This is Haskabelle, an importer from Haskell source files
to Isabelle/HOL Isar theories.

An overview how to use it can be found in the manual

    doc/haskabelle.pdf

If this is not present, you have to build it first;  for this you need
a source (!) distribution of Isabelle2009-2, as available from

    http://isabelle.in.tum.de/repos/isabelle/rev/!!!FIXME!!!

See further

    http://isabelle.in.tum.de/

for general hints on Isabelle2009-2.

Then, invoke

    admin/builddoc

By default, this uses the Isabelle version accessible on your PATH.
Set shell variable ISABELLE_TOOL explicitly if this does not use 
the desired Isabelle version.

Sources of Haskabelle itself are available via mercurial:

    https://isabelle.in.tum.de/repos/haskabelle