Lua function to change keyboard layout.

kbdswap.lua

function ()

    -- Rotate keyboards table,
    -- requires a global variable called keyboards with the layouts listed,
    -- e.g. keyboards = {'dvorak','us','us dvorak-intl'}
    table.insert(keyboards,table.remove(keyboards,1))

    -- Extract first layout
    local new_layout = keyboards[1]

    -- Set keymap to chosen layout
    awful.util.spawn("setxkbmap "..new_layout)

    -- Optional notification of new layout
    naughty.notify({preset = naughty.config.presets.normal,
        font = "monospace 10",
        screen = mouse.screen,
        text = "KB: "..new_layout,
        timeout = 1})
end