Re: [swift-users] How to write better Swift

[Gerriet M. Denkmann via swift-users]

> On 10 Jul 2017, at 22:35, Geordie J via swift-users <swift-users@swift.org> 
> wrote:
> 
> Would “didSet" on a normal variable work for you?

willSet/didSet usually is a good solution (which I had forgotten about).

But in my case it seems not to help - see the corrected code below

> var status: Int {
>  didSet { doSomething() }
> }
> 
> Geordie
> 
> 
>> Am 10.07.2017 um 17:34 schrieb Gerriet M. Denkmann via swift-users 
>> <swift-users@swift.org>:
>> 
>> This works (Xcode Version 8.3.2 (8E2002)):
>> 
>> class SomeClass
>> {
>>      private var privateStatus: Int  
>> 
>>      var status: Int
>>      {
>>              get{ return privateStatus }
>>              set(new)
>>              {
>>                      if new == privateStatus {return}

                                oldDerived = derivedStatus // depends on status
                                privateStatus = new
                                newDerived = derivedStatus 

                                if newDerived != oldDerived … do something … 

                                … do something more here …
>>              }
>>      }
>> }
>> 
>> But is this “privateStatus” really necessary?
>> If not, how can it be avoided?


Quincey had an excellent idea: one should be able to write:

var status: Int
{
        var privateStatus: Int  //      makes it much clearer that 
privateStatus really only belongs to status

        get{ return privateStatus }
        set(new)
        {
                …
                privateStatus = new
        }
}

Gerriet.

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