How to learn Haskell
This is a recommended path for learning Haskell based on experience helping others. A list of recommendations from one of the authors of the Haskell Book.
For non-English speakers
Don't sweat the stuff you don't understand immediately. Keep moving!
Community
Our IRC channel is #haskell-beginners on Libera Chat.
IRC web client here.
The haskell mailing lists.
Community Guidelines
See the community guidelines to understand the conduct that is expected in the IRC channel. You'll get a warning if you're not obviously trolling, but be aware the channel is exclusively for those learning or teaching Haskell.
Installing Haskell
Use Stack to get going with Haskell
Get Stack to get GHC installed and to build your projects.
If you don't know anything about Stack and would like an overview, check out this comprehensive Stack video tutorial.
Also, DO NOT INSTALL HASKELL PLATFORM
Instead of following the instructions on Haskell.org, get Stack.
Why not platform?
https://mail.haskell.org/pipermail/haskell-community/2015-September/000014.html
How should I learn Haskell?
The core recommendation is to read the lectures and complete all exercises/homework for the Spring 13 version of cis1940 followed by the FP course. Both are linked below. Everything else can be considered optional and is mentioned so you know where to look.
Haskell Programming from First Principles.
@dmvianna wanted me to let you know that the below are just the free recommended resources. If you're willing to check out a book, we heartily recommend our own Haskell Book! If you can't afford the book for any reasons, please email us using the contact information at our support page.
Haskell Book subsumes all of the primary resources recommended here
Yorgey's cis1940 course
Do this first if aren't getting the Haskell Book, this is the best free introduction to Haskell.
Available online.
Brent Yorgey's course is the best I've found so far. This course is valuable as it will not only equip you to write basic Haskell but also help you to understand parser combinators.
The only reason you shouldn't start with cis1940 is if you are not a programmer or are an inexperienced one. If that's the case, start with Thompson's book and transition to cis1940.
Functional Programming course
This is the course we recommend doing after Yorgey's cis1940 course
Available on github here.
This will reinforce and give you experience directly implementing the abstractions introduced in cis1940, this is practice which is critical to becoming comfortable with everyday uses of Functor/Applicative/Monad/etc. in Haskell. Doing cis1940 and then the FP course represents the core recommendation of my guide and is how we teach everyone Haskell.
Supplementary course after cis1940 and the FP course
Provides more material on intermediate topics
cs240h is available online:
This is Bryan O'Sullivan's online course from the class he teaches at Stanford. If you don't know who he is, take a gander at half the libraries any Haskell application ends up needing and his name is on it. Of particular note if you've already done the Yorgey course are the modules on phantom types, information flow control, language extensions, concurrency, pipes, and lenses.
Resources for specific topics in Haskell
These resources are not vetted or tested with learners as cis1940 and FP course have been, but they're linked in the topic listing so you have ideas on where to begin. This includes things like intermediate/advanced concepts and subjects like tooling and text editors.
Dialogues
Hosted in this repository here.
These are actually pretty important and helpful. Look here for deep dives on a variety of topics.