To me the short syntax should be a ‘macro’ expansion (syntax sugar only),
therefore option 1 in Nick’s example. I choose the syntax sugar option because
it is easy to explain.
-- Howard.
> On 12 Dec 2017, at 7:03 pm, Nick Keets via swift-evolution
> <swift-evolution@swift.org> wrote:
>
>
>
>> On Tue, Dec 12, 2017 at 12:42 AM, Slava Pestov via swift-evolution
>> <swift-evolution@swift.org> wrote:
>>
>> I think it gets confusing when you have multiple levels of nested
>> expressions, eg
>>
>> foo(bar(x?)) + y?
>>
>> Slava
>
> I'm not sure we need to optimize much for complicated nested examples, as I
> don't think this is something that will happen a lot in practice. I imagine
> the most common scenario will be a single call with one or more arguments.
>
> Having said that, we did receive 2 different reasonable answers on what the
> evaluation order would be for:
> f(a(), b?)
>
> (1) It desugars to:
>
> if let someB = b {
> f(a(), someB)
> }
>
> So a() doesn't get called if b is nil.
>
> (2) "If you were to write this logic out by hand then you would short-circuit
> it and this is analogous to current chaining behaviour so to me evaluating
> left to right (as Swift usually does) and stopping at the first failed unwrap
> would make sense"
>
> So a() gets called if b is nil.
>
>
>
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