title: Can swift closures be set to a default value when used as a parameter in a function?
body: <p>A pretty handy feature of Swift functions is that function parameters can have <a href="https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Functions.html" rel="noreferrer">default values</a>:</p>
  
  <pre><code>func someFunction(parameterWithDefault: Int = 42) {
      //if no arguments are passed to the function call,
      //value of parameterWithDefault is 42
  }
  </code></pre>
  
  <p>If a parameter is a closure, is there a way to make it have a default value? See the example below:</p>
  
  <pre><code>func sendBody(
      body: NSData? = nil,
      success: (data: NSData) -&gt; Void,
      failure: (data: NSData?) -&gt; Void) {
  }
  </code></pre>
  
  <p>Is there a way to not force the developer to pass a value for <code>success</code> or <code>failure</code> when calling <code>sendBody</code>?</p>