implicit def deriveTransformerFSupport[F[+_]](implicit F: Applicative[F]): TransformerFSupport[F] = new TransformerFSupport[F] {
override def pure[A](value: A): F[A] = F.pure(value)
override def product[A, B](fa: F[A], fb: => F[B]): F[(A, B)] = F.tuple2(fa, fb)
override def map[A, B](fa: F[A], f: A => B): F[B] = F.map(fa)(f)
override def traverse[M, A, B](it: Iterator[A], f: A => F[B])(implicit fac: Factory[B, M]): F[M] = {
F.map(it.foldRight(Eval.always(F.pure(CompatLazyList.empty[B]))) { (next: A, acc: Eval[F[CompatLazyList[B]]]) =>
F.map2Eval(f(next), acc) { (next: B, acc: CompatLazyList[B]) =>
next #:: acc
}
}.value)(fac.fromSpecific(_))
}
} import cats.data.ValidatedNec
import cats.implicits._
import io.scalaland.chimney.dsl._
import io.scalaland.chimney.cats._
Example("Hello", 1)
.into[Example]
.withFieldComputedF[VN, String, String](_.a, e => (e.a + "!").invalidNec[String])
.transform
// Valid(Example("Hello", 1)) <-- :(
Hi!
Probably a stupid question. I tried to write a generic implicit transformer for cats NonEmptyVector and so far derivation doesn't pick it up for me.
The transformer looks like this:
implicit def nevToVectorTransformer[T, S](implicit
elemTransformer: Transformer[T, S],
): Transformer[NonEmptyVector[T], Vector[S]] = (src: NonEmptyVector[T]) =>
src.toVector.map(elemTransformer.transform)
implicit def vectorToNevTransformer[T, S](implicit
elemTransformer: Transformer[T, S],
): Transformer[Vector[T], NonEmptyVector[S]] = (src: Vector[T]) =>
NonEmptyVector.fromVectorUnsafe(src.map(elemTransformer.transform))I've even pulled element transformers "explicitly" into implicit scope, still no luck. Is there some kind of limitation in the macro derivation related to this?
For now you need to have concrete instances as implicit vals/defs available in the implicit scope
So I need to have all required elemTransformer implicit instances defined explicitly in the scope, right?
Somehow it didn't work in my real code. At the same time when I tried to come up with a minimal example, I couldn't make it fail. I will dig dipper, maybe the issue is somewhere else.
My real code has those non-empty vectors nested inside a sealed trait hierarchy, with at least 2 levels of nesting.
Thanks, guys!