[swift-evolution] Alternative For Nested If Repetiion

[Ted F.A. van Gaalen]

Unexpected ways :o) 
All very nice and well but readable?
I was looking a new language element
that would be similar to
   Switch true ….
but then limited for cases
which are logical expressions only.  
Ok, Perhaps it is not that important.
I will forget it and will continue
to use “switch true”  case <logical expression>:  etc.
sorry I brought it forward.
TedvG


On 14.03.2016, at 18:52, Kurt Werle <kurt at circlew.org> wrote:
> 
> 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 <mailto:jgroff at apple.com>> wrote:
> 
>> On Mar 12, 2016, at 3:20 PM, Kurt Werle via swift-evolution <swift-evolution at swift.org <mailto: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 <mailto: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 <mailto:swift-evolution at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>> 
>> 
>> 
>> -- 
>> kurt at CircleW.org <mailto:kurt at circlew.org>
>> http://www.CircleW.org/kurt/ <http://www.circlew.org/kurt/>
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
> 
> 
> 
> 
> -- 
> kurt at CircleW.org
> http://www.CircleW.org/kurt/ <http://www.circlew.org/kurt/>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160314/ee44b4a6/attachment.html>