pybind11/tests/test_kwargs_and_defaults.cpp
Dean Moldovan c743e1b1b4 Support keyword arguments and generalized unpacking in C++
A Python function can be called with the syntax:
```python
foo(a1, a2, *args, ka=1, kb=2, **kwargs)
```
This commit adds support for the equivalent syntax in C++:
```c++
foo(a1, a2, *args, "ka"_a=1, "kb"_a=2, **kwargs)
```

In addition, generalized unpacking is implemented, as per PEP 448,
which allows calls with multiple * and ** unpacking:
```python
bar(*args1, 99, *args2, 101, **kwargs1, kz=200, **kwargs2)
```
and
```c++
bar(*args1, 99, *args2, 101, **kwargs1, "kz"_a=200, **kwargs2)
```
2016-09-06 16:41:50 +02:00

66 lines
1.9 KiB
C++

/*
tests/test_kwargs_and_defaults.cpp -- keyword arguments and default values
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#include "pybind11_tests.h"
#include <pybind11/stl.h>
std::string kw_func(int x, int y) { return "x=" + std::to_string(x) + ", y=" + std::to_string(y); }
std::string kw_func4(const std::vector<int> &entries) {
std::string ret = "{";
for (int i : entries)
ret += std::to_string(i) + " ";
ret.back() = '}';
return ret;
}
py::object call_kw_func(py::function f) {
py::tuple args = py::make_tuple(1234);
py::dict kwargs;
kwargs["y"] = py::cast(5678);
return f(*args, **kwargs);
}
py::tuple args_function(py::args args) {
return args;
}
py::tuple args_kwargs_function(py::args args, py::kwargs kwargs) {
return py::make_tuple(args, kwargs);
}
struct KWClass {
void foo(int, float) {}
};
test_initializer arg_keywords_and_defaults([](py::module &m) {
m.def("kw_func0", &kw_func);
m.def("kw_func1", &kw_func, py::arg("x"), py::arg("y"));
m.def("kw_func2", &kw_func, py::arg("x") = 100, py::arg("y") = 200);
m.def("kw_func3", [](const char *) { }, py::arg("data") = std::string("Hello world!"));
/* A fancier default argument */
std::vector<int> list;
list.push_back(13);
list.push_back(17);
m.def("kw_func4", &kw_func4, py::arg("myList") = list);
m.def("call_kw_func", &call_kw_func);
m.def("args_function", &args_function);
m.def("args_kwargs_function", &args_kwargs_function);
m.def("kw_func_udl", &kw_func, "x"_a, "y"_a=300);
m.def("kw_func_udl_z", &kw_func, "x"_a, "y"_a=0);
py::class_<KWClass>(m, "KWClass")
.def("foo0", &KWClass::foo)
.def("foo1", &KWClass::foo, "x"_a, "y"_a);
});