Translating Objective-C to Swift in Xcode 9.0 Beta 2

I’m putting together a post comparing Mac drag and drop APIs and iOS drag and drop APIs.

To prepare, I took the Xcode CocoaDragAndDrop sample project (here, last modified in 2011 with note “Updated for Xcode 4”) and converted it to Swift (here) using the second beta of Xcode 9.0.1

Since I haven’t internalized the pattern between Objective-C and Swift method conversions, I was often frustrated by how to translate Objective-C method calls to Swift method calls.

While I was working on the project, it seemed that 4 times out of 5, when I tried to go to a class or protocol’s declaration in Apple’s headers and see its Swift-ified methods, Xcode would take me to the Objective-C header instead, even though I was starting off in a Swift file.

Of course, now that I’m trying to reproduce it to file a Radar, it doesn’t happen. I wonder if that’s because the final project has no Objective-C files in it at all.

It doesn’t help that the translations changed between Swift 3 and Swift 4.

For example, NSPasteboardTypeTIFF in Swift 3 is now NSPasteboard.PasteboardType.tiff in Swift 4, with a similar pattern for all its friends.

register(forDraggedTypes newTypes: [String]) is now registerForDraggedTypes(_ newTypes: [NSPasteboard.PasteboardType]).


It’ll be nice to be working exclusively in Swift for the rest of this effort.

1. Feedback welcome! ↩︎