diff options
Diffstat (limited to 'src/library/scala/collection/generic/GenericTraversableTemplate.scala')
| -rw-r--r-- | src/library/scala/collection/generic/GenericTraversableTemplate.scala | 73 |
1 files changed, 60 insertions, 13 deletions
diff --git a/src/library/scala/collection/generic/GenericTraversableTemplate.scala b/src/library/scala/collection/generic/GenericTraversableTemplate.scala index f7a8a9aa88..54455c531a 100644 --- a/src/library/scala/collection/generic/GenericTraversableTemplate.scala +++ b/src/library/scala/collection/generic/GenericTraversableTemplate.scala @@ -8,7 +8,8 @@ -package scala.collection +package scala +package collection package generic import mutable.Builder @@ -24,7 +25,7 @@ import scala.language.higherKinds * @author Martin Odersky * @since 2.8 * @define coll collection - * @define Coll CC + * @define Coll Traversable */ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNewBuilder[A, CC[A] @uncheckedVariance] { @@ -44,7 +45,7 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew /** Selects the first element of this $coll. * * @return the first element of this $coll. - * @throws `NoSuchElementException` if the $coll is empty. + * @throws NoSuchElementException if the $coll is empty. */ def head: A @@ -73,11 +74,20 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew /** Converts this $coll of pairs into two collections of the first and second * half of each pair. * + * {{{ + * val xs = $Coll( + * (1, "one"), + * (2, "two"), + * (3, "three")).unzip + * // xs == ($Coll(1, 2, 3), + * // $Coll(one, two, three)) + * }}} + * * @tparam A1 the type of the first half of the element pairs * @tparam A2 the type of the second half of the element pairs * @param asPair an implicit conversion which asserts that the element type * of this $coll is a pair. - * @return a pair ${coll}s, containing the first, respectively second + * @return a pair of ${coll}s, containing the first, respectively second * half of each element pair of this $coll. */ def unzip[A1, A2](implicit asPair: A => (A1, A2)): (CC[A1], CC[A2]) = { @@ -88,18 +98,28 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew b1 += x b2 += y } - (b1.result, b2.result) + (b1.result(), b2.result()) } /** Converts this $coll of triples into three collections of the first, second, * and third element of each triple. * + * {{{ + * val xs = $Coll( + * (1, "one", '1'), + * (2, "two", '2'), + * (3, "three", '3')).unzip3 + * // xs == ($Coll(1, 2, 3), + * // $Coll(one, two, three), + * // $Coll(1, 2, 3)) + * }}} + * * @tparam A1 the type of the first member of the element triples * @tparam A2 the type of the second member of the element triples * @tparam A3 the type of the third member of the element triples * @param asTriple an implicit conversion which asserts that the element type * of this $coll is a triple. - * @return a triple ${coll}s, containing the first, second, respectively + * @return a triple of ${coll}s, containing the first, second, respectively * third member of each element triple of this $coll. */ def unzip3[A1, A2, A3](implicit asTriple: A => (A1, A2, A3)): (CC[A1], CC[A2], CC[A3]) = { @@ -113,7 +133,7 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew b2 += y b3 += z } - (b1.result, b2.result, b3.result) + (b1.result(), b2.result(), b3.result()) } /** Converts this $coll of traversable collections into @@ -133,10 +153,16 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew * static type of $coll. For example: * * {{{ - * val xs = List(Set(1, 2, 3), Set(1, 2, 3)) + * val xs = List( + * Set(1, 2, 3), + * Set(1, 2, 3) + * ).flatten * // xs == List(1, 2, 3, 1, 2, 3) * - * val ys = Set(List(1, 2, 3), List(3, 2, 1)) + * val ys = Set( + * List(1, 2, 3), + * List(3, 2, 1) + * ).flatten * // ys == Set(1, 2, 3) * }}} */ @@ -144,24 +170,45 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew val b = genericBuilder[B] for (xs <- sequential) b ++= asTraversable(xs).seq - b.result + b.result() } /** Transposes this $coll of traversable collections into * a $coll of ${coll}s. * + * The resulting collection's type will be guided by the + * static type of $coll. For example: + * + * {{{ + * val xs = List( + * Set(1, 2, 3), + * Set(4, 5, 6)).transpose + * // xs == List( + * // List(1, 4), + * // List(2, 5), + * // List(3, 6)) + * + * val ys = Vector( + * List(1, 2, 3), + * List(4, 5, 6)).transpose + * // ys == Vector( + * // Vector(1, 4), + * // Vector(2, 5), + * // Vector(3, 6)) + * }}} + * * @tparam B the type of the elements of each traversable collection. * @param asTraversable an implicit conversion which asserts that the * element type of this $coll is a `Traversable`. * @return a two-dimensional $coll of ${coll}s which has as ''n''th row * the ''n''th column of this $coll. - * @throws `IllegalArgumentException` if all collections in this $coll + * @throws IllegalArgumentException if all collections in this $coll * are not of the same size. */ @migration("`transpose` throws an `IllegalArgumentException` if collections are not uniformly sized.", "2.9.0") def transpose[B](implicit asTraversable: A => /*<:<!!!*/ GenTraversableOnce[B]): CC[CC[B] @uncheckedVariance] = { if (isEmpty) - return genericBuilder[CC[B]].result + return genericBuilder[CC[B]].result() def fail = throw new IllegalArgumentException("transpose requires all collections have the same size") @@ -179,7 +226,7 @@ trait GenericTraversableTemplate[+A, +CC[X] <: GenTraversable[X]] extends HasNew } val bb = genericBuilder[CC[B]] for (b <- bs) bb += b.result - bb.result + bb.result() } } |