From 2724ab99c8c81cdb032372871d8f1eebb171ebe7 Mon Sep 17 00:00:00 2001
From: David Wolever <david@wolever.net>
Date: Wed, 19 Mar 2008 02:35:45 +0000
Subject: Added zip, map, filter to future_bultins (#2171)

---
 Lib/test/test_future_builtins.py | 14 +++++++++++++-
 Lib/test/test_py3kwarn.py        | 11 +++++++++++
 Modules/future_builtins.c        | 15 ++++++++++++++-
 Modules/itertoolsmodule.c        | 13 +++++++++++--
 4 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/Lib/test/test_future_builtins.py b/Lib/test/test_future_builtins.py
index 69e719b..0e16caf 100644
--- a/Lib/test/test_future_builtins.py
+++ b/Lib/test/test_future_builtins.py
@@ -1,7 +1,8 @@
 import test.test_support, unittest
 
 # we're testing the behavior of these future builtins:
-from future_builtins import hex, oct
+from future_builtins import hex, oct, map, zip, filter
+from test import test_support
 
 class BuiltinTest(unittest.TestCase):
     def test_hex(self):
@@ -20,6 +21,17 @@ class BuiltinTest(unittest.TestCase):
         self.assertEqual(oct(-100L), '-0o144')
         self.assertRaises(TypeError, oct, ())
 
+    def test_itertools(self):
+        from itertools import imap, izip, ifilter
+        # We will assume that the itertools functions work, so provided
+        # that we've got identical coppies, we will work!
+        self.assertEqual(map, imap)
+        self.assertEqual(zip, izip)
+        self.assertEqual(filter, ifilter)
+        # Testing that filter(None, stuff) raises a warning lives in
+        # test_py3kwarn.py
+
+
 def test_main(verbose=None):
     test.test_support.run_unittest(BuiltinTest)
 
diff --git a/Lib/test/test_py3kwarn.py b/Lib/test/test_py3kwarn.py
index cdb1038..cc1e9f4 100644
--- a/Lib/test/test_py3kwarn.py
+++ b/Lib/test/test_py3kwarn.py
@@ -50,6 +50,17 @@ class TestPy3KWarnings(unittest.TestCase):
         with catch_warning() as w:
             self.assertWarning(cell0 < cell1, w, expected)
 
+    def test_filter(self):
+        from itertools import ifilter
+        from future_builtins import filter
+        expected = 'ifilter with None as a first argument is not supported '\
+                   'in 3.x.  Use a list comprehension instead.'
+
+        with catch_warning() as w:
+            self.assertWarning(ifilter(None, []), w, expected)
+        with catch_warning() as w:
+            self.assertWarning(filter(None, []), w, expected)
+
     def test_code_inequality_comparisons(self):
         expected = 'code inequality comparisons not supported in 3.x.'
         def f(x):
diff --git a/Modules/future_builtins.c b/Modules/future_builtins.c
index 686925d..5baaa60 100644
--- a/Modules/future_builtins.c
+++ b/Modules/future_builtins.c
@@ -59,11 +59,24 @@ static PyMethodDef module_functions[] = {
 PyMODINIT_FUNC
 initfuture_builtins(void)
 {
-	PyObject *m;
+	PyObject *m, *itertools, *iter_func;
+	char *it_funcs[] = {"imap", "ifilter", "izip", NULL};
+	char **cur_func;
 
 	m = Py_InitModule3("future_builtins", module_functions, module_doc);
 	if (m == NULL)
 		return;
 
+	itertools = PyImport_ImportModuleNoBlock("itertools");
+	if (itertools == NULL)
+		return;
+
+	for (cur_func = it_funcs; *cur_func; ++cur_func){
+		iter_func = PyObject_GetAttrString(itertools, *cur_func);
+		if (iter_func == NULL)
+			return;
+		PyModule_AddObject(m, *cur_func+1, iter_func);
+	}
+	Py_DECREF(itertools);
 	/* any other initialization needed */
 }
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 8c3375a..a369dc9 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -2542,7 +2542,7 @@ ifilter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	ifilterobject *lz;
 
 	if (Py_Py3kWarningFlag &&
-	    PyErr_Warn(PyExc_DeprecationWarning, 
+	    PyErr_Warn(PyExc_DeprecationWarning,
 		       "In 3.x, itertools.ifilter() was moved to builtin filter().") < 0)
 		return NULL;
 
@@ -2552,6 +2552,15 @@ ifilter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	if (!PyArg_UnpackTuple(args, "ifilter", 2, 2, &func, &seq))
 		return NULL;
 
+	if (func == Py_None) {
+		if (Py_Py3kWarningFlag &&
+		    PyErr_Warn(PyExc_DeprecationWarning,
+			       "ifilter with None as a first argument "
+			       "is not supported in 3.x.  Use a list "
+			       "comprehension instead.") < 0)
+			return NULL;
+	}
+
 	/* Get iterator. */
 	it = PyObject_GetIter(seq);
 	if (it == NULL)
@@ -3602,7 +3611,7 @@ inititertools(void)
 		&izip_type,
 		&iziplongest_type,
 		&permutations_type,
-		&product_type,         
+		&product_type,
 		&repeat_type,
 		&groupby_type,
 		NULL
-- 
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