From 8e235082b4e3649e06e768ec50a2b6b6382fa73d Mon Sep 17 00:00:00 2001
From: Etienne Kneuss <colder@php.net>
Date: Fri, 30 May 2014 15:23:50 +0200
Subject: [PATCH] Add List.take and List.drop, unproven, for convenience in
benchmarks
---
library/collection/List.scala | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/library/collection/List.scala b/library/collection/List.scala
index f2f629243..1f8253f13 100644
--- a/library/collection/List.scala
+++ b/library/collection/List.scala
@@ -64,6 +64,26 @@ sealed abstract class List[T] {
case Cons(x,xs) => xs.reverse :+ x
}
} ensuring (res => (res.size == size) && (res.content == content))
+
+ def take(i: Int): List[T] = (this, i) match {
+ case (Nil(), _) => Nil()
+ case (Cons(h, t), i) =>
+ if (i == 0) {
+ Nil()
+ } else {
+ Cons(h, t.take(i-1))
+ }
+ }
+
+ def drop(i: Int): List[T] = (this, i) match {
+ case (Nil(), _) => Nil()
+ case (Cons(h, t), i) =>
+ if (i == 0) {
+ Cons(h, t)
+ } else {
+ t.drop(i-1)
+ }
+ }
}
--
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