Merge pull request #32 from TinkoffCreditSystems/console

console typeclass

core/src/main/scala/tofu/common/Console.scala

@@ -0,0 +1,26 @@
+package tofu.common
+import cats.effect.Sync
+import cats.tagless.ApplyK
+
+import scala.io.StdIn
+
+trait Console[F[_]] {
+  def putStr(s: String): F[Unit]
+  def putStrLn(s: String): F[Unit]
+
+  def readStrLn: F[String]
+}
+
+object Console {
+  def putStr[F[_]](s: String)(implicit C: Console[F]): F[Unit]   = C.putStr(s)
+  def putStrLn[F[_]](s: String)(implicit C: Console[F]): F[Unit] = C.putStrLn(s)
+  def readStrLn[F[_]](implicit C: Console[F]): F[String]         = C.readStrLn
+
+  implicit val applyKInstance: ApplyK[Console] = cats.tagless.Derive.applyK
+
+  implicit def syncInstance[F[_]](implicit F: Sync[F]): Console[F] = new Console[F] {
+    def putStr(s: String): F[Unit]   = F.delay(print(s))
+    def putStrLn(s: String): F[Unit] = F.delay(println(s))
+    def readStrLn: F[String]         = F.delay(StdIn.readLine())
+  }
+}