Foreword

Joshua Suereth is one of the most complete programmers I know. Familiar with a whole gamut of programming languages and techniques, he is an expert in high-performance systems, build tools, type theory, and many other areas. He is also a gifted teacher, and all that combined is what makes Scala in Depth special.

This book provides in-depth coverage of several of the more intricate areas of Scala, including advanced aspects of its type system, implicits, composition techniques with traits, collections, actors, functional categories. But this is not a dry recollection of language and library concepts. The book is full of practical advice on how to apply these lesser known parts of Scala in useful ways, and what the best practices are. The explanations and examples demonstrate Joshua’s great experience constructing large-scale systems in Scala.

Scala in Depth is not a beginner’s introduction; it should primarily appeal to competent Scala programmers who want to become experts. The techniques that are taught are handy for constructing flexible and type-safe library abstractions. Many of these techniques were folklore until now; they have been, for the first time, written-up here.

I am particularly happy about one other thing: The book fills a gap in that it explains key parts of the formal Scala specification to programmers who are not language lawyers. Scala is one of few languages that actually has a specification. That specification consists mainly of definitions written in highly stylized prose and mathematical formulas; so it’s not everybody’s piece of cake. Joshua’s book manages to be both authorative and understandable as it explains these concepts.

MARTIN ODERSKY
CREATOR OF SCALA
HEAD OF PROGRAMMING
RESEARCH GROUP, EPFL