I know you can create and edit shortcuts in User Preferences > Input, but I can't figure out how to make a shortcut to toggle something on/off.
For example, I can right click on the Shade Smooth button on the Tool Shelf,
(N in the 3D view) and select "Create Shortcut" but I only can get one shortcut to shade smooth or shade flat, not one or the other based on what the current shading setting is.
So my question is,
is it possible to create a shortcut to toggle a setting?