Why is $M-; syntactically valid and what does it do?
<p>I don't consider myself as PHP expert but I've designed several pages now containing a couple of thousand lines of code each. For my current project which is for a game site I drew back on an existing function which contains the line</p>

<pre><code>$M–;
</code></pre>

<p>Now my basic understanding of PHP tells me this doesn't work since it should be -- for short -1. But it's not a dash, the script runs without error (<code>error_reporting (E_ALL)</code>) but echoing <code>$M</code> before and after gives me the same value.</p>

<p>So what does it do and why don't I get an error?</p>
