Referential Transparency example with Try and IO

RT.scala

import scala.util._
import cats.effect._

//See https://impurepics.com/posts/2018-04-01-referential-transparency.html for RT definition

println("-----------Try--------------")

println("-----------This will print only 1 line : --------------")
val t = Try(println(1+1))
for {
  a <- t
  b <- t
} yield (a, b)

println("-----------This will print 2 lines : --------------")
for {
  a <- Try(println(1+1))
  b <- Try(println(1+1))
} yield (a, b)

println("----------IO--------------")

val io = IO.delay(println(1+1))

val program = for {
  a <- io
  b <- io
} yield (a, b)

val program2 = for {
  a <- IO.delay(println(1+1))
  b <- IO.delay(println(1+1))
} yield (a, b)

println("-----------This will print 2 lines : --------------")
program.unsafeRunSync
println("-----------This will print 2 lines : --------------")
program2.unsafeRunSync