Implement and apply PEP 322, reverse iteration
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index 299f4a6..1f56728 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -171,6 +171,15 @@
};
static PyObject * range_iter(PyObject *seq);
+static PyObject * range_reverse(PyObject *seq);
+
+PyDoc_STRVAR(reverse_doc,
+"Returns a reverse iterator.");
+
+static PyMethodDef range_methods[] = {
+ {"__reversed__", (PyCFunction)range_reverse, METH_NOARGS, reverse_doc},
+ {NULL, NULL} /* sentinel */
+};
PyTypeObject PyRange_Type = {
PyObject_HEAD_INIT(&PyType_Type)
@@ -201,7 +210,7 @@
0, /* tp_weaklistoffset */
(getiterfunc)range_iter, /* tp_iter */
0, /* tp_iternext */
- 0, /* tp_methods */
+ range_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
@@ -246,6 +255,32 @@
}
static PyObject *
+range_reverse(PyObject *seq)
+{
+ rangeiterobject *it;
+ long start, step, len;
+
+ if (!PyRange_Check(seq)) {
+ PyErr_BadInternalCall();
+ return NULL;
+ }
+ it = PyObject_New(rangeiterobject, &Pyrangeiter_Type);
+ if (it == NULL)
+ return NULL;
+
+ start = ((rangeobject *)seq)->start;
+ step = ((rangeobject *)seq)->step;
+ len = ((rangeobject *)seq)->len;
+
+ it->index = 0;
+ it->start = start + (len-1) * step;
+ it->step = -step;
+ it->len = len;
+
+ return (PyObject *)it;
+}
+
+static PyObject *
rangeiter_next(rangeiterobject *r)
{
if (r->index < r->len)