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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection
package generic
import mutable.Builder
import annotation.unchecked.uncheckedVariance
/**
* @since 2.8
*/
trait GenericTraversableTemplate[+A, +CC[X] <: Traversable[X]] extends HasNewBuilder[A, CC[A] @uncheckedVariance] {
def foreach[U](f: A => U): Unit
def head: A
def isEmpty: Boolean
/** The factory companion object that builds instances of class CC */
def companion: GenericCompanion[CC]
/** The builder that builds instances of CC[A] */
protected[this] def newBuilder: Builder[A, CC[A]] = companion.newBuilder[A]
/** The generic builder that builds instances of CC at arbitrary element types. */
def genericBuilder[B]: Builder[B, CC[B]] = companion.newBuilder[B]
def unzip[A1, A2](implicit asPair: A => /*<:<!!!*/ (A1, A2)): (CC[A1], CC[A2]) = {
val b1 = genericBuilder[A1]
val b2 = genericBuilder[A2]
for (xy <- this) {
val (x, y) = asPair(xy)
b1 += x
b2 += y
}
(b1.result, b2.result)
}
def flatten[B](implicit asTraversable: A => /*<:<!!!*/ Traversable[B]): CC[B] = {
val b = genericBuilder[B]
for (xs <- this)
b ++= asTraversable(xs)
b.result
}
def transpose[B](implicit asTraversable: A => /*<:<!!!*/ Traversable[B]): CC[CC[B] @uncheckedVariance] = {
val bs: IndexedSeq[Builder[B, CC[B]]] = asTraversable(head).map(_ => genericBuilder[B]).toIndexedSeq
for (xs <- this) {
var i = 0
for (x <- asTraversable(xs)) {
bs(i) += x
i += 1
}
}
val bb = genericBuilder[CC[B]]
for (b <- bs) bb += b.result
bb.result
}
}
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