ios – Utilizing the brand new C++ Swift interop in a CocoaPod

I am constructing an iOS library that incorporates each Swift and C++ code.

Utilizing the brand new C++ <> Swift interop from Swift 5.10, I can now skip the Goal-C bridge – which was annoying to jot down, and likewise slowed every little thing down in efficiency important code.

I managed to arrange the CocoaPod and my instance challenge accordingly – SWIFT_OBJC_INTEROP_MODE is ready to objcxx, and I am utilizing C++ 20.

Now I created CxxInstance.hpp:

#embody "MyPod-Swift.h"

enum class SomeEnum { FIRST, SECOND }; 

class CxxInstance {
public:
  static void runIt() {
    auto swiftInstance = MyPod::SwiftInstance::init();
    int i = swiftInstance.getInt(); // <-- works ✅
    SomeEnum e = swiftInstance.getEnum(); // <-- construct error! ❌
  }
};

And SwiftInstance.swift:

public class SwiftInstance {
  public init() { }

  public func getInt() -> Int {
    return 13
  }

  public func getEnum() -> SomeEnum {
    return .FIRST
  }
}

MyPod-Swift.h was generated efficiently and I can name MyPod::SwiftInstance::init().

However whereas getInt() -> Int works advantageous and could be referred to as from C++, getEnum() -> SomeEnum fails to construct as a result of C++ can not resolve that methodology.

In Swift it exists and I can use the enum SomeEnum simply advantageous – it is simply the C++ half that fails to search out the getEnum() methodology.

Based on their Mixing Swift and C++ information, calling Swift capabilities from C++, the place the Swift operate makes use of C++ varieties needs to be a supported function, however I feel they created separate “Modules” – one for C++ and one for Swift.

In my case I’ve a single .podspec which incorporates all information – Swift and C++ – as source_files:

Pod::Spec.new do |s|
  s.identify         = "NitroImage"
  s.model      = bundle["version"]
  s.abstract      = bundle["description"]
  s.homepage     = bundle["homepage"]
  s.license      = bundle["license"]
  s.authors      = bundle["author"]

  s.platforms    = { :ios => min_ios_version_supported }

  s.source_files = [
    # C++ part
    "cpp/**/*.{hpp,cpp}",
    # Implementation (Swift)
    "ios/**/*.{swift}",
  ]

  s.pod_target_xcconfig = {
    # Use C++ 20
    "CLANG_CXX_LANGUAGE_STANDARD" => "c++20",
    # Allows C++ <-> Swift interop (by default it is solely C)
    "SWIFT_OBJC_INTEROP_MODE" => "objcxx",
  }
finish

And CocoaPods all the time generates a default module.modulemap:

module MyPod {
  umbrella header "MyPod-umbrella.h"

  export *
  module * { export * }
}

I feel I’m utilizing dynamically linked use_frameworks!, if that issues.

Any concepts of how I can correctly have cyclic dependencies on C++ <> Swift code inside the identical Pod?