keywords

Type Members

1. trait AsynchronousIo[Value] extends Keyword[AsynchronousIo[Value], Value]

   

2. final case class Await[Value](future: Future[Value]) extends AnyVal with Keyword[Await[Value], Value] with Product with Serializable

   

3. sealed class Break extends Keyword[Break, Nothing]

   

4. final case class Catch[Domain, Value](block: !![Domain, Value], catcher: Catcher[!![Domain, Value]]) extends Keyword[Catch[Domain, Value], Value] with Product with Serializable

   
   Author:

   杨博 (Yang Bo)

5. final case class Each[Element](elements: Traversable[Element]) extends Keyword[Each[Element], Element] with Product with Serializable

   
   Author:

   杨博 (Yang Bo)

6. final case class Fork[Element](elements: Traversable[Element]) extends AnyVal with Keyword[Fork[Element], Element] with Product with Serializable

   

7. final case class Monadic[F[*], A](fa: F[A]) extends Keyword[Monadic[F, A], A] with Product with Serializable

   

   A keyword for creating monadic control flow.

   A keyword for creating monadic control flow.

   To do

   Monadic should be a scala.AnyVal after https://github.com/scala/bug/issues/10595 is resolved.

   See also

   com.thoughtworks.dsl.domains.scalaz for using this Monadic keyword with scalaz.Monad.

   com.thoughtworks.dsl.domains.cats for using this Monadic keyword with cats.Monad.

8. final case class Return[ReturnValue](returnValue: ReturnValue) extends Keyword[Return[ReturnValue], Nothing] with Product with Serializable

   

   A Keyword to early return a lifted value from the enclosing function.

   A Keyword to early return a lifted value from the enclosing function.

   Author:

   杨博 (Yang Bo)

   Examples:

   1. Since this Return keyword can automatically lift the return type, TailCalls.done can be omitted.

      import scala.util.Random
      import scala.util.control.TailCalls
      import scala.util.control.TailCalls.TailRec
      def randomInt(): TailRec[Int] = {
        while (true) {
          val r = Random.nextInt(100)
          if (r % 10 != r / 10) {
            !Return(r)
          }
        }
        throw new AssertionError("Unreachable code");
      }
      val r = randomInt().result
      r should be < 100
      r % 10 should not be r / 10

   ,

   2. Suppose you are generating a random integer less than 100, whose first digit and second digit is different. A solution is generating integers in an infinite loop, and Return from the loop when the generated integer conforms with requirements.

      import scala.util.Random
      import scala.util.control.TailCalls
      import scala.util.control.TailCalls.TailRec
      def randomInt(): TailRec[Int] = {
        while (true) {
          val r = Random.nextInt(100)
          if (r % 10 != r / 10) {
            !Return(TailCalls.done(r))
          }
        }
        throw new AssertionError("Unreachable code");
      }
      val r = randomInt().result
      r should be < 100
      r % 10 should not be r / 10

9. final case class Shift[Domain, Value](continuation: !![Domain, Value]) extends AnyVal with Keyword[Shift[Domain, Value], Value] with Product with Serializable

   
   Author:

   杨博 (Yang Bo)

10. final case class Using[R <: AutoCloseable](open: () ⇒ R) extends AnyVal with Keyword[Using[R], R] with Product with Serializable

    
    Author:

    杨博 (Yang Bo)

11. final case class Yield[Element](element: Element) extends AnyVal with Keyword[Yield[Element], Unit] with Product with Serializable

    
    Author:

    杨博 (Yang Bo)

    Example:

    1. This Yield keyword must be put inside a function that returns Stream[Element] or Stream[Element] !! ..., or it will not compile.

       "def f(): Int = !Yield(1)" shouldNot compile