[xmonad] can one create layouts with fixed height or width for windows

New to XMonad, and loving it. Apologies if this has already come up and been answered, but I haven't been able to find anything through the usual suspects. Editing code in terminals would be the main reason I want this, but there are a couple of other apps that look better with their windows a fixed size. Is it possible, either through layouts or some other means to enforce that the maximum width a certain window can have? I don't mind if there is a little wasted space on the screen, I really don't like violating the 80th column, however. Pointers and/or suggestions would be welcome. -mdg -- Our problems are mostly behind us, now all we have to do is fight the solutions.