_text); from doit() function.
Is it ok to call any function from inside of itself?

If not then Is there any alternative way to get the same output?