ZIO learning - composing environments / published by https://github.com/dacr/code-examples-manager #c265c5e9-5189-4ce1-bc82-8a93fd0cee60/78f69dd7e9e8add9a7dda58ea786b6d8493ae552

zio-learning-4-env-2.sc

// summary : ZIO learning - composing environments
// keywords : scala, zio, learning, pure-functional, @testable
// publish : gist
// authors : David Crosson
// license : Apache License Version 2.0 (https://www.apache.org/licenses/LICENSE-2.0.txt)
// id : c265c5e9-5189-4ce1-bc82-8a93fd0cee60
// created-on : 2021-04-02T16:10:43+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "dev.zio::zio:2.0.13"
//> using dep "fr.janalyse::zio-worksheet:2.0.13.0"
// ---------------------

import zio.*, zio.worksheet.*

val logic: ZIO[Console & Random, Throwable, Unit] = for {
  name <- ZIO.succeed("toto")
  _    <- ZIO.logInfo(s"got name value : $name")
  num  <- Random.nextIntBetween(1,42)
  _    <- Console.printLine(s"Hello $name")
  _    <- ZIO.logInfo(s"$name processed")
} yield ()

// -------------------------------------------------------------
// Of course this is now useless as Console, System, Random, ...
// belong to the default environment and are now provided by default
// it was not the case in early ZIO releases
val layers = ZLayer.succeed(Console.ConsoleLive) ++ ZLayer.succeed(Random.RandomLive)

logic.provide(layers).unsafeRun