Complete the iterator interface: error handling and STL algorithms #662
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Before this, `py::iterator` didn't do any error handling, so code like:
```c++
for (auto item : py::int_(1)) {
// ...
}
```
would just silently skip the loop. The above now throws `TypeError` as
expected. This is a breaking behavior change, but any code which relied
on the silent skip was probably broken anyway.
Also, errors returned by `PyIter_Next()` are now properly handled.
The added type aliases are required by `std::iterator_traits`. Python iterators satisfy the `InputIterator` concept in C++.
Slightly reduces binary size (range for loops over tuple/list benefit a lot). The iterators are compatible with std algorithms.
* The definition of `PySequence_Fast` is more restrictive on PyPy, so use the slow path instead. * `PyDict_Next` has been fixed in PyPy -> remove workaround.
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This looks good to me. @jagerman? |
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Looks good to me. |
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Merged! Thank you, @dean0x7d |
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This PR fills in some of the missing bits in
py::iterator:PyObject_GetIterandPyIter_Nexterrors are now being handled properly.py::iteratorso that it can use used with<algorithm>. It models anInputIterator(std::input_iterator_tag) which is perfectly in line with the restrictions ofpy::iterator: copying doesn't clone the internal state, i.e. no multipass guarantee.py::iteratorworks for anypy::object, but the sequence types can get specialized implementations which are simultaneously slimmer and more capable:py::tuple,py::listget aPySequence_Fastiterator.py::sequencegets a slower but more generic sequence iterator.RandomAccessIteratorand are STL-compatible.py::dictalready had a specialized iterator. This PR just folds it in with the others. It models aForwardIterator(input + multipass).