[swift-evolution] [swift-evolution-announce] [Review] SE-0083: Remove bridging conversion behavior from dynamic casts
brent at architechies.com
Thu May 19 04:31:07 CDT 2016
> * What is your evaluation of the proposal?
The review is technically over, but I don't believe a decision has been announced yet, so...
I am generally in favor, but I have a serious concern about the readability of certain conversions with this change. To wit, conversions like these:
myArray as! [NSView]
myDictionary as! [String: NSView]
Are about to become something more like these:
[String: NSView](forcedLazyBridging: myDictionary)
Dictionary<String, NSView>(forcedLazyBridging: myDictionary)
Either option is a significant regression in code readability compared to the status quo.
It's enough to make me wonder if we shouldn't have special-cased conversion methods for NSArray, NSDictionary, and NSSet:
myArray.of(NSView) // returns [NSView]
myDictionary.of(NSView, for: String) // returns [String: NSView]
mySet.of(NSView) // returns Set<NSView>
On the other hand, if you *don't* have to specify an element type, these aren't so bad:
And it gets even better if you use something a little saner than `forcedLazyBridging` for the label.
> * Is the problem being addressed significant enough to warrant a change to Swift?
Yes. Conversions are a mess, and it'll be nice to clean them up.
> * Does this proposal fit well with the feel and direction of Swift?
> * If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
Most languages I've used have had much simpler cast systems with nothing particularly close to Swift's bridging casts.
> * How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
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