  Recently, Wadler presented a continuation-passing translation from a
session-typed functional language, GV, to a process calculus based on classical
linear logic, CP. However, this translation is one-way: CP is more expressive
than GV. We propose an extension of GV, called HGV, and give translations
showing that it is as expressive as CP. The new translations shed light both on
the original translation from GV to CP, and on the limitations in
expressiveness of GV.
