[swift-evolution] Brainstorming: Optional sugar inferred map

[Thorsten Seitz]

> Am 16.02.2016 um 05:52 schrieb Paul Ossenbruggen via swift-evolution <swift-evolution at swift.org>:
> 
> I guess if auto closure could take a parameter you could do something like this:
> 
> @warn_unused_result
> public func ??<T>(optional: T?, @autoclosure defaultValue: (result : T) throws -> T) rethrows -> T {
>     return optional != nil ? optional! : try defaultValue(result: optional!)
> }

This will always throw an exception as you are force unwrapping the optional in both branches of the ternary, i.e. also in the branch which is used when it is nil.

-Thorsten 
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