[swift-evolution] Deprecating Trailing Closures

[James Campbell]

I think the feature should stay but we need community guidelines on when
and when not to use them.

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On Thu, Mar 24, 2016 at 4:13 PM, William Dillon via swift-evolution <
swift-evolution at swift.org> wrote:

> On Mar 24, 2016, at 7:18 AM, Kurt Werle via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> Coming from ruby, I'm quite fond of trailing closures.  I couldn't really
> give you a concrete reason why - putting them in the ()'s really isn't that
> big a deal.  But I'll say that I move them outside every single time...
>
> I will say that your examples are the most trivial possible and that the
> more complex the closure (describing context variables and return types,
> throws, etc) the uglier it seem to me to put it inside parens.
>
>
> Agree.
>
> Another thing I like about trailing closures is that it allows me to make
> custom constructs that feel more like a part of the language.  For example,
> I really love this extension for NSLock that I have:
>
> extension NSLock {
>     func protect(action: (Void) -> Void) {
>         self.lock()
>         action()
>         self.unlock()
>     }
> }
>
> Now, whenever I need to use my lock, I can just do:
>
> peersLock.protect {
>     outputString += "\(self.peers.count) peers:\n"
>     for (_, peer) in self.peers {
>         outputString += "\(peer)\n"
>     }
> }
>
> To me, it looks cleaner to me to not have this paren dangling around at
> the end.  On this one I’d definitely say that if you don’t like it, don’t
> use it.  I don’t *think* that you’re forced to use it anywhere.  It’s a
> hard sell to take it away from everyone.
>
> - Will
>
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>
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