Swift Closure Capture Semantics
One important thing to note though is that in Swift the captured variables are evaluated at the closure execution’s time. We could say that it captures the reference (or pointer) to the variable.
For those of you who know Objective-C, you can notice that the Swift behavior is unlike Objective-C’s default block semantics but instead somewhat like if the variable had the
__blockmodifier in Objective-C.[…]
To capture the value of a variable at the point of the closure’s creation (instead of a reference to the variable itself), you can use the
[localVar = varToCapture]capture list.
