Multi null checking
<p>Is there any more efficient,cleaner and shorter form for following:</p>

<pre><code>if($x==null or $y==null or $z==null or $w==null) return true;
</code></pre>

<p><strong>In general how can I also get name of null variables?</strong></p>

<pre><code>function any_null(array $a){
    foreach($a as $v) if ($v==null) return //variable name;
    return false;
}
var_dump(any_null(array($x,$y,$z,$w)));
</code></pre>
