zippo

This light-weight library provides a basic, but fully-type-checked zipper implementation, suitable for any algebraic data structure. Our implementation has no notion of "left" and "right", and instead uses lenses (from the "yall" package) to indicate directions to "navigate down to". For a similar approach with many more features, but less type-safety see "pez". UPDATE: I have stopped developing this package; instead look into "lens" v3.0 which includes similar functionality CHANGES: 0.2 to 0.3: depend on new yall, depending on new categories