迭代器協(xié)議?

迭代器有兩個(gè)函數(shù)。

int PyIter_Check(PyObject *o)?

Part of the Stable ABI since version 3.8.

Return non-zero if the object o can be safely passed to PyIter_Next(), and 0 otherwise. This function always succeeds.

int PyAIter_Check(PyObject *o)?

Part of the Stable ABI since version 3.10.

Return non-zero if the object o provides the AsyncIterator protocol, and 0 otherwise. This function always succeeds.

3.10 新版功能.

PyObject *PyIter_Next(PyObject *o)?

Return value: New reference. Part of the Stable ABI.

Return the next value from the iterator o. The object must be an iterator according to PyIter_Check() (it is up to the caller to check this). If there are no remaining values, returns NULL with no exception set. If an error occurs while retrieving the item, returns NULL and passes along the exception.

要為迭代器編寫一個(gè)一個(gè)循環(huán)，C代碼應(yīng)該看起來像這樣

PyObject *iterator = PyObject_GetIter(obj);
PyObject *item;

if (iterator == NULL) {
    /* propagate error */
}

while ((item = PyIter_Next(iterator))) {
    /* do something with item */
    ...
    /* release reference when done */
    Py_DECREF(item);
}

Py_DECREF(iterator);

if (PyErr_Occurred()) {
    /* propagate error */
}
else {
    /* continue doing useful work */
}

type PySendResult?

用于代表 PyIter_Send() 的不同結(jié)果的枚舉值。

3.10 新版功能.

PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)?

Part of the Stable ABI since version 3.10.

將 arg 值發(fā)送到迭代器 iter。 返回:

• PYGEN_RETURN，如果迭代器返回的話。 返回值會(huì)通過 presult 來返回。

• PYGEN_NEXT，如果迭代器生成值的話。 生成的值會(huì)通過 presult 來返回。

• PYGEN_ERROR，如果迭代器引發(fā)異常的話。 presult 會(huì)被設(shè)為 NULL。

3.10 新版功能.