7.3

1 The Lens Guide

This guide is intended for programmers who are familiar with Racket but new to working with lenses or a certain part of this lens library. It contains a non-authorative introduction to lenses, including examples of usage and recipes for solving certain kinds of problems. It does not describe all features this library provides; for a complete API reference, see The Lens Reference.

    1.1 Introduction to Lenses

      1.1.1 What are lenses?

      1.1.2 Why use lenses?

    1.2 Lenses on Built-In Datatypes

      1.2.1 Lenses on Ordered Data

        1.2.1.1 Pairs and Lists

        1.2.1.2 Vectors and Strings

        1.2.1.3 Streams

      1.2.2 Lenses on Key-Value Data

        1.2.2.1 Hash Tables

        1.2.2.2 Dictionaries

    1.3 Lenses on User-Defined Datatypes

      1.3.1 Structures

      1.3.2 Constructing Entirely New Lenses