https://developer.apple.com/tutorials/swiftui/creating-a-macos-app
“The pattern for defining focused values resembles the pattern for definining new Environment values: Use a private key to read and write a custom property on the system-defined FocusedValues structure.”
“definining” lol
I am lost. Time to read the Swift language reference?
private struct SelectedLandmarkKey: FocusedValueKey {
typealias Value = Binding<Landmark>
}
extension FocusedValues {
var selectedLandmark: Binding<Landmark>? {
get { self[SelectedLandmarkKey.self] }
set { self[SelectedLandmarkKey.self] = newValue }
}
}
FocusedValues is a struct type defined in the SwiftUI framework, a “collection of state exported by the focused view and its ancestors”.
So, within the app, ¿FocusedValues knows if a given Landmark is selected/has focus?
[ ] Find a thorough explanation of the <AngleBrackets> syntax
[ ] And ¿what the heck is self[SelectedLandmarkKey.self]?
[ ] Also find documentation for SwiftUI .tag(x) modifier
SelectedLandmarkKey is a struct that I just defined.
So SelectedLandmarkKey.self is… a reference to that struct type?
And, in the extension, the first self is a reference to (an instance of?) FocusedValues
[ ] But FocusedValues is a struct, not an array or a dictionary, so ¿how does the square brackets syntax work with structs?