Merge pull request #13 from skiptools/swiftprojecting

Create SwiftProjecting protocol for use by bridging code

Sources/SkipLib/BridgeSupport.swift

@@ -0,0 +1,23 @@
+// Copyright 2024 Skip
+//
+// This is free software: you can redistribute and/or modify it
+// under the terms of the GNU Lesser General Public License 3.0
+// as published by the Free Software Foundation https://fsf.org
+
+/// Marker protocol for types that are custom bridged from the Swift side.
+///
+/// - Seealso: `KotlinConverting`
+public protocol SwiftCustomBridged {
+}
+
+/// Implemented by the generated Kotlin side of a bridged type to provide its Swift projection.
+///
+/// We keep this in SkipLib so that the Kotlin output of transpiled bridged modules does not have a
+/// dependency on SkipBridge. We can add the SkipBridge dependency only when compiling for bridging.
+///
+/// - Returns: A closure that returns a Swift projection of this object when invoked.
+/// - Warning: This protocol is not designed for general use. It is designed for generated bridge code.
+/// - Seealso: `SkipBridgeKt.BridgeSupport`
+public protocol SwiftProjecting {
+    func Swift_projection(options: Int) -> () -> Any
+}

Sources/SkipLib/Skip/KotlinSupport.kt

@@ -5,10 +5,6 @@
 // as published by the Free Software Foundation https://fsf.org
 package skip.lib
 
-/// Marker protocol for types that are custom bridged from the Swift side.
-interface SwiftCustomBridged {
-}
-
 /// A type that can convert to an underlying Kotlin instance.
 interface KotlinConverting<T> {
     /// Convert a transpiled Swift instance to its Kotlin equivalent.