void init_ex6(py::module &m) {
py::class_<Sequence> seq(m, "Sequence");
seq.def(py::init<size_t>())
.def(py::init<const std::vector<float>&>())
/// Bare bones interface
.def("__getitem__", [](const Sequence &s, size_t i) {
if (i >= s.size())
throw py::index_error();
return s[i];
})
.def("__setitem__", [](Sequence &s, size_t i, float v) {
if (i >= s.size())
throw py::index_error();
s[i] = v;
})
.def("__len__", &Sequence::size)
/// Optional sequence protocol operations
.def("__iter__", [](py::object s) { return PySequenceIterator(s.cast<const Sequence &>(), s); })
.def("__contains__", [](const Sequence &s, float v) { return s.contains(v); })
.def("__reversed__", [](const Sequence &s) -> Sequence { return s.reversed(); })
/// Slicing protocol (optional)
.def("__getitem__", [](const Sequence &s, py::slice slice) -> Sequence* {
py::ssize_t start, stop, step, slicelength;
if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
throw py::error_already_set();
Sequence *seq = new Sequence(slicelength);
for (int i=0; i<slicelength; ++i) {
(*seq)[i] = s[start]; start += step;
}
return seq;
})
.def("__setitem__", [](Sequence &s, py::slice slice, const Sequence &value) {
py::ssize_t start, stop, step, slicelength;
if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
throw py::error_already_set();
if ((size_t) slicelength != value.size())
throw std::runtime_error("Left and right hand size of slice assignment have different sizes!");
for (int i=0; i<slicelength; ++i) {
s[start] = value[i]; start += step;
}
})
/// Comparisons
.def(py::self == py::self)
.def(py::self != py::self);
// Could also define py::self + py::self for concatenation, etc.
py::class_<PySequenceIterator>(seq, "Iterator")
.def("__iter__", [](PySequenceIterator &it) -> PySequenceIterator& { return it; })
.def("__next__", &PySequenceIterator::next);
}
void init_ex_sequences_and_iterators(py::module &m) {
py::class_<Sequence> seq(m, "Sequence");
seq.def(py::init<size_t>())
.def(py::init<const std::vector<float>&>())
/// Bare bones interface
.def("__getitem__", [](const Sequence &s, size_t i) {
if (i >= s.size())
throw py::index_error();
return s[i];
})
.def("__setitem__", [](Sequence &s, size_t i, float v) {
if (i >= s.size())
throw py::index_error();
s[i] = v;
})
.def("__len__", &Sequence::size)
/// Optional sequence protocol operations
.def("__iter__", [](const Sequence &s) { return py::make_iterator(s.begin(), s.end()); },
py::keep_alive<0, 1>() /* Essential: keep object alive while iterator exists */)
.def("__contains__", [](const Sequence &s, float v) { return s.contains(v); })
.def("__reversed__", [](const Sequence &s) -> Sequence { return s.reversed(); })
/// Slicing protocol (optional)
.def("__getitem__", [](const Sequence &s, py::slice slice) -> Sequence* {
size_t start, stop, step, slicelength;
if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
throw py::error_already_set();
Sequence *seq = new Sequence(slicelength);
for (size_t i=0; i<slicelength; ++i) {
(*seq)[i] = s[start]; start += step;
}
return seq;
})
.def("__setitem__", [](Sequence &s, py::slice slice, const Sequence &value) {
size_t start, stop, step, slicelength;
if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
throw py::error_already_set();
if (slicelength != value.size())
throw std::runtime_error("Left and right hand size of slice assignment have different sizes!");
for (size_t i=0; i<slicelength; ++i) {
s[start] = value[i]; start += step;
}
})
/// Comparisons
.def(py::self == py::self)
.def(py::self != py::self);
// Could also define py::self + py::self for concatenation, etc.
#if 0
// Obsolete: special data structure for exposing custom iterator types to python
// kept here for illustrative purposes because there might be some use cases which
// are not covered by the much simpler py::make_iterator
struct PySequenceIterator {
PySequenceIterator(const Sequence &seq, py::object ref) : seq(seq), ref(ref) { }
float next() {
if (index == seq.size())
throw py::stop_iteration();
return seq[index++];
}
const Sequence &seq;
py::object ref; // keep a reference
size_t index = 0;
};
py::class_<PySequenceIterator>(seq, "Iterator")
.def("__iter__", [](PySequenceIterator &it) -> PySequenceIterator& { return it; })
.def("__next__", &PySequenceIterator::next);
On the actual Sequence object, the iterator would be constructed as follows:
.def("__iter__", [](py::object s) { return PySequenceIterator(s.cast<const Sequence &>(), s); })
#endif
}
