title: How is optional binding used in swift?
body: <p>In swift the following syntax is allowed for flow  control</p>
  
  <pre><code>if let constantName = someOptional {
      statements
  }
  </code></pre>
  
  <p>In this context <strong>what are the semantics of the truth value context</strong> ? </p>
  
  <p>Is <strong>expression chaining</strong> (like below) permitted ? </p>
  
  <pre><code>if let constantName = someOptional &amp;&amp;  constantName2 = someOptional2 {
      statements
  }
  </code></pre>
  
  <p>If so, does the boolean expression short circuit ? </p>