The recent C# feature called interceptors [1] pretty much looks like comefrom from where I stand. Yet everyone talking about it has either been serious, or very good at trolling.
[InterceptsLocation("/Users/khalidabuhakmeh/RiderProjects/ConsoleApp12/ConsoleApp12/Program.cs", line: 3, character: 3)]
they added a language feature which is sensitive to precise line/character offsets in your source code, so the tiniest change to the source code invalidates your code…
I’m speechless. Whatever they are aiming to achieve here, surely there is a more elegant, less ugly way
You can read about how they work here: https://github.com/dotnet/roslyn/blob/main/docs/features/inc...
Basically they get the files (and ambient metadata) that are part of the compilation, filter to the parts it depends on, transforms to a in-mem representation of the data needed for the code generation, and then finally adds new files to the compilation. Since they can only add new files they cannot e.g. add code to be executed before or after user code is executed like with AOP. Interceptors are a solution to that problem.
I don't think there's much that's scary about generating source code in general. If it's self-contained and you have to actually call the generated code to use it, it's not really much different than any other code. But the idea of having code A change the behavior of code B is what's horrifying, regardless of whether code A is generated or not. If I'm reading code B I want to be able to reason about what I see without having to worry about some spooky action at a distance coming from somewhere else.
Things are constantly doing this. Frameworks use reflection or markup or all other kinds of things that count as magic if you don't bother to understand what's going on.