Function recursivity versus variable scope

[lordofgore]

I need some advice on <post subject>

 

I am using recursivity to browse through some classes tree containing references. Mainly think of an object of class tree holding an array of references to another objects:

 

<?php

class tree {

var $name;

 

function __construct($leafname){

$this->name = $leafname;

}

 

function add_leaf ($leafname) {

$this->leafs[count($this->leafs)] = new tree($leafname);

}

}

 

What I want now is to search recursively through this tree for a particular name let's say and return the object:

 

function search_tree($obj, $search_string, $rec = false) {

global $ret;

if (!$rec) unset ($ret);

 

if ($obj->name == $search_string)

$ret = $obj;

 

if (isset($this->leafs))

foreach ($this->leafs as $leaf)

search_tree ($obj, $search_string, true);

 

if (!$rec) return $ret;

}

 

 

$root = populate_tree_from_db();

search_tree ($root, 'What string you want');

?>

 

Pretty straightforward I think, ok? The only problem is that the global variable $ret doesn't make it to the first recursion and the function doesn't return anything. I am sure I am missing something but don't know exactly what.

Can anybody help me?

 

Thank you in advance

 

 

[lordofgore]

I think I am missing something on variable scope and function recursivity.

I have rebuilt the functions like this:

 

function parse_tree($obj, $tpl_phase_id){

 

global $ret_srch;

global $lvl;

 

$lvl++;

print 'Lvl '.$lvl.': tpl_phase_id '.$tpl_phase_id.' vs. obj '.$obj->phase_info->name.'('.$obj->phase_info->tpl_phase_id.')<BR>';

print $ret_srch->phase_info->name.'<BR>';

if ($obj->phase_info->tpl_phase_id == $tpl_phase_id)

$ret_srch = $obj;

if (isset($obj->leafs))

foreach ($obj->leafs as $leaf)

parse_tree($leaf, $tpl_phase_id);

 

print 'Lvl: '.$lvl.' ret srch: '.$ret_srch->phase_info->name.'<BR>';

}

 

function search_tree ($obj, $tpl_phase_id) {

 

unset($ret_srch);

unset ($lvl);

 

print 'Searching for phase id '.$tpl_phase_id.'<BR>';

 

parse_tree($obj, $tpl_phase_id);

 

return $ret_srch;

}

 

$leaf1 = search_tree($root, $first_id)

 

print 'Obj? '.$leaf->phase_info->name;

 

$leaf2 = search_tree ($root, $second_id);

 

print 'Obj? '.$leaf->phase_info->name;

 

Output is:

 

Searching for phase id 16

Lvl 1: tpl_phase_id 16 vs. obj Project root()

 

Lvl 2: tpl_phase_id 16 vs. obj Aviz Urbanism(16)

 

Lvl: 2 ret srch: Aviz Urbanism

Lvl 3: tpl_phase_id 16 vs. obj Inca o etapa(20)

Aviz Urbanism

Lvl: 3 ret srch: Aviz Urbanism

Lvl: 3 ret srch: Aviz Urbanism

obj:

Dependinta: 19 - 16

searching for id ... 19

Searching for phase id 19

Lvl 4: tpl_phase_id 19 vs. obj Project root()

Aviz Urbanism

Lvl 5: tpl_phase_id 19 vs. obj Aviz Urbanism(16)

Aviz Urbanism

Lvl: 5 ret srch: Aviz Urbanism

Lvl 6: tpl_phase_id 19 vs. obj Inca o etapa(20)

Aviz Urbanism

Lvl: 6 ret srch: Aviz Urbanism

Lvl: 6 ret srch: Aviz Urbanism

Obj?

 

 

So not only the value doesn't return to the main code but inside the function parse_tree() the values of $lvl and $ret_srch are not destroyed when the function is ended and not even when search_tree is called again and both variables are unset.

 

What is the reason for this strange behaviour?

 

Thank you