Book excerpt: A step-by-step guide that enables you to quickly implement a DSL with Xtext and Xtend in a test-driven way with the aid of simplified examples.This book is for programmers who want to learn about Xtext and how to use it to implement a DSL (or a programming language) together with Eclipse IDE tooling. It assumes that the user is familiar with Eclipse and its functionality. Existing basic knowledge of a compiler implementation would be useful, though not strictly required, since the book will explain all the stages of the development of a DSL.