@hackage zipper0.1

The Zipper is a data structure that allows typed navigation on a value. It maintains a subterm as a current point of focus. The rest of the value is the context. Focus and context are automatically updated when navigating up, down, left or right in the value. The term that is in focus can also be modified.

This library offers a generic Zipper for systems of datatypes. In particular, it is possible to move the focus between subterms of different types, in an entirely type-safe way. This library is built on top of the multirec library, so all that is required to get a Zipper for a datatype system is to instantiate the multirec library for that system.