Implementation of #bundle

Sources/FoundationMacros/BundleMacro.swift

@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftSyntax
+import SwiftSyntaxMacros
+import Foundation
+
+#if FOUNDATION_FRAMEWORK
+/// Returns the bundle most likely to contain resources for the calling code.
+///
+/// Code in an app, app extension, framework, etc. will return the bundle associated with that target.
+/// Code in a Swift Package target will return the resource bundle associated with that target.
+@available(macOS 10.0, iOS 2.0, tvOS 9.0, watchOS 2.0, *)
+@freestanding(expression)
+public macro bundle() -> Bundle = #externalMacro(module: "FoundationMacros", type: "BundleMacro")
+#endif
+
+
+public struct BundleMacro: SwiftSyntaxMacros.ExpressionMacro, Sendable {
+    public static func expansion(of node: some FreestandingMacroExpansionSyntax, in context: some MacroExpansionContext) throws -> ExprSyntax {
+        """
+        {
+            #if SWIFT_MODULE_RESOURCE_BUNDLE_AVAILABLE
+                return Bundle.module
+            #elseif SWIFT_MODULE_RESOURCE_BUNDLE_UNAVAILABLE
+                #error("No resource bundle is available for this module. If resources are included elsewhere, specify the bundle manually.")
+            #else
+                return Bundle(_dsoHandle: #dsohandle) ?? .main
+            #endif
+        }()
+        """
+    }
+}

Sources/FoundationMacros/CMakeLists.txt

@@ -63,6 +63,7 @@ target_compile_options(FoundationMacros PRIVATE -parse-as-library)
 
 target_sources(FoundationMacros PRIVATE
     FoundationMacros.swift
+    BundleMacro.swift
     PredicateMacro.swift)
 
 target_compile_options(FoundationMacros PRIVATE

Sources/FoundationMacros/FoundationMacros.swift

@@ -17,7 +17,11 @@ import SwiftCompilerPlugin
 
 @main
 struct FoundationMacros: CompilerPlugin {
-    var providingMacros: [Macro.Type] = [PredicateMacro.self, ExpressionMacro.self]
+    var providingMacros: [Macro.Type] = [
+        PredicateMacro.self,
+        ExpressionMacro.self,
+        BundleMacro.self
+    ]
 }
 
 #endif

Tests/FoundationMacrosTests/BundleTests.swift

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022-2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import XCTest
+import FoundationMacros
+
+final class BundleTests: XCTestCase {
+
+    func testSimple() {
+        AssertMacroExpansion(
+            macros: ["bundle": BundleMacro.self],
+            """
+            #bundle
+            """,
+            """
+            {
+                #if SWIFT_MODULE_RESOURCE_BUNDLE_AVAILABLE
+                    return Bundle.module
+                #elseif SWIFT_MODULE_RESOURCE_BUNDLE_UNAVAILABLE
+                    #error("No resource bundle is available for this module. If resources are included elsewhere, specify the bundle manually.")
+                #else
+                    return Bundle(_dsoHandle: #dsohandle) ?? .main
+                #endif
+            }()
+            """
+        )
+    }
+
+    func testUsingParenthesis() {
+        AssertMacroExpansion(
+            macros: ["bundle": BundleMacro.self],
+            """
+            #bundle()
+            """,
+            """
+            {
+                #if SWIFT_MODULE_RESOURCE_BUNDLE_AVAILABLE
+                    return Bundle.module
+                #elseif SWIFT_MODULE_RESOURCE_BUNDLE_UNAVAILABLE
+                    #error("No resource bundle is available for this module. If resources are included elsewhere, specify the bundle manually.")
+                #else
+                    return Bundle(_dsoHandle: #dsohandle) ?? .main
+                #endif
+            }()
+            """
+        )
+    }
+}