diff options
Diffstat (limited to 'src/library')
| -rw-r--r-- | src/library/scala/collection/SeqExtractors.scala | 21 | ||||
| -rw-r--r-- | src/library/scala/package.scala | 3 |
2 files changed, 24 insertions, 0 deletions
diff --git a/src/library/scala/collection/SeqExtractors.scala b/src/library/scala/collection/SeqExtractors.scala new file mode 100644 index 0000000000..cb3cb27f18 --- /dev/null +++ b/src/library/scala/collection/SeqExtractors.scala @@ -0,0 +1,21 @@ +package scala.collection + +/** An extractor used to head/tail deconstruct sequences. */ +object +: { + def unapply[T,Coll <: SeqLike[T, Coll]]( + t: Coll with SeqLike[T, Coll]): Option[(T, Coll)] = + if(t.isEmpty) None + else Some(t.head -> t.tail) +} + +/** An extractor used to init/last deconstruct sequences. */ +object :+ { + /** Splits a sequence into init :+ tail. + * @returns Some(init, tail) if sequence is non-empty. + * None otherwise. + */ + def unapply[T,Coll <: SeqLike[T, Coll]]( + t: Coll with SeqLike[T, Coll]): Option[(Coll, T)] = + if(t.isEmpty) None + else Some(t.init -> t.last) +} diff --git a/src/library/scala/package.scala b/src/library/scala/package.scala index 366af34ee9..1ef1911fd3 100644 --- a/src/library/scala/package.scala +++ b/src/library/scala/package.scala @@ -64,6 +64,9 @@ package object scala { type ::[A] = scala.collection.immutable.::[A] val :: = scala.collection.immutable.:: + val +: = scala.collection.+: + val :+ = scala.collection.:+ + type Stream[+A] = scala.collection.immutable.Stream[A] val Stream = scala.collection.immutable.Stream val #:: = scala.collection.immutable.Stream.#:: |