>> * The ability to name a closure parameter `self`, which would make bare
>> method calls be directed to that parameter.
>
> Could this would this tie into the weak-strong dance? And if so, how?
Actually, one of my motivations for wanting `self` parameters is the
block-based undo registration API:
func add(_ amount: Int) {
value += amount
undoManager.registerUndo(target: self) { self in
subtract(amount) }
}
Since undo managers reference targets weakly, this API encapsulates the
weak-strong dance for you. But without `self` parameters, you end up having to
invent a different name:
func add(_ amount: Int) {
value += amount
undoManager.registerUndo(target: self) { target in
target.subtract(amount) }
}
And if you forget and accidentally use `self`, the block references `self`
strongly, which could create a retain cycle. So `self` parameters would make
this pattern—which is really the best way to handle a weak-strong dance—safer
and cleaner, encouraging its use.
--
Brent Royal-Gordon
Architechies
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