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315fc52db1
I think that none of these API calls can fail, but only few of them are documented as such. Add the sentence "This function always succeeds" (which is the same already used e.g. by PyNumber_Check) to all of them.
65 lines
1.7 KiB
ReStructuredText
65 lines
1.7 KiB
ReStructuredText
.. highlight:: c
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.. _iterator:
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Iterator Protocol
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=================
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There are two functions specifically for working with iterators.
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.. c:function:: int PyIter_Check(PyObject *o)
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Return true if the object *o* supports the iterator protocol. This
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function always succeeds.
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.. c:function:: PyObject* PyIter_Next(PyObject *o)
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Return the next value from the iteration *o*. The object must be an iterator
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(it is up to the caller to check this). If there are no remaining values,
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returns ``NULL`` with no exception set. If an error occurs while retrieving
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the item, returns ``NULL`` and passes along the exception.
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To write a loop which iterates over an iterator, the C code should look
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something like this::
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PyObject *iterator = PyObject_GetIter(obj);
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PyObject *item;
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if (iterator == NULL) {
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/* propagate error */
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}
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while ((item = PyIter_Next(iterator))) {
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/* do something with item */
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...
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/* release reference when done */
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Py_DECREF(item);
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}
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Py_DECREF(iterator);
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if (PyErr_Occurred()) {
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/* propagate error */
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}
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else {
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/* continue doing useful work */
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}
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.. c:type:: PySendResult
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The enum value used to represent different results of :c:func:`PyIter_Send`.
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.. versionadded:: 3.10
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.. c:function:: PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)
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Sends the *arg* value into the iterator *iter*. Returns:
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- ``PYGEN_RETURN`` if iterator returns. Return value is returned via *presult*.
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- ``PYGEN_NEXT`` if iterator yields. Yielded value is returned via *presult*.
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- ``PYGEN_ERROR`` if iterator has raised and exception. *presult* is set to ``NULL``.
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.. versionadded:: 3.10
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