Hello, World

This is the same example as presented in the tutorial, See section A Haggis tutorial:

module Main(main) where

import Haggis

main =
 wopen ["*title: Hello"] 
       (label "Hello, World") >>
 return ()

The Hello, World example consist of two parts:

• The label component that displays the Hello, World string. The label is a user interface abstraction provided by Haggis

  
  label :: Picture -> Component (Label, DisplayHandle)
  
  

• wopen, the function that opens up a toplevel window for the label to display itself in. Think of wopen as opening up a virtual device, in this case a static label, and displaying it in a window. The user can then interact with the virtual device inside the window.