return function (e: E.Either<F, G>): T.Task<Loop<E.Either<F, G>>> {
return E.either(
(fi: F) => ls.loop(fi).map(v => tick(v, rs)),
(gi: G) => rs.loop(gi).map(v => tick(ls, v)),
e
);
};
)).chain(e => either(T.raise, T.pure, e));