Enhancements to Macro Examples: Unit Tests and Code Organization

Examples/Package.swift

@@ -52,7 +52,9 @@ let package = Package(
     .testTarget(
       name: "MacroExamplesImplementationTests",
       dependencies: [
-        "MacroExamplesImplementation"
+        "MacroExamplesImplementation",
+        .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+        .product(name: "SwiftSyntaxMacrosTestSupport", package: "swift-syntax"),
       ],
       path: "Tests/MacroExamples/Implementation"
     ),

Examples/Sources/MacroExamples/Implementation/DictionaryIndirectionMacro.swift → Examples/Sources/MacroExamples/Implementation/ComplexMacros/DictionaryIndirectionMacro.swift

@@ -81,16 +81,14 @@ public struct DictionaryStoragePropertyMacro: AccessorMacro {
 
     return [
       """
-
-        get {
-          _storage[\(literal: identifier.text), default: \(defaultValue)] as! \(type)
-        }
+      get {
+        _storage[\(literal: identifier.text), default: \(defaultValue)] as! \(type)
+      }
       """,
       """
-
-        set {
-            _storage[\(literal: identifier.text)] = newValue
-        }
+      set {
+        _storage[\(literal: identifier.text)] = newValue
+      }
       """,
     ]
   }

Examples/Sources/MacroExamples/Implementation/FontLiteralMacro.swift → Examples/Sources/MacroExamples/Implementation/Expression/FontLiteralMacro.swift

@@ -16,13 +16,13 @@ import SwiftSyntaxMacros
 /// Implementation of the `#fontLiteral` macro, which is similar in spirit
 /// to the built-in expressions `#colorLiteral`, `#imageLiteral`, etc., but in
 /// a small macro.
-public struct FontLiteralMacro: ExpressionMacro {
+public enum FontLiteralMacro: ExpressionMacro {
   public static func expansion(
-    of macro: some FreestandingMacroExpansionSyntax,
+    of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext
-  ) -> ExprSyntax {
+  ) throws -> ExprSyntax {
     let argList = replaceFirstLabel(
-      of: macro.arguments,
+      of: node.arguments,
       with: "fontLiteralName"
     )
     return ".init(\(argList))"
@@ -40,6 +40,9 @@ private func replaceFirstLabel(
   }
 
   var tuple = tuple
-  tuple[tuple.startIndex] = firstElement.with(\.label, .identifier(newLabel))
+  tuple[tuple.startIndex] =
+    firstElement
+    .with(\.label, .identifier(newLabel))
+    .with(\.colon, .colonToken())
   return tuple
 }

Examples/Sources/MacroExamples/Implementation/StringifyMacro.swift → Examples/Sources/MacroExamples/Implementation/Expression/StringifyMacro.swift

@@ -23,7 +23,7 @@ import SwiftSyntaxMacros
 ///  will expand to
 ///
 ///     (x + y, "x + y")
-public struct StringifyMacro: ExpressionMacro {
+public enum StringifyMacro: ExpressionMacro {
   public static func expansion(
     of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext

Examples/Sources/MacroExamples/Implementation/URLMacro.swift → Examples/Sources/MacroExamples/Implementation/Expression/URLMacro.swift

@@ -16,12 +16,11 @@ import SwiftSyntaxMacros
 
 /// Creates a non-optional URL from a static string. The string is checked to
 /// be valid during compile time.
-public struct URLMacro: ExpressionMacro {
+public enum URLMacro: ExpressionMacro {
   public static func expansion(
     of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext
   ) throws -> ExprSyntax {
-
     guard let argument = node.arguments.first?.expression,
       let segments = argument.as(StringLiteralExprSyntax.self)?.segments,
       segments.count == 1,

Examples/Sources/MacroExamples/Implementation/WarningMacro.swift → Examples/Sources/MacroExamples/Implementation/Expression/WarningMacro.swift

@@ -16,12 +16,12 @@ import SwiftSyntaxMacros
 
 /// Implementation of the `myWarning` macro, which mimics the behavior of the
 /// built-in `#warning`.
-public struct WarningMacro: ExpressionMacro {
+public enum WarningMacro: ExpressionMacro {
   public static func expansion(
-    of macro: some FreestandingMacroExpansionSyntax,
+    of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext
   ) throws -> ExprSyntax {
-    guard let firstElement = macro.arguments.first,
+    guard let firstElement = node.arguments.first,
       let stringLiteral = firstElement.expression
         .as(StringLiteralExprSyntax.self),
       stringLiteral.segments.count == 1,
@@ -32,10 +32,10 @@ public struct WarningMacro: ExpressionMacro {
 
     context.diagnose(
       Diagnostic(
-        node: Syntax(macro),
+        node: Syntax(node),
         message: SimpleDiagnosticMessage(
           message: messageString.content.description,
-          diagnosticID: MessageID(domain: "test", id: "error"),
+          diagnosticID: MessageID(domain: "test123", id: "error"),
           severity: .warning
         )
       )

Examples/Sources/MacroExamples/Implementation/CaseDetectionMacro.swift → Examples/Sources/MacroExamples/Implementation/Member/CaseDetectionMacro.swift

@@ -13,25 +13,11 @@
 import SwiftSyntax
 import SwiftSyntaxMacros
 
-extension TokenSyntax {
-  fileprivate var initialUppercased: String {
-    let name = self.text
-    guard let initial = name.first else {
-      return name
-    }
-
-    return "\(initial.uppercased())\(name.dropFirst())"
-  }
-}
-
-public struct CaseDetectionMacro: MemberMacro {
-  public static func expansion<
-    Declaration: DeclGroupSyntax,
-    Context: MacroExpansionContext
-  >(
+public enum CaseDetectionMacro: MemberMacro {
+  public static func expansion(
     of node: AttributeSyntax,
-    providingMembersOf declaration: Declaration,
-    in context: Context
+    providingMembersOf declaration: some DeclGroupSyntax,
+    in context: some MacroExpansionContext
   ) throws -> [DeclSyntax] {
     declaration.memberBlock.members
       .compactMap { $0.decl.as(EnumCaseDeclSyntax.self) }
@@ -50,3 +36,14 @@ public struct CaseDetectionMacro: MemberMacro {
       }
   }
 }
+
+extension TokenSyntax {
+  fileprivate var initialUppercased: String {
+    let name = self.text
+    guard let initial = name.first else {
+      return name
+    }
+
+    return "\(initial.uppercased())\(name.dropFirst())"
+  }
+}

Examples/Sources/MacroExamples/Implementation/CustomCodable.swift → Examples/Sources/MacroExamples/Implementation/Member/CustomCodable.swift

@@ -13,14 +13,12 @@
 import SwiftSyntax
 import SwiftSyntaxMacros
 
-public struct CustomCodable: MemberMacro {
-
+public enum CustomCodable: MemberMacro {
   public static func expansion(
     of node: AttributeSyntax,
     providingMembersOf declaration: some DeclGroupSyntax,
     in context: some MacroExpansionContext
   ) throws -> [DeclSyntax] {
-
     let memberList = declaration.memberBlock.members
 
     let cases = memberList.compactMap({ member -> String? in
@@ -46,15 +44,22 @@ public struct CustomCodable: MemberMacro {
     })
 
     let codingKeys: DeclSyntax = """
-
-        enum CodingKeys: String, CodingKey {
-          \(raw: cases.joined(separator: "\n"))
-        }
-
+      enum CodingKeys: String, CodingKey {
+        \(raw: cases.joined(separator: "\n"))
+      }
       """
 
-    return [
-      codingKeys
-    ]
+    return [codingKeys]
+  }
+}
+
+public struct CodableKey: PeerMacro {
+  public static func expansion(
+    of node: AttributeSyntax,
+    providingPeersOf declaration: some DeclSyntaxProtocol,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    // Does nothing, used only to decorate members with data
+    return []
   }
 }

Examples/Sources/MacroExamples/Implementation/MetaEnumMacro.swift → Examples/Sources/MacroExamples/Implementation/Member/MetaEnumMacro.swift

@@ -41,36 +41,39 @@ public struct MetaEnumMacro {
 
   func makeMetaEnum() -> DeclSyntax {
     // FIXME: Why does this need to be a string to make trailing trivia work properly?
-    let caseDecls = childCases.map { childCase in
-      "    case \(childCase.name)"
-    }.joined(separator: "\n")
+    let caseDecls =
+      childCases
+      .map { childCase in
+        "  case \(childCase.name)"
+      }
+      .joined(separator: "\n")
 
     return """
-
-        \(access)enum Meta {
+      \(access)enum Meta {
       \(raw: caseDecls)
       \(makeMetaInit())
-        }
-
+      }
       """
   }
 
   func makeMetaInit() -> DeclSyntax {
     // FIXME: Why does this need to be a string to make trailing trivia work properly?
-    let caseStatements = childCases.map { childCase in
-      """
-            case .\(childCase.name):
-              self = .\(childCase.name)
-      """
-    }.joined(separator: "\n")
+    let caseStatements =
+      childCases
+      .map { childCase in
+        """
+          case .\(childCase.name):
+            self = .\(childCase.name)
+        """
+      }
+      .joined(separator: "\n")
 
     return """
-
-          \(access)init(_ \(parentParamName): \(parentTypeName)) {
-            switch \(parentParamName) {
+      \(access)init(_ \(parentParamName): \(parentTypeName)) {
+        switch \(parentParamName) {
       \(raw: caseStatements)
-            }
-          }
+        }
+      }
       """
   }
 }

Examples/Sources/MacroExamples/Implementation/AddAsyncMacro.swift → Examples/Sources/MacroExamples/Implementation/Peer/AddAsyncMacro.swift

@@ -101,12 +101,12 @@ public struct AddAsyncMacro: PeerMacro {
 
     let switchBody: ExprSyntax =
       """
-        switch returnValue {
-        case .success(let value):
-            continuation.resume(returning: value)
-        case .failure(let error):
-            continuation.resume(throwing: error)
-        }
+            switch returnValue {
+            case .success(let value):
+              continuation.resume(returning: value)
+            case .failure(let error):
+              continuation.resume(throwing: error)
+            }
       """
 
     let newBody: ExprSyntax =
@@ -115,8 +115,7 @@ public struct AddAsyncMacro: PeerMacro {
         \(raw: isResultReturn ? "try await withCheckedThrowingContinuation { continuation in" : "await withCheckedContinuation { continuation in")
           \(raw: funcDecl.name)(\(raw: callArguments.joined(separator: ", "))) { \(raw: returnType != nil ? "returnValue in" : "")
 
-          \(raw: isResultReturn ? switchBody : "continuation.resume(returning: \(raw: returnType != nil ? "returnValue" : "()"))")
-
+      \(raw: isResultReturn ? switchBody : "continuation.resume(returning: \(raw: returnType != nil ? "returnValue" : "()"))")
           }
         }
 

Examples/Sources/MacroExamples/Interface/Macros.swift → Examples/Sources/MacroExamples/Interface/ComplexMacros.swift

@@ -10,46 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import Foundation
-
-/// "Stringify" the provided value and produce a tuple that includes both the
-/// original value as well as the source code that generated it.
-@freestanding(expression) public macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "MacroExamplesImplementation", type: "StringifyMacro")
-
-/// Macro that produces a warning on "+" operators within the expression, and
-/// suggests changing them to "-".
-@freestanding(expression) public macro addBlocker<T>(_ value: T) -> T = #externalMacro(module: "MacroExamplesImplementation", type: "AddBlocker")
-
-/// Macro that produces a warning, as a replacement for the built-in
-/// #warning("...").
-@freestanding(expression) public macro myWarning(_ message: String) = #externalMacro(module: "MacroExamplesImplementation", type: "WarningMacro")
-
-public enum FontWeight {
-  case thin
-  case normal
-  case medium
-  case semiBold
-  case bold
-}
-
-public protocol ExpressibleByFontLiteral {
-  init(fontLiteralName: String, size: Int, weight: FontWeight)
-}
-
-/// Font literal similar to, e.g., #colorLiteral.
-@freestanding(expression) public macro fontLiteral<T>(name: String, size: Int, weight: FontWeight) -> T =
-  #externalMacro(module: "MacroExamplesImplementation", type: "FontLiteralMacro")
-where T: ExpressibleByFontLiteral
-
-/// Check if provided string literal is a valid URL and produce a non-optional
-/// URL value. Emit error otherwise.
-@freestanding(expression) public macro URL(_ stringLiteral: String) -> URL = #externalMacro(module: "MacroExamplesImplementation", type: "URLMacro")
-
-/// Apply the specified attribute to each of the stored properties within the
-/// type or member to which the macro is attached. The string can be
-/// any attribute (without the `@`).
-@attached(memberAttribute)
-public macro wrapStoredProperties(_ attributeName: String) = #externalMacro(module: "MacroExamplesImplementation", type: "WrapStoredPropertiesMacro")
+// MARK: - Dictionary Storage
 
 /// Wrap up the stored properties of the given type in a dictionary,
 /// turning them into computed properties.
@@ -66,6 +27,8 @@ public macro DictionaryStorage() = #externalMacro(module: "MacroExamplesImplemen
 @attached(accessor)
 public macro DictionaryStorageProperty() = #externalMacro(module: "MacroExamplesImplementation", type: "DictionaryStoragePropertyMacro")
 
+// MARK: - Observable
+
 public protocol Observable {}
 
 public protocol Observer<Subject> {
@@ -108,29 +71,7 @@ public macro Observable() = #externalMacro(module: "MacroExamplesImplementation"
 @attached(accessor)
 public macro ObservableProperty() = #externalMacro(module: "MacroExamplesImplementation", type: "ObservablePropertyMacro")
 
-/// Adds a "completionHandler" variant of an async function, which creates a new
-/// task , calls thh original async function, and delivers its result to the completion
-/// handler.
-@attached(peer, names: overloaded)
-public macro AddCompletionHandler() =
-  #externalMacro(module: "MacroExamplesImplementation", type: "AddCompletionHandlerMacro")
-
-@attached(peer, names: overloaded)
-public macro AddAsync() =
-  #externalMacro(module: "MacroExamplesImplementation", type: "AddAsyncMacro")
-
-/// Add computed properties named `is<Case>` for each case element in the enum.
-@attached(member, names: arbitrary)
-public macro CaseDetection() = #externalMacro(module: "MacroExamplesImplementation", type: "CaseDetectionMacro")
-
-@attached(member, names: named(Meta))
-public macro MetaEnum() = #externalMacro(module: "MacroExamplesImplementation", type: "MetaEnumMacro")
-
-@attached(peer)
-public macro CodableKey(name: String) = #externalMacro(module: "MacroExamplesImplementation", type: "CodableKey")
-
-@attached(member, names: named(CodingKeys))
-public macro CustomCodable() = #externalMacro(module: "MacroExamplesImplementation", type: "CustomCodable")
+// MARK: - Option Set
 
 /// Create an option set from a struct that contains a nested `Options` enum.
 ///