---

yaml
---
r: 71952
b: refs/heads/dist-snap
c: 2cb6974
h: refs/heads/master
v: v3

Author: bors

[refs]

@@ -7,7 +7,7 @@ refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: 147ecfdd8221e4a4d4e090486829a06da1e0ca3c
 refs/heads/incoming: b50030718cf28f2a5a81857a26b57442734fe854
-refs/heads/dist-snap: 8b74efaa7b584428a00812697d66a4449884e3e1
+refs/heads/dist-snap: 2cb69748563f7b9ab94160943eea6ec787b27a4d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0

branches/dist-snap/src/libcore/cmp.rs

@@ -116,6 +116,19 @@ totalord_impl!(i64)
 totalord_impl!(int)
 totalord_impl!(uint)
 
+/**
+Return `o1` if it is not `Equal`, otherwise `o2`. Simulates the
+lexical ordering on a type `(int, int)`.
+*/
+// used in deriving code in libsyntax
+#[inline(always)]
+pub fn lexical_ordering(o1: Ordering, o2: Ordering) -> Ordering {
+    match o1 {
+        Equal => o2,
+        _ => o1
+    }
+}
+
 /**
 * Trait for values that can be compared for a sort-order.
 *
@@ -184,6 +197,8 @@ pub fn max<T:Ord>(v1: T, v2: T) -> T {
 
 #[cfg(test)]
 mod test {
+    use super::lexical_ordering;
+
     #[test]
     fn test_int_totalord() {
         assert_eq!(5.cmp(&10), Less);
@@ -204,4 +219,16 @@ mod test {
         assert!(Less < Equal);
         assert_eq!(Greater.cmp(&Less), Greater);
     }
+
+    #[test]
+    fn test_lexical_ordering() {
+        fn t(o1: Ordering, o2: Ordering, e: Ordering) {
+            assert_eq!(lexical_ordering(o1, o2), e);
+        }
+        for [Less, Equal, Greater].each |&o| {
+            t(Less, o, Less);
+            t(Equal, o, o);
+            t(Greater, o, Greater);
+         }
+    }
 }