Add BitXor to EnumSet.

src/libcollections/enum_set.rs

@@ -16,7 +16,6 @@
 use core::prelude::*;
 use core::fmt;
 
-// FIXME(conventions): implement BitXor
 // FIXME(contentions): implement union family of methods? (general design may be wrong here)
 // FIXME(conventions): implement len
 
@@ -196,6 +195,12 @@ impl<E:CLike> BitAnd<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
     }
 }
 
+impl<E:CLike> BitXor<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
+    fn bitxor(&self, e: &EnumSet<E>) -> EnumSet<E> {
+        EnumSet {bits: self.bits ^ e.bits}
+    }
+}
+
 /// An iterator over an EnumSet
 pub struct Items<E> {
     index: uint,