-- GUI for a temperature converter import GUI import Read -- only a scale for Celsius: temp_widget = Col [] [ Label [Text "Temperature in Celsius:"], Scale 0 100 [WRef cels, Cmd convert], Row [] [Label [Text "Fahrenheit: "], Message [WRef fahr, Background "white"], Label [Text "Kelvin: "], Message [WRef kelv, Background "white"]], Button exitGUI [Text "Stop"]] where cels,fahr,kelv free convert wp = do cs <- getValue cels wp let c = readInt cs setValue fahr (show (c * 9 `div` 5 + 32)) wp setValue kelv (show (c + 273)) wp main = runGUI "Temperature Conversion" temp_widget