You may already have Haskell! That’s excellent, you can skip right down to Step 2, installing EdPrelude. To check, open a terminal and type “ghci --version” to see if you have “ghci” already installed on your computer. If not, install by following the link below and picking the correct version for your OS (Windows, OS X for Mac, Linux). Choose the minimal installation.
https://www.haskell.org/downloads#minimal
After following those instructions, congratulations! You have Haskell.
With Haskell installed, you’ll have a copy of Prelude, which is Haskell’s standard library of useful functions. However, though Prelude is powerful, it is also complex. EdPrelude is an alternative version of Prelude, containing simple and straightforward definitions of the standard functions with a restricted set of available types. It also automatically derives a pretty-printer for data structures you specify, making it easier to read command-line output.
To install EdPrelude, follow the link below to get the zip file.
EdPrelude Download
You should download a file named e-prelude-master.zip. Unzip this file, and navigate a terminal to the e-prelude-master folder (likely within your Downloads folder). At the terminal, within the folder, run the command below:
$ sudo ./install.sh (This command will require root access.)
If it succeeded without any errors, you should be done! As a test, run the following command from a new terminal:
$ edhci
It should open up an interactive REPL with EdPrelude loaded. As a further test, you can run the following command at the interactive prompt:
*EdPrelude> :type length
You should get back the following:
length :: [a] -> Integer
Demonstrating that you are using EdPrelude’s definition of the length function compared to Prelude’s.
If you ever want to uninstall EPrelude, you can navigate to the same file (or re-download it if you’ve deleted it) and run the command below:
$ sudo ./uninstall.sh (This command will require root access.)
To update EPrelude, download the newest version from the link above, follow the instructions for installing again. You will be prompted before overwriting any of the old versions of files; confirm each overwrite to update.