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  1. object Main extends App {
  2.   trait TTrue
  3.   trait TFalse
  4.  
  5.   class Myclass[TA, TB, TC] private(){
  6.     def withServiceA(x: => Unit)(implicit e: TA =:= TFalse) = {x; new Myclass[TTrue, TB, TC]}
  7.     def withServiceB(x: => Unit)(implicit e: TB =:= TFalse) = {x; new Myclass[TA, TTrue, TC]}
  8.     def withServiceC(x: => Unit)(implicit e: TC =:= TFalse) = {x; new Myclass[TA, TB, TTrue]}
  9.     def withClient(x: => Unit)(implicit e1: TA =:= TTrue, e2: TB =:= TTrue) = x
  10.   }
  11.  
  12.   object Myclass{
  13.     def apply(c: Context) = new Myclass[TFalse, TFalse, TFalse]
  14.   }
  15.  
  16.   sealed class Context private()
  17.   object Context {
  18.      def withContext(f: Context => Myclass[TTrue, TTrue, _])(withClient: => Unit) =
  19.        f(new Context).withClient(withClient)
  20.   }
  21.  
  22.   Context
  23.     .withContext(
  24.       Myclass(_)
  25.         .withServiceA(println("with A"))
  26.         .withServiceC(println("with C"))
  27.         .withServiceB(println("with B"))
  28.     )(println("withClient"))
  29. }
Success #stdin #stdout 0.39s 322176KB
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with A
with C
with B
withClient
https://ideone.com/Pqw5v5
language:
Scala (scala 2.12.8)
created:
10 years ago
visibility:
public

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