Enable conditionally building macros

Author: colemancda

Package.swift

@@ -3,8 +3,13 @@ import PackageDescription
 import CompilerPluginSupport
 import class Foundation.ProcessInfo
 
+// get environment variables
+let environment = ProcessInfo.processInfo.environment
+let dynamicLibrary = environment["SWIFT_BUILD_DYNAMIC_LIBRARY"] == "1"
+let enableMacros = environment["SWIFTPM_ENABLE_MACROS"] != "0"
+let buildDocs = environment["BUILDING_FOR_DOCUMENTATION_GENERATION"] == "1"
+
 // force building as dynamic library
-let dynamicLibrary = ProcessInfo.processInfo.environment["SWIFT_BUILD_DYNAMIC_LIBRARY"] != nil
 let libraryType: PackageDescription.Product.Library.LibraryType? = dynamicLibrary ? .dynamic : nil
 
 let package = Package(
@@ -22,37 +27,85 @@ let package = Package(
             targets: [
                 "CoreModel"
             ]
-        ),
-        .library(
-            name: "CoreDataModel",
-            type: libraryType,
-            targets: [
-                "CoreDataModel"
-            ]
-        )
-    ],
-    dependencies: [
-        .package(
-            url: "https://github.com/swiftlang/swift-syntax.git",
-            from: "600.0.1"
         )
     ],
     targets: [
         .target(
-            name: "CoreModel",
-            dependencies: [
-                "CoreModelMacros"
-            ]
+            name: "CoreModel"
         ),
-        .target(
-            name: "CoreDataModel",
+        .testTarget(
+            name: "CoreModelTests",
             dependencies: [
                 "CoreModel"
-            ],
-            swiftSettings: [
-                .swiftLanguageMode(.v5)
             ]
-        ),
+        )
+    ]
+)
+
+#if canImport(Darwin)
+package.products.append(
+    .library(
+        name: "CoreDataModel",
+        type: libraryType,
+        targets: [
+            "CoreDataModel"
+        ]
+    )
+)
+package.targets.insert(
+    .target(
+        name: "CoreDataModel",
+        dependencies: [
+            "CoreModel"
+        ],
+        swiftSettings: [
+            .swiftLanguageMode(.v5)
+        ]
+    ),
+    at: 1
+)
+package.targets[package.targets.count - 1] = .testTarget(
+    
+    .byName(
+        name: "CoreModelTests",
+        dependencies: [
+            "CoreModel",
+            .byName(
+                name: "CoreDataModel",
+                condition: .when(platforms: [.macOS, .iOS, .macCatalyst, .watchOS, .tvOS, .visionOS])
+            )
+        ]
+    )
+)
+#endif
+
+// SwiftPM plugins
+if buildDocs {
+    package.dependencies += [
+        .package(
+            url: "https://github.com/swiftlang/swift-docc-plugin.git",
+            from: "1.4.5"
+        )
+    ]
+}
+
+if enableMacros {
+    let version: Version
+    #if swift(>=6.1)
+    version = "601.0.1"
+    #else
+    version = "600.0.1"
+    #endif
+    package.targets[0].swiftSettings = [
+        .define("SWIFTPM_ENABLE_MACROS")
+    ]
+    package.dependencies += [
+        .package(
+            url: "https://github.com/swiftlang/swift-syntax.git",
+            from: version
+        )
+    ]
+    package.targets += [
         .macro(
           name: "CoreModelMacros",
           dependencies: [
@@ -65,17 +118,9 @@ let package = Package(
                   package: "swift-syntax"
               )
           ]
-        ),
-        .testTarget(
-            name: "CoreModelTests",
-            dependencies: [
-                "CoreModel",
-                "CoreModelMacros",
-                .byName(
-                    name: "CoreDataModel",
-                    condition: .when(platforms: [.macOS, .iOS, .macCatalyst, .watchOS, .tvOS, .visionOS])
-                )
-            ]
         )
     ]
-)
+    package.targets[0].dependencies += [
+        "CoreModelMacros"
+    ]
+}

Sources/CoreModel/Macros.swift

@@ -5,6 +5,7 @@
 //  Created by Alsey Coleman Miller on 6/17/25.
 //
 
+#if !hasFeature(Embedded) && SWIFTPM_ENABLE_MACROS
 @attached(member, names: arbitrary)
 @attached(extension, conformances: CoreModel.Entity)
 public macro Entity(_ name: String? = nil) = #externalMacro(
@@ -23,3 +24,4 @@ public macro Relationship<T: CoreModel.Entity>(destination: T.Type, inverse: T.C
     module: "CoreModelMacros",
     type: "RelationshipMacro"
 )
+#endif