Either<L, R> class abstract

Implemented types
Implementers

Constructors

Either()
const

Properties

hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

all(bool f(R r)) → bool
override
andThen<R2>(covariant Either<L, R2> next) → Either<L, R2>
override
any(bool f(R r)) → bool
override
ap<B>(covariant Either<L, Function1<R, B>> ff) → Either<L, B>
override
bimap<LL, RR>(LL ifLeft(L l), RR ifRight(R r)) → Either<LL, RR>
bind<R2>(covariant Function1<R, Either<L, R2>> f) → Either<L, R2>
override
concatenate(Monoid<R> mi) → R
override
concatenateO(Semigroup<R> si) → Option<R>
override
ensure(bool predicate(R r), R fallback()) → Either<L, R>
every(bool f(R r)) → bool
override
filter(bool predicate(R r), L fallback()) → Either<L, R>
flatMap<R2>(covariant Function1<R, Either<L, R2>> f) → Either<L, R2>
override
fold<B>(B ifLeft(L l), B ifRight(R r)) → B
foldLeft<B>(B z, B f(B previous, R r)) → B
override
foldLeftWithIndex<B>(B z, B f(B previous, int i, R r)) → B
override
foldMap<B>(Monoid<B> bMonoid, B f(R r)) → B
override
foldMapO<B>(Semigroup<B> si, B f(R r)) → Option<B>
override
foldRight<B>(B z, B f(R r, B previous)) → B
override
foldRightWithIndex<B>(B z, B f(int i, R r, B previous)) → B
override
forEach(void sideEffect(R r)) → void
getOrElse(R dflt()) → R
intercalate(Monoid<R> mi, R r) → R
override
isLeft() → bool
isRight() → bool
iterator() → Iterator<R>
leftMap<L2>(L2 f(L l)) → Either<L2, R>
length() → int
override
map<R2>(R2 f(R r)) → Either<L, R2>
override
mapWithIndex<B>(B f(int i, R r)) → Either<L, B>
override
maximum(Order<R> or) → Option<R>
override
minimum(Order<R> or) → Option<R>
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
orElse(Either<L, R> other()) → Either<L, R>
replace<B>(B replacement) → Either<L, B>
override
reverse() → Either<L, R>
strengthL<B>(B b) → Either<L, Tuple2<B, R>>
override
strengthR<B>(B b) → Either<L, Tuple2<R, B>>
override
swap() → Either<R, L>
toIterable() → Iterable<R>
toOption() → Option<R>
toString() → String
A string representation of this object.
override
traverseFuture<R2>(Future<R2> f(R r)) → Future<Either<L, R2>>
traverseIList<R2>(IList<R2> f(R r)) → IList<Either<L, R2>>
traverseIVector<R2>(IVector<R2> f(R r)) → IVector<Either<L, R2>>
traverseState<S, R2>(State<S, R2> f(R r)) → State<S, Either<L, R2>>
traverseTask<R2>(Task<R2> f(R r)) → Task<Either<L, R2>>
where(bool predicate(R r), L fallback()) → Either<L, R>
zipWithIndex() → Either<L, Tuple2<int, R>>
override

Operators

operator ==(Object other) → bool
The equality operator.
inherited
operator |(R dflt) → R

Static Methods

cond<L, R>(bool predicate(), Function0<R> r, Function0<L> l) → Either<L, R>
lift<L, A, B>(B f(A a)) → Function1<Either<L, A>, Either<L, B>>
lift10<L, A, B, C, D, E, F, G, H, I, J, K>(K f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j)) → Function10<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>>
lift11<L, A, B, C, D, E, F, G, H, I, J, K, LL>(LL f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k)) → Function11<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>>
lift12<L, A, B, C, D, E, F, G, H, I, J, K, LL, M>(M f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l)) → Function12<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>>
lift13<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N>(N f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m)) → Function13<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>>
lift14<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O>(O f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n)) → Function14<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>>
lift15<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P>(P f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o)) → Function15<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>>
lift16<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q>(Q f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p)) → Function16<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>>
lift17<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R>(R f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q)) → Function17<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>>
lift18<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R, S>(S f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r)) → Function18<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>, Either<L, S>>
lift19<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R, S, T>(T f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s)) → Function19<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>, Either<L, S>, Either<L, T>>
lift2<L, A, B, C>(C f(A a, B b)) → Function2<Either<L, A>, Either<L, B>, Either<L, C>>
lift20<L, A, B, C, D, E, F, G, H, I, J, K, LL, M, N, O, P, Q, R, S, T, U>(U f(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s, T t)) → Function20<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>, Either<L, K>, Either<L, LL>, Either<L, M>, Either<L, N>, Either<L, O>, Either<L, P>, Either<L, Q>, Either<L, R>, Either<L, S>, Either<L, T>, Either<L, U>>
lift3<L, A, B, C, D>(D f(A a, B b, C c)) → Function3<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>>
lift4<L, A, B, C, D, E>(E f(A a, B b, C c, D d)) → Function4<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>>
lift5<L, A, B, C, D, E, F>(F f(A a, B b, C c, D d, E e)) → Function5<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>>
lift6<L, A, B, C, D, E, F, G>(G f(A a, B b, C c, D d, E e, F f)) → Function6<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>>
lift7<L, A, B, C, D, E, F, G, H>(H f(A a, B b, C c, D d, E e, F f, G g)) → Function7<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>>
lift8<L, A, B, C, D, E, F, G, H, I>(I f(A a, B b, C c, D d, E e, F f, G g, H h)) → Function8<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>>
lift9<L, A, B, C, D, E, F, G, H, I, J>(J f(A a, B b, C c, D d, E e, F f, G g, H h, I i)) → Function9<Either<L, A>, Either<L, B>, Either<L, C>, Either<L, D>, Either<L, E>, Either<L, F>, Either<L, G>, Either<L, H>, Either<L, I>, Either<L, J>>
map10<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, K fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j)) → Either<L, K>
map11<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, LL fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k)) → Either<L, LL>
map12<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, M fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l)) → Either<L, M>
map13<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, N fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m)) → Either<L, N>
map14<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, O fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n)) → Either<L, O>
map15<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, P fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o)) → Either<L, P>
map16<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P, P2 extends P, Q>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Q fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p)) → Either<L, Q>
map17<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P, P2 extends P, Q, Q2 extends Q, R>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, R fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q)) → Either<L, R>
map18<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P, P2 extends P, Q, Q2 extends Q, R, R2 extends R, S>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, Either<L, R> fr, S fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r)) → Either<L, S>
map19<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P, P2 extends P, Q, Q2 extends Q, R, R2 extends R, S, S2 extends S, T>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, Either<L, R> fr, Either<L, S> fs, T fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s)) → Either<L, T>
map2<L, A, A2 extends A, B, B2 extends B, C>(Either<L, A2> fa, Either<L, B2> fb, C fun(A a, B b)) → Either<L, C>
map20<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J, J2 extends J, K, K2 extends K, LL, LL2 extends LL, M, M2 extends M, N, N2 extends N, O, O2 extends O, P, P2 extends P, Q, Q2 extends Q, R, R2 extends R, S, S2 extends S, T, T2 extends T, U>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, Either<L, J2> fj, Either<L, K2> fk, Either<L, LL> fl, Either<L, M> fm, Either<L, N> fn, Either<L, O> fo, Either<L, P> fp, Either<L, Q> fq, Either<L, R> fr, Either<L, S> fs, Either<L, T> ft, U fun(A a, B b, C c, D d, E e, F f, G g, H h, I i, J j, K k, LL l, M m, N n, O o, P p, Q q, R r, S s, T t)) → Either<L, U>
map3<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, D fun(A a, B b, C c)) → Either<L, D>
map4<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, E fun(A a, B b, C c, D d)) → Either<L, E>
map5<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, F fun(A a, B b, C c, D d, E e)) → Either<L, F>
map6<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, G fun(A a, B b, C c, D d, E e, F f)) → Either<L, G>
map7<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, H fun(A a, B b, C c, D d, E e, F f, G g)) → Either<L, H>
map8<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, I fun(A a, B b, C c, D d, E e, F f, G g, H h)) → Either<L, I>
map9<L, A, A2 extends A, B, B2 extends B, C, C2 extends C, D, D2 extends D, E, E2 extends E, F, F2 extends F, G, G2 extends G, H, H2 extends H, I, I2 extends I, J>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C2> fc, Either<L, D2> fd, Either<L, E2> fe, Either<L, F2> ff, Either<L, G2> fg, Either<L, H2> fh, Either<L, I2> fi, J fun(A a, B b, C c, D d, E e, F f, G g, H h, I i)) → Either<L, J>
mapM2<L, A, A2 extends A, B, B2 extends B, C>(Either<L, A2> fa, Either<L, B2> fb, Either<L, C> f(A a, B b)) → Either<L, C>
sequenceFuture<L, R>(Either<L, Future<R>> efr) → Future<Either<L, R>>
sequenceIList<L, R>(Either<L, IList<R>> elr) → IList<Either<L, R>>
sequenceIVector<L, R>(Either<L, IVector<R>> evr) → IVector<Either<L, R>>
sequenceState<S, L, R>(Either<L, State<S, R>> esr) → State<S, Either<L, R>>
sequenceTask<L, R>(Either<L, Task<R>> efr) → Task<Either<L, R>>