Learn Haskell by Example

Learn Haskell by doing Haskell projects! In this book, you’ll get practical experience writing Haskell code and applying functional programming to actual development challenges. In Learn Haskell by Example, you’ll build your Haskell skills by working through hands-on challenges and conundrums. You’ll learn to look at each project through a Haskell lens, and then solve it using features like lazy evaluation, immutable data structures, and monads. In Learn Haskell by Example you will learn how to: • Use Haskell for daily programming tasks • Effectively apply functional concepts • Avoid common beginner pitfalls of Haskell • Apply abstract concepts in the Haskell language • Debug and profile Haskell applications • Improve the performance of Haskell applications Haskell is an amazing choice for applications that need an extra guarantee of safety, such as in smart contracts, data intensive applications, and large scale distributed systems. In this book, you’ll see just how practical Haskell can be for creating programs by building your own engaging projects! Learn how to structure real-world applications, how to work with the Haskell tool chain effectively, and what to look out for when writing critical sections in the program's logic. Best of all, each project in this book is fully extensible and customizable so you can keep tinkering with your favorites! About the technology Programmers spend a lot of time debugging and refactoring code, reading comments and documentation, and trying to make sense out of complex designs. Haskell, a powerful, beautiful, and challenging functional programming language, promises a different path. By focusing your attention on simple functions, clearly-defined behaviors, and the right high-level abstractions, Haskell disallows the dangerous behaviors that usually lead to bugs and crashes. About the book Learn Haskell by Example teaches you to build applications in Haskell by designing and coding fun and engaging projects. In this easy-to-follow guide, you’ll create a domain specific language for music, an image processing library, and more! You’ll learn Haskell from the ground-up with a focus on important concepts like function design, composition, and data immutability. Each project gives you a new insight into how to think in Haskell and helps you understand why many Haskell developers say they will never use another language again. What's inside • Use Haskell for daily programming tasks • Purely functional programming • Avoid common Haskell pitfalls About the reader For readers who know how to program in an object-oriented language. About the author Philipp Hagenlocher is a full time Haskell developer, and the creator of the beloved Haskell for Imperative Programmers YouTube course. The technical editor on this book was Alexander Vershilov. Table of Contents 1 Introduction 2 Ancient secret keeping on modern machines 3 Every line counts 4 Line numbering tool 5 Words and graphs 6 Solving the ladder game 7 Working with CSV files 8 A tool for CSV 9 Quick checks and random tests 10 Digital music box 11 Programming musical compositions 12 Parsing pixel data 13 Parallel image processing 14 Files and exceptions 15 Transformers for synchronizing 16 JSON and SQL 17 APIs using Servant Appendix A The Haskell Toolchain Appendix B Lazy evaluation