sshark · April 14, 2024 13:45 · Apr 14, 2024
diff --git a/traverse.sc b/traverse.sc
@@ -0,0 +1,28 @@
+//import cats.Applicative
+//import cats.implicits.*
+
+/*
+def sequence[A, F[_], G[_]](fga: F[G[A]])(using Traverse[F], Applicative[G]): G[F[A]] =
+  traverse(fga)(identity)
+
+trait Traverse[F[_]]:
+  def traverse[A, B, G[_]](fa: F[A])(f: A => G[B])(using Applicative[G]): G[F[B]]
+*/  
+
+trait Functor[F[_]] {
+  def map[A, B](fa: F[A])(f: A => B): F[B]
+}
+
+trait Applicative[F[_]] extends Functor[F] {
+  override def map[A, B](fa: F[A])(f: A => B): F[B] = ???
+
+  def apply[A, B](fa: F[A])(ff: F[A => B]): F[B] = ???
+
+  def map2[A, B, C](fa: F[A])(fb: F[B])(f: (A, B) => C)(implicit ev: Functor[F]): F[C] =
+    apply(fb)(ev.map(fa)(a => (b => f(a, b))))
+}
+
+/*
+val foo: Either[Nothing, List[Int]] = List(Right(1), Right(2)).traverse(r => r.asInstanceOf[Either[Nothing, Int]])
+println(foo)
+*/