Functional languages have their own patterns that enable you to solve problems with less code than object-oriented programming alone. This book introduces you, the experienced Java programmer, to Scala and Clojure: practical, production-quality languages that run on the JVM and interoperate with existing Java. By using both the statically typed, type-inferred Scala and the dynamically typed, modern Lisp Clojure, you’ll gain a broad understanding of functional programming. For each pattern, you’ll first see the traditional object-oriented solution, and then dig into the functional replacements in both Scala and Clojure. These patterns are common in the functional world and deserve to become part of your problem-solving toolkit. On the object-oriented side, you’ll see many common patterns, such as Command, Strategy, and Null Object. On the functional side, you’ll learn core functional patterns such as Memoization, Lazy Sequence, and Tail Recursion. Each pattern helps you solve a common programming problem. Working through them gives you a set of patterns you can use to solve problems you come across while writing programs. Finally, you’ll learn how to work your existing Java code into new Scala or Clojure projects. You can start off small, adding functional code little by little, so you can complement your existing knowledge with Scala and Clojure as these languages gain popularity on the JVM.

Clojure是一门Lisp方言。它通过函数式编程技术，直接支持并发软件开发，得到众多开发人员的欢迎。 《Clojure编程乐趣》并非Clojure初学指南，也不是一本Clojure的编程操作手册，而是通过对Clojure详尽地探究，教授函数式的程序设计方式，帮助读者理解和体会Clojure编程的乐趣，进而开发出优美的软件。 全书分为5个部分共13章。第1部分是基础，包括第1章到第3章，从Clojure背后的思想开始，介绍了Clojure的基础知识，并带领读者初步尝试Clojure编程。第2部分包括第4章和第5章，介绍了Clojure的各种数据类型。第3部分是第6章和第7章，介绍了函数式编程的特性。第4部分包括第8章到第11章，分别介绍了宏、组合数据域代码、Clojure对Java的调用，以及并发编程等较为高级的话题。第5部分为第12章和第13章，探讨了Clojure的性能问题及其带给我们的思考。 《Clojure编程乐趣》适合有一定基础的Clojure程序员阅读，进而掌握函数编程的思考方法和程序设计方法，也可以作为读者学习函数式编程的参考资料。

DESCRIPTION Clojure is a new version of Lisp that runs on the Java Virtual Machine. It's a functional language, which means that it's ideal for the growing need for concurrent programming and for specialized tasks like creating domain specific languages. Clojure in Action is a hands-on tutorial for the working programmer who has written code in a language like Java or Ruby, but has no prior experience with Lisp. It teaches Clojure from the basics to advanced topics using practical, real-world application examples. Readers will move quickly through the theory and dive into practical matters like unit-testing, environment set up, and all the way through building a scalable web-application using domain-specific languages, Hadoop, HBase, and RabbitMQ. KEY POINTS * A complete tutorial, from basics to applied techniques * Covers creation of Domain-Specific Languages * Contains numerous practical examples