zipper -package:streams -package:traverse-with-class -package:ListZipper is:module

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.
This module provides a two-dimensional text zipper data structure. This structure represents a body of text and an editing cursor which can be moved throughout the text, along with a set of editing transformations. Text zippers are generalized over the set of data types that might be used to store lists of characters (e.g., String, Text, etc.). As a result, the most general way to create a text zipper is to use mkZipper and provide all of the functions required to manipulate the underlying text data. Implementations using Text and String are provided.
This module provides a Zipper with fairly strong type checking guarantees. The code here is inspired by Brandon Simmons' zippo package, but uses a different approach to represent the Zipper that makes the whole thing look like his breadcrumb trail, and can move side-to-side through traversals. Some examples types: Since individual levels of a Zipper are managed by an arbitrary IndexedTraversal, you can move left and right through the IndexedTraversal selecting neighboring elements.
>>> zipper ("hello","world") & downward _1 & fromWithin traverse & focus .~ 'J' & rightmost & focus .~ 'y' & rezip
("Jelly","world")
This is particularly powerful when compiled with plate, uniplate or biplate for walking down into self-similar children in syntax trees and other structures. Given keys in ascending order you can jump directly to a given key with moveTo. When used with traversals for balanced tree-like structures such as an IntMap or Map, searching for a key with moveTo can be done in logarithmic time.
Creation date: Thu Jul 23 08:42:37 2020.
Spine-lazy radix tree location manipulation. Allows lookup and successive insertion without retaining the entirety of the key in memory.
Spine-strict radix tree location manipulation. Allows lookup and successive insertion without retaining the entirety of the key in memory.
Zipper over the Data.Tree data structure. This module is based on rosezipper.