  A novel approach to HPSG based natural language processing is described that
uses an off-line compiler to automatically prime a declarative grammar for
generation or parsing, and inputs the primed grammar to an advanced
Earley-style processor. This way we provide an elegant solution to the problems
with empty heads and efficient bidirectional processing which is illustrated
for the special case of HPSG generation. Extensive testing with a large HPSG
grammar revealed some important constraints on the form of the grammar.
