mongodb in codeigniter, debug problem

in some_code.php

$query = new MongoCode('
    function (index, val开发者_StackOverflowue){
        .... 
         // I need to check some value of some_variable in here
         // etc ) some_variable = 1 or "abc"
        ....
    }
');
$run = $this->db->command($query);

How could I print mongodb variables in php?

var_dump() is always your friend.