Swift 4.1で-swift-version 3を使うとSwift 3.3になるぽい。

$ TOOLCHAINS=org.swift.4120171207a swift -swift-version 3 Welcome to Apple Swift version 4.1-dev (LLVM 67b9a8e8c2, Clang e617c83242, Swift 65b4172032). Type :help for assistance. 1> #if swift(>=4.1) 2. let versions = "swift-4.1" 3. #elseif swift(>=4.0.3) 4. let versions = "swift-4.0.3" 5. #elseif swift(>=4.0.2) 6. let versions = "swift-4.0.2" 7. #elseif swift(>=4.0) 8. let versions = "swift-4.0" 9. #elseif swift(>=3.3) 10. let versions = "swift-3.3" 11. #elseif swift(>=3.2.3) 12. let versions = "swift-3.2.3" 13. #elseif swift(>=3.2.2) 14. let versions = "swift-3.2.2" 15. #else // if swift(>=3.2) 16. let versions = "swift-3.2" 17. #endif 18. versions: String = "swift-3.3" 18>

(edited)