Installing Haskell Platform

Installing the Haskell platform is pretty straight forward. You will have to first download the appropriate setup file from http://hackage.haskell.org/platform/.

Running the setup file will install Haskell compiler and runtime environments in your computer.

After installing the platform you may have to add the <GEC_HOME>/bin directory to the system path.

Running the first program – “Hello World”

Once installing Haskell platform, let’s see how we can run our first “Hello World” program. You can run a program in two ways:

1. Using the Haskell interpreter for interactive processing (best option to learning Haskell)
2. Compile and executing *.hs files

“Hello World” program using GHC interpreter

1. Open terminal / command prompt of your system
2. Type ‘ghci’ to get the GHC Interpreter terminal
3. Just type in : “Hello, World!” and see what you get!!!
4. Another alternative is to us the ‘putStrLn’ statement. Try typing : putStrLn “Hello, World!”

“Hello World” program using GHC compiler

1. Create a source file helloworld.hs with content

   main = putStrLn "Hello, World!"

2. Open terminal and go to the directory where the helloworld.hs file is saved.
3. Compile helloworld.hs file using the command. This would create a helloworld.exe file

   ghc -o helloworld helloworld.hs

4. Now you can run the executable file

Haskell Compilers and Interpreters

The Glasglow Haskell Compiler (GHC) is the most commonly used and the de-facto-standard compiler for Haskell. We have many other important Haskell compilers like:

• Haskell User´s Gofer System (Hugs)
• nhc98
• York Haskell Compiler (YHC)
• HBI  and HBC, Chalmers’ Haskell Interpreter and Compiler (Chalmers Haskell-B)
• Utrecht Haskell Compiler (UHC)
• JHC
• LHC
• Yale Haskell
• Disciplined Disciple Compiler (DDC)

The following table tries to compare these compilers.