The Haskell School Of Expression: Getting Started on Ubuntu

PC sent me a copy of Hudak’s The Haskell School of Expression for my birthday. I was trying to get started with some of the code in the book and could not find a good writeup on it. Here is how I got it going on my Ubuntu Gutsy laptop.

First, install GHC and HGL as:

sudo apt-get install ghc6
sudo apt-get install libghc6-hgl-dev

Then, copy the following code to a file simple.hs somewhere on the disk. This code is from Chapter 3 of the book.

import Graphics.SOE
main0
   = runGraphics $
     do w <- openWindow "My First Graphics Program" (300, 300)
        drawInWindow w (text (100, 200) "HelloGraphicsWorld")
        k <- getKey w
        closeWindow w

Launch GHC interpreter and load the code into it.

$ ghci
   ___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version 6.6.1, for Haskell 98.
/ /_\\/ __  / /___| |      http://www.haskell.org/ghc/
\____/\/ /_/\____/|_|      Type : ? for help.

Loading package base ... linking ... done.
Prelude> :l /path/to/simple.hs
[1 of 1] Compiling Main             ( /path/to/simple.hs, interpreted )
Ok, modules loaded: Main.

Now, run the application as:

*Main> main0
Loading package X11-1.2.1 ... linking ... done.
Loading package HGL-3.1.1 ... linking ... done.
*Main>

If everything is set up properly, this should show a GUI window with the text ‘HelloGraphicsWorld’ written on it. Pressing any key should dismiss this window.

Furniture charity

Here is an interesting article (via HN) on how IKEA cons the taxman by posing as a charity. I started reading the book Perfectly Legal, but discontinued after few pages. The IKEA story reminded me to pick it up again – maybe soon after I am done with my current reading list.