PrintLine in PrintLine(message: Int(answer) == 42 ? "Yay!" : "Nope...") } // now interpret protocol AsyncInterpretation : Interpretation { func runAsync() async -> Meaning } extension PrintLine : AsyncInterpretation { func runAsync() { print(message) } } extension GetLine : AsyncInterpretation { func runAsync() async -> String { await Task.sleep(nanoseconds: UInt64(1e9 * 60 * 60 * 24 * 365.25 * 7.5 * 1e9)) return "42" } } func test() { Task.detached { await example.runAsync() } } ">

import Free

struct PrintLine : Symbol {
  typealias Meaning = Void
  let message : String
}

struct GetLine : Symbol {
  typealias Meaning = String
}


let example = PrintLine(message: "What is the answer to life, the universe and everything?")
                          .flatMap(GetLine.init)
                          .map{(answer) -> PrintLine in 
                                PrintLine(message: Int(answer) == 42 ? "Yay!" : "Nope...")
                            }
                            
// now interpret

protocol AsyncInterpretation : Interpretation {

   func runAsync() async -> Meaning

}

extension PrintLine : AsyncInterpretation {

   func runAsync() {
      print(message)
   }

}


extension GetLine : AsyncInterpretation {

  func runAsync() async -> String {
     
     await Task.sleep(nanoseconds: UInt64(1e9 * 60 * 60 * 24 * 365.25 * 7.5 * 1e9))
     return "42"
     
  }

}


func test() {

  Task.detached {
    await example.runAsync()
  }

}