title: How can a string be both callable and a string?
body: <p>I have the following, very weird, code:</p>
  
  <pre><code>$var = 'key';
  
  var_dump(is_callable($var)) // true;
  var_dump(is_string($var)) // true;
  </code></pre>
  
  <p>How can one variable be both callable and a string? And when I set the <code>$var</code> variable to another string. <code>is_callable()</code> will return <code>false</code> (what I think is normal behavior).</p>
  
  <p>What is going on here? Why is this?</p>
  
  <p>Thank you in advance.</p>