Obtaining the mangled name of a type from the fully qualified type name only

Using Swift
8

The lazy deserialization is evident if you print a decoded path.

For example, given this path:

var path = NavigationPath()
path.append("Hello")
path.append(123)
print(path)

Here is the output (reformatted for legibility):

NavigationPath(
    _items: blahblahblah.Representation.eager(
        [
            SwiftUI.(unknown context at $11567e6b8).CodableItemBox<Swift.String>,
            SwiftUI.(unknown context at $11567e6b8).CodableItemBox<Swift.Int>
        ]
    ),
    subsequentItems: [],
    iterationIndex: 0
)

And if we create a new path from that path's codable:

let path2 = NavigationPath(path.codable!)
print(path2)

we get this output:

NavigationPath(
    _items: blahblahblah.Representation.lazy(
        SwiftUI.NavigationPath.CodableRepresentation(
            resolvedItems: [
                SwiftUI.(unknown context at $11567e6b8).CodableItemBox<Swift.String>,
                SwiftUI.(unknown context at $11567e6b8).CodableItemBox<Swift.Int>
            ],
            remainingItemsReversed: [],
            subsequentItems: []
        )
    ),
    subsequentItems: [],
    iterationIndex: 0
)

Furthermore, the old and new paths are not equal:

print(path == path, path2 == path2, path == path2)
// true true false

If we go all the way through the JSON representation:

let path3 = NavigationPath(try! JSONDecoder().decode(NavigationPath.CodableRepresentation.self, from: try! JSONEncoder().encode(path.codable!)))
print(path3)

then we get a different lazy representation in which we can see that it stores each path element's type and JSON representation, with no individual path element decoded:

NavigationPath(
    _items: blahblahblah.Representation.lazy(
        SwiftUI.NavigationPath.CodableRepresentation(
            resolvedItems: [],
            remainingItemsReversed: [
                (tag: "Swift.Int", item: "123"),
                (tag: "Swift.String", item: "\"Hello\"")
            ],
            subsequentItems: []
        )
    ),
    subsequentItems: [],
    iterationIndex: 0
)
2 Likes