Move EquatableExtensionMacro from ExamplePlugin to MacroExamples target

Author: Matejkob

Examples/Sources/MacroExamples/Implementation/Extension/EquatableExtensionMacro.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 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
+
+public enum EquatableExtensionMacro: ExtensionMacro {
+  public static func expansion(
+    of node: AttributeSyntax,
+    attachedTo declaration: some DeclGroupSyntax,
+    providingExtensionsOf type: some TypeSyntaxProtocol,
+    conformingTo protocols: [TypeSyntax],
+    in context: some MacroExpansionContext
+  ) throws -> [ExtensionDeclSyntax] {
+    let equatableExtension = try ExtensionDeclSyntax("extension \(type.trimmed): Equatable {}")
+
+    return [equatableExtension]
+  }
+}

Examples/Sources/MacroExamples/Implementation/Plugin.swift

@@ -38,6 +38,7 @@ struct MyPlugin: CompilerPlugin {
     FuncUniqueMacro.self,
     PeerValueWithSuffixNameMacro.self,
     MemberDeprecatedMacro.self,
+    EquatableExtensionMacro.self,
   ]
 }
 #endif

Examples/Sources/MacroExamples/Interface/ExtensionMacros.swift

@@ -0,0 +1,16 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 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
+//
+//===----------------------------------------------------------------------===//
+
+// MARK: - Equatable Extension
+
+@attached(extension, conformances: Equatable)
+public macro equatable() = #externalMacro(module: "MacroExamplesImplementation", type: "EquatableExtensionMacro")

Examples/Sources/MacroExamples/Playground/ExtensionMacrosPlayground.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 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 MacroExamplesInterface
+
+// MARK: - Equatable Extension
+
+@equatable
+struct Pet {
+  let name: String
+}
+
+func runEquatableExtensionMacroPlayground() {
+  let cat = Pet(name: "Tom")
+  let mouse = Pet(name: "Jerry")
+
+  print("Has the cat \(cat) the same name as the mouse \(mouse)?", cat == mouse ? "Yes." : "No.")
+}

Examples/Sources/MacroExamples/Playground/main.swift

@@ -32,7 +32,7 @@ runExpressionMacrosPlayground()
 
 // MARK: - Extension Macros
 
-// TODO: Add example of extension macro
+runEquatableExtensionMacroPlayground()
 
 // MARK: - Member Attribute Macros
 

Examples/Tests/MacroExamples/Implementation/Extension/EquatableExtensionMacroTests.swift

@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 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 MacroExamplesImplementation
+import SwiftSyntaxMacros
+import SwiftSyntaxMacrosTestSupport
+import XCTest
+
+final class EquatableExtensionMacroTests: XCTestCase {
+  private let macros = ["equatable": EquatableExtensionMacro.self]
+
+  func testExpansionAddsExtensionWithEquatableConformance() {
+    assertMacroExpansion(
+      """
+      @equatable
+      final public class Message {
+        let text: String
+        let sender: String
+      }
+      """,
+      expandedSource: """
+        final public class Message {
+          let text: String
+          let sender: String
+        }
+
+        extension Message: Equatable {
+        }
+        """,
+      macros: macros,
+      indentationWidth: .spaces(2)
+    )
+  }
+}