[swift-evolution] Proposal: Replace ?? by an (optional) argument to ?

[Amir Michail]

> On Jan 30, 2016, at 11:31 AM, Thorsten Seitz <tseitz42 at icloud.com> wrote:
> 
>> 
>> Am 26.01.2016 um 03:30 schrieb Amir Michail via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>>:
>> 
>> 
>>> On Jan 25, 2016, at 9:28 PM, Erica Sadun <erica at ericasadun.com <mailto:erica at ericasadun.com>> wrote:
>>> 
>>> Not loving this.  I'm quite happy with ??-coalescing and don't see
>>> a compelling reason it needs to be "cleaner". I find your suggested
>>> enhancement less readable. Looks like an optional chaining across 
>>> a function.
>>> 
>> 
>> ?? puts the least important part of the expression in the most important position — namely, the end.
> 
> 
> I think that’s actually a very good place as it is the option that is considered last.

After thinking about it some more, it’s not really the position that is the problem.

I think the problems with ?? are as follows:

* not specialized to a boolean context (i.e, it is too general for most cases)
* “??" is too catchy for something this minor
* true/false contain too many letters for something this minor

I would like to type something like this:

if x?.isEmpty || nil { … }
if x?.isNotEmpty && !nil { … }

So one might consider turning “|| nil” into a suffix, say |nil.
Similarly, one might consider turning “&& !nil” into a suffix, say &!nil.

So maybe:

if x?.isEmpty |nil { … }
if x?.isNotEmpty &!nil { … }


> 
> -Thorsten
> 
> 
>> 
>>> -- E
>>> 
>>>> On Jan 25, 2016, at 7:03 PM, Amir Michail via swift-evolution <swift-evolution at swift.org> wrote:
>>>> 
>>>> Examples:
>>>> 
>>>> * instead of x ?? false, you would have x?(false)
>>>> * instead of x?.isEmpty ?? false, you would have x?(false).isEmpty
>>>> 
>>>> I think this change would result in cleaner looking code.
>>>> 
>>>> 
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>> 
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