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Opinionated set of tools for functional programming in Scala

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package tofu.higherKind

import cats.FlatMap
import cats.free.Free

import tofu.internal.EffectCompHK

trait Embed[U[_[_]]] {
  def embed[F[_]: FlatMap](ft: F[U[F]]): U[F]
}

object Embed extends EmbedInstanceChain[Embed] with EffectCompHK[Embed] {
  def of[U[_[_]], F[_]: FlatMap](fuf: F[U[F]])(implicit embed: Embed[U]): U[F] = embed.embed(fuf)
}

trait EmbedInstanceChain[TC[u[_[_]]] >: Embed[u]] extends RepresentableKInstanceChain[TC] {
  private[this] def freeInstance[A]: Embed[({ type L[x[_]] = Free[x, A] })#L] =
    new Embed[({ type L[x[_]] = Free[x, A] })#L] {
      def embed[F[_]: FlatMap](ft: F[Free[F, A]]): Free[F, A] = Free.roll(ft)
    }

  private[this] val freeEmbedAny = freeInstance[Any]

  final implicit def freeEmbed[A]: TC[({ type L[x[_]] = Free[x, A] })#L] =
    freeEmbedAny.asInstanceOf[TC[({ type L[x[_]] = Free[x, A] })#L]]

}