mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-26 11:45:20 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 10

Implement and apply PEP 322, reverse iteration

Browse source
This commit is contained in:
Raymond Hettinger 2003-11-06 14:06:48 +00:00
parent f607fc5395
commit 85c20a41df
12 changed files with 198 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

37
Objects/rangeobject.c
View file

@ -171,6 +171,15 @@ static PySequenceMethods range_as_sequence = {
};
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 @@ PyTypeObject PyRange_Type = {
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 */
@ -245,6 +254,32 @@ range_iter(PyObject *seq)
return (PyObject *)it;
}
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)
{