Typeclassopedia
by Brent Yorgey · HaskellWiki
Brent Yorgey's reference to Haskell's standard type class hierarchy, covering Functor, Applicative, Monad, Monoid, Foldable, Traversable, Category, Arrow and Comonad with their laws, intuitions, exercises and primary references. Readers understand how the classes relate and why their laws matter.
More resources on Functional Programming & Haskell
Category Theory
Recorded lecture series by Bartosz Milewski introducing category theory for programmers: categories, morphisms, initial and terminal objects, products and coproducts, functors, exponentials, natural transformations and monads, illustrated with Haskell. Viewers learn to connect categorical constructions to type systems and functional programming.
Effective Haskell: Solving Real-World Problems with Strongly Typed Functional Programming
Rebecca Skinner's 668-page 2023 book on writing production Haskell, covering monad transformers, type families, concurrency, database access and RESTful services. The most current major Haskell book, written against modern GHC extensions and tooling.
Programming in Haskell (2nd Edition)
Graham Hutton's Cambridge University Press textbook, second edition, building Haskell from first principles through 120 exercises. Covers type classes, recursion, folds, monads, reasoning about programs and a compiler case study. The author's site hosts free lecture videos and slides.
Learn You a Haskell for Great Good! (Community Version)
Community-maintained fork of Miran Lipovaca's introductory Haskell text, forked with the author's permission and updated as the language evolves. Covers types, type classes, recursion, higher-order functions, functors, applicatives and monads. Conceptual rather than project-oriented.
Haskell MOOC (University of Helsinki)
Two-part self-paced functional programming course from the University of Helsinki, worth 10 ECTS credits. Exercises are automatically checked against test suites, and the material is actively maintained against current GHC and Stack.
CIS 194: Introduction to Haskell (Spring 2013)
Penn's twelve-week Haskell course by Brent Yorgey, with lecture notes and graded homework covering algebraic data types, type classes, laziness, folds, monoids, functors, applicatives and monads. Tooling references predate modern Cabal and Stack.