PHP：preg_replace（），`e`-modifier和object

Question

I'm writing a method which returns an function argument by its number.

protected function parseArgs($str, $args)
{
    return preg_replace('|#(\d)|e', '$args[\\1 - 1]', $str);
}

$str - a string with '#N' where N is a number of argument $args - array of arguments

So if i write '#1' - it returns $arg[0], the first argument. It works with string arguments, integers... But don't work with object as argument. In returns string Object. How do i get the object with this function?

Answer 1

You cannot get it to work like that, because preg_replace always returns a string. In fact this version also fails to preserve the type of all other non-string values, which means that after parseArgs is called you cannot distinguish between e.g. null, false and '' as values.

That said, what is the purpose of this function anyway? Why would I write this

$args = ('foo', 'bar');
$value = parseArgs('#1', $args);

instead of this?

$args = ('foo', 'bar');
$value = $args[0];