Additional functions about vectors
mapWithPos : (Fin n -> a -> b) -> Vect n a -> Vect n b
Version of `map` with access to the current position
mapWithElem : (xs : Vect n a) -> ((x : a) -> (0 _ : Elem x xs) -> b) -> Vect n b
Version of `map` with runtime-irrelevant information that the
argument is an element of the vector