  We show that more head-driven parsing algorithms can be formulated than those
occurring in the existing literature. These algorithms are inspired by a family
of left-to-right parsing algorithms from a recent publication. We further
introduce a more advanced notion of ``head-driven parsing'' which allows more
detailed specification of the processing order of non-head elements in the
right-hand side. We develop a parsing algorithm for this strategy, based on LR
parsing techniques.
