module Main whereimport HTk    import Randommain:: IO ()main =  do main <- initHTk []     b <- newButton main [text "Press me!"]     b2 <- newButton main [text "Close"]     pack b [Side AtTop, Fill X]     pack b2 [Side AtBottom, Fill X]     click  <- clicked b     click2 <- clicked b2     spawnEvent       (forever         ((click >>> do nu_label <- mapM randomRIO                                       (replicate 5 ('a','z'))                       b # text nu_label                       done)        +> (click2 >>> destroy main)))     finishHTk