----------------------------------------------------------------

linearStep :: RevIndex -> FA -> FB -> FC -> FD -> Token -> HeaderValue -> IO ()
linearStep rev fa fb fc fd t v = lookupRevIndex t v fa fb fc fd rev
linearStep :: RevIndex -> FA -> FB -> FC -> FD -> Token -> HeaderValue -> IO ()
linearStep rev fa fb fc fd t v = lookupRevIndex t v fa fb fc fd rev
linearStep rev fa fb fc fd t v = lookupRevIndex t v fa fb fc fd rev