-optpair _ _ = Nothing
-
-pushpair :: GArrowSkeletonY m x y -> GArrowSkeletonY m y z -> Maybe (GArrowSkeletonL m x z)
-pushpair (GASY_first gy1) (GASY_first gy2) = liftM gasl_firstify $ pushpair gy1 gy2
-pushpair (GASY_second gy1) (GASY_second gy2) = liftM gasl_secondify $ pushpair gy1 gy2
-pushpair (GASY_first gy1) (GASY_second gy2) = Just $ GASL_comp (GASY_second gy2) (GASL_Y $ GASY_first gy1)
-pushpair (GASY_second gy1) (GASY_first gy2) = Just $ GASL_comp (GASY_first gy2) (GASL_Y $ GASY_second gy1)
-pushpair (GASY_first gy1) (GASY_X GASX_unassoc) = Just $ GASL_comp(GASY_X GASX_unassoc) (GASL_Y $ GASY_first (GASY_first gy1))
-pushpair (GASY_second gy1) (GASY_X GASX_assoc ) = Just $ GASL_comp(GASY_X GASX_assoc ) (GASL_Y $ GASY_second (GASY_second gy1))
-pushpair (GASY_second (GASY_X GASX_uncancelr)) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_X GASX_uncancelr
-pushpair (GASY_first (GASY_X GASX_uncancell)) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_X GASX_uncancell
-pushpair (GASY_X GASX_uncancelr) (GASY_first gy) = Just $ GASL_comp gy (GASL_Y $ GASY_X $ GASX_uncancelr)
-pushpair (GASY_X GASX_uncancell) (GASY_second gy) = Just $ GASL_comp gy (GASL_Y $ GASY_X $ GASX_uncancell)
-pushpair (GASY_first (GASY_second gy)) (GASY_X GASX_assoc ) = Just $ GASL_comp (GASY_X GASX_assoc ) $ GASL_Y (GASY_second (GASY_first gy))
-pushpair (GASY_second (GASY_first gy)) (GASY_X GASX_unassoc ) = Just $ GASL_comp (GASY_X GASX_unassoc) $ GASL_Y (GASY_first (GASY_second gy))
-pushpair (GASY_second (GASY_second gy)) (GASY_X GASX_unassoc ) = Just $ GASL_comp (GASY_X GASX_unassoc) $ GASL_Y (GASY_second gy)
-pushpair (GASY_first (GASY_first gy)) (GASY_X GASX_assoc ) = Just $ GASL_comp (GASY_X GASX_assoc) $ GASL_Y (GASY_first gy)
-pushpair (GASY_X GASX_uncancell) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_first $ GASY_X GASX_uncancell
-pushpair (GASY_X GASX_uncancelr) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_second $ GASY_X GASX_uncancelr
-pushpair (GASY_first (GASY_X GASX_uncancelr)) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_second $ GASY_X GASX_uncancell
-pushpair (GASY_second (GASY_X GASX_uncancell)) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_first $ GASY_X GASX_uncancelr
-pushpair (GASY_first gy) (GASY_X GASX_swap ) = Just $ GASL_comp (GASY_X GASX_swap) $ GASL_Y (GASY_second gy)
-pushpair (GASY_second gy) (GASY_X GASX_swap ) = Just $ GASL_comp (GASY_X GASX_swap) $ GASL_Y (GASY_first gy)
-pushpair (GASY_X GASX_uncancell) (GASY_X GASX_swap ) = Just $ GASL_Y $ GASY_X $ GASX_uncancelr
-pushpair (GASY_X GASX_uncancelr) (GASY_X GASX_swap ) = Just $ GASL_Y $ GASY_X $ GASX_uncancell
-pushpair _ _ = Nothing
+optpair (GASY_X GASX_assoc) (GASY_X GASX_cancell) = Just $ GASL_Y $ GASY_first $ GASY_X GASX_cancell
+optpair (GASY_X GASX_unassoc) (GASY_X GASX_cancelr) = Just $ GASL_Y $ GASY_second $ GASY_X GASX_cancelr
+optpair (GASY_second (GASY_X GASX_uncancelr)) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_X GASX_uncancelr
+optpair (GASY_first (GASY_X GASX_uncancell)) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_X GASX_uncancell
+optpair (GASY_X GASX_uncancell) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_first $ GASY_X GASX_uncancell
+optpair (GASY_X GASX_uncancelr) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_second $ GASY_X GASX_uncancelr
+optpair (GASY_first (GASY_X GASX_uncancelr)) (GASY_X GASX_assoc ) = Just $ GASL_Y $ GASY_second $ GASY_X GASX_uncancell
+optpair (GASY_second (GASY_X GASX_uncancell)) (GASY_X GASX_unassoc ) = Just $ GASL_Y $ GASY_first $ GASY_X GASX_uncancelr
+optpair (GASY_X GASX_assoc) (GASY_second (GASY_X GASX_cancelr)) = Just $ GASL_Y $ GASY_X $ GASX_cancelr
+optpair (GASY_X GASX_unassoc) (GASY_first (GASY_X GASX_cancell)) = Just $ GASL_Y $ GASY_X $ GASX_cancell
+optpair (GASY_first g) (GASY_X GASX_cancelr) = Just $ GASL_comp (GASY_X GASX_cancelr) $ GASL_Y $ g
+optpair (GASY_second g) (GASY_X GASX_cancell) = Just $ GASL_comp (GASY_X GASX_cancell) $ GASL_Y $ g
+optpair (GASY_X GASX_uncancelr) (GASY_first g) = Just $ GASL_comp g $ GASL_Y (GASY_X GASX_uncancelr)
+optpair (GASY_X GASX_uncancell) (GASY_second g) = Just $ GASL_comp g $ GASL_Y (GASY_X GASX_uncancell)
+
+-- swap with an {un}cancel{l,r} before/after it
+optpair (GASY_X GASX_uncancell) (GASY_X GASX_swap ) = Just $ GASL_Y $ GASY_X $ GASX_uncancelr
+optpair (GASY_X GASX_uncancelr) (GASY_X GASX_swap ) = Just $ GASL_Y $ GASY_X $ GASX_uncancell
+optpair (GASY_X GASX_swap) (GASY_X GASX_cancell) = Just $ GASL_Y $ GASY_X $ GASX_cancelr
+optpair (GASY_X GASX_swap) (GASY_X GASX_cancelr) = Just $ GASL_Y $ GASY_X $ GASX_cancell
+
+{-
+optpair (GASY_X GASX_uncancelr) (GASY_X (GASX_loopl gl)) =
+ Just $ GASL_Y $ (GASY_X $ GASX_loopl $ GASL_comp (GASY_second $ GASY_X GASX_uncancelr) gl)
+optpair (GASY_X GASX_uncancell) (GASY_X (GASX_loopl gl)) =
+ Just $ GASL_Y $ (GASY_X $ GASX_loopl $ GASL_comp (GASY_second $ GASY_X GASX_uncancell) gl)
+optpair (GASY_X GASX_uncancelr) (GASY_X (GASX_loopr gl)) =
+ Just $ GASL_Y $ (GASY_X $ GASX_loopr $ GASL_comp (GASY_first $ GASY_X GASX_uncancelr) gl)
+optpair (GASY_X GASX_uncancell) (GASY_X (GASX_loopr gl)) =
+ Just $ GASL_Y $ (GASY_X $ GASX_loopr $ GASL_comp (GASY_first $ GASY_X GASX_uncancell) gl)
+-}
+optpair q (GASY_X (GASX_loopl gl)) | pushin q = Just $ GASL_Y $ (GASY_X $ GASX_loopl $ GASL_comp (GASY_second $ q) gl)
+optpair q (GASY_X (GASX_loopr gl)) | pushin q = Just $ GASL_Y $ (GASY_X $ GASX_loopr $ GASL_comp (GASY_first $ q) gl)
+
+optpair (GASY_first gy1) (GASY_second gy2) | pushleft gy2, not (pushleft gy1)
+ = Just $ GASL_comp (GASY_second gy2) $ GASL_Y $ GASY_first gy1
+optpair (GASY_second gy1) (GASY_first gy2) | pushleft gy2, not (pushleft gy1)
+ = Just $ GASL_comp (GASY_first gy2) $ GASL_Y $ GASY_second gy1
+
+optpair (GASY_first gy1) (GASY_first gy2) = liftM gasl_firstify $ optpair gy1 gy2
+optpair (GASY_second gy1) (GASY_second gy2) = liftM gasl_secondify $ optpair gy1 gy2
+optpair _ _ = Nothing
+
+swappair :: GArrowSkeletonY m x y -> GArrowSkeletonY m y z -> Maybe (GArrowSkeletonL m x z)
+
+swappair q (GASY_atomicl g) = Just $ GASL_comp (GASY_atomicl g) $ GASL_Y $ GASY_second q
+swappair q (GASY_atomicr g) = Just $ GASL_comp (GASY_atomicr g) $ GASL_Y $ GASY_first q
+
+swappair (GASY_first gy1) (GASY_second gy2) = Just $ GASL_comp (GASY_second gy2) (GASL_Y $ GASY_first gy1)
+swappair (GASY_second gy1) (GASY_first gy2) = Just $ GASL_comp (GASY_first gy2) (GASL_Y $ GASY_second gy1)
+swappair (GASY_first gy1) (GASY_X GASX_unassoc) = Just $ GASL_comp(GASY_X GASX_unassoc) (GASL_Y $ GASY_first (GASY_first gy1))
+swappair (GASY_second gy1) (GASY_X GASX_assoc ) = Just $ GASL_comp(GASY_X GASX_assoc ) (GASL_Y $ GASY_second (GASY_second gy1))
+swappair (GASY_X GASX_uncancelr) (GASY_first gy) = Just $ GASL_comp gy (GASL_Y $ GASY_X $ GASX_uncancelr)
+swappair (GASY_X GASX_uncancell) (GASY_second gy) = Just $ GASL_comp gy (GASL_Y $ GASY_X $ GASX_uncancell)
+swappair (GASY_first (GASY_second gy)) (GASY_X GASX_assoc ) = Just $ GASL_comp (GASY_X GASX_assoc ) $ GASL_Y (GASY_second (GASY_first gy))
+swappair (GASY_second (GASY_first gy)) (GASY_X GASX_unassoc ) = Just $ GASL_comp (GASY_X GASX_unassoc) $ GASL_Y (GASY_first (GASY_second gy))
+swappair (GASY_second (GASY_second gy)) (GASY_X GASX_unassoc ) = Just $ GASL_comp (GASY_X GASX_unassoc) $ GASL_Y (GASY_second gy)
+swappair (GASY_first (GASY_first gy)) (GASY_X GASX_assoc ) = Just $ GASL_comp (GASY_X GASX_assoc) $ GASL_Y (GASY_first gy)
+swappair (GASY_first gy) (GASY_X GASX_swap ) = Just $ GASL_comp (GASY_X GASX_swap) $ GASL_Y (GASY_second gy)
+swappair (GASY_second gy) (GASY_X GASX_swap ) = Just $ GASL_comp (GASY_X GASX_swap) $ GASL_Y (GASY_first gy)
+swappair gy (GASY_X (GASX_loopl gl)) = Just $ GASL_Y $ GASY_X $ GASX_loopl $ GASL_comp (GASY_second gy) gl
+swappair gy (GASY_X (GASX_loopr gl)) = Just $ GASL_Y $ GASY_X $ GASX_loopr $ GASL_comp (GASY_first gy) gl
+
+swappair (GASY_first gy1) (GASY_first gy2) = liftM gasl_firstify $ swappair gy1 gy2
+swappair (GASY_second gy1) (GASY_second gy2) = liftM gasl_secondify $ swappair gy1 gy2
+swappair _ _ = Nothing