Today I made my first Haskell Project !

It was a text-based hangman game, and it was heavily guided by the book, even-so it brought everything together and it was quite cool actually producing something tangible.

So the basics for setting up any project is by the following commands:

stack new my-project
cd my-project
stack setup
stack build
stack exec my-project-exe

• stack new builds a project directory for a new Haskell Project
• stack setup will download or update the necessary GHC compiler
• stack build will build the minimal project in order to execute teh project.
• Then depending on what executable command you give the project in the .cabal file, stack exec will execute your project.

The .cabal file

This file is a file in the project directory to document build and library dependencies and write executables. By using the stack build commands above, a pre-configured .config file is created.

Basic terms to know pre-monad enlightenment

IO

As touched upon in previous blogs, the IO (Input/Output) type is used to control side effects and keep them explicitly separate to other types. methods that inherit the IO typeclass are usually defined as a Unary constructer with a Type signature of IO a which when used with a binding <- becomes type a (binding is a way of equally the output of a IO a method to a value of type a (this is very simplified, as I do not yet understand Monads).

do

do is syntactic sugar to sequentially order function calls. They make things more readable by explicitly showing in what order things are being called.

The main function is the one that usually needs to introduce side effects, by either pulling data or reading from the console. Therefore it is usually the case that this would be a do block of type IO

main :: IO ()
main = do
  name <- getLine
  return name

Key bits

To make import aliases: import qualified Data.Bool as B

return, returns a monad value in IO. Without it, the value would not be returned.

forever, from the Control.Monad library allows the creation of an infinite loop, analogous to a While loop.

exitSuccess from the System.Exit library is a safe way to exit the programme.