mouse listener in Haskell

Question

I'm trying to make a program in Haskell using opengl that draws a circle when the mouse is clicked, where it is clicked. The trouble is, I can't find anything that can show me how to make a mouse listener. Does anybody know any good tutorial sites?

Answer 1

If you are using GLUT, you'll find what you need in Graphics.UI.GLUT.Callbacks.Window, specifically, keyboardMouseCallback. Note that mouse buttons are treated like keyboard keys:

myKeyboardMouseCallback key keyState modifiers position =
  case (key, keyState) of
    (MouseButton LeftButton, Down) -> do
      {- draw circle @ position ... -}
    _ -> return () -- ignore other buttons

attachMyKeyboardMouseCallback = keyboardMouseCallback $= Just myKeyboardMouseCallback