> On 9 Apr 2017, at 05:12, Tony Allevato <tony.allev...@gmail.com> wrote: > > Agreed—I think the parentheses have to go on the outside for this to work. In > this sense, `\Person.mother.age` is an expression that returns a keypath > type, with the idea that the parser is greedy and tries to take as many > dotted names that follow. The parentheses halt that if needed, but the > backslash needs to be bound to the type name for the part inside the > parentheses to be interpreted as a keypath. > > `\(Foo.bar)` looks like it would try to evaluate `Foo.bar` first and then > compute the "keypath" of that, which doesn't make sense, whereas `(\Foo.bar)` > makes it clear that the keypath expression is being separated from whatever > might come after it.
I kind of like having it outside the brackets for the consistency with inserting variables etc. within strings; I've learned to think of that as a special type of escape from the "string" context, so it could make sense for key-paths in the same way. I'm just thinking that since we're using a backlash it feels a lot like we're escaping from normal type access in order to define the key-path instead, and since \() is a form of escape used inside strings to encompass something larger it makes a kind of sense to me. As Brent says though it shouldn't be a very common case so it doesn't really matter; I'd be fine with either style. I suppose using the backslash inside the brackets may be simpler to parse since it's using the parenthesis as normal? _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
