What are the cases in which I should still use Objective-C instead of Swift?

While Swift is a powerful and modern language, there are still some cases where you might consider using Objective-C instead:

1. Legacy Codebases: If you are working on a project with a significant amount of existing Objective-C code, it might be more practical to continue using Objective-C, especially if the codebase is stable and well-tested.

2. Interoperability with C/C++: Although Swift has good interoperability with C and C++, there might be scenarios where the integration is more straightforward in Objective-C. For example, certain C++ features and libraries might be easier to use directly in Objective-C.

3. Performance Considerations: In some performance-critical applications, you might find that certain low-level optimizations are easier to achieve in Objective-C. For instance, managing memory manually can sometimes be more efficient than relying on Swift's Automatic Reference Counting (ARC).

4. Dynamic Features: Objective-C's runtime is highly dynamic, allowing for features like method swizzling, dynamic method resolution, and more. If your application relies heavily on these dynamic features, Objective-C might be a better fit.

5. Third-Party Libraries: Some third-party libraries and frameworks are still written in Objective-C. While you can use these libraries in Swift, you might find it easier to work with them directly in Objective-C.

For more details on Swift's performance and interoperability, you can refer to the sessions from WWDC:

• Explore Swift performance
• Analyze heap memory
• What’s new in Swift

These sessions provide insights into Swift's capabilities and how it compares to Objective-C in various scenarios.