Introduction to Haskell
Pure, lazy, functional — types as a superpower.
What Haskell is, why it matters, and how to navigate this track.
Haskell is purely functional and lazily evaluated — a language that will change how you think about code.
What is Haskell?
Haskell is a statically-typed, purely functional language where functions have no side effects by default.
Its powerful type system lets the compiler prove a great deal about your program before it runs.
Your first example
Here is Haskell saying hello. Read it top to bottom — every line earns its place.
main :: IO ()
main = putStrLn "Hello, world!"Hello, world!
Why learn Haskell?
- Purity and types make whole categories of bugs impossible.
- It teaches functional thinking that improves all your other code.
- A favourite for compilers, finance, and correctness-critical work.
Where it is used
- Compilers & DSLs
- Finance
- Correctness-critical systems
- Learning functional programming
How this track works
Every topic here has four views, switchable with the tabs at the top of each page:
- Learn — the clear, practical walkthrough you are reading now.
- Deep — every detail: edge cases, the full API, and what is really happening.
- Reference — a scannable, no-fluff lookup for when you already know the shape.
- Cheatsheet — the one-page summary, printable, for quick recall.
More like this
HTML Headings
h1 through h6 are the page’s table of contents. Use them for structure, never for size — that’s what CSS is for.
HTML Headings
h1–h6 are instances of HTMLHeadingElement. They take no special attributes — only the global set and ARIA — but there’s real depth in how they form the document outline and what you can do with them from JavaScript.
Liked this one?
Pass it on
Discussion
Be the first to ask
Your questions stay private with the team. We can pin answers to share with everyone.
Sign in to ask a question privately on this tutorial.
Sign inNo pinned answers yet for this tutorial.