4 files changed, 29 insertions, 10 deletions
diff --git a/Lib/UserString.py b/Lib/UserString.py
index f4f5cab..292e852 100755
--- a/Lib/UserString.py
+++ b/Lib/UserString.py
@@ -128,6 +128,7 @@ class UserString:
     def translate(self, *args):
         return self.__class__(self.data.translate(*args))
     def upper(self): return self.__class__(self.data.upper())
+    def zfill(self, width): return self.__class__(self.data.zfill(width))
 
 class MutableString(UserString):
     """mutable string objects
diff --git a/Lib/string.py b/Lib/string.py
index d68b0bf..cd9909e 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -190,7 +190,10 @@ def rfind(s, *args):
 _float = float
 _int = int
 _long = long
-_StringTypes = (str, unicode)
+try:
+    _StringTypes = (str, unicode)
+except NameError:
+    _StringTypes = (str,)
 
 # Convert string to float
 def atof(s):
@@ -277,13 +280,8 @@ def zfill(x, width):
 
     """
     if not isinstance(x, _StringTypes):
-        x = str(x)
-    n = len(x)
-    if n >= width: return x
-    sign = ''
-    if x[0] in '-+':
-        sign, x = x[0], x[1:]
-    return sign + '0'*(width-n) + x
+        x = repr(x)
+    return x.zfill(width)
 
 # Expand tabs in a string.
 # Doesn't take non-printing chars into account, but does understand \n.
diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index 5c8dd93..ea25983 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -227,6 +227,16 @@ def run_method_tests(test):
     test('endswith', 'ab', 0, 'ab', 0, 1)
     test('endswith', 'ab', 0, 'ab', 0, 0)
 
+    test('zfill', '123', '123', 2)
+    test('zfill', '123', '123', 3)
+    test('zfill', '123', '0123', 4)
+    test('zfill', '+123', '+123', 3)
+    test('zfill', '+123', '+123', 4)
+    test('zfill', '+123', '+0123', 5)
+    test('zfill', '-123', '-123', 3)
+    test('zfill', '-123', '-123', 4)
+    test('zfill', '-123', '-0123', 5)
+    test('zfill', '', '000', 3)
     test('zfill', '34', '34', 1)
     test('zfill', '34', '0034', 4)
     
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 4b77e75..29dd819 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -206,8 +206,18 @@ if 0:
     test('capwords', u'abc\tdef\nghi', u'Abc Def Ghi')
     test('capwords', u'abc\t   def  \nghi', u'Abc Def Ghi')
 
-verify(string.zfill(u'34', 1) == u'34')
-verify(string.zfill(u'34', 5) == u'00034')
+test('zfill', u'123', u'123', 2)
+test('zfill', u'123', u'123', 3)
+test('zfill', u'123', u'0123', 4)
+test('zfill', u'+123', u'+123', 3)
+test('zfill', u'+123', u'+123', 4)
+test('zfill', u'+123', u'+0123', 5)
+test('zfill', u'-123', u'-123', 3)
+test('zfill', u'-123', u'-123', 4)
+test('zfill', u'-123', u'-0123', 5)
+test('zfill', u'', u'000', 3)
+test('zfill', u'34', u'34', 1)
+test('zfill', u'34', u'00034', 5)
 
 # Comparisons:
 print 'Testing Unicode comparisons...',