libphonenumber-csharp VS Roslyn

I have to write a feature to clean up / reformat shit data for phone numbers. I do have alpha-2 country code and was going to use this: https://github.com/twcclegg/libphonenumber-csharp

My understanding is that the .NET team is working toward this with Interceptors: https://github.com/dotnet/roslyn/blob/main/docs/features/int...

.NET is a little smarter about switch code generation these days: https://github.com/dotnet/roslyn/pull/66081

Recently, while creating some experimental C# source code generators (xafero/csharp-generators), I was just concatenating strings together. Like you do, you know, if things have to go very quickly. If you have a simple use case, use a formatted multi-line string or some template library like scriban. But I searched for a way to generate more and more complicated logic easily - like for example, adding raw SQL handler methods to my pre-generated DBSet-like classes for my ADO.NET experiment. You could now say: Use Roslyn and that's really fine if you look everything up in a website like SharpLab, which shows immediately the syntax tree of our C# code.

At runtime, the Case C# expressions are embedded into a function and dynamically compiled into an assembly using the Roslyn C# compiler. Then the function that contains the expression is called (e.g. CaseAvailableFunction.Availablle()). At runtime, the function provides various methods to access stored case values as well as the current input data.