This means designing systems as small composable units, expressing constraints and interactions via the type system, and using composition to guide the construction of large systems in a way that maintains the original architectural vision.The book also serves as an introduction to the Cats library. We use abstractions from Cats, and we explain the structure of Cats so you can use it without fear in your own code base. The broad ideas are not specific to Cats, but Cats provides an excellent implementation that is beneficial to learn in its own right.

    Akka uses Actors-independently executing processes that communicate via message passing—as the foundation for fault-tolerant applications where individual actors can fail without crashing everything. Perfect for high-volume applications that need to scale rapidly, Akka is an efficient foundation for event-driven systems that want to scale elastically up and out on demand, both on multi-core processors and across server nodes.Akka in Action is a comprehensive tutorial on building message-oriented systems using Akka. The book takes a hands-on approach, where each new concept is followed by an example that shows you how it works, how to implement the code, and how to (unit) test it. You'll learn to test and deploy an actor system and scale it up and out, showing off Akka's fault tolerance. As you move along, you'll explore a message-oriented event-driven application in Akka. You'll also tackle key issues like how to model immutable messages and domain models, and apply patterns like Event Sourcing, and CQRS. The book concludes with practical advice on how to tune and customize a system built with Akka.

    The vision behind Clojure is of a radically simple language framework holding together a sophisticated collection of programming features. Learning Clojure involves much more than just learning the mechanics of the language. To really get Clojure you need to understand the ideas underlying this structure of framework and features. You need this book: an accessible introduction to Clojure that focuses on the ideas behind the language as well as the practical details of writing code.

    These 30 short chapters each deal with a particular programming problem drawn from sources as diverse as games and puzzles, intriguing combinatorial tasks, and more familiar areas such as data compression and string matching. Each pearl starts with the statement of the problem expressed using the functional programming language Haskell, a powerful yet succinct language for capturing algorithmic ideas clearly and simply. The novel aspect of the book is that each solution is calculated from an initial formulation of the problem in Haskell by appealing to the laws of functional programming. Pearls of Functional Algorithm Design will appeal to the aspiring functional programmer, students and teachers interested in the principles of algorithm design, and anyone seeking to master the techniques of reasoning about programs in an equational style.

    It has become popular in recent years because of its simplicity, conciseness, and clarity. This book teaches functional programming as a way of thinking and problem solving, using Haskell, the most popular purely functional language. Rather than using the conventional (boring) mathematical examples commonly found in other programming language textbooks, the author uses examples drawn from multimedia applications, including graphics, animation, and computer music, thus rewarding the reader with working programs for inherently more interesting applications. Aimed at both beginning and advanced programmers, this tutorial begins with a gentle introduction to functional programming and moves rapidly on to more advanced topics. Details about progamming in Haskell are presented in boxes throughout the text so they can be easily found and referred to.

    The authors' enthusiasm for their subject is compelling as they present abstract concepts in a humorous and easy-to-grasp fashion. Together, these books will open new doors of thought to anyone who wants to find out what computing is really about. The Little Schemer introduces computing as an extension of arithmetic and algebra; things that everyone studies in grade school and high school. It introduces programs as recursive functions and briefly discusses the limits of what computers can do. The authors use the programming language Scheme, and interesting foods to illustrate these abstract ideas. The Seasoned Schemer informs the reader about additional dimensions of computing: functions as values, change of state, and exceptional cases. The Little LISPer has been a popular introduction to LISP for many years. It had appeared in French and Japanese. The Little Schemer and The Seasoned Schemer are worthy successors and will prove equally popular as textbooks for Scheme courses as well as companion texts for any complete introductory course in Computer Science.

    Through concrete examples and jargon-free explanations, this book teaches you how to apply functional programming to real-life development tasks. The book includes insightful comparisons to object-oriented or imperative programming, which will allow you to ease into functional design. Moreover, you'll learn a repertoire of techniques including function chaining and pipelining, recursion, currying, binding, functional composition, lazy evaluation, fluent error handling, memoization, and much more. By the end of the book, you'll think about application design in a fresh new way.About the technologyAs web developers build increasingly complex applications in JavaScript, the code base for these projects can become exponentially larger and harder to maintain. The result? Application performance suffers, and readability and extensibility are severely compromised. For applications like these, Functional Programming provides a saner approach, allowing you to write elegant, readable code that raises the level of abstraction while being less prone to errors. Although not a "pure" functional language, JavaScript's native functional capabilities unlock access to proven functional programming techniques and practices.What's insideFoundations of functional programming and designExplore JavaScript's functional programming capabilities and the functional library ecosystemCreate more reliable code by embracing immutabilityLearn to write code that's easier to reason aboutSeparate core logic from program structure to write extensible codeAdopt a new approach to error handling and testingApply functional programming to solve real-world problemsAbout the readerReaders need to be comfortable with JavaScript programming and object-oriented design. No previous experience with functional programming is required.About the authorLuis Atencio is a Staff Software Engineer for Citrix Systems in Ft. Lauderdale, FL. He develops and architects applications leveraging Java, PHP, and JavaScript platforms. Luis is very involved in the community and has presented at local meet-ups. He blogs about software engineering at luisatencio.net and writes articles for PHP magazines and DZone. Follow Luis on twitter at @luijar.

    This is necessary because, in the words of Michael Polanyi, "we can know more than we can tell." Our design choices are not the result of an ineluctable chain of logic; they come from a deeper place, one which is visceral and inarticulate.Polanyi calls this "tacit knowledge", a thing which we only understand as part of something else. When we speak, we do not focus on making sounds, we focus on our words. We understand the muscular act of speech, but would struggle to explain it.To write software, we must learn where to draw boundaries. Good software is built through effective indirection. We seem to have decided that this skill can only be learned through practice; it cannot be taught, except by example. Our decisions may improve with time, but not our ability to explain them. It's true that the study of these questions cannot yield a closed-form solution for judging software design. We can make our software simple, but we cannot do the same to its problem domain, its users, or the physical world. Our tacit knowledge of this environment will always inform our designs.This doesn't mean that we can simply ignore our design process. Polanyi tells us that tacit knowledge only suffices until we fail, and the software industry is awash with failure. Our designs may never be provably correct, but we can give voice to the intuition that shaped them. Our process may always be visceral, but it doesn't have to be inarticulate.And so this book does not offer knowledge, it offers clarity. It is aimed at readers who know Clojure, but struggle to articulate the rationale of their designs to themselves and others. Readers who use other languages, but have a passing familiarity with Clojure, may also find this book useful.

    The Reactive Application model addresses these demands through new patterns designed to "react" effectively to user and system events, changes in load, competition for shared system resources, and unanticipated failures. Although reactive design patterns can be implemented using standard enterprise development tools, you best realize the benefits when you pair them with a functional programming language like Scala and an Actor-based concurrency system like Akka.Reactive Design Patterns is a clearly-written guide for building event-driven distributed systems that are resilient, responsive, and scalable. Written by the authors of the Reactive Manifesto, this book teaches you to apply reactive design principles to the real problems of distributed application development. You'll discover technologies and paradigms that can be used to build reactive applications including Akka and other actor-based systems, functional programming, replication and distribution, and implementation techniques such as futures, iteratees, and reactive streams. While the book presents concrete examples in Scala, Java, JavaScript, and Erlang, the primary goal is to introduce patterns and best practices that you can use to apply reactive principles to common problems you'll face when building distributed systems.WHAT'S INSIDE* Discover best practices and patterns for building responsive applications* Build applications that can withstand hardware or software failure at any level* Patterns for fault tolerance, scalability, and responsiveness* Maximize multicore hardware using asynchronous and event-driven solutions* Scale applications under tremendous loadReaders should be familiar with a standard programming language like Java, C++ or C# and be comfortable with the basics of distributed systems. Software engineers and architects will learn how to avoid common pitfalls and apply patterns for solving day-to-day problems in a fault-tolerant and scalable way to maximize their application's responsiveness to users and clients. Project leaders and CTOs will gain a deeper understanding of the philosophy behind resilience and scalability in distributed systems, as well as their limitations, challenges and benefits.

    Domain modeling is a technique for creating a conceptual map of a problem space such as a business system or a scientific application, so that the developer can write the software more efficiently. The domain model doesn't present a solution to the problem, but instead describes the attributes, roles, and relationships of the entities involved, along with the constraints of the system.Reactive application design, which uses functional programming principles along with asynchronous non-blocking communication, promises to be a potent pattern for developing performant systems that are relatively easy to manage, maintain and evolve. Typically we call such models "reactive" because they are more responsive both to user requests and to system loads. But designing and implementing such models requires a different way of thinking. Because the core behaviors are implemented using pure functions, you can reason about the domain model just like mathematics, so your model becomes verifiable and robust.Functional and Reactive Domain Modeling teaches you how to think of the domain model in terms of pure functions and how to compose them to build larger abstractions. You will start with the basics of functional programming and gradually progress to the advanced concepts and patterns that you need to know to implement complex domain models. The book demonstrates how advanced FP patterns like algebraic data types, typeclass based design, and isolation of side-effects can make your model compose for readability and verifiability.On the subject of reactive modeling, the book focuses on higher order concurrency patterns like actors and futures. It uses the Akka framework as the reference implementation and demonstrates how advanced architectural patterns like event sourcing and CQRS can be put to great use in implementing scalable models. You will learn techniques that are radically different from the standard RDBMS based applications that are based on mutation of records. You'll also pick up important patterns like using asynchronous messaging for interaction based on non blocking concurrency and model persistence, which delivers the speed of in-memory processing along with suitable guarantees of reliability.

    As a result, functional code is easier to test and reuse, simpler to parallelize, and less prone to bugs. Scala is an emerging JVM language that offers strong support for FP. Its familiar syntax and transparent interoperability with existing Java libraries make Scala a great place to start learning FP.Functional Programming in Scala is a serious tutorial for programmers looking to learn FP and apply it to the everyday business of coding. The book guides readers from basic techniques to advanced topics in a logical, concise, and clear progression. In it, they'll find concrete examples and exercises that open up the world of functional programming.Purchase of the print book comes with an offer of a free PDF, ePub, and Kindle eBook from Manning. Also available is all code from the book.

    Using Scala, you can write programs more concisely than in Java, as well as leverage the full power of concurrency. Since Scala runs on the JVM, it can access any Java library and is interoperable with Java frameworks. Scala for the Impatient concisely shows developers what Scala can do and how to do it. In this book, Cay Horstmann, the principal author of the international best-selling Core Java(TM), offers a rapid, code-based introduction that's completely practical. Horstmann introduces Scala concepts and techniques in "blog-sized" chunks that you can quickly master and apply. Hands-on activities guide you through well-defined stages of competency, from basic to expert. Coverage includes Getting started quickly with Scala's interpreter, syntax, tools, and unique idioms Mastering core language features: functions, arrays, maps, tuples, packages, imports, exception handling, and more Becoming familiar with object-oriented programming in Scala: classes, inheritance, and traits Using Scala for real-world programming tasks: working with files, regular expressions, and XML Working with higher-order functions and the powerful Scala collections library Leveraging Scala's powerful pattern matching and case classes Creating concurrent programs with Scala actors Implementing domain-specific languages Understanding the Scala type system Applying advanced "power tools" such as annotations, implicits, and delimited continuations Scala is rapidly reaching a tipping point that will reshape the experience of programming. This book will help object-oriented programmers build on their existing skills, allowing them to immediately construct useful applications as they gradually master advanced programming techniques.

    Web Development With Clojure shows you how to apply Clojure programming fundamentals to build real-world solutions. You'll develop all the pieces of a full web application in this powerful language. If you already have some familiarity with Clojure, you'll learn how to put it to serious practical use. If you're new to the language, the book provides just enough Clojure to get down to business.You'll learn the full process of web development using Clojure while getting hands-on experience with current tools, libraries, and best practices in the language. You'll develop Clojure apps with both the Light Table and Eclipse development environments. Rather than frameworks, Clojure development builds on rich libraries. You'll acquire expertise in the popular Ring/Compojure stack, and you'll learn to use the Liberator library to quickly develop RESTful services. Plus, you'll find out how to use ClojureScript to work in one language on the client and server sides.Throughout the book, you'll develop key components of web applications, including multiple approaches to database access. You'll create a simple guestbook app and an app to serve resources to users. By the end, you will have developed a rich Picture Gallery web application from conception to packaging and deployment.This book is for anyone interested in taking the next step in web development.Q&A with Dmitri SotnikovWhy did you write Web Development with Clojure?When I started using Clojure, I found that it took a lot of work to find all the pieces needed to put together a working application. There was very little documentation available on how to organize the code, what libraries to use, or how to package the application for deployment. Having gone through the process of figuring out what works, I thought that it would be nice to make it easier for others to get started.What are the advantages of using a functional language?Over the course of my career, I have developed a great appreciation for functional programming. I find that it addresses a number of shortcomings present in the imperative paradigm. For example, in a functional language any changes to the data are created via revisions to the existing data. So they only exist in the local scope. This fact allows us to safely reason about individual parts of the program in isolation, which is critical for writing and supporting large applications.Why use Clojure specifically?Clojure is a simple and pragmatic language that is designed for real-world usage. It combines the productivity of a high-level language with the excellent performance seen in languages like C# or Java. It's also very easy to learn because it allows you to use a small number of concepts to solve a large variety of problems.If I already have a preferred web development platform, what might I get out of this book?If you're using an imperative language, you'll get to see a very different approach to writing code. Even if you're not going to use Clojure as your primary language, the concepts you'll learn will provide you with new ways to approach problems.Is the material in the book accessible to somebody who is not familiar with Clojure?Absolutely. The book targets developers who are already familiar with the basics of web development and are interested in learning Clojure in this context. The book introduces just enough of the language to get you productive and allows you to learn by example.

    By presenting the emerging best practices and designs from the Scala community, it guides you through dozens of powerful techniques example by example.About the BookScala is a powerful JVM language that blends the functional and OO programming models. You'll have no trouble getting introductions to Scala in books or online, but it's hard to find great examples and insights from experienced practitioners. You'll find them in Scala in Depth.There's little heavy-handed theory here—just dozens of crisp, practical techniques for coding in Scala. Written for readers who know Java, Scala, or another OO language.Purchase of the print book comes with an offer of a free PDF, ePub, and Kindle eBook from Manning. Also available is all code from the book.What's InsideConcise, expressive, and readable code style How to integrate Scala into your existing Java projects Scala's 2.8.0 collections API How to use actors for concurrent programming Mastering the Scala type system Scala's OO features—type member inheritance, multiple inheritance, and composition Functional concepts and patterns—immutability, applicative functors, and monads========================================​==========Table of ContentsScala—a blended language The core rules Modicum of style—coding conventions Utilizing object orientation Using implicits to write expressive code The type system Using implicits and types together Using the right collection Actors Integrating Scala with Java Patterns in functional programming

    Clojure's clean, careful design lets you write programs that get right to the essence of a problem, without a lot of clutter and ceremony. Clojure is Lisp reloaded. Clojure has the power inherent in Lisp, but is not constrained by the history of Lisp. Clojure is a functional language. Data structures are immutable, and functions tend to be side-effect free. This makes it easier to write correct programs, and to compose large programs from smaller ones. Clojure is concurrent. Rather than error-prone locking, Clojure provides software transactional memory. Clojure embraces Java. Calling from Clojure to Java is direct, and goes through no translation layer. Clojure is fast. Wherever you need it, you can get the exact same performance that you could get from hand-written Java code. Many other languages offer some of these features, but the combination of them all makes Clojure sparkle. Programming Clojure shows you why these features are so important, and how you can use Clojure to build powerful programs quickly.