[swift-evolution] Alternative For Nested If Repetiion

[Kurt Werle]

Oooh - didn't know about that - very nice.

Thanks,
Kurt

On Mon, Mar 14, 2016 at 10:31 AM, Joe Groff <jgroff at apple.com> wrote:

>
> On Mar 12, 2016, at 3:20 PM, Kurt Werle via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> let x = 1
> let y = 2
> let z = 3
>
> let condition1 = x > y
> let condition2 = z > x
>
> switch (condition1, condition2) { // Treat your conditions as peers
> case (true, _): // true & whatever
>     break
> case (false, true): // false, true
>     break
> case (false, false): // false, false
>     break
> // no default needed - we covered all the cases
> }
>
>
> You can also use tuple labels here to aid readability:
>
> switch (x_y: x > y, z_x: z > x) {
> case (x_y: true, z_x: _):
>   ...
> }
>
> -Joe
>
>
> On Sat, Mar 12, 2016 at 1:17 PM, Ted F.A. van Gaalen via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>> a block of nested 'if else’  is not really nice, i think:
>>
>>         • if condition 1 {
>>         • statements to execute if condition 1 is true
>>         • } else if condition 2 {
>>         • statements to execute if condition 2 is true
>>         • } else {
>>         • statements to execute if both conditions are false
>>         • }
>>
>> what I currently do to prevent this:
>>
>>  switch true
>>  {
>> case  film == 2010:
>>          itsFullOfStars(monolith)
>>
>> case terriblyWrongPresident():
>>         initiateNewElections()
>>
>> case b > c:
>>         c = b
>>
>> case d > c:
>>         c = d
>>
>> default:
>>        break    // or something else to do, if all other conditions are
>> fase
>> }
>>
>>
>> This works perfectly well, looks good too, I think, but is it right thing
>> to do it this way,
>> as in principle 'switch’  is perhaps more intended to evaluate variables?
>>
>> Python has its “elif”  keyword…
>>
>> So what about, an ‘ifs’  statement group in Swift:
>>
>>
>> ifcases      // or another keyword, perhaps
>> {
>>  case a > b:
>>     b = a
>> case  c < d:
>>    b = c
>> }
>> without  fall-through option.
>> perhaps also without  default
>>
>>
>> What do you think?
>>
>> TedvG
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>
>
>
>
> --
> kurt at CircleW.org <kurt at circlew.org>
> http://www.CircleW.org/kurt/ <http://www.circlew.org/kurt/>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
>


-- 
kurt at CircleW.org
http://www.CircleW.org/kurt/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160314/221256a7/attachment.html>