Getting name of the running script from inside the class.

I know that normally you can use mfilename to find the name and address of the file currently running.

I need something a little different: I need the name of the file constructing an instance of the class. I need that filename inside the class body (and of course I want to avoid adding additional argument for passing that filename.)

If I use mfilename inside the class it will obviously return class file which is not useful for me. dbstack seems to be my only option but I don't like it since it seems like the function was not intended for this use case.

Thanks.