Minor improvements to itertools.tee():

* tee object is no longer subclassable
* independent iterators renamed to "itertools.tee_iterator"
* fixed doc string typo and added entry in the module doc string

diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index ce03b1aefb6b5e708074f59762c06fdeea37c3d0..e12aa4177567db67684a62da0f38ac3312d151d5 100644 (file)
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -243,6 +243,18 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, tee, 3)
         self.assertRaises(TypeError, tee, [1,2], 'x')
 
+        try:
+            class A(tee): pass
+        except TypeError:
+            pass
+        else:
+            self.fail("tee constructor should not be subclassable")
+
+        # tee_iterator should not be instantiable
+        a, b = tee(xrange(10))
+        self.assertRaises(TypeError, type(a))
+        self.assert_(a is iter(a))  # tee_iterator should support __iter__
+
     def test_StopIteration(self):
         self.assertRaises(StopIteration, izip().next)
 

diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index b37dec119b5f64ecc9de33d0637a76306c87c226..7cafc14eaa8099b1d74be06f8e1c22b001f7cde3 100644 (file)
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -113,12 +113,12 @@ ii_traverse(iiobject *ii, visitproc visit, void *arg)
        return 0;
 }
 
-PyDoc_STRVAR(ii_doc, "Independent iterators linked to a tee() object.");
+PyDoc_STRVAR(ii_doc, "Independent iterator created by tee(iterable).");
 
 static PyTypeObject ii_type = {
        PyObject_HEAD_INIT(&PyType_Type)
        0,                                      /* ob_size */
-       "itertools.independent_iterator",       /* tp_name */
+       "itertools.tee_iterator",               /* tp_name */
        sizeof(iiobject),                       /* tp_basicsize */
        0,                                      /* tp_itemsize */
        /* methods */
@@ -173,7 +173,7 @@ tee_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
        outbasket = PyList_New(0);
        if (outbasket == NULL) goto fail;
 
-       to = (teeobject *)type->tp_alloc(type, 0);
+       to = PyObject_GC_New(teeobject, &tee_type);
        if (to == NULL)  goto fail;
 
        to->it = it;
@@ -181,6 +181,7 @@ tee_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
        to->outbasket = outbasket;
        to->save_mode = 1;
        to->num_seen = 0;
+       PyObject_GC_Track(to);
 
        /* create independent iterators */
        result = PyTuple_New(2);
@@ -212,7 +213,7 @@ tee_dealloc(teeobject *to)
        Py_XDECREF(to->inbasket);
        Py_XDECREF(to->outbasket);
        Py_XDECREF(to->it);
-       to->ob_type->tp_free(to);
+       PyObject_GC_Del(to);
 }
 
 static int
@@ -241,7 +242,7 @@ tee_traverse(teeobject *to, visitproc visit, void *arg)
 PyDoc_STRVAR(tee_doc,
 "tee(iterable) --> (it1, it2)\n\
 \n\
-Split the iterable into to independent iterables.");
+Split the iterable into two independent iterables.");
 
 static PyTypeObject tee_type = {
        PyObject_HEAD_INIT(NULL)
@@ -262,11 +263,10 @@ static PyTypeObject tee_type = {
        0,                              /* tp_hash */
        0,                              /* tp_call */
        0,                              /* tp_str */
-       PyObject_GenericGetAttr,        /* tp_getattro */
+       0,                              /* tp_getattro */
        0,                              /* tp_setattro */
        0,                              /* tp_as_buffer */
-       Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-               Py_TPFLAGS_BASETYPE,    /* tp_flags */
+       Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,        /* tp_flags */
        tee_doc,                        /* tp_doc */
        (traverseproc)tee_traverse,     /* tp_traverse */
        0,                              /* tp_clear */
@@ -285,7 +285,6 @@ static PyTypeObject tee_type = {
        0,                              /* tp_init */
        0,                              /* tp_alloc */
        tee_new,                        /* tp_new */
-       PyObject_GC_Del,                /* tp_free */
 };
 
 /* cycle object **********************************************************/
@@ -2092,6 +2091,7 @@ islice(seq, [start,] stop [, step]) --> elements from\n\
        seq[start:stop:step]\n\
 imap(fun, p, q, ...) --> fun(p0, q0), fun(p1, q1), ...\n\
 starmap(fun, seq) --> fun(*seq[0]), fun(*seq[1]), ...\n\
+tee(it) --> (it1, it2) splits one iterator into two \n\
 chain(p, q, ...) --> p0, p1, ... plast, q0, q1, ... \n\
 takewhile(pred, seq) --> seq[0], seq[1], until pred fails\n\
 dropwhile(pred, seq) --> seq[n], seq[n+1], starting when pred fails\n\