title: Shortcode Attribute Containing Bracket Issue
body: <p>The <a href="http://codex.wordpress.org/Shortcode_API" rel="noreferrer">Shortcode API</a> states that you can't have square brackets in your attribute. Thus, the following would not work:</p>
  
  <pre><code>[tag attribute="[Some value]"]
  </code></pre>
  
  <p>In my case, the square bracket is required. What would be the best solution of getting around this problem? I've already tried escaping the content in my shortcode function, but had no luck.</p>
  
  <p>I am using WordPress 3.3.1.</p>