Introduce modularization

.github/workflows/test-macos.yml

@@ -16,4 +16,4 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Test
-      run: swift test
+      run: cd "Example" && swift test

Example/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

Example/Package.swift

@@ -0,0 +1,52 @@
+// swift-tools-version: 5.9
+
+import PackageDescription
+
+let package = Package(
+    name: "macro-toolkit-example",
+    products: [
+        .library(
+          name: "Example",
+          targets: ["Example"]
+        ),
+    ],
+    dependencies: [
+        // For basic functionality you can just depend on `swift-macro-toolkit`
+        // `swift-syntax` will be added as nested dependency. "SwiftSyntax", "SwiftDiagnostics",
+        // and "SwiftCompilerPlugin" targets will be importable
+        .package("../"),
+
+        // However `swift-syntax` is needed for testing
+        // You may consider using https://github.com/pointfreeco/swift-macro-testing instead
+        .package(
+          url: "https://github.com/apple/swift-syntax.git",
+          exact: "509.0.0"
+        ),
+    ],
+    targets: [
+        // Declares macros used by `swift-macro-toolkit` tests
+        .target(
+          name: "MacroToolkitExample",
+          dependencies: ["MacroToolkitExamplePlugin"]
+        ),
+
+        // Implementations of macros tested by `swift-macro-toolkit` tests
+        .macro(
+            name: "MacroToolkitExamplePlugin",
+            dependencies: [
+                .product(name: "MacroToolkit", package: "swift-macro-toolkit")
+            ]
+        ),
+
+        .testTarget(
+            name: "MacroToolkitTests",
+            dependencies: [
+                "MacroToolkitExample",
+                .product(name: "MacroToolkit", package: "swift-macro-toolkit")
+                .product(name: "SwiftSyntax", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxMacrosTestSupport", package: "swift-syntax"),
+            ]
+        ),
+    ]
+)

Package.resolved

@@ -5,8 +5,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/SwiftPackageIndex/SPIManifest.git",
       "state" : {
-        "revision" : "59b957c55c274ae08da9aaa36efcaac3fb7a326c",
-        "version" : "0.19.0"
+        "revision" : "5569d7aca29b7d7f4f793ba997bfaa72ca99fca7",
+        "version" : "0.12.0"
       }
     },
     {

Package.swift

@@ -10,49 +10,56 @@ let package = Package(
         .library(
             name: "MacroToolkit",
             targets: ["MacroToolkit"]
+        ),
+        .library(
+            name: "DiagnosticBuilder",
+            targets: ["DiagnosticBuilder"]
+        ),
+        .library(
+            name: "MacroToolkitTypes",
+            targets: ["MacroToolkitTypes"]
         )
     ],
     dependencies: [
         .package(
             url: "https://github.com/apple/swift-syntax.git",
             exact: "509.0.0"
         ),
-        .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.3.0"),
-        .package(url: "https://github.com/SwiftPackageIndex/SPIManifest.git", from: "0.12.0"),
+        .package(
+            url: "https://github.com/apple/swift-docc-plugin",
+            from: "1.3.0"
+        ),
+        .package(
+            url: "https://github.com/SwiftPackageIndex/SPIManifest.git",
+            .upToNextMinor(from: "0.12.0")
+        ),
     ],
     targets: [
-        // Implementations of macros tested by tests
-        .macro(
-            name: "MacroToolkitExamplePlugin",
+        .target(
+            name: "MacroToolkit",
             dependencies: [
-                .product(name: "SwiftSyntax", package: "swift-syntax"),
-                .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
-                .product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
-                "MacroToolkit",
+                .target(name: "DiagnosticBuilder"),
+                .target(name: "MacroToolkitTypes")
             ]
         ),
 
-        // Declares macros used by tests
-        .target(name: "MacroToolkitExample", dependencies: ["MacroToolkitExamplePlugin"]),
-
         .target(
-            name: "MacroToolkit",
+            name: "DiagnosticBuilder",
             dependencies: [
                 .product(name: "SwiftSyntax", package: "swift-syntax"),
-                .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+                .product(name: "SwiftDiagnostics", package: "swift-syntax"),
                 .product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
             ]
         ),
 
-        .testTarget(
-            name: "MacroToolkitTests",
+        .target(
+            name: "MacroToolkitTypes",
             dependencies: [
-                "MacroToolkitExample",
-                "MacroToolkit",
+                .target(name: "DiagnosticBuilder"),
                 .product(name: "SwiftSyntax", package: "swift-syntax"),
                 .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
-                .product(name: "SwiftSyntaxMacrosTestSupport", package: "swift-syntax"),
+                .product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
             ]
-        ),
+        )
     ]
 )

Sources/MacroToolkit/Diagnostics.swift → Sources/DiagnosticBuilder/DiagnosticBuilder.swift

@@ -2,44 +2,6 @@ import Foundation
 import SwiftDiagnostics
 import SwiftSyntax
 
-// Taken from: https://github.com/DougGregor/swift-macro-examples/blob/f61ac7cdca8dc3557e53f86e7e03df1353908d3e/MacroExamplesPlugin/Diagnostics.swift
-/// A simple diagnostic with a message, id, and severity.
-public struct SimpleDiagnosticMessage: DiagnosticMessage, Error {
-    /// The human-readable message.
-    public let message: String
-    /// The unique diagnostic id (should be the same for all diagnostics produced by the same codepath).
-    public let diagnosticID: MessageID
-    /// The diagnostic's severity.
-    public let severity: DiagnosticSeverity
-
-    /// Creates a new diagnostic message.
-    public init(message: String, diagnosticID: MessageID, severity: DiagnosticSeverity) {
-        self.message = message
-        self.diagnosticID = diagnosticID
-        self.severity = severity
-    }
-}
-
-extension SimpleDiagnosticMessage: FixItMessage {
-    /// The unique fix-it id (should be the same for all fix-its produced by the same codepath).
-    public var fixItID: MessageID { diagnosticID }
-}
-
-/// A generic macro error. If you are making a widely used macro I'd encourage you
-/// to instead provide more detailed diagnostics through the diagnostics API that
-/// macros have access to.
-public struct MacroError: LocalizedError {
-    let message: String
-
-    public init(_ message: String) {
-        self.message = message
-    }
-
-    public var errorDescription: String? {
-        message
-    }
-}
-
 /// A way to create rich diagnostics with no unnecessary boilerplate code. Only provide the
 /// important details and the rest will be given sensible defaults.
 public struct DiagnosticBuilder {

Sources/DiagnosticBuilder/MacroError.swift

@@ -0,0 +1,16 @@
+import Foundation
+
+/// A generic macro error. If you are making a widely used macro I'd encourage you
+/// to instead provide more detailed diagnostics through the diagnostics API that
+/// macros have access to.
+public struct MacroError: LocalizedError {
+    let message: String
+
+    public init(_ message: String) {
+        self.message = message
+    }
+
+    public var errorDescription: String? {
+        message
+    }
+}

Sources/DiagnosticBuilder/SimpleDiagnosticMessage.swift

@@ -0,0 +1,24 @@
+import SwiftDiagnostics
+
+// Taken from: https://github.com/DougGregor/swift-macro-examples/blob/f61ac7cdca8dc3557e53f86e7e03df1353908d3e/MacroExamplesPlugin/Diagnostics.swift
+/// A simple diagnostic with a message, id, and severity.
+public struct SimpleDiagnosticMessage: DiagnosticMessage, Error {
+    /// The human-readable message.
+    public let message: String
+    /// The unique diagnostic id (should be the same for all diagnostics produced by the same codepath).
+    public let diagnosticID: MessageID
+    /// The diagnostic's severity.
+    public let severity: DiagnosticSeverity
+
+    /// Creates a new diagnostic message.
+    public init(message: String, diagnosticID: MessageID, severity: DiagnosticSeverity) {
+        self.message = message
+        self.diagnosticID = diagnosticID
+        self.severity = severity
+    }
+}
+
+extension SimpleDiagnosticMessage: FixItMessage {
+    /// The unique fix-it id (should be the same for all fix-its produced by the same codepath).
+    public var fixItID: MessageID { diagnosticID }
+}

Sources/MacroToolkit/Exports.swift

@@ -0,0 +1,2 @@
+@_exported import DiagnosticBuilder
+@_exported import MacroToolkitTypes

Sources/MacroToolkitTypes/Diagnostics.swift

@@ -0,0 +1 @@
+