[swift-evolution] [Pitch] Typed throws

[Kevin Nattinger]

protocol MyError: Error {}
enum MyFooError: MyError { … }
enum MyBarError: MyError { … }

func baz() throws(MyError)

> On Feb 17, 2017, at 11:03 AM, Adrian Zubarev via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I suggest we need to find a way to shorten the list of the possible error types with a the help of typeallias
> 
> extension MyError1: Error { ... }
> extension MyError2: Error { ... }
> extension MyError3: Error { ... }
> 
> typealias MyErrors = MyError1 | MyError2 | MyError3  
> 
> func foo() throws(MyErrors) -> MyResult
> func bar<T : Error>(_: () throws(T) -> Void) rethrows(MyErrors, T) -> MyResult
> 
> 
> 
> -- 
> Adrian Zubarev
> Sent with Airmail
> 
> Am 17. Februar 2017 um 19:47:47, Anton Zhilin via swift-evolution (swift-evolution at swift.org <mailto:swift-evolution at swift.org>) schrieb:
> 
>> Now this is on-topic, I guess.
>> Last time we stopped at John McCall’s syntax:
>> 
>> extension MyError: Error { ... }
>> 
>> func foo() throws(MyError) -> MyResult
>> It’s conservative and prevents visual ambiguity with extra parentheses.
>> 
>> If we (somewhat) agree on this, then submitting a proposal will be trivial.
>> 
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> 
> 
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