diff options
Diffstat (limited to 'src/library-aux')
| -rw-r--r-- | src/library-aux/scala/Any.scala | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/library-aux/scala/Any.scala b/src/library-aux/scala/Any.scala index 031b7d9d8c..07a9ffa8d5 100644 --- a/src/library-aux/scala/Any.scala +++ b/src/library-aux/scala/Any.scala @@ -10,6 +10,25 @@ package scala /** Class `Any` is the root of the Scala class hierarchy. Every class in a Scala * execution environment inherits directly or indirectly from this class. + * + * Starting with Scala 2.10 it is possible to directly extend `Any` using ''universal traits''. + * A ''universal trait'' is a trait that extends `Any`, only has `def`s as members, and does no initialization. + * + * The main use case for universal traits is to allow basic inheritance of methods for [[scala.AnyVal value classes]]. + * For example, + * + * {{{ + * trait Printable extends Any { + * def print(): Unit = println(this) + * } + * class Wrapper(val underlying: Int) extends AnyVal with Printable + * + * val w = new Wrapper(3) + * w.print() + * }}} + * + * See the [[http://docs.scala-lang.org/sips/pending/value-classes.html value classes guide]] for more + * details on the interplay of universal traits and value classes. */ abstract class Any { /** Compares the receiver object (`this`) with the argument object (`that`) for equivalence. |