> On Feb 20, 2017, at 10:55 AM, Michel Fortin via swift-evolution > <swift-evolution@swift.org> wrote: > > a) Structs/Locals: > Structs and local variables behave similarly. You can access `let` and `var` > properties and mutate the later.
What if the struct contains class ivars, including private ones that you may not know about but nonetheless get accessed as a side effect of accessing the struct’s “var” properties? > b) Classes: > You can't access the variables of a class in a pure function. But you can > access its `let` properties. That's because as long as there is no `var` in > the dereferencing path, you are guarantied to be accessing a constant. In > classes, `let` properties are thus implicitly pure; stored `var` properties > are not. Which means that pure instance methods on classes can only access > `let` properties, in addition to computed properties that are themselves > `pure` and other `pure` methods. What if the “let” property becomes a “var” property in a future version of the library you’re linking against? Charles
_______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
