Arr.php

<?php

class Arr
{
	static function get($arr, $keys = null, $default = null)
	{
		if (is_null($keys))
			return $arr;
		foreach((array)$keys as $k)
		{
			# We expect an array because we are given a key to extract
			if (!is_array($arr) || !array_key_exists($k, $arr))
				return $default;
			$arr = $arr[$k];
		}
		return $arr;
	}

	static function clear(&$arr, $keys)
	{
		if (is_array($arr) && !is_null($keys))
			foreach((array)$keys as $k)
				unset($arr[$k]);
	}

	static function hasKeys($arr, $keys)
	{
		if (!is_array($arr) || is_null($keys))
			return false;
		foreach((array)$keys as $k)
			if (!array_key_exists($k, $arr))
				return false;
		return true;

	}

	/*static function test()
	{
		$a = array('x' => 'x-value', 'y' => 'y-value');
		$aCleared = array('y' => 'y-value');
		$bInner = array('y1' => 'y1-value', 'y2' => 'y2-value');
		$b = array('x' => 'x-value', 'y' => $bInner);

		$tests = array(
			array('get', array($a, null, 3), $a),
			array('get', array($a, 'x', '~'), 'x-value'),
			array('get', array($a, 'y', '~'), 'y-value'),
			array('get', array($a, 'z', '~'), '~'),
			array('get', array($b, 'y', '~'), $bInner),
			array('get', array($b, array('y', 'y2'), '~'), 'y2-value'),
			array('get', array($b, array('y', 'z'), '~'), '~'),
			array('get', array($b, array('y', 'y1', 'z'), '~'), '~'),

			array('clear', array($a, 'x'), null, array(0 => $aCleared)),
			array('clear', array($a, array('x')), null, array(0 => $aCleared)),
			array('clear', array($a, array('x', 'y')), null, array(0 => array())),
			array('clear', array($a, 'z'), null, array(0 => $a)),

			array('hasKeys', array($a, null), false),
			array('hasKeys', array($a, 'x'), true),
			array('hasKeys', array($a, array('x', 'y')), true),
			array('hasKeys', array($a, array('x', 'y', 'z')), false),
			array('hasKeys', array($a, 'z'), false),
		);

		foreach($tests as $ind => $t)
		{
			$paramsValues = array_values($t[1]);
			$params = array(); # copy
			foreach($paramsValues as $key => &$value)
				$params[$key] = &$value;
			$paramsJson = json_encode($params);
			$res = call_user_func_array(array(__CLASS__, $t[0]), $params);
			if ($res != $t[2])
				return 'Error in test #' . $ind . "(zero-based)\n"
					. $t[0] . '( ' . substr($paramsJson, 1, strlen($paramsJson) - 2) . " )\n"
					. 'Result: ' . json_encode($res) . "\n"
					. 'Expected: ' . json_encode($t[2]);
			if (array_key_exists(3, $t)) # check input parameters
				foreach($t[3] as $i => $expectedParamValue)
					if ($params[$i] != $expectedParamValue)
						return 'Error in test #' . $ind . "(zero-based)\n"
						. $t[0] . '( ' . substr($paramsJson, 1, strlen($paramsJson) - 2) . " )\n"
						. 'After call, parameter #' . $i .' (zero-based) is expected to be' . json_encode($expectedParamValue) . "\n"
						. 'Actual parameter value: ' . json_encode($params[$i]);
		}

		return 'OK';
	}*/
}

#echo Arr::test();