> On Apr 3, 2017, at 1:47 PM, Joshua Alvarado via swift-evolution
> <[email protected]> wrote:
>
> Example:
> struct Foo {
> var firstName: String
> var lastName: String
> }
>
You would need to spell out #keyPath(Foo, .firstName) here, or decorate the
type on keyPaths like so:
let keyPaths : [KeyPath<Foo, String>] = ... or let keyPaths :
[PartialKeyPath<Foo>] = ... to use the short hand in your value declaration.
The difference between the two is that the PartialKeyPath lets you refer to
non-string properties, whereas the other is more strongly typed.
> let keyPaths = [#keyPath(.firstName), #keyPath(.lastName)]
The same would be true on the inference:
> let keyPaths = [#keyPath(Foo, .firstName), #keyPath(Foo, .lastName)]
Infers that keyPaths is a [KeyPath<Foo, String>] since everything agrees;
let keyPaths = [#keyPath(Foo, .firstName), #keyPath(Foo, .age)] // suppose it
returns Int
Would only be able to infer up to PartialKeyPath<Foo>.
> for key in keyPaths {
> foo[keyPath: key] = "bar"
> }
>
> print(foo) // firstName = bar, lastName = bar
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