title: What is trailing closure syntax in Swift?
body: <p>Swift's <a href="https://docs.swift.org/swift-book/LanguageGuide/Closures.html#//apple_ref/doc/uid/TP40014097-CH11-ID102" rel="noreferrer">documentation on closures</a> states:</p>
  
  <blockquote>
    <p>Swift’s closure expressions have a clean, clear style, with optimizations that encourage brief, clutter-free syntax in common scenarios. These optimizations include:</p>
    
    <ul>
    <li>Inferring parameter and return value types from context</li>
    <li>Implicit returns from single-expression closures</li>
    <li>Shorthand argument names</li>
    <li><strong>Trailing closure syntax</strong></li>
    </ul>
  </blockquote>
  
  <p>What exactly is "trailing closure syntax" for Swift closures?</p>