Master Source Code Generation in Just 2 Parts

Master Source Code Generation in Just 2 Parts

Table of Contents

1. Introduction
2. Building Source Generators
   1. Part 1: Setting up the project
   2. Part 2: Extending the project
3. Adding Metadata and Warnings
4. Source Syntax and Retrieving Information
   1. Creating a StringBuilder
   2. Getting a Symbol
   3. Getting the Declared Symbol
5. Building Strings for Class Names
6. Compiling and Running the Code
   1. Handling Console Apps
   2. Providing Class Names
7. Error Handling and Reporting
   1. Creating a Diagnostic Descriptor
   2. Setting the Category and Severity
   3. Reporting the Diagnostic
8. Debugging and Testing
9. Helpful Tips and Tricks
10. Conclusion

Building Source Generators: Extending the Project

In the second part of this series on building source generators, we will be extending the project that we set up in the previous part. Our goal is to read metadata and implement additional functionalities such as showing warnings. This will give you a better understanding of source generators and what they can do.

Before we delve into the details, I would like to mention that I have some upcoming courses in April and May. If you're interested, you can find more information in the provided link. Your support by liking this video and subscribing to my channel would be greatly appreciated.

Let's get started by building upon the code we created in the first part. In this section, we will focus on reading metadata and performing some operations based on that information. To begin with, we will create a public static list of strings called names. This list will contain the class names that we will be working with.

In order to retrieve the necessary information from the classes, we will need to use the TypeList feature. We will start by creating a StringBuilder. This will allow us to construct the necessary text that we will then include in our classes. We will iterate through each class syntax in the TypeList and extract useful information using the Symbol feature. To accomplish this, we will utilize a compilation and the semantic model.

Once we have the semantic model, we can retrieve the declared symbol that represents the class. This will give us access to the class name, among other things. We will append the class name to our StringBuilder using the Append method. Before doing so, we will check if the symbol is not null to ensure that we are working with valid data.

After building all the necessary strings, we can proceed to initialize our classes. Surrounding the code with the required pieces will ensure proper initialization. Once the changes are implemented, we can build and run the project to see the results.

However, there is an issue that needs to be addressed. If the TypeList does not contain any classes, we want to display a warning message to inform the user. To achieve this, we can utilize a diagnostic descriptor. By creating a new diagnostic descriptor with the appropriate error name, title, and severity, we can generate a warning message that will be shown to the user when there are no classes declared in the project.

To report the diagnostic, we need to call Diagnostic.Create within the context. This method requires the descriptor we created earlier and the location of the error. In our case, since we don't know the exact location, we can simply report the diagnostic without providing the line or column numbers.

In conclusion, in this part, we expanded our project to read metadata and perform various operations based on the retrieved information. We also implemented a diagnostic descriptor to display a warning message when there are no classes declared in the project. Debugging and testing techniques were also discussed. Stay tuned for the next part where we will explore more advanced concepts of source generators.

Highlights

• Building source generators allows for automated code generation based on metadata.
• Extending the project by reading metadata and showing warnings adds more functionality to the source generators.
• Using the TypeList feature, we can retrieve information about classes in the project.
• Creating a StringBuilder helps build the strings that will be included in the generated classes.
• The Symbol feature allows us to extract valuable information from the classes.
• Implementing error handling and reporting with diagnostic descriptors provides useful feedback to the user.
• Debugging and testing techniques can be applied to ensure the source generator functions as intended.

FAQ

Q: Can source generators be used in any type of project?\ A: Source generators can be used in various types of projects, including console apps. However, the availability and usefulness of the generated code may vary depending on the project's nature.

Q: How can I debug a source generator?\ A: One approach is to attach a debugger to the project and utilize breakpoints to inspect the code and its variables. Additionally, using conditional statements like Debugger.IsAttached can help facilitate debugging.

Q: Can I customize the warning and error messages generated by the diagnostic descriptor?\ A: Yes, you can customize the messages according to your requirements. The diagnostic descriptor allows you to set the error name, title, category, severity, and description, providing flexibility in the error messages displayed to the user.