## Docs

- Syllabus
- Haskell style guide
- lhs2TeX and SProof

## Quizzes

## Lectures

T 16 Jan — Introduction to Haskell

In-class codeTh 18 Jan — Lists, algebraic data types & pattern matching

In-class codeT 23 Jan — basic polymorphism, inference rules & propositional logic

In-class codeTh 25 Jan — Propositional logic

T 31 Jan — Polymorphism and recursion patterns

In-class codeTh 1 Feb — Folds

In-class codeT 6 Feb — Currying, induction

In-class codeTh 8 Feb — Structural induction

T 13 Feb — Untyped

*λ*-calculus I (definitions)Th 15 Feb — Untyped

*λ*-calculus II (Turing-completeness)T 20 Feb —

`fix`

and the Y combinator

In-class codeTh 22 Feb — STLC and the Curry-Howard Isomorphism

T 27 Feb — Intro to Idris (Basics, inductive proofs)

In-class codeTh 1 Mar — Idris II (Dependent functions and pairs)

In-class codeT 6 Mar — Idris III (Equational reasoning)

In-class codeTh 8 Mar — Idris IV (Structured proofs)

In-class codeT 13 Mar — Idris V (More Curry-Howard, induction)

In-class codeTh 15 Mar — Idris VI (Encoding the STLC)

In-class codeT 27 Mar — Type classes, kinds, and Functors

In-class codeTh 31 Mar — Functors; intro to Applicative functors

In-class codeT 3 Apr — Applicative functors

In-class codeTh 5 Apr — Applicative functors II

In-class codeT 10 Apr — Monads I

In-class codeTh 12 Apr — Applicative and type jigsaw practice

T 17 Apr — Monads II

In-class codeTh 19 Apr — Monads III

In-class codeT 24 Apr — Active library

In-class codeTh 26 Apr — Laziness

In-class code

## Assignments

Weekly assignments will be posted here, and are due every **Tuesday** before the beginning of class.

Please submit assignments via this form.

Week 1: Intro to Haskell [ lhs ]. Due Tuesday, 23 January.

Week 2: Algebraic Data Types and Proof Trees [ lhs, Proof.hs ]. Due Tuesday, 30 January.

Week 3: Polymorphism and Recursion Patterns [ lhs ]. Due Tuesday, 6 February.

Week 4: Idiomatic Haskell and Induction [ lhs ]. Due Thursday, 15 February.

Week 5: Lambda calculus. Due Thursday, 22 February.

To install the command-line lambda-calculus interpreter:

If you do not already have the

`stack`

tool installed, do so by following the instructions here.In the directory where you extracted the above, run

`stack build`

(you may have to run`stack setup`

first). This may take a while.Once

`stack build`

has completed successfully, you should be able to run`stack exec lc`

to run the lambda calculus interpreter.

Week 6: STLC [ lhs STLC.hs ]. Due Thursday, 1 March (problem #6 extended to Thursday, 8 March).

Week 7: Idris Basics. Due Thursday, 8 March.

Week 8: Idris Proofs. Due Thursday, 15 March.

Week 10: Type classes [ lhs, ExprT.hs, StackVM.hs, Parser.hs ]. Due Thursday, 5 April.

Week 11: Applicative functors [ lhs, AParser.hs, SExpr.hs ]. Due Thursday, 19 April.

Week 13: Monads [ Risk.hs ] Due Thursday, 26 April.

## Final project

### Overview/important dates

You will complete a final project which will extend or tie together some of the things we have learned over the course of the semester.

Important dates:

**Tuesday, April 17**– Project proposals due**April 23–27**– Checkpoint meetings**Wednesday, May 2, 8:30-11:30am**– Final project presentations

### Format

You may work by yourself, or in groups of up to *three* students. Groups of five are *right out*.

You have quite a bit of latitude in what sort of project you choose to complete (subject to approval, of course). Possible types of projects include (but are not limited to):

- Developing some sort of Haskell application or library
- Encoding some proofs using Idris
- An expository presentation;
*e.g.*pick a functional pearl (I’m happy to suggest some good ones), or a functional data structure, etc., understand and possibly re-implement it, and present it to the class.

Your project should somehow go beyond what we have covered in class, that is, completing the project should require you to learn something new.

### Project proposal

You must submit a project proposal explaining what you intend to do. The proposal should be about 1 page, and should clearly explain:

- What you intend to do
- Your specific goals for the project,
*i.e.*what are the criteria for a successful project? - An explanation of what you expect to learn,
*i.e.*how does your project go beyond what we have covered in class?

### Checkpoint meetings

During the week of April 23–27, your group must schedule a 30-minute meeting with me to discuss your progress, ask questions, *etc.*. (Of course I am happy to meet with you at other times as well.)

### Presentations

In the morning on Wednesday, May 2, you will give a 15–20 minute presentation on your project. The presentation could take many forms depending on the type of project. For example, it could just be a demo, if you primarily produced some sort of artifact; it could be a presentation with slides or a chalkboard talk explaining something.

### Final submission

You may submit your project in one of two ways:

By emailing me a

`.tar`

,`.tgz`

or`.zip`

fileBy emailing me a link to a publically accessible source repository,

*e.g.*on github, bitbucket, or hub.darcs.net. Be sure to submit a link to one or more specific commits, tags,*etc.*representing what you would like to be graded, rather than just to the repository in general.

### Grading

Grading will be as follows:

Proposal (10%).

Style (10%). Your project should use good Haskell or Idris style and be well-documented.

Checkpoint (10%). Did you make some progress on your project by the time of the checkpoint meeting? Were you prepared with good questions to ask?

Presentation (20%). Your presentation should be clear and instructive, demonstrating your project and what you learned.

Correctness (25%). Your project should be free of compilation errors and should correctly accomplish whatever it is supposed to accomplish. This means that if the deadline is looming, your time would be better spent fixing bugs in what you already have than adding one last feature.

Effort/accomplishment (25%). I will be looking for evidence that you put energy and effort into your project and that you have learned something. In your presentation, you should be sure to highlight work you did and things you learned, especially if it is not obvious from looking at the final product. For example, if you spent a bunch of time trying an approach that ultimately did not work, you should talk about that and what you learned from the experience.

## Resources

### Installation and coding environment

You can try using repl.it. I haven’t tried it, but it looks nice, and could be a convenient way to write and run Haskell code without having to install anything.

If you want to install Haskell on your computer, follow the instructions here to install the

`stack`

tool. You should then be able to run`ghci`

using the command`stack ghci`

. (You may have to run`stack setup`

first.) Come ask for help if you are stuck.If you have a favorite text editor it will probably work just fine for editing Haskell programs. If you use emacs I recommend installing Intero. Other editors commonly used with Haskell include Atom, TextMate, and Sublime Text.

### Help/community

The #haskell IRC channel is a great place to get help. Strange as it may seem if you’ve spent time in other IRC channels, #haskell tends to be full of friendly, helpful people.

tryhaskell.org gives you a ghci session in your browser, and includes a very simple tutorial. It also features an interface to the #haskell IRC channel.

lpaste.net is a good place to paste programs you’re having trouble with in order to get help from people in #haskell.

Many people from the Haskell community are active on StackOverflow, which can be a good place to ask questions.

The Haskell-beginners mailing list is a good place to ask beginner-level questions.

The Haskell-cafe mailing list can also be a good place to ask questions, but is much higher-traffic.

The Haskell wiki has a list of frequently asked questions.

### Reading

Graham Hutton’s Programming in Haskell is a required text for the class.

Haskell Programming from first principles is a book in progress which has been getting good reviews. An early access, electronic version is currently available for purchase.

The Typeclassopedia explains many of the type classes in the standard libraries (

`Functor`

,`Applicative`

,`Monad`

,`Monoid`

,`Arrow`

,`Foldable`

,`Traversable`

…).The Haskell wikibook actually contains a substantial amount of well-written information; a great resource if you’re having trouble understanding a particular topic and want a different approach.

Learn You a Haskell for Great Good! is a whimsical Haskell tutorial with funny illustrations. Might be good as an extra reference though I disagree with many of the pedagogical choices it makes. Available for free online or in dead tree form.

The Haskell wiki is a huge grab-bag of all sorts of information, examples, explanations. The quality varies but it’s definitely a great resource.

Planet Haskell aggregates blog posts from the Haskell community.

There is a Haskell subreddit for aggregating Haskell-related websites, blog posts, and news.

### Reference

A useful Haskell cheatsheet.

Hackage is a huge repository of Haskell packages. If it isn’t on Hackage, it doesn’t exist. Packages can be automatically downloaded and installed from Hackage using the cabal-install tool.

Looking for a function but don’t know what it’s called? Want to see the documentation for a particular function? Hoogle searches many standard libraries and can search either by name or by type.

Hayoo is another search engine for the Haskell documentation, which is much more complete (it searches all of Hackage).

If you really want the nitty-gritty details of the Haskell language standard, see the 2010 Haskell report.