Please find the old Frank darcs repo preserved as the contents of the "old" directory.
Meanwhile, the src directory has a new version which

  * assumes that top-level functions and operators are to be *used*, not *mentioned*
  * removes the empty type
  * allows operations to be polymorphic, with skolemized type variables in request patterns
  * allows individual sig operations to demand extra capabilities (amounting to effects
      the environment can do)

Plenty still to do.