Log Message:
Import hs-syb-0.3 as wip/hs-syb.

This package contains the generics system described in the Scrap Your
Boilerplate papers (see
http://www.cs.uu.nl/wiki/GenericProgramming/SYB). It defines the Data
class of types permitting folding and unfolding of constructor
applications, instances of this class for primitive types, and a
variety of traversals.