From 32d2b15d5db3e9e582632cc8f995dcc362751d6a Mon Sep 17 00:00:00 2001 From: Paul Phillips Date: Mon, 13 Jun 2011 20:51:39 +0000 Subject: Views using methods implemented in terms of isE... Views using methods implemented in terms of isEmpty (in particular, headOption and lastOption) were traversing the collection twice up to the nonEmpty element, because "if (isEmpty) None else Some(head)" means calling isEmpty separately from head. I overrode those methods in TraversableViewLike to avoid the second traversal. This leaves at least init and tail still in that boat, but they were getting too involved. How do I say "review by pool of reviewers", who can help set that up? In the meantime no review. --- test/files/run/view-headoption.check | 28 ++++++++++++++++++++++++++++ test/files/run/view-headoption.scala | 18 ++++++++++++++++++ 2 files changed, 46 insertions(+) create mode 100644 test/files/run/view-headoption.check create mode 100644 test/files/run/view-headoption.scala (limited to 'test/files/run') diff --git a/test/files/run/view-headoption.check b/test/files/run/view-headoption.check new file mode 100644 index 0000000000..5c98b54b46 --- /dev/null +++ b/test/files/run/view-headoption.check @@ -0,0 +1,28 @@ +fail +success +f1: Some(5) +fail +success +f2: 5 +fail +success +fail +fail +success +fail +fail +fail +success +f3: Some(5) +fail +success +fail +success +fail +fail +success +fail +fail +fail +success +f4: 5 diff --git a/test/files/run/view-headoption.scala b/test/files/run/view-headoption.scala new file mode 100644 index 0000000000..659c7e6b82 --- /dev/null +++ b/test/files/run/view-headoption.scala @@ -0,0 +1,18 @@ +object Test { + val failer = () => { println("fail") ; None } + val succeeder = () => { println("success") ; Some(5) } + val fs = List(failer, succeeder, failer, failer, succeeder, failer, failer, failer, succeeder) + + def f0 = fs.view flatMap (f => f()) + def f1 = f0.headOption + def f2 = f0.head + def f3 = f0.lastOption + def f4 = f0.last + + def main(args: Array[String]): Unit = { + println("f1: " + f1) + println("f2: " + f2) + println("f3: " + f3) + println("f4: " + f4) + } +} -- cgit v1.2.3