pybind11/tests/test_kwargs_and_defaults.cpp
Jason Rhinelander 2686da8350 Add support for positional args with args/kwargs
This commit rewrites the function dispatcher code to support mixing
regular arguments with py::args/py::kwargs arguments.  It also
simplifies the argument loader noticeably as it no longer has to worry
about args/kwargs: all of that is now sorted out in the dispatcher,
which now simply appends a tuple/dict if the function takes
py::args/py::kwargs, then passes all the arguments in a vector.

When the argument loader hit a py::args or py::kwargs, it doesn't do
anything special: it just calls the appropriate type_caster just like it
does for any other argument (thus removing the previous special cases
for args/kwargs).

Switching to passing arguments in a single std::vector instead of a pair
of tuples also makes things simpler, both in the dispatch and the
argument_loader: since this argument list is strictly pybind-internal
(i.e. it never goes to Python) we have no particular reason to use a
Python tuple here.

Some (intentional) restrictions:
- you may not bind a function that has args/kwargs somewhere other than
  the end (this somewhat matches Python, and keeps the dispatch code a
  little cleaner by being able to not worry about where to inject the
  args/kwargs in the argument list).
- If you specify an argument both positionally and via a keyword
  argument, you get a TypeError alerting you to this (as you do in
  Python).
2017-01-31 17:24:41 +01:00

94 lines
3.0 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::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);
}
py::tuple mixed_plus_args(int i, double j, py::args args) {
return py::make_tuple(i, j, args);
}
py::tuple mixed_plus_kwargs(int i, double j, py::kwargs kwargs) {
return py::make_tuple(i, j, kwargs);
}
py::tuple mixed_plus_args_kwargs(int i, double j, py::args args, py::kwargs kwargs) {
return py::make_tuple(i, j, args, kwargs);
}
// pybind11 won't allow these to be bound: args and kwargs, if present, must be at the end.
void bad_args1(py::args, int) {}
void bad_args2(py::kwargs, int) {}
void bad_args3(py::kwargs, py::args) {}
void bad_args4(py::args, int, py::kwargs) {}
void bad_args5(py::args, py::kwargs, int) {}
void bad_args6(py::args, py::args) {}
void bad_args7(py::kwargs, py::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("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);
m.def("mixed_plus_args", &mixed_plus_args);
m.def("mixed_plus_kwargs", &mixed_plus_kwargs);
m.def("mixed_plus_args_kwargs", &mixed_plus_args_kwargs);
m.def("mixed_plus_args_kwargs_defaults", &mixed_plus_args_kwargs,
py::arg("i") = 1, py::arg("j") = 3.14159);
// Uncomment these to test that the static_assert is indeed working:
// m.def("bad_args1", &bad_args1);
// m.def("bad_args2", &bad_args2);
// m.def("bad_args3", &bad_args3);
// m.def("bad_args4", &bad_args4);
// m.def("bad_args5", &bad_args5);
// m.def("bad_args6", &bad_args6);
// m.def("bad_args7", &bad_args7);
});