[xmonad] Screen independent workspaces

[Douglas K. Rand]

Is there a way to have workspaces on a per-screen basis? I have 3
displays and on each display I'd like 5 workspaces. Right now my 10
workspaces are shared across all screens, and I'm pretty sure this is
the default behaviour. (I'm fairly new to XMonad.) I'm probably going
against the grain of XMonad users, but this approach fits me better.