zipper package:uniplate

Create a zipper, focused on the top-left value.

A zipper is a structure for walking a value and manipulating it in constant time. This module was inspired by the paper: Michael D. Adams. Scrap Your Zippers: A Generic Zipper for Heterogeneous Types, Workshop on Generic Programming 2010.

Zipper structure, whose root type is the first type argument, and whose focus type is the second type argument.

Create a zipper with a different focus type from the outer type. Will return Nothing if there are no instances of the focus type within the original value.

From a zipper take the whole structure, including any modifications.