chyanged implicits so that implicit Builder pat...

chyanged implicits so that implicit Builder pattern works.

1 files changed, 66 insertions, 0 deletions

diff --git a/test/files/pos/builders.scala b/test/files/pos/builders.scala
new file mode 100755
index 0000000000..0b620769c0
--- /dev/null
+++ b/test/files/pos/builders.scala
@@ -0,0 +1,66 @@
+object builders {
+
+  trait Builder[-From, +To, -Elem] {
+    def += (elem: Elem)
+    def result: To
+  }
+
+  implicit def iterableBuilder[A, B] = new Builder[Iterable[A], Iterable[B], B] {
+    println("new iterable builder")
+    private val buf = new scala.collection.mutable.ListBuffer[B]
+    def += (elem: B) { buf += elem }
+    def result: Iterable[B] = buf.toList
+  }
+
+  implicit def listBuilder[A, B] = new Builder[List[A], List[B], B] {
+    println("new list builder")
+    private val buf = new scala.collection.mutable.ListBuffer[B]
+    def += (elem: B) { buf += elem }
+    def result: List[B] = buf.toList
+  }
+/*
+  def fill[A, Dim1, Dim2, Coll](n1: Int, n2: Int, elem: A)(implicit b1: Builder[Coll, Dim1, A], b2: Builder[Coll, Dim2, Dim1]) = {
+    for (i <- 0 until n1) {
+      for (j <- 0 until n2) {
+        b1 += elem
+      }
+      b2 += b1.result
+    }
+    b2.result
+  }
+*/
+/*
+  implicit def arrayBuilder[A, B] = new Builder[Array[A], Array[B], B] {
+    println("new arr ay builder")
+    private val buf = new scala.collection.mutable.ListBuffer[B]
+    def += (elem: B) { buf += elem }
+    def result: Array[B] = buf.toArray
+  }
+*/
+  class Iter[A, C](elems: List[A]) {
+    def ++ [B  >: A, D](xs: Iterable[B])(implicit b: Builder[C, D, B]): D = {
+      for (x <- elems) b += x
+      for (x <- xs) b += x
+      b.result
+    }
+    def map[B, D](f: A => B)(implicit b: Builder[C, D, B]): D = {
+      for (x <- elems) b += f(x)
+      b.result
+    }
+  }
+
+  def main(args : Array[String]) : Unit = {
+    val x1 = new Iter[Int, List[Int]](List(1, 2, 3))
+//    val x2 = new Iter[Int, Array[Int]](List(1, 2, 3))
+    val x3 = new Iter[Int, Iterable[Int]](List(1, 2, 3))
+    val y1: List[Int] = x1.map (_ + 1)
+//    val y2: Array[Int] = x2.map (_ + 1)
+    val y3: Iterable[Int] = x3.map (_ + 1)
+    val z1: List[Int] = y1
+//    val z2: Array[Int] = y2
+    val z3: Iterable[Int] = y3
+    println(z1)
+//    println(z2)
+    println(z3)
+  }
+}