Issue #20186: Converted builtins enumerate() and reversed() to Argument Clinic.

Patch by Tal Einat.

Objects/clinic/enumobject.c.h

@@ -0,0 +1,71 @@
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+PyDoc_STRVAR(enum_new__doc__,
+"enumerate(iterable, start=0)\n"
+"--\n"
+"\n"
+"Return an enumerate object.\n"
+"\n"
+"  iterable\n"
+"    an object supporting iteration\n"
+"\n"
+"The enumerate object yields pairs containing a count (from start, which\n"
+"defaults to zero) and a value yielded by the iterable argument.\n"
+"\n"
+"enumerate is useful for obtaining an indexed list:\n"
+"    (0, seq[0]), (1, seq[1]), (2, seq[2]), ...");
+
+static PyObject *
+enum_new_impl(PyTypeObject *type, PyObject *iterable, PyObject *start);
+
+static PyObject *
+enum_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"iterable", "start", NULL};
+    static _PyArg_Parser _parser = {"O|O:enumerate", _keywords, 0};
+    PyObject *iterable;
+    PyObject *start = 0;
+
+    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
+        &iterable, &start)) {
+        goto exit;
+    }
+    return_value = enum_new_impl(type, iterable, start);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(reversed_new__doc__,
+"reversed(sequence, /)\n"
+"--\n"
+"\n"
+"Return a reverse iterator over the values of the given sequence.");
+
+static PyObject *
+reversed_new_impl(PyTypeObject *type, PyObject *seq);
+
+static PyObject *
+reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    PyObject *seq;
+
+    if ((type == &PyReversed_Type) &&
+        !_PyArg_NoKeywords("reversed", kwargs)) {
+        goto exit;
+    }
+    if (!PyArg_UnpackTuple(args, "reversed",
+        1, 1,
+        &seq)) {
+        goto exit;
+    }
+    return_value = reversed_new_impl(type, seq);
+
+exit:
+    return return_value;
+}
+/*[clinic end generated code: output=9008c36999c57218 input=a9049054013a1b77]*/