Clojure for Domain-specific Languages : Learn How to Use Clojure Language with Examples and Develop Domain-specific Languages on the Go

Enhance your existing Clojure know-how with this example-packed tutorial on building custom languages. It will help you unlock the potential of Clojure in a way you probably never thought possible. **Overview** * Explore DSL concepts from existing Clojure DSLs and libraries * Bring Clojure into your Java applications as Clojure can be hosted on a Java platform * A tutorial-based guide to develop custom domain-specific languages **In Detail** Clojure is a very new and rapidly growing language that runs on top of the JVM. The language being hosted on the Java platform allows for Clojure applications to use existing Java components. Although there are objects in Clojure, the language is not object oriented. "Clojure for Domain-specific Languages" is an example-oriented guide to building custom languages. Many of the core components of Clojure are covered to help you understand your options when making a domain-specific language. By the end of this book, you should be able to make an internal DSL. Starting with a comparison of existing DSLs, this book will move on to guide you through general programming, Clojure editing, and project management. The chapters after that are code oriented. "Clojure for Domain-specific Languages" tries to expose you to as much Clojure code as possible. Many of the examples are executed in a Read-Evaluate-Print-Loop environment, so the reader can also follow along on their own machine. This book uses Leiningen, but no prior knowledge of it is required. "Clojure for Domain-Specific Languages" aims to make you familiar with the Clojure language and help you learn the tools to make your own language. **What you will learn from this book** * Understand the pros and cons of a domain-specific language * Learn general programming design concepts * Know the benefits of a Lisp-based syntax * Edit Clojure files in Emacs * Learn to operate a Read-Evaluate-Loop session from within Emacs * Build Clojure projects with Leiningen * Manipulate and make polymorphic objects in a non-object-oriented language * Create a Twitter domain-specific language to understand Clojure, its Java, and Lisp foundation closely * Use your Clojure applications inside of a Java project **Approach** An example-oriented approach to develop custom domain-specific languages. **Who this book is written for** If you've already developed a few Clojure applications and wish to expand your knowledge on Clojure or domain-specific languages in general, then this book is for you. If you're an absolute Clojure beginner, then you may only find the detailed examples of the core Clojure components of value. If you've developed DSLs in other languages, this Lisp and Java-based book might surprise you with the power of Clojure. Content: Cover Copyright Credits About the Author About the Reviewers www.PacktPub.com Table of Contents Preface Chapter 1: An Overview of Domain-Specific Languages with Clojure Domain-specific languages (DSL) Limited scope Syntax Using a DSL Popular DSLs A contract between language and domain The language of trust Internal versus External DSLs External DSLs Internal DSL Clojure libraries Characteristics of a Clojure library The current state of Clojure libraries Database domains HTML domain Formative Hiccup Mustache Clostache ECMA/JavaScript domain ClojureScript. Comparing ClojureScript and JavaScriptAudio domain Music-as-data Overtone Image domains Summary Chapter 2: Design Concepts with Clojure Every function is a little program A pure function Floor to roof development Each function only does one thing Patterns for success DRY KISS YAGNI Writing Clojure Spacing and alignment Syntax Name conventions Collection types Summary Chapter 3: Clojure Editing and Project Creation The origin of Emacs and its usage Installing and setting up Emacs24 Setting up Emacs Creating and editing CLJ files in Emacs. Running a Clojure REPL inside EmacsThe nrepl.el Emacs extension Leiningen and project management Installing Leiningen and starting a project Including Clojure or Java libraries in your project Compiling your project to a Java JAR Leiningen Summary Chapter 4: Features, Functions, and Macros Namespaces Java inside Clojure Immutability Dynamic objects Metadata Lazy sequences Destructuring Functions and arity Anonymous functions Macros Summary Chapter 5: Collections and Sequencing Collections Collections by example Vectors Vectors by example Lists Lists by example Maps. Maps by exampleSets Sets by example Sequences Sequences by example :let, :while, and :when Summary Chapter 6: Assignment and Concurrency Variables Transients Atoms Agents Refs Futures Promises Summary Chapter 7: Flow Control, Error Handling, and Math Flow control Object comparison Casting Error handling Arithmetic Addition and subtraction Multiplication Division Remainder and modulus Increment and decrement Greatest and least values Equality Summary Chapter 8: Methods for Abstraction Creating and constructing classes. Creating interfaces and implementing them with deftypeUsing records, protocols, and type extensions Overriding methods with reify and proxy Working with reify Implementing interface methods with proxy Custom symbol definitions with macros Definitions using records Making definitions using proxy Making definitions using deftype Multimethod polymorphism Creating the Bottle and Customer classes Testing the customer-drink methods Relationships with hierarchies Resolving parent relationship conflicts Assertion testing with metadata Input constraints with :pre.

In Detail

Clojure is a very new and rapidly growing language that runs on top of the JVM. The language being hosted on the Java platform allows for Clojure applications to use existing Java components. Although there are objects in Clojure, the language is not object oriented.

"Clojure for Domain-specific Languages" is an example-oriented guide to building custom languages. Many of the core components of Clojure are covered to help you understand your options when making a domain-specific language. By the end of this book, you should be able to make an internal DSL. Starting with a comparison of existing DSLs, this book will move on to guide you through general programming, Clojure editing, and project management. The chapters after that are code oriented.

"Clojure for Domain-specific Languages" tries to expose you to as much Clojure code as possible. Many of the examples are executed in a Read-Evaluate-Print-Loop environment, so the reader can also follow along on their own machine. This book uses Leiningen, but no prior knowledge of it is required.

"Clojure for Domain-Specific Languages" aims to make you familiar with the Clojure language and help you learn the tools to make your own language.

Approach

An example-oriented approach to develop custom domain-specific languages.

Who this book is for

If you've already developed a few Clojure applications and wish to expand your knowledge on Clojure or domain-specific languages in general, then this book is for you. If you're an absolute Clojure beginner, then you may only find the detailed examples of the core Clojure components of value. If you've developed DSLs in other languages, this Lisp and Java-based book might surprise you with the power of Clojure.