both arguments are right, but not because of a subjective goodness. because they're talking about 2 different parts of the patch: - the "bad" part is RowType.f

both arguments are right, but not because of a subjective goodness. because they're talking about 2 different parts of the patch: - the "bad" part is RowType.for(), where a type is dynamically called forth based on manipulations on some string. I agree that a more concrete mapping from string-to-type would be preferable (I'm assuming the use of a string is required for some reason). - the "good" part of the patch is that he replaced a conditional with type dispatch. I agree that this is a basic technique of object-oriented programming.