diff -r adbcba130143 Lib/functools.py
--- a/Lib/functools.py	Tue Mar 29 12:09:45 2011 -0700
+++ b/Lib/functools.py	Sat Apr 02 22:52:11 2011 +0200
@@ -92,28 +92,30 @@
             opfunc.__doc__ = getattr(int, opname).__doc__
             setattr(cls, opname, opfunc)
     return cls
-
-def cmp_to_key(mycmp):
-    """Convert a cmp= function into a key= function"""
-    class K(object):
-        __slots__ = ['obj']
-        def __init__(self, obj, *args):
-            self.obj = obj
-        def __lt__(self, other):
-            return mycmp(self.obj, other.obj) < 0
-        def __gt__(self, other):
-            return mycmp(self.obj, other.obj) > 0
-        def __eq__(self, other):
-            return mycmp(self.obj, other.obj) == 0
-        def __le__(self, other):
-            return mycmp(self.obj, other.obj) <= 0
-        def __ge__(self, other):
-            return mycmp(self.obj, other.obj) >= 0
-        def __ne__(self, other):
-            return mycmp(self.obj, other.obj) != 0
-        def __hash__(self):
-            raise TypeError('hash not implemented')
-    return K
+try:
+    from _functools import cmp_to_key
+except ImportError:
+    def cmp_to_key(mycmp):
+        """Convert a cmp= function into a key= function"""
+        class K(object):
+            __slots__ = ['obj']
+            def __init__(self, obj, *args):
+                self.obj = obj
+            def __lt__(self, other):
+                return mycmp(self.obj, other.obj) < 0
+            def __gt__(self, other):
+                return mycmp(self.obj, other.obj) > 0
+            def __eq__(self, other):
+                return mycmp(self.obj, other.obj) == 0
+            def __le__(self, other):
+                return mycmp(self.obj, other.obj) <= 0
+            def __ge__(self, other):
+                return mycmp(self.obj, other.obj) >= 0
+            def __ne__(self, other):
+                return mycmp(self.obj, other.obj) != 0
+            def __hash__(self):
+                raise TypeError('hash not implemented')
+        return K
 
 _CacheInfo = namedtuple("CacheInfo", "hits misses maxsize currsize")
 
diff -r adbcba130143 Modules/_functoolsmodule.c
--- a/Modules/_functoolsmodule.c	Tue Mar 29 12:09:45 2011 -0700
+++ b/Modules/_functoolsmodule.c	Sat Apr 02 22:52:11 2011 +0200
@@ -330,6 +330,116 @@
 };
 
 
+/* cmp_to_key ***************************************************************/
+
+typedef struct {
+    PyObject_HEAD;
+    PyObject *cmp;
+    PyObject *object;
+} keyobject;
+
+static void
+keyobject_dealloc(keyobject *ko)
+{
+    PyObject_FREE(ko);
+}
+
+static PyObject *
+keyobject_call(keyobject *ko, PyObject *args, PyObject *kw);
+
+static PyObject *
+keyobject_richcompare(PyObject *ko, PyObject *other, int op)
+{
+    if (!((keyobject *) ko)->object){
+        PyErr_Format(PyExc_AttributeError, "object");
+        return NULL;
+    }
+    PyObject *res = PyObject_CallFunction(((keyobject *) ko)->cmp, "OO", 
+                                          ((keyobject *) ko)->object, other);
+    if (!res)
+        return NULL;
+    PyObject *zero = PyLong_FromLong(0);
+    if (!zero)
+        return NULL;
+    PyObject *bool = PyObject_RichCompare(res, zero, op);
+    if (!bool)
+        return NULL;
+    return bool;
+}
+
+static PyMethodDef keyobject_methods[] = {
+    {NULL,              NULL}           /* sentinel */
+};
+
+static PyTypeObject keyobject_type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "functools.K",                      /* tp_name */
+    sizeof(keyobject),                  /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    /* methods */
+    (destructor)keyobject_dealloc,      /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_reserved */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    (ternaryfunc)keyobject_call,        /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    0,                                  /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    keyobject_richcompare,              /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    keyobject_methods,                  /* tp_methods */
+    0
+};
+
+static PyObject *
+keyobject_call(keyobject *ko, PyObject *args, PyObject *kw)
+{    
+    PyObject *object;
+    keyobject *result;
+    
+    if (!PyArg_UnpackTuple(args, "", 1, 1, &object))
+        return NULL;
+    result = PyObject_New(keyobject, &keyobject_type);
+    if (!result)
+        return NULL;
+    Py_INCREF(ko->cmp);
+    result->cmp = ko->cmp;
+    Py_INCREF(object);
+    result->object = object;
+    return (PyObject *) result;
+}
+
+static PyObject *
+functools_cmp_to_key(PyObject *self, PyObject *args){
+    PyObject *cmp = NULL;
+    
+    if (!PyArg_UnpackTuple(args, "cmp_to_key", 1, 1, &cmp))
+        return NULL;
+    keyobject *object = PyObject_New(keyobject, &keyobject_type);
+    if (!object)
+        return NULL;
+    object->cmp = cmp;
+    object->object = NULL;
+    Py_INCREF(cmp);
+    return (PyObject *) object;
+    
+}
+PyDoc_STRVAR(functools_cmp_to_key_doc,
+"Convert a cmp= function into a key= function.");
+
 /* reduce (used to be a builtin) ********************************************/
 
 static PyObject *
@@ -413,6 +523,7 @@
 
 static PyMethodDef module_methods[] = {
     {"reduce",          functools_reduce,     METH_VARARGS, functools_reduce_doc},
+    {"cmp_to_key",      functools_cmp_to_key, METH_VARARGS, functools_cmp_to_key_doc},
     {NULL,              NULL}           /* sentinel */
 };
 
diff -r adbcba130143 Lib/functools.py
--- a/Lib/functools.py	Tue Mar 29 12:09:45 2011 -0700
+++ b/Lib/functools.py	Sat Apr 02 22:52:37 2011 +0200
@@ -92,28 +92,31 @@
             opfunc.__doc__ = getattr(int, opname).__doc__
             setattr(cls, opname, opfunc)
     return cls
-
-def cmp_to_key(mycmp):
-    """Convert a cmp= function into a key= function"""
-    class K(object):
-        __slots__ = ['obj']
-        def __init__(self, obj, *args):
-            self.obj = obj
-        def __lt__(self, other):
-            return mycmp(self.obj, other.obj) < 0
-        def __gt__(self, other):
-            return mycmp(self.obj, other.obj) > 0
-        def __eq__(self, other):
-            return mycmp(self.obj, other.obj) == 0
-        def __le__(self, other):
-            return mycmp(self.obj, other.obj) <= 0
-        def __ge__(self, other):
-            return mycmp(self.obj, other.obj) >= 0
-        def __ne__(self, other):
-            return mycmp(self.obj, other.obj) != 0
-        def __hash__(self):
-            raise TypeError('hash not implemented')
-    return K
+    
+try:
+    from _functools import cmp_to_key
+except ImportError:
+    def cmp_to_key(mycmp):
+        """Convert a cmp= function into a key= function"""
+        class K(object):
+            __slots__ = ['obj']
+            def __init__(self, obj, *args):
+                self.obj = obj
+            def __lt__(self, other):
+                return mycmp(self.obj, other.obj) < 0
+            def __gt__(self, other):
+                return mycmp(self.obj, other.obj) > 0
+            def __eq__(self, other):
+                return mycmp(self.obj, other.obj) == 0
+            def __le__(self, other):
+                return mycmp(self.obj, other.obj) <= 0
+            def __ge__(self, other):
+                return mycmp(self.obj, other.obj) >= 0
+            def __ne__(self, other):
+                return mycmp(self.obj, other.obj) != 0
+            def __hash__(self):
+                raise TypeError('hash not implemented')
+        return K
 
 _CacheInfo = namedtuple("CacheInfo", "hits misses maxsize currsize")
 
diff -r adbcba130143 Modules/_functoolsmodule.c
--- a/Modules/_functoolsmodule.c	Tue Mar 29 12:09:45 2011 -0700
+++ b/Modules/_functoolsmodule.c	Sat Apr 02 22:52:37 2011 +0200
@@ -330,6 +330,116 @@
 };
 
 
+/* cmp_to_key ***************************************************************/
+
+typedef struct {
+    PyObject_HEAD;
+    PyObject *cmp;
+    PyObject *object;
+} keyobject;
+
+static void
+keyobject_dealloc(keyobject *ko)
+{
+    PyObject_FREE(ko);
+}
+
+static PyObject *
+keyobject_call(keyobject *ko, PyObject *args, PyObject *kw);
+
+static PyObject *
+keyobject_richcompare(PyObject *ko, PyObject *other, int op)
+{
+    if (!((keyobject *) ko)->object){
+        PyErr_Format(PyExc_AttributeError, "object");
+        return NULL;
+    }
+    PyObject *res = PyObject_CallFunction(((keyobject *) ko)->cmp, "OO", 
+                                          ((keyobject *) ko)->object, other);
+    if (!res)
+        return NULL;
+    PyObject *zero = PyLong_FromLong(0);
+    if (!zero)
+        return NULL;
+    PyObject *bool = PyObject_RichCompare(res, zero, op);
+    if (!bool)
+        return NULL;
+    return bool;
+}
+
+static PyMethodDef keyobject_methods[] = {
+    {NULL,              NULL}           /* sentinel */
+};
+
+static PyTypeObject keyobject_type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "functools.K",                      /* tp_name */
+    sizeof(keyobject),                  /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    /* methods */
+    (destructor)keyobject_dealloc,      /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_reserved */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    (ternaryfunc)keyobject_call,        /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    0,                                  /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    keyobject_richcompare,              /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    keyobject_methods,                  /* tp_methods */
+    0
+};
+
+static PyObject *
+keyobject_call(keyobject *ko, PyObject *args, PyObject *kw)
+{    
+    PyObject *object;
+    keyobject *result;
+    
+    if (!PyArg_UnpackTuple(args, "", 1, 1, &object))
+        return NULL;
+    result = PyObject_New(keyobject, &keyobject_type);
+    if (!result)
+        return NULL;
+    Py_INCREF(ko->cmp);
+    result->cmp = ko->cmp;
+    Py_INCREF(object);
+    result->object = object;
+    return (PyObject *) result;
+}
+
+static PyObject *
+functools_cmp_to_key(PyObject *self, PyObject *args){
+    PyObject *cmp = NULL;
+    
+    if (!PyArg_UnpackTuple(args, "cmp_to_key", 1, 1, &cmp))
+        return NULL;
+    keyobject *object = PyObject_New(keyobject, &keyobject_type);
+    if (!object)
+        return NULL;
+    object->cmp = cmp;
+    object->object = NULL;
+    Py_INCREF(cmp);
+    return (PyObject *) object;
+    
+}
+PyDoc_STRVAR(functools_cmp_to_key_doc,
+"Convert a cmp= function into a key= function.");
+
 /* reduce (used to be a builtin) ********************************************/
 
 static PyObject *
@@ -413,6 +523,7 @@
 
 static PyMethodDef module_methods[] = {
     {"reduce",          functools_reduce,     METH_VARARGS, functools_reduce_doc},
+    {"cmp_to_key",      functools_cmp_to_key, METH_VARARGS, functools_cmp_to_key_doc},
     {NULL,              NULL}           /* sentinel */
 };