test_kwargs_and_defaults.cpp revision 14299:2fbea9df56d2 
1/*
2    tests/test_kwargs_and_defaults.cpp -- keyword arguments and default values
3
4    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
5
6    All rights reserved. Use of this source code is governed by a
7    BSD-style license that can be found in the LICENSE file.
8*/
9
10#include "pybind11_tests.h"
11#include "constructor_stats.h"
12#include <pybind11/stl.h>
13
14TEST_SUBMODULE(kwargs_and_defaults, m) {
15    auto kw_func = [](int x, int y) { return "x=" + std::to_string(x) + ", y=" + std::to_string(y); };
16
17    // test_named_arguments
18    m.def("kw_func0", kw_func);
19    m.def("kw_func1", kw_func, py::arg("x"), py::arg("y"));
20    m.def("kw_func2", kw_func, py::arg("x") = 100, py::arg("y") = 200);
21    m.def("kw_func3", [](const char *) { }, py::arg("data") = std::string("Hello world!"));
22
23    /* A fancier default argument */
24    std::vector<int> list{{13, 17}};
25    m.def("kw_func4", [](const std::vector<int> &entries) {
26        std::string ret = "{";
27        for (int i : entries)
28            ret += std::to_string(i) + " ";
29        ret.back() = '}';
30        return ret;
31    }, py::arg("myList") = list);
32
33    m.def("kw_func_udl", kw_func, "x"_a, "y"_a=300);
34    m.def("kw_func_udl_z", kw_func, "x"_a, "y"_a=0);
35
36    // test_args_and_kwargs
37    m.def("args_function", [](py::args args) -> py::tuple {
38        return std::move(args);
39    });
40    m.def("args_kwargs_function", [](py::args args, py::kwargs kwargs) {
41        return py::make_tuple(args, kwargs);
42    });
43
44    // test_mixed_args_and_kwargs
45    m.def("mixed_plus_args", [](int i, double j, py::args args) {
46        return py::make_tuple(i, j, args);
47    });
48    m.def("mixed_plus_kwargs", [](int i, double j, py::kwargs kwargs) {
49        return py::make_tuple(i, j, kwargs);
50    });
51    auto mixed_plus_both = [](int i, double j, py::args args, py::kwargs kwargs) {
52        return py::make_tuple(i, j, args, kwargs);
53    };
54    m.def("mixed_plus_args_kwargs", mixed_plus_both);
55
56    m.def("mixed_plus_args_kwargs_defaults", mixed_plus_both,
57            py::arg("i") = 1, py::arg("j") = 3.14159);
58
59    // test_args_refcount
60    // PyPy needs a garbage collection to get the reference count values to match CPython's behaviour
61    #ifdef PYPY_VERSION
62    #define GC_IF_NEEDED ConstructorStats::gc()
63    #else
64    #define GC_IF_NEEDED
65    #endif
66    m.def("arg_refcount_h", [](py::handle h) { GC_IF_NEEDED; return h.ref_count(); });
67    m.def("arg_refcount_h", [](py::handle h, py::handle, py::handle) { GC_IF_NEEDED; return h.ref_count(); });
68    m.def("arg_refcount_o", [](py::object o) { GC_IF_NEEDED; return o.ref_count(); });
69    m.def("args_refcount", [](py::args a) {
70        GC_IF_NEEDED;
71        py::tuple t(a.size());
72        for (size_t i = 0; i < a.size(); i++)
73            // Use raw Python API here to avoid an extra, intermediate incref on the tuple item:
74            t[i] = (int) Py_REFCNT(PyTuple_GET_ITEM(a.ptr(), static_cast<ssize_t>(i)));
75        return t;
76    });
77    m.def("mixed_args_refcount", [](py::object o, py::args a) {
78        GC_IF_NEEDED;
79        py::tuple t(a.size() + 1);
80        t[0] = o.ref_count();
81        for (size_t i = 0; i < a.size(); i++)
82            // Use raw Python API here to avoid an extra, intermediate incref on the tuple item:
83            t[i + 1] = (int) Py_REFCNT(PyTuple_GET_ITEM(a.ptr(), static_cast<ssize_t>(i)));
84        return t;
85    });
86
87    // pybind11 won't allow these to be bound: args and kwargs, if present, must be at the end.
88    // Uncomment these to test that the static_assert is indeed working:
89//    m.def("bad_args1", [](py::args, int) {});
90//    m.def("bad_args2", [](py::kwargs, int) {});
91//    m.def("bad_args3", [](py::kwargs, py::args) {});
92//    m.def("bad_args4", [](py::args, int, py::kwargs) {});
93//    m.def("bad_args5", [](py::args, py::kwargs, int) {});
94//    m.def("bad_args6", [](py::args, py::args) {});
95//    m.def("bad_args7", [](py::kwargs, py::kwargs) {});
96
97    // test_function_signatures (along with most of the above)
98    struct KWClass { void foo(int, float) {} };
99    py::class_<KWClass>(m, "KWClass")
100        .def("foo0", &KWClass::foo)
101        .def("foo1", &KWClass::foo, "x"_a, "y"_a);
102}
103