Why is the output of `echo true ? 'a' : true ? 'b' : 'c';` 'b'?
<p>I have this bit of PHP code:</p>

<pre><code>echo true ? 'a' : true ? 'b' : 'c';
</code></pre>

<p>The output of this is:</p>

<blockquote>
  <p>b</p>
</blockquote>

<p>But the output I expected was:</p>

<blockquote>
  <p>a</p>
</blockquote>
