Users demand iterable input for named tuples. The author capitulates.

2 files changed, 6 insertions, 1 deletions

diff --git a/Lib/collections.py b/Lib/collections.py
index 3d98f7c..c6d0d0f 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -62,6 +62,7 @@ def namedtuple(typename, field_names, verbose=False):
         __slots__ = () \n
         def __new__(cls, %(argtxt)s):
             return tuple.__new__(cls, (%(argtxt)s)) \n
+        _cast = classmethod(tuple.__new__) \n
         def __repr__(self):
             return '%(typename)s(%(reprtxt)s)' %% self \n
         def _asdict(t):
@@ -69,7 +70,7 @@ def namedtuple(typename, field_names, verbose=False):
             return {%(dicttxt)s} \n
         def _replace(self, **kwds):
             'Return a new %(typename)s object replacing specified fields with new values'
-            return %(typename)s(*map(kwds.get, %(field_names)r, self)) \n
+            return %(typename)s._cast(map(kwds.get, %(field_names)r, self)) \n
         @property
         def _fields(self):
             return %(field_names)r \n\n''' % locals()
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 73ae62a..edffbbe 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -46,6 +46,7 @@ class TestNamedTuple(unittest.TestCase):
         self.assertEqual(repr(p), 'Point(x=11, y=22)')
         self.assert_('__dict__' not in dir(p))                              # verify instance has no dict
         self.assert_('__weakref__' not in dir(p))
+        self.assertEqual(p, Point._cast([11, 22]))                          # test _cast classmethod
         self.assertEqual(p._fields, ('x', 'y'))                             # test _fields attribute
         self.assertEqual(p._replace(x=1), (1, 22))                          # test _replace method
         self.assertEqual(p._asdict(), dict(x=11, y=22))                     # test _asdict method
@@ -90,12 +91,14 @@ class TestNamedTuple(unittest.TestCase):
     def test_odd_sizes(self):
         Zero = namedtuple('Zero', '')
         self.assertEqual(Zero(), ())
+        self.assertEqual(Zero._cast([]), ())
         self.assertEqual(repr(Zero()), 'Zero()')
         self.assertEqual(Zero()._asdict(), {})
         self.assertEqual(Zero()._fields, ())
 
         Dot = namedtuple('Dot', 'd')
         self.assertEqual(Dot(1), (1,))
+        self.assertEqual(Dot._cast([1]), (1,))
         self.assertEqual(Dot(1).d, 1)
         self.assertEqual(repr(Dot(1)), 'Dot(d=1)')
         self.assertEqual(Dot(1)._asdict(), {'d':1})
@@ -108,6 +111,7 @@ class TestNamedTuple(unittest.TestCase):
         Big = namedtuple('Big', names)
         b = Big(*range(n))
         self.assertEqual(b, tuple(range(n)))
+        self.assertEqual(Big._cast(range(n)), tuple(range(n)))
         for pos, name in enumerate(names):
             self.assertEqual(getattr(b, name), pos)
         repr(b)                                 # make sure repr() doesn't blow-up