<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 27, 2016, at 1:26 PM, Jordan Rose via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hey, all. An engineer at Apple noticed the following behavior:<div class=""><br class=""></div>1. class Foo: NSObject → exposed to Objective-C, Swift-style (mangled) runtime name<br class="">2. @objc class Foo: NSObject → exposed to Objective-C, Swift-style (mangled) runtime name<div class="">3. @objc(Foo) class Foo: NSObject → exposed to Objective-C, unmangled runtime name</div><div class=""><br class=""></div><div class="">(and 4. @objc class Foo → illegal, classes must have ObjC heritage to be @objc.)</div><div class=""><br class=""></div><div class="">They specifically observed that (1) and (2) have the same behavior, and suggested that maybe (2) should be shorthand for (3).</div><div class=""><br class=""></div><div class="">Pros:</div><div class="">- There aren't two ways to spell (1).</div><div class="">- Removing the mangling (and module uniquing) from the runtime name is probably one of the most common uses of @objc on a class.</div><div class=""><br class=""></div><div class="">Cons:</div><div class="">- It's a source-breaking change, for all that the "@objc" in (2) is redundant.</div><div class="">- For protocols, (1) and (2) are <i class="">not</i> equivalent, because @objc isn't inherited there.</div><div class="">- Mangling is used to namespace class names at run time; if you drop that, the ObjC name should probably have a prefix. (This applies more to frameworks than apps, though.)</div></div></div></blockquote><br class=""></div><div>I’m -1 on this, because bare “@objc” in other contexts means “make sure this is exposed to Objective-C, but I don’t want to be explicit about the name” while “@objc(something)” means “make sure this is exposed to Objective-C, and ‘something’ is the name”. </div><div><br class=""></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>- Doug</div><div><br class=""></div><br class=""></body></html>