title: How to get NSLayoutConstraint's identifier by Its pointer?
body: <p>I setup in Storyboard <code>identifier</code> for each constraint:</p>
  <p><a href="https://i.stack.imgur.com/QlEh5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QlEh5.png" alt="enter image description here" /></a></p>
  <p>Now I get error with <code>unsatisfiable constraints</code>. I try to debug this by printing constraint's pointer:</p>
  <pre><code>po 0x17db78d0
  </code></pre>
  <p>Now to order investigate what constraint it is, I would like to print its <code>identifier</code> just like:</p>
  <pre><code>po 0x17db78d0.identifer.
  </code></pre>
  <p>...but it is not working. I get an error:</p>
  <blockquote>
  <p>error: hexadecimal floating constants require an exponent</p>
  <p>error: 1 errors parsing expression</p>
  </blockquote>
  <p>Hence, how to print identifier for specific <code>NSLayoutConstraint</code>?</p>