[swift-evolution] ternary operator ?: suggestion

[J. Cheyo Jimenez]

The motive is to desist the use of the question mark outside of the swift
optional context.
I like the rust style if-expression as an alternative.
Imo consistency and readability is a little more important than brevity.


On Friday, December 4, 2015, David Hart <david at hartbit.com> wrote:

> Best proposition since, but still more verbose than the ternary operator.
>
> On 04 Dec 2015, at 18:27, David Owens II <david at owensd.io
> <javascript:_e(%7B%7D,'cvml','david at owensd.io');>> wrote:
>
> There’s no need for the “then" keyword if you just allow if-expressions as
> well.
>
> ```
> let result = if condition { 1 } else { 2 }
> ```
>
> Or more verbosely:
>
> ```
> let result =
>     if condition {
>         return 1
>     }
>     else {
>         return 2
>     }
> ```
>
> The same could be for switch statements as well.
>
> ```
> let result = switch item {
>     case foo: 1
>     case bar: 2
> }
> ```
>
> The above assume implicit returns on single-line statements on the
> condition/case branches.
>
> -David
>
> On Dec 3, 2015, at 11:26 PM, David Hart <david at hartbit.com
> <javascript:_e(%7B%7D,'cvml','david at hartbit.com');>> wrote:
>
> I also tend to agree but I don't like the ordering in the Python version
> and would rather see the introduction of the then keyword
>
> On 04 Dec 2015, at 06:08, Sean Heber <sean at fifthace.com
> <javascript:_e(%7B%7D,'cvml','sean at fifthace.com');>> wrote:
>
> I agree that using ? for ternary feels.. uncomfortable in Swift. I
> wouldn't mind seeing Python-style or just eliminating it entirely in favor
> of simplicity.
>
> l8r
> Sean
>
> On Dec 3, 2015, at 10:48 PM, Dan Appel <dan.appel00 at gmail.com
> <javascript:_e(%7B%7D,'cvml','dan.appel00 at gmail.com');>> wrote:
>
> I agree that ternary can make code unreadable, especially so with the ‘?’.
> I personally like the Haskel option the most, but it introduces a new
> keyword ‘then’, which isn’t great either. Python’s "y if x else z" is
> therefore, in my opinion, the best alternative.
>
> Also, I found it interesting how split the Rust community was about
> removing the ternary operator.
>
> —
> Dan Appel
>
> On Thu, Dec 3, 2015 at 7:58 PM J. Cheyo Jimenez <cheyo at masters3d.com
> <javascript:_e(%7B%7D,'cvml','cheyo at masters3d.com');>> wrote:
>
>> Would you consider replacing the C style ?: ternary operator to something
>> that does not use the question mark and colon ?
>>
>> The use of "?" can be confusing when speed reading code with optionals.
>>
>> Consider this code as somebody learning swift as their first language.
>>
>> let result = !condition ? 1 : 2
>>
>> Some alternatives:
>>
>> Haskel
>>
>> if predicate then expr1 else expr2
>>
>> Python
>>
>> result = x if a > b else y
>>
>> The advantage of not using the question mark is that the language will be
>> more consistency on the use of "?" to mean only optionals.
>>
>>
>> References:
>> https://devforums.apple.com/message/1020139#1020139
>> https://github.com/rust-lang/rust/issues/1698#issuecomment-3705066
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>>
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