In fact, bind is only a simplified version of the
function HTk.html#HTk.bindbind
where
HTk.html#HTk.WishEventModifierWishEventModifier
desribes possible event modifiers such as Shift,
Alt, Meta (corresponding to the Shift, Alt or Meta
key being held), Button1, ..., Button5
(corresponding to mouse button 1 thru 5 being pressed) or Double and
Triple. Again, not all combinations of modifiers and events
make sense; for example, double and triple pertain to mouse button
presses, and modifying a mouse button press with a different button is
not really helpful. Note that the argument of bind is a list of
events, meaning that the interface events have to occur in (rapid)
sequence to generate the event.
Here, the first component of the return value is an event of
EventInfo, which is a labelled record as
follows:
The information here is the x and y component of the mouse position,
both relative to the window in which the event occurs, and the root
window (i.e. the screen), and the button being pressed.