Checking in the code for PEP 357.
This was mostly written by Travis Oliphant.
I've inspected it all; Neal Norwitz and MvL have also looked at it
(in an earlier incarnation).
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 0ff61e2..966d659 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2452,11 +2452,14 @@
"list() -> new list\n"
"list(sequence) -> new list initialized from sequence's items");
+#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
+
static PyObject *
list_subscript(PyListObject* self, PyObject* item)
{
- if (PyInt_Check(item) || PyLong_Check(item)) {
- Py_ssize_t i = PyInt_AsSsize_t(item);
+ PyNumberMethods *nb = item->ob_type->tp_as_number;
+ if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
+ Py_ssize_t i = nb->nb_index(item);
if (i == -1 && PyErr_Occurred())
return NULL;
if (i < 0)
@@ -2503,14 +2506,9 @@
static int
list_ass_subscript(PyListObject* self, PyObject* item, PyObject* value)
{
- if (PyInt_Check(item)) {
- Py_ssize_t i = PyInt_AS_LONG(item);
- if (i < 0)
- i += PyList_GET_SIZE(self);
- return list_ass_item(self, i, value);
- }
- else if (PyLong_Check(item)) {
- Py_ssize_t i = PyInt_AsSsize_t(item);
+ PyNumberMethods *nb = item->ob_type->tp_as_number;
+ if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
+ Py_ssize_t i = nb->nb_index(item);
if (i == -1 && PyErr_Occurred())
return -1;
if (i < 0)