From 3edad3555e1f5c01572f32e84480383c1ae2b472 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Sun, 12 Feb 2012 02:50:37 -0800
Subject: [PATCH] core: Add iter::count

---
 src/libcore/iter.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index 8500ce7a783..6af10bd8a35 100644
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -82,6 +82,16 @@ fn reverse<A:copy,IA:iterable<A>>(self: IA, blk: fn(A)) {
     vec::riter(to_list(self), blk)
 }
 
+fn count<A,IA:iterable<A>>(self: IA, x: A) -> uint {
+    foldl(self, 0u) {|count, value|
+        if value == x {
+            count + 1u
+        } else {
+            count
+        }
+    }
+}
+
 fn repeat(times: uint, blk: fn()) {
     let i = 0u;
     while i < times {
@@ -223,4 +233,9 @@ fn test_max_empty() {
 #[test]
 fn test_reverse() {
     assert to_list(bind reverse([1, 2, 3], _)) == [3, 2, 1];
+}
+
+#[test]
+fn test_count() {
+    assert count([1, 2, 1, 2, 1], 1) == 3u;
 }
\ No newline at end of file