Modular edit lenses

Abstract

This article is a reading guide to the theory of symmetric edit lenses by Pierce, Wagner, and the author, which form a general framework for the modular construction of bidirectional synchronizers and which generalize the popular lenses framework by Foster and Pierce to a truly symmetric, bidirectional setting. The article describes both the state-based and the edit-based version, as well as an extended example instantiation involving tree-structured data. The main focus is on edit lenses and the categorical combinators which allow for their modular construction. The article is based on three original research papers [9–11, 22] and summarises these in a concise form but does not contain new scientific material.