[swift-users] How to write better Swift

[Gerriet M. Denkmann]

> On 10 Jul 2017, at 22:35, Geordie J via swift-users <swift-users at 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 at 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.