Why it's impossible to throw exception from __toString()?

Question

Why it\'s impossible to throw exception from __toString()?

class a
{
    public function __toString()
    {
        throw new Exception();
    }
}

$a = new          


        

Answer 1

My guess would be that __toString is hackish and therefore exists outside of the typical stack. A thrown exception, then, wouldn't know where to go.