On 3/6/07, Georg Brandl <[EMAIL PROTECTED]> wrote:
> 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;
> +}
http://docs.python.org/dev/api/type-structs.html#l2h-1017 doesn't say
that a NULL return can be used as a signal that iterator is exhausted
without raising StopIteration. That would mean the above could be
simplified somewhat in terms of return value checking.
-Brett
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