**Course Title:** Functional Programming with Haskell: From Fundamentals to Advanced Concepts **Section Title:** Introduction to Functional Programming and Haskell **Topic:** Setting up the Haskell environment (GHC, GHCi, Stack, Cabal) **Objective:** By the end of this topic, you will understand how to set up a Haskell development environment, including installing the Glasgow Haskell Compiler (GHC), GHCi, Stack, and Cabal. You will be able to write and run Haskell code effectively. **1. Introduction** To start programming in Haskell, you need to set up a development environment. This includes installing the Glasgow Haskell Compiler (GHC), the interactive REPL GHCi, the Stack build tool, and the Cabal package manager. In this topic, we will walk through each of these components and show you how to set up your environment. **2. Installing GHC and GHCi** GHC is the primary compiler for Haskell. To install GHC, you can download the installer from the [Glasgow Haskell Compiler download page](https://www.haskell.org/ghc/download.html). Follow the installation instructions to install GHC on your system. GHCi is an interactive REPL (Read-Eval-Print Loop) environment that allows you to experiment with Haskell code. Once you have installed GHC, you can start GHCi by opening a terminal or command prompt and typing `ghci`. **Example:** Starting GHCi ```bash $ ghci GHCi, version 9.2.5: https://www.haskell.org/ghc/ :? for help Prelude> ``` **3. Installing Stack** Stack is a build tool for Haskell that allows you to easily manage dependencies and build projects. To install Stack, you can download the installer from the [Stack download page](https://docs.haskellstack.org/en/stable/install_and_upgrade/). Follow the installation instructions to install Stack on your system. **Example:** Installing Stack on macOS using Homebrew ```bash $ brew install haskell-stack ``` **4. Installing Cabal** Cabal is a package manager for Haskell that allows you to easily manage dependencies and build projects. Stack includes Cabal, so if you installed Stack, you already have Cabal. However, if you want to use Cabal without Stack, you can install it separately using the following command: ```bash $ cabal --version cabal version 3.8.1.0 ``` **5. Creating a New Project with Stack** To create a new Haskell project with Stack, navigate to the directory where you want to create the project and run the following command: ```bash $ stack new myproject $ cd myproject ``` This will create a new directory with a basic Haskell project structure. You can then open the `myproject.hs` file in your favorite text editor to start writing Haskell code. **6. Running Haskell Code** To run Haskell code, you can use GHCi or compile it with GHC. To run code in GHCi, simply type the code into the GHCi prompt: **Example:** Running Haskell Code in GHCi ```haskell Prelude> 2 + 2 4 ``` To compile Haskell code with GHC, use the following command: ```bash $ ghc --make myproject.hs ``` This will compile the `myproject.hs` file and create an executable file called `myproject`. **Conclusion:** In this topic, we have covered how to set up a Haskell development environment, including installing GHC, GHCi, Stack, and Cabal. You have learned how to create a new Haskell project with Stack, run Haskell code in GHCi, and compile Haskell code with GHC. With this setup, you are now ready to start writing and running Haskell code. **What to Do Next:** * Start experimenting with Haskell code in GHCi. * Create a new Haskell project with Stack and explore the project structure. * Read the [Stack documentation](https://docs.haskellstack.org/en/stable/) to learn more about Stack and Cabal. **Leave a Comment/Ask for Help:** If you have any questions or issues with setting up your Haskell environment, please leave a comment below. We will be happy to help you troubleshoot and get started with Haskell programming.