1 files changed, 11 insertions, 0 deletions
diff --git a/src/libstd/str.rs b/src/libstd/str.rs
index 21f747317f4..aa6b1470b26 100644
--- a/src/libstd/str.rs
+++ b/src/libstd/str.rs
@@ -27,6 +27,7 @@ use container::Container;
 use iter::Times;
 use iterator::{Iterator, IteratorUtil, FilterIterator, AdditiveIterator, MapIterator};
 use libc;
+use num::Zero;
 use option::{None, Option, Some};
 use old_iter::{BaseIter, EqIter};
 use ptr;
@@ -2201,6 +2202,16 @@ impl<'self> Iterator<u8> for StrBytesRevIterator<'self> {
     }
 }
 
+impl Zero for ~str {
+    fn zero() -> ~str { ~"" }
+    fn is_zero(&self) -> bool { self.len() == 0 }
+}
+
+impl Zero for @str {
+    fn zero() -> @str { @"" }
+    fn is_zero(&self) -> bool { self.len() == 0 }
+}
+
 #[cfg(test)]
 mod tests {
     use iterator::IteratorUtil;