MongoDB array tools (assoc <-> object consversions)

mongo-array-tools.php

<?php
class mongo_tools {
	public static function assoc2obj($a){
		self::assoc2objects_inplace($a);
		return $a;
	}

	public static function obj2assoc($o){
		self::objects2assoc_inplace($o);
		return $o;
	}

	public static function assoc2objects_inplace(&$a){
		if(!is_array($a)) return;
		if(count($a)===0) return;
		foreach ($a as $key => &$value) {
			self::assoc2objects_inplace($value);
		}
		if(!array_key_exists(0, $a)) $a = (object)$a;
	}

	public static function objects2assoc_inplace(&$a){
		if(is_object($a)){
			if(get_class($a)==='stdClass') 
				$a=(array)$a;
			else
				return;
		}
		if(!is_array($a)) return;
		if(count($a)===1 && array_key_exists('$id', $a)){
			$a = new MongoId($a['$id']);
			return;
		}
		foreach ($a as $key => &$value) {
			self::objects2assoc_inplace($value);
		}
	}
}

$o=mongo_tools::assoc2obj(['A'=>['B'=>1337]]);
$a=mongo_tools::obj2assoc($o);
var_dump($a);