Concepts, Techniques, and Models of Computer Programming

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Summary: The Power of Programming Without Dogmatic Restraints
Review: In 1976 Edsger W. Dijkstra elevated programming to an intellectual discipline and taught us how to reason about what we now call "imperative programming". To illustrate his methodology Dijkstra solved challenging problems with unforgetably beautiful, yet simple and powerful example programs that are as relevant today as they were forty years ago. Since then, programming has splintered into paradigms, methodologies and suffers from baroqueness, perpetuation of obsolete conventions and other practices that restrict the full expressive power of programming "as a whole".

In 2004 Van Roy and Seif Haridi have given us a glimpse of what programming can be like without unnecessary restrictions imposed by paradigms and other heavy baggage caused by politics, ideology and historical inertia. Using the remarkably mature implementation of the Mozart system and the conceptually clean, simple, elegant, yet powerful programming language Oz, Van Roy and Haridi show us how dogmatic heavy baggage falls away when we can look at programming as a whole and choose the best programming concepts that the solution of a problem requires. Such a program becomes simpler, more elegant and therefore less error prone than an equivalent solution that is restricted to a specific paradigm.

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Summary: Will change how you think about program design completely
Review: This book is a real mind-bender that illuminates paths for computer design at both the conceptual and practical levels I'd never travelled down before.

The notion that one language can be so flexible as to accomodate both the syntax and semantics of so many different computational models, or paradigms, took some unlearning of bad programming practice before its power, elegance and potential began to sink in.

It also explodes the myth that "pure" languages -- i.e., pure OO, or pure functional, etc., languages--have some kind of innate advantage over so-called "hybrid" languages. In fact, "hybrid" (or as the authors would prefer to call them, "multi-paradigm") languages come out of this book looking even more powerful than the "pure" ones, insofar as they allow the programmer to use the right model for each task, instead of trying to make OO fit, for instance, in places where it doesn't fit so well.

The idea here is that each computational model represents a completely different way of approaching a domain problem. Used by themselves, each has its niche. For instance, everybody knows OO is good for domain modelling and busines objects. Prolog-type languages are good for applications that need to apply rules over a set of data. Functional languages are great in mathematical applications. And so on. What is new here is that one can program in an environment in which all of these tools are available in a single core semantics that seamlessly weaves these computational models into a complementary whole. Used together judiciously, with an eye toward program correctness, they make things possible that have long been considered very hard -- for instance, constraint programming.

Mozart-Oz, the underlying technology, is a strange language when you first look at it. It's hard at first to get used to concepts like "higher-order programming" or "by need execution" or "lazy execution" if you are the programming grunt in the field of most modern IT shops, forced by bosses to code in your standard fare -- Java, C#, VB, etc. If OO in Java is like the hammer that makes everything look like a nail, in Mozart-Oz you have a language that is like walking into Ace hardware store, a swiss army knife of a language (conceptually speaking) that challenges you to become a highly skill code craftsman, not just a programmer.

But, if only for the personal growth you will experience grappling with the concepts in this book, I recommend it very highly even to "non academic" programmers (like myself) as well as to any advanced student of computer science. It may be painful, you may scratch your head in places where the concepts just seemed to leap over your cranium, but if you are patient, do the exercises (and at least think about what it would take to tackle some of the research projects), you will grow.

Unfortunately, you may find the languages you work on to be rather confining, and maybe even boring, after you get a whiff of what multi-paradigm programming can do. More likely, however, is that you will grasp very clearly how the language you code in today works, and that can only make you a better software engineer. So do it-buy this book!