From 2e198dcf81b87c3ef02440306b03fa9af60b5c3b Mon Sep 17 00:00:00 2001
From: Manos Koukoutos <emmanouil.koukoutos@epfl.ch>
Date: Wed, 2 Sep 2015 18:44:35 +0200
Subject: [PATCH] List.tailOption in lib
---
library/collection/List.scala | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/library/collection/List.scala b/library/collection/List.scala
index 0fc2d4f84..e75b588c7 100644
--- a/library/collection/List.scala
+++ b/library/collection/List.scala
@@ -266,6 +266,14 @@ sealed abstract class List[T] {
None[T]()
}} ensuring { _.isDefined != this.isEmpty }
+ def tailOption: Option[List[T]] = { this match {
+ case Cons(h, t) =>
+ Some(t)
+ case Nil() =>
+ None[List[T]]()
+ }} ensuring { _.isDefined != this.isEmpty }
+
+
def unique: List[T] = this match {
case Nil() => Nil()
case Cons(h, t) =>
--
GitLab