Ivo Balbaert & Simon St. Laurent 
Programming Crystal [PDF ebook] 
Create High-Performance, Safe, Concurrent Apps

Crystal is for Ruby programmers who want more performance, or for developers who enjoy working in a high-level scripting environment. Crystal combines native execution speed and concurrency with Ruby-like syntax, so you will feel right at home. This book, the first available on Crystal, shows you how to write applications that have the beauty and elegance of a modern language, combined with the power of types and modern concurrency tooling. Now you can write beautiful code that runs faster, scales better, and is a breeze to deploy.Crystal is elegant to read and easy to program like Ruby, allowing full object-oriented development. Its compiler is powerful enough to nearly always infer the type of your variables. So you get the benefits of a statically typed language: more robust code, safety and execution speed, while still reaching high productivity in development. Null pointer exceptions as in Java Script, Java or C#, are a thing of the past: Crystal annihilates them, just like Rust.Explore the building blocks and design of the language, and how you can use the Crystal tool-chain to build and manage powerful applications. Harness the power of the macro system, as well as how to work with fibers and channels, making concurrency as easy as possible. Learn how to use the Kemal web framework and access databases, and how to tap the potential of existing Crystal libraries. Find the spot that Crystal fills in today’s software world with real-world examples.With Crystal, you can combine the best of both worlds: the high-level coding of dynamic languages, and the safety and blazing performance of a natively compiled language.What You Need:To develop in Crystal, you only need Crystal v 0.26 the latest version, a common text editor and a browser.