invokeDefault tok = fail . emsg where
    emsg v = "{" ++ tok ++ "} token not recognized @ " ++ show v
invokeDefault tok = fail . emsg where
    emsg v = "{" ++ tok ++ "} token not recognized @ " ++ show v
invokeDefault tok = fail . emsg where
    emsg v = "{" ++ tok ++ "} token not recognized @ " ++ show v