Fudgets - Tutorial - Hello World

Hello, world!

This program just opens a small window displaying the message "Hello, world!". The window will look something like this (depending on your setup):

Here is the source code:

import Fudgets

main = fudlogue (shellF "Hello" (labelF "Hello, world!"))

To use the fudget library, you should import the module Fudgets. Assuming the Fudgets library has been installed (with cabal install) and the program is stored in a file called Hello.hs, the command line to compile the program is
ghc Hello
A fudget program consists of a number of fudgets combined in a hierarchical structure into one main fudget. The function fudlogue is used to connect the main fudget to the Haskell I/O system. It also handles various initialisation and administration.
A fudget program with a graphical user interface needs one or more shell windows (top level windows). These can be created with the function shellF. The last argument is the fudget which determines the contents of the window.
In this simple program, the contents of the shell window is just a simple string display, which is created with the function labelF. The argument is the string to be displayed.