<html><body><div>But if the closure can escape it is difficult to guarantee that it is executed at all (e.g. in your examples such as dispatch_async).<br></div><div><br data-mce-bogus="1"></div><div>-Thorsten<br data-mce-bogus="1"></div><div><br>Am 29. Januar 2016 um 11:58 schrieb Brent Royal-Gordon via swift-evolution <swift-evolution@swift.org>:<br><br><div><blockquote type="cite"><div class="msg-quote"><div class="_stretch"><span class="body-text-content"><blockquote type="cite" class="quoted-plain-text">You are right Jacob, a modifier `@noescape(once)` would be better, as it would help compiler distinguish between assignment and initialization of captured variables.</blockquote><blockquote type="cite" class="quoted-plain-text"><br></blockquote><blockquote type="cite" class="quoted-plain-text">The utility of such a new feature is maybe tiny, but clear: it extends the opportunities to declare variables before initializing them. The Swift 1 to 2 transition has already extended those opportunities, so we’re just following an existing trend, here.</blockquote><br>I actually think that `once` is orthogonal to `noescape`. There are a *lot* of closures that are not noescape, but are called exactly once, such as dispatch_async and most completion handlers.<br><br>-- <br>Brent Royal-Gordon<br>Architechies<br><br>_______________________________________________<br>swift-evolution mailing list<br><a href="mailto:swift-evolution@swift.org" data-mce-href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a><br><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" data-mce-href="https://lists.swift.org/mailman/listinfo/swift-evolution">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br></span></div></div></blockquote></div></div></body></html>