A First look at Haskell

What is Haskell?

A functional programming language with a bunch of cool features. If you want to know why to learn this read here

Start By Installing

To work with Haskell you need : A Haskell Compiler The simplest way to get started is by downloading the Haskell Platform here

Start By Trying it out

First lets see if it works. Go to the console (command prompt) and type ghci

GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help  
Loading package .... //some packages

If you see that you have successfully installed Haskell. Now lets type some commands and see what we get

Prelude> 6+3
Prelude>  9/3

First functions

Okay now lets move on from writing command line codes to our first function. Create a file named abc.hs and save it in any folder. Enter this in the file. It is basically a function called double me that takes x and returns (x+x)

doubleMe x = x + x  

Now cd to the folder where you saved it using the Command Prompt. Run ghci. Once inside the GHCI, run :l abc

Prelude> :l abc  
[1 of 1] Compiling Main             ( abc.hs, interpreted )  
Ok, modules loaded: Main.  
Prelude> doubleMe 4
Prelude> doubleMe 3.2 

If, Then, Else

The if else condition can be written simply in Haskell. First specify the condition. Then mention what is to be done if true. The difference between Haskell and imperitive languages (say, Java) is that Haksell must specify the else condition.

doubleSmallNumber x = if x > 100  
                    then x  
                    else x*2   


We learned how to install haskell and write our first Haskell functions. More to be done in part 2

15 Apr 2014