Programmers spend a lot of time understanding and improving their tools: editors, profilers, debuggers, and so forth. Technical magazines sometimes call to mind stores that sell outdoor gear: It's a rough world out there, you need all the equipment and gadgetry you can get. You, too, may have stared in admiration and longing at a particularly powerful syntax highlighter at some point in time.

Often lost in this analysis is a proper understanding of what tools and technologies can have the greatest impact. Irrespective of how you choose to write code and where you might run it, perhaps the single most important technology is the programming language itself. Languages both enable solutions and inhibit them; they save time and waste it; and most importantly, they either expand or contract our imagination. Yet how much have you thought about this, and how well do you understand the issues?

Whereas prior courses may have taught you how to program, this course teaches you how to analyze programming languages. What are the questions one asks when confronting a new language? What intellectual tools do we have for studying languages? What does a language designer need to know? How can we implement new languages? You should have much better answers to these questions when we're done than I expect you have now.

A major difference between this course at Brown and ones with a similar title at other universities is that we will use a much better way of classifying languages. In particular, we will move past cliched and relatively useless divisions such as "functional", "object-oriented" and "imperative". We will instead decompose languages into building blocks, and understand these building blocks in depth. The goal is to give you a richer verbal and intellectual vocabulary so that, when you are confronted with a new language, you have a broad set of concepts, each of which you understand well, to use to dissect the language.

Welcome to cs173. We hope you learn a lot in return for the hard work you're going to invest.

— Your Course Staff