General information

Goals of course

This is a course in typed, functional programming using Haskell. Haskell was invented by committee in 1990 to experiment with the possibilities of lazy, typed, pure functional langauge. It has since grown substantially and now attracts a small but growing industrial user base. In particular, Haskell’s type system is often recognized as best-in-class; novel ideas about type systems are frequently phrased in terms of Haskell.

During this course, you will learn Haskell with an eye to understanding the benefits, drawbacks, and power of its type system. While Haskell can indeed be used for quotidian tasks (writing games, interacting through websites through their APIs, processing data), we will instead focus on types. By the end of the course, you will learn about dependent types which give you the ability to encode machine-checked invariants in your programs. For example, you can give a sort function a type that says that the output list must appear in non-decreasing order. If the implementation of such a function is incorrect, the program is rejected at compile time.

Course Philosophy

In order to learn any programming skill, you must simply do it. Reading a website or watching me code will not help you get better. This course is thus programming-intensive. You will be expected to spend a significant amount of time weekly (6-8 hours) outside of class programming to complete the homework assignments. If you run into a snag, the programming burden may prove to be even higher. Of course, programming is fun, so the time should fly by.

Class time in CS380 will be spent primarily working with peers to solve small programming problems, conduct peer reviews, and complete other exercises. It is expected that you complete the reading before class and come with questions; I will try to avoid spending large chunks of class time repeating what the reading has already covered.

Materials

There is no required textbook for this course. Below are several resources you might find helpful while learning Haskell; however, none of them dive into the type system the way we will in this course.

• Haskell from First Principles, by Christopher Allen and Julie Moronuki. This comprehensive book has been the multi-year effort of two prominent Haskell educators, who have refined the presentation of Haskell in this book as they have taught many classes of students. This was nearly the selected textbook for this course, but it does not have enough on Haskell’s advanced type system features for this course. I recommend it as a companion text, however. The book is currently online-only (for $59), available at http://haskellbook.com/.

• Real World Haskell, by Bryan O’Sullivan, Don Stewart, and John Goerzen. This book has been a standard text for learning Haskell for some time, but it is now somewhat out of date. I learned Haskell from this book. It is available for free online at http://book.realworldhaskell.org/.

• Learn You a Haskell for Great Good, by Miran Lipovača. This is another, slightly outdated book on learning Haskell. It is also free online at http://learnyouahaskell.com/.

• Stephen Diehl has written a comprehensive page covering all kinds of Haskell goodies at http://dev.stephendiehl.com/hask/.

• Lots of tutorials are available at https://www.schoolofhaskell.com/.

• Standard library documentation is at http://hackage.haskell.org/package/base.

• The Hoogle search engine (you can search by type!) is at https://www.stackage.org/.

It can be hard to sort through all of this. If you find a tidbit (individual chapter of a book, tutorial, etc.) that you find helpful, tell us all.

This website is generated by Hakyll and Pandoc, both written in Haskell.