- New builtin function enumerate(x), from PEP 279. Example:
enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
The argument can be an arbitrary iterable object.
diff --git a/Objects/enumobject.c b/Objects/enumobject.c
new file mode 100644
index 0000000..1964956
--- /dev/null
+++ b/Objects/enumobject.c
@@ -0,0 +1,139 @@
+/* enumerate object */
+
+#include "Python.h"
+
+typedef struct {
+ PyObject_HEAD
+ long en_index; /* current index of enumeration */
+ PyObject* en_sit; /* secondary iterator of enumeration */
+} enumobject;
+
+PyTypeObject PyEnum_Type;
+
+static PyObject *
+enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+ enumobject *en;
+ PyObject *seq = NULL;
+ static char *kwlist[] = {"sequence", 0};
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:enumerate", kwlist,
+ &seq))
+ return NULL;
+
+ en = (enumobject *)type->tp_alloc(type, 0);
+ if (en == NULL)
+ return NULL;
+ en->en_index = 0;
+ en->en_sit = PyObject_GetIter(seq);
+ if (en->en_sit == NULL) {
+ Py_DECREF(en);
+ return NULL;
+ }
+ return (PyObject *)en;
+}
+
+static void
+enum_dealloc(enumobject *en)
+{
+ PyObject_GC_UnTrack(en);
+ Py_XDECREF(en->en_sit);
+ en->ob_type->tp_free(en);
+}
+
+static int
+enum_traverse(enumobject *en, visitproc visit, void *arg)
+{
+ if (en->en_sit)
+ return visit(en->en_sit, arg);
+ return 0;
+}
+
+static PyObject *
+enum_next(enumobject *en)
+{
+ PyObject *result;
+ PyObject *next_index;
+
+ PyObject *next_item = PyIter_Next(en->en_sit);
+ if (next_item == NULL)
+ return NULL;
+
+ result = PyTuple_New(2);
+ if (result == NULL) {
+ Py_DECREF(next_item);
+ return NULL;
+ }
+
+ next_index = PyInt_FromLong(en->en_index++);
+ if (next_index == NULL) {
+ Py_DECREF(next_item);
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ PyTuple_SET_ITEM(result, 0, next_index);
+ PyTuple_SET_ITEM(result, 1, next_item);
+ return result;
+}
+
+static PyObject *
+enum_getiter(PyObject *en)
+{
+ Py_INCREF(en);
+ return en;
+}
+
+static PyMethodDef enum_methods[] = {
+ {"next", (PyCFunction)enum_next, METH_NOARGS,
+ "return the next (index, value) pair, or raise StopIteration"},
+ {NULL, NULL} /* sentinel */
+};
+
+static char enum_doc[] =
+ "enumerate(iterable) -> create an enumerating-iterator";
+
+PyTypeObject PyEnum_Type = {
+ PyObject_HEAD_INIT(&PyType_Type)
+ 0, /* ob_size */
+ "enumerate", /* tp_name */
+ sizeof(enumobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)enum_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_compare */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+ Py_TPFLAGS_BASETYPE, /* tp_flags */
+ enum_doc, /* tp_doc */
+ (traverseproc)enum_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ (getiterfunc)enum_getiter, /* tp_iter */
+ (iternextfunc)enum_next, /* tp_iternext */
+ enum_methods, /* tp_methods */
+ 0, /* tp_members */
+ 0, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ 0, /* tp_init */
+ PyType_GenericAlloc, /* tp_alloc */
+ enum_new, /* tp_new */
+ PyObject_GC_Del, /* tp_free */
+};