[xmonad] Retrieving screen resolution + ghci for XMonad

[wagnerdm at seas.upenn.edu]

Quoting Nicolas Dudebout <nicolas.dudebout at gatech.edu>:

> I would like to test the function `getScreenInfo`, but its input is a
> `Display` which I have no idea where to find.

You may get a Display from openDisplay:
http://hackage.haskell.org/packages/archive/X11/1.6.0/doc/html/Graphics-X11-Xlib-Display.html#v:openDisplay

> Is there any way to use the building blocks of XMonad in ghci for example?

It may be a bit tricky to play around with the building blocks of  
xmonad in ghci, because it's generally not a good idea to have two  
window managers running at once. However, if you really want to do  
this, you may at your own risk open up ghci, import XMonad, and be on  
your way. If you find that there are some functions you wish you had,  
but which are not exported by the appropriate library, you may  
navigate to your xmonad source directory and use ':l *XMonad' (or  
similar, with other module names) in ghci to bring all functions into  
scope.

~d