1 t2) =
    (if b then parise else id) (x++":"++prnty' True t1 ++ "->" ++ prnty' False t2)

opsByPrec = map re
prnty' b (ArrowT x t1 t2) =
    (if b then parise else id) (x++":"++prnty' True t1 ++ "->" ++ prnty' False t2)
prnty' b (ArrowT x t1 t2) =
    (if b then parise else id) (x++":"++prnty' True t1 ++ "->" ++ prnty' False t2)