You and jules provided excellent examples for how to do my example without classes - but you do assume that the csv parser never needs to peek across lines. That's probably fine for csv files, but in general, lexers/parsers may need to. My point is, you're taking advantage of the fact that files are already objects which can be processed line by line. You can't always do this. I think that things like files and sockets are very nice to have as objects.