How to get current recursion level in a PHP function

Question

How to get current recursion level in a PHP function ? I mean, is there any \"magical\" (or eventually normal) function like this :

function doSomething($thi         


        

Answer 1

You need to count it yourself, the only alternative would be something like XDebug which profiles your complete software. But this is highly inefficient.

<?php

function my_recursive_fn($param) {
    static $counter = 0;
    if (is_array($param)) {
        ++$counter;
        foreach ($param as $k => $v) {

        }
    }
    else {
        echo $counter;
        --$counter;

        // If we're returning (only PHP 5.5+)
        try {
            return $counter;
        }
        finally {
            --$counter;
        }
    }
}

?>

This allows you to count without a second public parameter.

Answer 2

In java you can inspect the call stack. I think you can do the same in php:

debug-backtrace Is this the one you are looking for?

Since php does not optimize recursion with tail calls this should tel you the depth of the recursion.

Answer 3

    function doSomething($things) {
static $level = 0;
    if (is_array($things)) {
        foreach ($things as $thing) {
$level++;
            doSomething($thing);
        }
    } else {
        // This is what I want :
        echo $level
    }
}

Answer 4

private function select($modules, $level = 0)
{
    $return_html = '';
    $level_html = '';
    $new_level = 0;
    
    foreach($modules as $module)
    {
        $repeat = str_repeat('     ', $level);
        
        if(!empty($module['children']))
        {
            $return_html .= '<option>'.$repeat.' '.$module['title'].'</option>';
            
            $new_level = $level+1;
            
            $return_html .= $this->select($module['children'], $new_level);
        }
        else
        {
            
            $return_html .= '<option>'.$repeat.' '.$module['title'].'</option>';
        }
    }
    
    return $return_html;
}

Answer 5

If you are just looking to avoid hitting PHP's 100 level recursion limit then

count(debug_backtrace()); 

should be sufficient. Otherwise you've no choice to pass a depth argument, though the precrement operator makes it somewhat cleaner as seen in the example below.

function recursable ( $depth = 0 ) {
  if ($depth > 3) {
    debug_print_backtrace();
    return true;
  } else {
    return recursable( ++$depth );
  }
}