The OOP version of https://igor.io/2014/01/08/functional-library-traversal.html for ghits and shiggles.

Traverse.php

<?php
class Traverse implements ArrayAccess {
	protected $container;

	function __construct($array) {
		$this->container = $array;
	}
	public function offsetExists($offset) {
		return isset($this->container[$offset]);
	}
	public function offsetGet($offset) {
		if (isset($this->container[$offset])) {
			if (is_array($this->container[$offset])) {
				$this->container[$offset] = new Traverse($this->container[$offset]);
			}

			return $this->container[$offset];
		}

		return null;
	}

	public function offsetSet($offset, $value) {
		if (is_null($offset)) {
			$this->container[] = $value;
		} else {
			$this->container[$offset] = is_array($value) ? new Traverse($value) : $value;
		}
	}
	public function offsetUnset($offset) {
		unset($this->container[$offset]);
	}

	public function __get($offset) {
		return $this->offsetGet($offset);
	}
}

class JSONTraverse extends Traverse {
	function __construct($json, $assoc = false, $depth = 512, $options = 0) {
		if (PHP_VERSION_ID < 50400) {
			parent::__construct((array)json_decode($json, $assoc, $depth));
		} else {
			parent::__construct((array)json_decode($json, $assoc, $depth, $options));
		}
	}

	public function offsetGet($offset) {
		if ($this->container[$offset] instanceof stdClass) {
			$this->container[$offset] = (array)$this->container[$offset];
		}
		return parent::offsetGet($offset);
	}
}

$data     = array('a'=>'-a','b'=>'-b','c' => array('x'=>-1,'y'=>-2,'z'=>-3), 'd'=>'-d');
$jsonData = '{"a":"-a","b":"-b","c":{"x":-1,"y":-2,"z":-3},"d":"-d"}';

echo "Array Traverse\n";
echo "--------------\n";
$t = new Traverse($data);

var_dump($t['c']['x']);
var_dump($t['c']['x']['y']);
var_dump($t->c->x);
// NOTICE - can't get 'y' index of integer value -1
var_dump($t->c->x->y);

echo "\nJSON Traverse\n";
echo "-------------\n";
$t = new JSONTraverse($jsonData);

var_dump($t['c']['x']);
var_dump($t['c']['x']['y']);
var_dump($t->c->x);
// NOTICE - can't get 'y' index of integer value -1
var_dump($t->c->x->y);

echo "\igor.io test\n";
echo "-----------\n";
$data = array(
	'foo' => array(
		'bar' => array(
			'baz' => 'Ya got me!'
		)
	)
);

$t = new Traverse($data);

var_dump($t['foo']['bar']['baz']);