Clojure Cookbook

With more than 150 detailed recipes, this cookbook shows experienced Clojure developers how to solve a variety of programming tasks with this JVM language. The solutions cover everything from building dynamic websites and working with databases to network communication, cloud computing, and advanced testing strategies. And more than 60 of the world’s best Clojurians contributed recipes. Each recipe includes code that you can use right away, along with a discussion on how and why the solution works, so you can adapt these patterns, approaches, and techniques to situations not specifically covered in this cookbook. Master built-in primitive and composite data structures Create, develop and publish libraries, using the Leiningen tool Interact with the local computer that’s running your application Manage network communication protocols and libraries Use techniques for connecting to and using a variety of databases Build and maintain dynamic websites, using the Ring HTTP server library Tackle application tasks such as packaging, distributing, profiling, and logging Take on cloud computing and heavyweight distributed data crunching Dive into unit, integration, simulation, and property-based testing Clojure Cookbook is a collaborative project with contributions from some of the world’s best Clojurians, whose backgrounds range from aerospace to social media, banking to robotics, AI research to e-commerce.

With more than 150 detailed recipes, this cookbook shows experienced Clojure developers how to solve a variety of programming tasks with this JVM language. The solutions cover everything from building dynamic websites and working with databases to network communication, cloud computing, and advanced testing strategies. And more than 60 of the world’s best Clojurians contributed recipes. Each recipe includes code that you can use right away, along with a discussion on how and why the solution works, so you can adapt these patterns, approaches, and techniques to situations not specifically covered in this cookbook. Master built-in primitive and composite data structures Create, develop and publish libraries, using the Leiningen tool Interact with the local computer that’s running your application Manage network communication protocols and libraries Use techniques for connecting to and using a variety of databases Build and maintain dynamic websites, using the Ring HTTP server library Tackle application tasks such as packaging, distributing, profiling, and logging Take on cloud computing and heavyweight distributed data crunching Dive into unit, integration, simulation, and property-based testing Clojure Cookbook is a collaborative project with contributions from some of the world’s best Clojurians, whose backgrounds range from aerospace to social media, banking to robotics, AI research to e-commerce.

Handle every problem you come across in the world of Clojure programming with this expert collection of recipes About This Book Discover a wide variety of practical cases and real world techniques to enhance your productivity with Clojure. Learn to resolve the everyday issues you face with a functional mindset using Clojure You will learn to write highly efficient, more productive, and error-free programs without the risk of deadlocks and race-conditions Who This Book Is For This book is for Clojure developers who have some Clojure programming experience and are well aware of their shortcomings. If you want to learn to tackle common problems, become an expert, and develop a solid skill set, then this book is for you. What You Will Learn Manipulate, access, filter, and transform your data with Clojure Write efficient parallelized code through Clojure abstractions Tackle Complex Concurrency easily with Reactive Programming Build on Haskell abstractions to write dynamic functional tests Write AWS Lambda functions effortlessly Put Clojure in use into your IoT devices Use Clojure with Slack for instant monitoring Scaling your Clojure application using Docker Develop real-time system interactions using MQTT and websockets In Detail When it comes to learning and using a new language you need an effective guide to be by your side when things get rough. For Clojure developers, these recipes have everything you need to take on everything this language offers. This book is divided into three high impact sections. The first section gives you an introduction to live programming and best practices. We show you how to interact with your connections by manipulating, transforming, and merging collections. You'll learn how to work with macros, protocols, multi-methods, and transducers. We'll also teach you how to work with languages such as Java, and Scala. The next section deals with intermediate-level content and enhances your Clojure skills, here we'll teach you concurrency programming with Clojure for high performance. We will provide you with advanced best practices, tips on Clojure programming, and show you how to work with Clojure while developing applications. In the final section you will learn how to test, deploy and analyze websocket behavior when your app is deployed in the cloud. Finally, we will take you through DevOps. Developing with Clojure has never been easier with these recipes by your side! Style and approach This book takes a recipe-based approach by diving directly into helpful programming concepts. It will give you a foolproof approach to programming and teach you how to deal with problems that may arise while working with Clojure. The book is divided into three sections giving you the freedom skip to the section of your choice depending on the problem faced.

25 recipes to deeply understand and implement advanced algorithms in ClojureAbout This Book• Explore various advanced algorithms and learn how they are used to address many real-world computing challenges• Construct elegant solutions using impressive techniques including zippers, parsing, and pattern matching• Solve complex problems by adopting innovative approaches such as logic or asynchronous programmingIn DetailData-structures and algorithms often cross your path when you compress files, compile programs, access databases, or simply use your favourite text editor. Understanding and implementing them can be daunting. Curious learners and industrial developers can find these complex, especially if they focus on the detailed implementation of these data structures.Clojure is a highly pragmatic and expressive language with efficient and easy data manipulation capabilities. As such, it is great for implementing these algorithms. By abstracting away a great share of the unnecessary complexity resulting from implementation, Clojure and its contrib libraries will help you address various algorithmic challenges, making your data exploration both profitable and enjoyable.Through 25 recipes, you'll explore advanced algorithms and data-structures, well served by a sound Clojure implementation.This book opens with an exploration of alternative uses of the array data-structure, covering LZ77 compression, drawing fractals using Pascal's triangles, simulating a multi-threaded program execution, and implementing a call-stack winding and un-winding operations.The book elaborates on linked lists, showing you how to construct doubly linked ones, speed up search times over the elements of such structures, use a linked-list as the foundation of a shift-reduce parser, and implement an immutable linked-list using skew binary numbers representation.After that, the tree data-structure is explored, focusing on building self-balancing Splay Trees, designing a B-Tree backing-up an efficient key-value data-store, constructing an undo capable Rope, and showing how Tries can make for an auto-completing facility.Next, some optimization and machine learning techniques are discussed, namely for building a co-occurrence-based recommendation engine, using branch-and-bound to optimize integral cost and profit problems, using Dijkstra's algorithm to determine optimal paths and summarizing texts using the LexRank algorithm.Particular attention is given to logic programming, you will learn to use this to discover interesting relations between social website data, by designing a simple type inferencer for a mini Java-like language, and by building a simple checkers game engine.Asynchronous programming will be addressed and you will design a concurrent web-crawler, an interactive HTML5 game, and an online taxi booking platform.Finally, you'll explore advanced cases for higher order functions in Clojure while implementing a recursive descent parser using efficient mutual resucrsion, devising a mini resusable firewall simulator thanks to Clojure 1.7 new tansducers feature or building a simple unification engine with the help of Continuation Passing Style.What You Will Learn• Explore alternative uses of classical data-structures like arrays and linked-lists• Discover advanced types of tree data-structures• Explore advanced machine learning and optimization techniques• Utilise powerful Clojure libraries, such as Instaparse for parsing, core.match for pattern matching, clojure.zip for zippers, and clojure.matrix for matrix operations• Learn logic programming through the usage of the library core.logic• Master asynchronous programming using the core.async library• See the transducers in action while resolving real-world use-casesWho This Book Is ForIf you are an experienced Clojure developer, longing to take your knowledge to the next level by discovering and using advanced algorithms and seeing how they can be applied to real-world problems, then this book is for you.Style and approachThis book consists of a set of step-by-step recipes, each demonstrating the material covered in action so it is put in context. When necessary, pointers to further resources are provided.

With more than 150 detailed recipes, this cookbook shows experienced Clojure developers how to solve a variety of programming tasks with this JVM language. The solutions cover everything from building dynamic websites and working with databases to network communication, cloud computing, and advanced testing strategies. And more than 60 of the world{u2019}s best Clojurians contributed recipes. Each recipe includes code that you can use right away, along with a discussion on how and why the solution works, so you can adapt these patterns, approaches, and techniques to situations not specifically covered in this cookbook. Master built-in primitive and composite data structures Create, develop and publish libraries, using the Leiningen tool Interact with the local computer that{u2019}s running your application Manage network communication protocols and libraries Use techniques for connecting to and using a variety of databases Build and maintain dynamic websites, using the Ring HTTP server library Tackle application tasks such as packaging, distributing, profiling, and logging Take on cloud computing and heavyweight distributed data crunching Dive into unit, integration, simulation, and property-based testingClojure Cookbook is a collaborative project with contributions from some of the world{u2019}s best Clojurians, whose backgrounds range from aerospace to social media, banking to robotics, AI research to e-commerce.

This book is for those with a basic knowledge of Clojure, who are looking to push the language to excel with data analysis.

“There’s something for everyone here. . . . You can pick up and read this book and build an industry-standard system in a weekend: It has everything you need to get started with a new project. I also found it helpful in reviewing the structure of existing projects.” —Timothy Pratley, developer Developers are discovering the exceptional power of Clojure’s functional programming model to quickly solve problems in domains ranging from social networking to Big Data. Clojure is fast and efficient—ideal for rapid prototyping and lean development. And it is highly expressive and extremely extensible, which makes Clojure one of today’s leading tools for software innovation. Since it targets the Java Virtual Machine, Clojure also leverages the Java platform’s maturity and enormous ecosystem. Clojure Recipes is a wide-ranging, up-to-date “code recipe book” for this increasingly popular language. With practical and self-contained examples, author Julian Gamble illuminates Clojure’s key features and best practices, showing how to solve real-world problems one step at a time. Focusing on Clojure 1.7 and higher, Gamble fully reflects recent enhancements that ensure you’re getting the most up-to-date code for your project. Gamble first walks you through the essential steps required to set up your Clojure development environment, from setting up the Leiningen build tool to packaging Clojure for Java EE environments. He then shows you how to build both basic and advanced REST servers, before turning to a wide range of increasingly sophisticated applications. In this book you will find Innovative Clojure code for diverse web, security, administration, and development tasks, from log reading and app monitoring to software testing Detailed instructions for using concurrency primitives, writing new DSLs, simplifying cloud database development, and more “Learn by doing” projects, which offer practical experience with Clojurescript, Storm, Pedestal, Datomic, and other advanced tools Coverage of using Clojure with Cascalog 2.0 to write complex Hadoop queries with minimal code The breadth and quality of Gamble’s examples make Clojure Recipes uniquely valuable both to developers who are exploring Clojure for the first time and to those already using it in production.

Planning to deploy and maintain a public, private, or hybrid cloud service? This cookbook’s handy how-to recipes help you quickly learn and install Apache CloudStack, along with several API clients, API wrappers, data architectures, and configuration management technologies that work as part of CloudStack’s ecosystem. You’ll learn how to use Vagrant, Ansible, Chef, Fluentd, Libcloud, and several other open source tools that let you build and operate CloudStack better and faster. If you’re an experienced programmer, system administrator, or DevOps practitioner familiar with bash, Git, package management, and some Python, you’re ready to go. Learn basic CloudStack installation from source, including features such as DevCloud, the CloudStack sandbox Get a step-by-step guide for installing CloudStack from packages on Ubuntu 14.04 using KVM Write your own applications on top of the CloudStack API, using CloudMonkey, Libcloud, jclouds, and CloStack Expose different APIs on CloudStack with the EC2Stack, Boto, and Eutester API wrappers Deploy applications easily, using Puppet, Salt, Ansible, Chef, and Vagrant Dive into cloud monitoring and storage with RiakCS, Fluentd, and Apache Whirr