Guido van Rossum schrieb:
Having now read this entire thread I am going to accept Ping's PEP.
Adding the sentinel argument to the next() builtin was what did it for
me: it neatly solves the problem if having to catch that StopIteration
in 99% of the cases.
Attached is a possible implementation for the next() function, regardless
of how the next method is going to be called in the future.
Georg
Index: Python/bltinmodule.c
===================================================================
--- Python/bltinmodule.c (Revision 54016)
+++ Python/bltinmodule.c (Arbeitskopie)
@@ -1029,6 +1029,45 @@
static PyObject *
+builtin_next(PyObject *self, PyObject *args)
+{
+ PyObject *it, *res;
+ PyObject *def = NULL;
+
+ if (!PyArg_UnpackTuple(args, "next", 1, 2, &it, &def))
+ return NULL;
+ if (!PyIter_Check(it)) {
+ PyErr_Format(PyExc_TypeError,
+ "%.200s object is not an iterator",
it->ob_type->tp_name);
+ return NULL;
+ }
+
+ res = (*it->ob_type->tp_iternext)(it);
+ if (res == NULL) {
+ if (def) {
+ if (PyErr_Occurred() &&
+ !PyErr_ExceptionMatches(PyExc_StopIteration))
+ return NULL;
+ Py_INCREF(def);
+ return def;
+ } else if (PyErr_Occurred()) {
+ return NULL;
+ } else {
+ PyErr_SetNone(PyExc_StopIteration);
+ return NULL;
+ }
+ }
+ return res;
+}
+
+PyDoc_STRVAR(next_doc,
+"next(iterator[, default])\n\
+\n\
+Return the next item from the iterator. If default is given and the iterator\n\
+is exhausted, it is returned instead of raising StopIteration.");
+
+
+static PyObject *
builtin_setattr(PyObject *self, PyObject *args)
{
PyObject *v;
@@ -2132,6 +2171,7 @@
{"map", builtin_map, METH_VARARGS, map_doc},
{"max", (PyCFunction)builtin_max, METH_VARARGS |
METH_KEYWORDS, max_doc},
{"min", (PyCFunction)builtin_min, METH_VARARGS |
METH_KEYWORDS, min_doc},
+ {"next", (PyCFunction)builtin_next, METH_VARARGS,
next_doc},
{"oct", builtin_oct, METH_O, oct_doc},
{"open", (PyCFunction)builtin_open, METH_VARARGS |
METH_KEYWORDS, open_doc},
{"ord", builtin_ord, METH_O, ord_doc},
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