[Assorted-commits] SF.net SVN: assorted:[1561] sandbox/trunk/src/scala/Continuations.scala

[<yan...@us...>]

Revision: 1561
          http://assorted.svn.sourceforge.net/assorted/?rev=1561&view=rev
Author:   yangzhang
Date:     2010-02-04 18:57:03 +0000 (Thu, 04 Feb 2010)

Log Message:
-----------
more playing with continuations

Modified Paths:
--------------
    sandbox/trunk/src/scala/Continuations.scala

Modified: sandbox/trunk/src/scala/Continuations.scala
===================================================================
--- sandbox/trunk/src/scala/Continuations.scala	2010-02-04 18:49:25 UTC (rev 1560)
+++ sandbox/trunk/src/scala/Continuations.scala	2010-02-04 18:57:03 UTC (rev 1561)
@@ -1,11 +1,100 @@
 import scala.continuations.ControlContext._
 
+/*
+class YieldReturnIterator[+T] extends Iterator[T] {
+  private[this] var nextValue: Option[Option[T]] = None
+  private[this] var getNext: () => Unit = null
+  protected def yieldReturn(x: T): Unit @cps[Unit, Unit] = {
+    shift { cont =>
+      nextValue = Some(Some(x))
+      getNext = cont
+    }
+  }
+  protected def body: Unit @cps[Unit, Unit] {
+    getNext = { () =>
+      reset {
+        body
+        nextValue = Some(None)
+        getNext = null
+      }
+    }
+  }
+  def hasNext: Boolean = {
+    if (nextValue.isEmpty)
+      getNext()
+    nextValue.get.isDefined
+  }
+  def next: String = {
+    if (nextValue.isEmpty)
+      getNext()
+    val e = nextValue.get.get
+    nextValue = None
+    e
+  }
+}
+
+class My(array: Array[String]) extends YieldReturnIterator[String] {
+  def body = for (s <- array) yieldReturn(s)
+}
+*/
+
 object Continuations {
   def main(args: Array[String]) {
     reset {
-      println("first")
-      shift { k: (Unit => Unit) => k(k(())) }
-      println("last")
+      println("outside pre")
+      val shi = shift { k: (Unit => Unit) =>
+        println("inside pre")
+        k()
+        println("inside mid")
+        k()
+        println("inside post")
+      }
+      println("outside post")
+    } // reset always just returns Unit
+
+    println
+
+    reset {
+      println("outside pre")
+      val a = shift { k: (Int => Double) =>
+        println("inside pre")
+        val b = k(2) // think of there being two cothreads; this thread msg-passes a 2
+        println("inside mid " + b)
+        val c = k(4) // pass a 4
+        println("inside post " + c)
+      }
+      println("outside post " + a)
+      6.0
+    } // reset always just returns Unit
+
+    println
+
+    def next = shift { k: (Int => Unit) =>
+      k(1)
+      k(2)
+      k(3)
     }
+
+    reset { println(next) } // prints 1 2 3
+    reset { println(next) } // prints 1 2 3
+
+    println
+
+    //var nextVal: Int = 0
+    //var getNext: () => Int = null
+    //def next2 = shift { k: (Unit => Unit) =>
+    //  getNext = { () =>
+    //    nextVal += 1
+    //    k()
+    //    nextVal
+    //  }
+    //}
+
+    //reset {
+    //  next2
+    //  println(getNext)
+    //  next2
+    //  println(getNext)
+    //}
   }
 }


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