---

yaml
---
r: 149613
b: refs/heads/try2
c: 52524bf
h: refs/heads/master
i:
  149611: dc16dae
v: v3

Author: brunoabinader

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 2b362768ff3cab2c966f1f18cf119b21fc96ea30
+refs/heads/try2: 52524bfe880f3722d8d70e4433429c1b4a3f31d3
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libcollections/list.rs

@@ -17,6 +17,42 @@ pub enum List<T> {
     Nil,
 }
 
+pub struct Items<'a, T> {
+    priv head: &'a List<T>,
+    priv next: Option<&'a @List<T>>
+}
+
+impl<'a, T> Iterator<&'a T> for Items<'a, T> {
+    fn next(&mut self) -> Option<&'a T> {
+        match self.next {
+            None => match *self.head {
+                Nil => None,
+                Cons(ref value, ref tail) => {
+                    self.next = Some(tail);
+                    Some(value)
+                }
+            },
+            Some(next) => match **next {
+                Nil => None,
+                Cons(ref value, ref tail) => {
+                    self.next = Some(tail);
+                    Some(value)
+                }
+            }
+        }
+    }
+}
+
+impl<T> List<T> {
+    /// Returns a forward iterator
+    pub fn iter<'a>(&'a self) -> Items<'a, T> {
+        Items {
+            head: self,
+            next: None
+        }
+    }
+}
+
 /**
  * Left fold
  *
@@ -181,6 +217,16 @@ mod tests {
 
     use std::option;
 
+    #[test]
+    fn test_iter() {
+        let list = List::from_vec([0, 1, 2]);
+        let mut iter = list.iter();
+        assert_eq!(&0, iter.next().unwrap());
+        assert_eq!(&1, iter.next().unwrap());
+        assert_eq!(&2, iter.next().unwrap());
+        assert_eq!(None, iter.next());
+    }
+
     #[test]
     fn test_is_empty() {
         let empty : @list::List<int> = @List::from_vec([]);