Celestin Apprentice 7/Apprentice-Release7.iso/Environments/Clean 1.2.4/IO Examples/Small IO Examples/HelloWorld.icl

Text File | 1997-04-25 | 1.3 KB | 34 lines | [TEXT/3PRM]

module HelloWorld

/*    Hello World!
*/

import deltaEventIO, deltaWindow, deltaPicture

DontCareId    :==    0

Start :: *World -> *World
Start world
#    (events,world)    = OpenEvents world                                // fetch the event stream from the world
    (_,events)        = StartIO ioSystem initProgramState [] events    // perform our IO function on the event stream
    world            = CloseEvents events world                        // close the event stream
=    world
where
    ioSystem                                                        // this program uses only a window
        = [WindowSystem [window]]
    window
        = FixedWindow DontCareId (10,10) "Greeting" ((0,0),(162,100)) updateFunction
            [    Keyboard Able quitFunction                            // pressing any key quits the program
            ,    Mouse    Able quitFunction                            // pressing the mouse quits the program
            ,    GoAway   quit                                        // closing the window quits the program
            ]
    quitFunction _ programState io                                    // ignore the first argument of mouse or keyboard information
        = quit programState io
    quit programState io                                            // bye, bye: causes StartIO to terminate
        = (programState, QuitIO io)
    updateFunction _ programState                                    // display the contens of the window
        = (programState, [MovePenTo (30,30), DrawString "Hello World!"])

    initProgramState                                                // arbitrary because this program doesn't use the program state
        = 0