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