Optimization of Predef implicits.

All those wildcards in a default-scoped implicit are expensive,
they each lead to a typevar on every search.  Restructured the
Tuple2/Tuple3 Zipped classes, they're better this way anyway.
This also gets all that Tuple[23] code out of genprod.

1 files changed, 130 insertions, 0 deletions

diff --git a/src/library/scala/runtime/Tuple2Zipped.scala b/src/library/scala/runtime/Tuple2Zipped.scala
new file mode 100644
index 0000000000..5ad364c8a5
--- /dev/null
+++ b/src/library/scala/runtime/Tuple2Zipped.scala
@@ -0,0 +1,130 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2002-2011, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.runtime
+
+import scala.collection.{ TraversableLike, IterableLike }
+import scala.collection.generic.{ CanBuildFrom => CBF }
+
+/** This interface is intended as a minimal interface, not complicated
+ *  by the requirement to resolve type constructors, for implicit search (which only
+ *  needs to find an implicit conversion to Traversable for our purposes.)
+ */
+trait ZippedTraversable2[+El1, +El2] {
+  def foreach[U](f: (El1, El2) => U): Unit
+}
+object ZippedTraversable2 {
+  implicit def zippedTraversable2ToTraversable[El1, El2](zz: ZippedTraversable2[El1, El2]): Traversable[(El1, El2)] = {
+    new collection.AbstractTraversable[(El1, El2)] {
+      def foreach[U](f: ((El1, El2)) => U): Unit = zz foreach Function.untupled(f)
+    }
+  }
+}
+
+class Tuple2Zipped[El1, Repr1, El2, Repr2](
+  coll1: TraversableLike[El1, Repr1],
+  coll2: IterableLike[El2, Repr2]
+) extends ZippedTraversable2[El1, El2] {
+  def map[B, To](f: (El1, El2) => B)(implicit cbf: CBF[Repr1, B, To]): To = {
+    val b = cbf(coll1.repr)
+    b.sizeHint(coll1)
+    val elems2 = coll2.iterator
+
+    for (el1 <- coll1) {
+      if (elems2.hasNext)
+        b += f(el1, elems2.next)
+      else
+        return b.result
+    }
+
+    b.result
+  }
+
+  def flatMap[B, To](f: (El1, El2) => TraversableOnce[B])(implicit cbf: CBF[Repr1, B, To]): To = {
+    val b = cbf(coll1.repr)
+    val elems2 = coll2.iterator
+
+    for (el1 <- coll1) {
+      if (elems2.hasNext)
+        b ++= f(el1, elems2.next)
+      else
+        return b.result
+    }
+
+    b.result
+  }
+
+  def filter[To1, To2](f: (El1, El2) => Boolean)(implicit cbf1: CBF[Repr1, El1, To1], cbf2: CBF[Repr2, El2, To2]): (To1, To2) = {
+    val b1 = cbf1(coll1.repr)
+    val b2 = cbf2(coll2.repr)
+    val elems2 = coll2.iterator
+
+    for (el1 <- coll1) {
+      if (elems2.hasNext) {
+        val el2 = elems2.next
+        if (f(el1, el2)) {
+          b1 += el1
+          b2 += el2
+        }
+      }
+      else return (b1.result, b2.result)
+    }
+
+    (b1.result, b2.result)
+  }
+
+  def exists(f: (El1, El2) => Boolean): Boolean = {
+    val elems2 = coll2.iterator
+
+    for (el1 <- coll1) {
+      if (elems2.hasNext) {
+        if (f(el1, elems2.next))
+          return true
+      }
+      else return false
+    }
+    false
+  }
+
+  def forall(f: (El1, El2) => Boolean): Boolean =
+    !exists((x, y) => !f(x, y))
+
+  def foreach[U](f: (El1, El2) => U): Unit = {
+    val elems2 = coll2.iterator
+
+    for (el1 <- coll1) {
+      if (elems2.hasNext)
+        f(el1, elems2.next)
+      else
+        return
+    }
+  }
+}
+
+object Tuple2Zipped {
+  class Ops[T1, T2](x: (T1, T2)) {
+    def invert[El1, CC1[X] <: TraversableOnce[X], El2, CC2[X] <: TraversableOnce[X], That]
+      (implicit w1: T1 <:< CC1[El1],
+                w2: T2 <:< CC2[El2],
+                bf: collection.generic.CanBuildFrom[CC1[_], (El1, El2), That]
+      ): That = {
+        val buf = bf(x._1)
+        val it1 = x._1.toIterator
+        val it2 = x._2.toIterator
+        while (it1.hasNext && it2.hasNext)
+          buf += ((it1.next, it2.next))
+        
+        buf.result
+      }
+
+    def zipped[El1, Repr1, El2, Repr2]
+      (implicit w1: T1 => TraversableLike[El1, Repr1],
+                w2: T2 => IterableLike[El2, Repr2]
+      ): Tuple2Zipped[El1, Repr1, El2, Repr2] = new Tuple2Zipped(x._1, x._2)
+  }
+}