typedef void distinct_func (double v, casenumber n, double w, void *aux);
struct casereader *
casereader_create_append_rank (struct casereader *,
const struct variable *v, const struct variable *w,
typedef void distinct_func (double v, casenumber n, double w, void *aux);
struct casereader *
casereader_create_append_rank (struct casereader *,
const struct variable *v, const struct variable *w,