I have a code for dynamic tree view using php mysql.

```
function fetchCategoryTreeList($parent = '', $user_tree_array = '') 
{
  // code here 
}

```

i just want ...like. i have a variable 

```
$top = '1234';

```

now how to put in this function like

```
function fetchCategoryTreeList($parent = $top, $user_tree_array = '') 
{
  // code here 
}

```

if i put $top in this function then i got fatal error. Please help me