Enable macros for Dart and Flutter Projects

To enable macros for Dart and Flutter projects, you need to follow a few key steps:

Update Flutter and Dart

First, ensure you’re using the latest Flutter version that supports macros:

1. Switch to the master channel:

   flutter channel master
   flutter upgrade
   

2. Update your pubspec.yaml to use a DEV version of Dart:

   environment:
     sdk: ^3.7.0-243.0.dev
   

Enable Macros in Project Configuration

1. Create or update your analysis_options.yaml file in the project root:

   analyzer:
     enable-experiment:
       - macros
   

Configure VS Code for Macros

To enable macros at runtime in VS Code:

1. Create or open the .vscode/launch.json file in your project.

2. Add a new configuration or modify an existing one to include the macros experiment flag:

   a. For Dart CLI project:

    ```json
    {
        "version": "0.2.0",
        "configurations": [
            {
                "name": "Dart CLI",
                "request": "launch",
                "type": "dart",
                "vmAdditionalArgs": ["--enable-experiment=macros"]
            }
        ]
    }
    ```
   

   b. For Flutter project:

    {
        "version": "0.2.0",
        "configurations": [
            {
                "name": "Flutter",
                "request": "launch",
                "type": "dart",
                "toolArgs": [
                    "--enable-experiment=macros"
                ]
            }
        ]
    }
   

This configuration ensures that when you run or debug your Dart CLI or Flutter application from VS Code, it will enable the macros experiment.

Additional Steps

• If you’re using the json package for macros, add it to your pubspec.yaml:

  dependencies:
    json: ^1.0.0
  

  Then run flutter pub get to install it.

• For Dart CLI projects, you may need to adjust the program field in the launch configuration to point to your main Dart file, typically bin/main.dart.

• In some recent Dart SDK versions, you might see this compiling error when using macros:

    The part-of directive must be the only directive in a part. Try removing the other directives, or moving them to the library for which this is a part.
  

  You can fix it by updating your analysis_options.yaml file in the project root to enable enhanced-parts flag along with macros:

    analyzer:
      enable-experiment:
        - macros
        - enhanced-parts
  

By following these steps, you’ll have macros enabled in your Dart CLI or Flutter project, both for analysis and at runtime when launching from VS Code.