Learning Haskell

This portal points to places where you can go if you want to learn Haskell.

The Introduction to Haskell on the Haskell website tells you what Haskell gives you: substantially increased programmer productivity, shorter, clearer, and more maintainable code, fewer errors, higher reliability, a smaller semantic gap between the programmer and the language, shorter lead times. There is an old but still relevant paper about Why Functional Programming Matters (PDF) by John Hughes. More recently, Sebastian Sylvan wrote an article about Why Haskell Matters.

Join the Haskell subreddit, where we do regular Q&A threads called Hask Anything (that's the archive).

There is also a table comparing Haskell to other functional languages. Many questions about functional programming are answered by the comp.lang.functional FAQ.

You can ask questions to members of the Haskell community on mailing lists, IRC, or StackOverflow. We recommend installing the Haskell Platform.

Training courses

Short training courses aimed at existing programmers

• On-site and public training courses by Well-Typed (2-day intro, 2-day advanced, custom on-site courses)
• Public training courses by NobleProg and Nilcons
• Software Engineering course on Functional Programming at the University of Oxford (1-week course)
• Summerschool on Advanced Functional Programming at Utrecht University (1-week course)

Material for self-study

Below there are links to certain introductory material. If you want to dig deeper, see Books and tutorials.

Textbooks

• Haskell from the Very Beginning
• Haskell Programming from first principles
• The Haskell School of Expression
• Haskell: the Craft of Functional Programming
• Introduction to Functional Programming using Haskell
• An Introduction to Functional Programming Systems Using Haskell
• Algorithms: A functional programming approach
• The Haskell Road to Logic, Maths, and Programming (also freely available online).
• Programming in Haskell
• Real World Haskell
• Learn You a Haskell for Great Good!
• Happy Learn Haskell Tutorial

Online tutorials

• Meta-tutorial
• Haskell Fundamentals - get started and learn key concepts at Pluralsight (2-part, 5 hour online course)
• Haskell Wikibook A thorough textbook with a step-by-step beginners track assuming no programming background. Also includes many advanced concepts, and adaptations of "Yet Another Haskell Tutorial", "Write Yourself a Scheme in 48 Hours", and "All about monads".
• YAHT - Yet Another Haskell Tutorial (good tutorial available online)
• Two dozen short lessons
• A Gentle Introduction to Haskell - classic text, but not so gentle really :D
• Haskell-Tutorial
• Online Haskell Course (German)
• Haskell tutorial for C Programmers
• Learn You a Haskell for Great Good! Beautiful, illustrated Haskell tutorial for programmers with less of a functional programming background.
• Happy Learn Haskell Tutorial Up to date complete beginner illustrated tutorial that uses many basic examples and exercises , going very slowly step by step.
• Learning Haskell Ongoing tutorial in the form of YouTube videos; updates slowly.
• Pattern matching, first-class functions, and abstracting over recursion in Haskell, a simulation of the evaluation of map, foldr and foldl.
• School of Haskell
• Learning Haskell — a tutorial combining clear explanations, graphics programming, and hands-on screencasts to teach you the essential concepts of functional programming in Haskell.

Advanced tutorials

• Hitchhikers guide to Haskell
• Write Yourself a Scheme in 48 Hours
• Tackling the Awkward Squad (on I/O, interfacing to C, concurrency and exceptions)

Monads

• You Could Have Invented Monads! (And Maybe You Already Have.)
• Monads for Functional Programming
• All about monads
• IO inside: down the Rabbit Hole

Type classes

• The paper that for the first time introduced type classes and their implementation using dictionaries
• More papers on the type classes

Generic programming

• Scrap your boilerplate

Popular libraries

• ByteStrings?
• Parsec, a fast combinator parser
• Modern array libraries
• Gtk2Hs, the GUI library
• 24 Days of Hackage (blog posts about many popular libraries)

Reference

• The official language definition: Language and library specification
• Tour of the Haskell Prelude
• Haskell Reference
• Haskell Reference card
• Tour of the Helium Prelude
• Some common Hugs error messages
• The Haskell Cheatsheet - A reference card and mini-tutorial in one.
• A Glossary of common terminology.
• What I Wish I Knew When Learning Haskell by Stephen Diehl

Course material

• Introduction to Functional Programming, Chalmers (for beginners at programming)
• Functional Programming, Chalmers
• Advanced Functional Programming, Chalmers
• Parallel Functional Programming, Chalmers
• Introduction to Haskell, University of Virginia CS 1501
• CS 11 Caltech
• Functional programming: course notes (English, Dutch, Spanish), slides in Dutch
• CS1011: Tutorials, lab exercises and solutions
• Stanford - Functional Systems in Haskell
• CIS 194 Introduction to Haskell, University of Pennsylvania

Trying Haskell online

There are several websites where you can enter a Haskell program and run it. They are (in no particular order):

• CoCalc app, formerly SageMathCloud
• Try Haskell
• CodeWorld
• Bubble Pop!, the satisfaction of popping bubble wrap, combined with the satisfaction of really elegant functional programming!
• Try Haste & HPlayground client-side framework; the source code is on GitHub
• Koding is a cloud based IDE which supports Haskell and several other languages. Free accounts allow one virtual machine.

To create a browser based environment yourself:

• IHaskell