From 84321d1f59232f547aefff16667b8a68f2c8bb57 Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Thu, 17 Mar 2011 11:21:11 -0700
Subject: [PATCH] Add an option.is_none() method

---
 src/lib/option.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/lib/option.rs b/src/lib/option.rs
index 25f82b52a0e..29a6f6eb96b 100644
--- a/src/lib/option.rs
+++ b/src/lib/option.rs
@@ -31,6 +31,13 @@ fn map[T, U](&operator[T, U] f, &t[T] opt) -> t[U] {
     fail;   // FIXME: remove me when exhaustiveness checking works
 }
 
+fn is_none[T](&t[T] opt) -> bool {
+    alt (opt) {
+        case (none[T])      { ret true; }
+        case (some[T](_))   { ret false; }
+    }
+}
+
 // Local Variables:
 // mode: rust;
 // fill-column: 78;