Preface

After 60 years of high-level language development, programming is still too difficult. The demand for software of ever-increasing size and complexity has exploded due to hardware advances, while programming languages have improved far more slowly. Creating new languages for specific purposes is one antidote for this software crisis.

This book is about building new programming languages. The topic of programming language design is introduced, although the primary emphasis is on programming language implementation. Within this heavily studied subject, the novel aspect of this book is its fusing of traditional compiler-compiler tools (Flex and Byacc) with two higher-level implementation languages. A very high-level language (Unicon) plows through a compiler's data structures and algorithms like butter, while a mainstream modern language (Java) shows how to implement the same code in a more typical production environment.

One thing I didn't really understand after my college compiler class is that the compiler is only one part of a programming language implementation. Higher-level languages, including most newer languages, may have a runtime system that dwarfs their compiler. For this reason, the second half of this book spends quality time on a variety of aspects of language runtime systems, ranging from bytecode interpreters to garbage collection.