system/HTTP/Files/FileCollection.php
protected function getValueDotNotationSyntax(array $index, array $value)
	{
		if (is_array($index) && ! empty($index))
		{
			$current_index = array_shift($index);
		}
		if (is_array($index) && $index && is_array($value[$current_index]) && $value[$current_index])
		{
			return $this->getValueDotNotationSyntax($index, $value[$current_index]);
		}

		return (isset($value[$current_index])) ? $value[$current_index] : null;
	}
protected function getValueDotNotationSyntax(array $index, array $value)
	{
		if (is_array($index) && ! empty($index))
		{
			$current_index = array_shift($index);
		}
		if (is_array($index) && $index && is_array($value[$current_index]) && $value[$current_index])
		{
			return $this->getValueDotNotationSyntax($index, $value[$current_index]);
		}

		return (isset($value[$current_index])) ? $value[$current_index] : null;
	}
Navigate through a array looking for a particular index

@param array $index The index sequence we are navigating down
@param array $value The portion of the array to process

@return mixed