Pile operators

Operators for changing the current component to display in the pile + operations for dynamicaly adding components to the stack:

pileUp :: Pile -> IO ()

pileDown :: Pile -> IO ()

move `display point' up or down by one.

pileTop :: Pile -> IO ()

pileBottom :: Pile -> IO ()

move `display point' to the top or bottom of the Pile list.

pileGoto :: Pile -> Int -> IO ()

move the `display point' to a particular component in the Pile list.

getPileSize :: Pile -> IO Int

returns the current number of components in the Pile.

getPilePos :: Pile -> IO Int

return the position of the component currently being displayed.

getPileComponents :: Pile -> IO [DisplayHandle]

returns the current set of components.

setPileComponents :: Pile -> [DisplayHandle] -> IO ()

replace the Pile's component with a new set. Displays initially the topmost element of the new list.

addPileBottom :: Pile -> [DisplayHandle] -> IO ()

addPileTop :: Pile -> [DisplayHandle] -> IO ()

add components to the top or bottom of the pile.

addPileBelow :: Pile -> [DisplayHandle] -> IO ()

addPileAbove :: Pile -> [DisplayHandle] -> IO ()

add components above or below the component currently being displayed.