--
(==>) :: (VName, JoinPoint) -> JoinPoint -> Binding
(i, j1) ==> j2 = Binding External i j1 j2
(==>) :: (VName, JoinPoint) -> JoinPoint -> Binding
(i, j1) ==> j2 = Binding External i j1 j2
(i, j1) ==> j2 = Binding External i j1 j2