How to get started with Haskell: A beginner's guide

Are you ready to take on a new programming language? One that is known for its scalability, readability, and safety? Look no further than Haskell!

Haskell is a functional programming language that has been around since the late 1980s. It has gained popularity in recent years for its ability to catch errors at compile-time, making it an ideal choice for building large-scale applications.

If you're new to Haskell, don't fret! This beginner's guide will show you how to get started with Haskell and provide you with the resources you need to succeed.

Installing Haskell

First things first, you'll need to install Haskell. Luckily, installing Haskell is straightforward and can be done on Windows, macOS, and Linux.

To install Haskell on Windows, visit https://www.haskell.org/platform/windows.html and download the appropriate installer. Follow the installation instructions, and you're good to go!

If you're on a macOS, you can install Haskell using Homebrew. Open your terminal, and run the following command:

brew install ghc

Finally, if you're on Linux, follow the instructions for your distribution at https://www.haskell.org/platform/linux.html.

Congratulations! You've successfully installed Haskell.

Learning Haskell

Now that you have Haskell installed, it's time to start learning. Haskell has a steep learning curve but don't let that discourage you. There are plenty of resources to help you get started.

Haskell Books

One of the best resources for learning Haskell is a good book. There are several great books that cover Haskell, ranging from beginner-friendly to advanced. Here are some of our favorites:

• Learn You a Haskell for Great Good! by Miran Lipovača
• Real World Haskell by Bryan O'Sullivan, John Goerzen, and Don Stewart
• Haskell Programming from First Principles by Christopher Allen and Julie Moronuki

Online Resources

If you prefer online resources, there are plenty of those too! Here are some websites that offer tutorials, courses, and documentation:

• Haskell.org. The Haskell homepage has plenty of documentation to help you get started.
• School of Haskell. A collection of interactive tutorials for Haskell.
• FP Complete. FP Complete offers several Haskell courses, including a free Introduction to Haskell course.

Meetups and Conferences

Meetups and conferences are great ways to network with other Haskell developers and learn from experienced Haskellers. Check out Meetup.com or search for Haskell conferences online to find events near you.

Writing Haskell

You've installed Haskell, and you've learned the basics. It's time to start writing Haskell.

The Haskell REPL

One of the best ways to get started with Haskell is to use the Haskell REPL (Read-Eval-Print Loop). A REPL is an environment where you can enter code and immediately see its output.

To start the Haskell REPL, open your terminal, and run the following command:

ghci

You should see something like this:

GHCi, version 8.6.5: http://www.haskell.org/ghc/ :? for help
Prelude>

This is the prompt for the Haskell REPL. You can enter Haskell code at the Prelude> prompt, and it will be immediately evaluated. Try entering the following code:

Prelude> 5 + 3
8

Haskell will evaluate the expression 5 + 3 to 8 and display the result.

Writing Haskell Scripts

While the REPL is a great way to experiment with Haskell code, you'll eventually want to write longer programs. Haskell programs are typically stored in files with the extension .hs.

Here's a simple Haskell program that prints the classic "Hello, World!" message:

main :: IO ()
main = putStrLn "Hello, World!"

To run this program, create a file called hello.hs and paste in the code above. Then, save the file and navigate to its directory in your terminal. Finally, run the following command:

runghc hello.hs

You should see the message "Hello, World!" printed to your terminal.

Building Haskell Projects

As your Haskell programs grow in complexity, you'll want to organize your code into multiple files and possibly use external libraries. That's where building Haskell projects comes in.

The most popular build tool for Haskell is Stack. Stack makes it easy to create and maintain Haskell projects, manage dependencies, and build and run your code.

To install Stack, follow the instructions at https://docs.haskellstack.org/en/stable/README/.

Once you've installed Stack, you can create a new Haskell project with the following command:

stack new my-project

This will create a new directory called my-project with the following files:

.
├── README.md
├── app
│   └── Main.hs
├── my-project.cabal
├── src
│   └── Lib.hs
├── stack.yaml
├── test
│   └── Spec.hs
└── LICENSE

This is a basic scaffolding for a Haskell project. You can modify these files to suit your needs, add dependencies to your my-project.cabal file, and build your project with the following command:

stack build

Conclusion

Congratulations! You're well on your way to becoming a Haskell programmer. Haskell is a powerful programming language that is well-suited for building scalable, safe, and readable applications. We hope this beginner's guide has been helpful and that you're excited to continue your Haskell journey.

Remember, there are plenty of resources to help you along the way. Never hesitate to ask questions and seek out help. Happy coding!

Additional Resources