[swift-evolution] idea: immutable setters for structs and tuples?

[Erica Sadun]

> On Mar 24, 2016, at 3:39 PM, Brent Royal-Gordon <brent at architechies.com> wrote:
> 
>>> I think this is better modeled in Swift as something like:
>>> 
>>> 	let john = (firstName:"John", lastName:"Doe")
>>> 	let alice = with(john) {
>>> 		$0.firstName = "Alice"
>>> 	}
>> 
>> You can kind of do this now:
>> 
>> struct Person {
>>    var firstName, lastName: String
>> }
>> 
>> func modify<T>(item: T, update: (inout T) -> Void) -> T {
>>    var this = item
>>    update(&this)
>>    return this
>> }
>> 
>> let carol: Person = modify(john) {
>>    $0.firstName = "Carol"
>> }
>> 
>> print(carol)
> 
> You *can* do this now. I'm suggesting it be added to Stdlib.
> 

Ah, then that's a "pass it by Dmitri" kind of thing, isn't it?

-- E