I would like to configure a macro to write the input file name into a field, capturing the file name from the macro input. I can't rely on the 'Output File Name as Field' option being used, since the file input is outside the scope of the macro. I was hoping there was some sort of function that would parse the source filename from a data stream, but have as yet been unable to find it.
Screen shot attached below, for general reference:

Thanks,
-Dan