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.send { color:#77bb77; }
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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>I’m slightly confused by this. How is a trailing closure different from a code block in Swift? It’s basically the same thing with some extra syntax sugar because it happens to be the last parameter of your function.</p>
<p>You can simply write this if you wanted to:</p>
<pre><code class="swift">myFucntion(someLabel: abc, closureLabel: { …; return })
</code></pre>
<p>Parentheses are indicating that your closure is immediately invoked.</p>
<pre><code class="swift">let someInt = { return 42 }()
print(someInt)
let someClosureWhichReturnsAnInt = { return 42 } // You can reuse the closure
print(someClosureWhichReturnsAnInt()) // Invocation happens now here
</code></pre>
<p><code>return</code> is scope based and it’s totally clear (to me) that in your case <code>return</code> will return from your closure with a value of <code>Void</code>.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1489575108947471104" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 15. März 2017 um 11:35:39, Rien via swift-evolution (<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>What does the following code fragment do?<br><br>serverCert.write(to: certificateUrl) { showErrorInKeyWindow(message); return }<br><br>The only possible answer is: I don’t know.<br><br>The problem is finding out what the “return” statement will do.<br><br>Without knowing if the {...} is a code block or a trailing closure it is impossible to know what the return statement will do. It will either end the closure or it will end the function that contains this code block.<br><br>This could be disambiguated by using the same syntax as for lazy variables:<br><br>serverCert.write(to: serverCertificateUrl) { showErrorInKeyWindow(message: message); return }()<br><br>Now it is clear that the return statement will only terminate the (trailing) closure.<br><br>A question to the educators on the list: Is this a real problem?<br><br>Personally, I dislike this situation, but I am also ambivalent towards the solution I just described.<br><br>Regards,<br>Rien<br><br>Site: http://balancingrock.nl<br>Blog: http://swiftrien.blogspot.com<br>Github: http://github.com/Balancingrock<br>Project: http://swiftfire.nl<br><br><br><br><br><br>_______________________________________________<br>swift-evolution mailing list<br>swift-evolution@swift.org<br>https://lists.swift.org/mailman/listinfo/swift-evolution<br></div></div></span></blockquote></div><div class="bloop_markdown"><p></p></div></body></html>