clean up macro examples and README.md, remove run.dart script (#3582)

- Delete run.dart script and update the README.md to indicate you can just pass `--enable-experiment=macros`.
- Break up `user_main.dart` into separate scripts for each macro example, which allows you to run the ones that do work, and also keeps the example apps more targetted. These were only combined into one previously to make it easier to run them through `run.dart`.
- Update the observable example so it is runnable.
- Update the data class example to create the unnamed constructor instead of one called `gen`.

working/macros/example/README.md

@@ -1,15 +1,20 @@
 **DISCLAIMER**: All code in this package is experimental and should be treated
-as such.
-
-This package some example macros (under `lib`), as well as some utilities to try
-actually running those examples.
+as such. The examples are unstable and may or may not work at any given time,
+depending on the implementation status.
 
 ## Setup
 
 Your SDK will need to match roughly the commit pinned in the pubspec.yaml file
 of this package (see the `ref` lines). Otherwise you will get a kernel version
 mismatch.
 
+## Examples
+
+The example macros live under `lib/` and there are programs using them under
+`bin/`. To try and run an example, you need to enable the `macros` experiment,
+`dart --enable-experiment=macros <script>`, but the implementations do not yet
+support all the examples here so you should expect errors.
+
 ## Benchmarks
 
 There is a basic benchmark at `benchmark/simple.dart`. You can run this tool
@@ -19,12 +24,3 @@ environment (compiler).
 
 This benchmark uses a synthetic program, and only benchmarks the overhead of
 running the macro itself, and the communication to and from the host program.
-
-## Examples
-
-There is an example program at `bin/user_main.dart`. This _cannot_ be directly
-executed but you can compile and execute it with the `bin/run.dart` script.
-
-**NOTE**: This is not meant to be a representative example of how a script using
-macros would be compiled and ran in the real world, but it does allow you to
-execute the program.

working/macros/example/analysis_options.yaml

@@ -7,6 +7,5 @@ analyzer:
     # TODO: remove these when the analyzer supports macros enough to run them
     - bin/checks_main.dart
     - bin/injectable_main.dart
-    - bin/user_main.dart
     - bin/json_serializable_main.dart
     - bin/observable_main.dart

working/macros/example/bin/auto_dispose_main.dart

@@ -0,0 +1,41 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:macro_proposal/auto_dispose.dart';
+
+void main() {
+  var state = MyState(a: ADisposable(), b: BDisposable(), c: 'hello world');
+  state.dispose();
+}
+
+@AutoDispose()
+class MyState extends State {
+  final ADisposable a;
+  final ADisposable? a2;
+  final BDisposable b;
+  final String c;
+
+  MyState({required this.a, this.a2, required this.b, required this.c});
+
+  @override
+  String toString() => 'MyState!';
+}
+
+class State {
+  void dispose() {
+    print('disposing of $this');
+  }
+}
+
+class ADisposable implements Disposable {
+  void dispose() {
+    print('disposing of ADisposable');
+  }
+}
+
+class BDisposable implements Disposable {
+  void dispose() {
+    print('disposing of BDisposable');
+  }
+}

working/macros/example/bin/checks_main.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
 @ChecksExtensions([Person])
 library;
 

working/macros/example/bin/data_class_main.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:macro_proposal/data_class.dart';
+
+void main() {
+  var joe = User(age: 25, name: 'Joe', username: 'joe1234');
+  print(joe);
+
+  var phoenix = joe.copyWith(name: 'Phoenix', age: 23);
+  print(phoenix);
+}
+
+@DataClass()
+class User {
+  final int age;
+  final String name;
+  final String username;
+}
+
+@DataClass()
+class Manager extends User {
+  final List<User> reports;
+}

working/macros/example/bin/injectable_main.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
 import 'package:macro_proposal/injectable.dart';
 
 void main() {

working/macros/example/bin/observable_main.dart

@@ -1,3 +1,7 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
 import 'package:macro_proposal/observable.dart';
 
 void main() {
@@ -16,6 +20,6 @@ class ObservableUser {
   ObservableUser({
     required int age,
     required String name,
-  }) : _age = age,
-       _name = name;
+  })  : _age = age,
+        _name = name;
 }