Prefer non-converting argument overloads

This changes the function dispatching code for overloaded functions into
a two-pass procedure where we first try all overloads with
`convert=false` for all arguments.  If no function calls succeeds in the
first pass, we then try a second pass where we allow arguments to have
`convert=true` (unless, of course, the argument was explicitly specified
with `py::arg().noconvert()`).

For non-overloaded methods, the two-pass procedure is skipped (we just
make the overload-allowed call).  The second pass is also skipped if it
would result in the same thing (i.e. where all arguments are
`.noconvert()` arguments).
This commit is contained in:
Jason Rhinelander
2017-02-03 18:25:34 -05:00
parent abc29cad02
commit e550589b42
5 changed files with 138 additions and 23 deletions

View File

@@ -50,10 +50,14 @@ public:
int *internal4() { return &value; } // return by pointer
const int *internal5() { return &value; } // return by const pointer
py::str overloaded(int, float) { return "(int, float)"; }
py::str overloaded(float, int) { return "(float, int)"; }
py::str overloaded(int, float) const { return "(int, float) const"; }
py::str overloaded(float, int) const { return "(float, int) const"; }
py::str overloaded(int, float) { return "(int, float)"; }
py::str overloaded(float, int) { return "(float, int)"; }
py::str overloaded(int, int) { return "(int, int)"; }
py::str overloaded(float, float) { return "(float, float)"; }
py::str overloaded(int, float) const { return "(int, float) const"; }
py::str overloaded(float, int) const { return "(float, int) const"; }
py::str overloaded(int, int) const { return "(int, int) const"; }
py::str overloaded(float, float) const { return "(float, float) const"; }
int value = 0;
};
@@ -100,6 +104,7 @@ class CppDerivedDynamicClass : public DynamicClass { };
// py::arg/py::arg_v testing: these arguments just record their argument when invoked
class ArgInspector1 { public: std::string arg = "(default arg inspector 1)"; };
class ArgInspector2 { public: std::string arg = "(default arg inspector 2)"; };
class ArgAlwaysConverts { };
namespace pybind11 { namespace detail {
template <> struct type_caster<ArgInspector1> {
public:
@@ -131,6 +136,18 @@ public:
return str(src.arg).release();
}
};
template <> struct type_caster<ArgAlwaysConverts> {
public:
PYBIND11_TYPE_CASTER(ArgAlwaysConverts, _("ArgAlwaysConverts"));
bool load(handle, bool convert) {
return convert;
}
static handle cast(const ArgAlwaysConverts &, return_value_policy, handle) {
return py::none();
}
};
}}
test_initializer methods_and_attributes([](py::module &m) {
@@ -159,15 +176,25 @@ test_initializer methods_and_attributes([](py::module &m) {
.def("internal4", &ExampleMandA::internal4)
.def("internal5", &ExampleMandA::internal5)
#if defined(PYBIND11_OVERLOAD_CAST)
.def("overloaded", py::overload_cast<int, float>(&ExampleMandA::overloaded))
.def("overloaded", py::overload_cast<float, int>(&ExampleMandA::overloaded))
.def("overloaded_const", py::overload_cast<int, float>(&ExampleMandA::overloaded, py::const_))
.def("overloaded_const", py::overload_cast<float, int>(&ExampleMandA::overloaded, py::const_))
.def("overloaded", py::overload_cast<int, float>(&ExampleMandA::overloaded))
.def("overloaded", py::overload_cast<float, int>(&ExampleMandA::overloaded))
.def("overloaded", py::overload_cast<int, int>(&ExampleMandA::overloaded))
.def("overloaded", py::overload_cast<float, float>(&ExampleMandA::overloaded))
.def("overloaded_float", py::overload_cast<float, float>(&ExampleMandA::overloaded))
.def("overloaded_const", py::overload_cast<int, float>(&ExampleMandA::overloaded, py::const_))
.def("overloaded_const", py::overload_cast<float, int>(&ExampleMandA::overloaded, py::const_))
.def("overloaded_const", py::overload_cast<int, int>(&ExampleMandA::overloaded, py::const_))
.def("overloaded_const", py::overload_cast<float, float>(&ExampleMandA::overloaded, py::const_))
#else
.def("overloaded", static_cast<py::str (ExampleMandA::*)(int, float)>(&ExampleMandA::overloaded))
.def("overloaded", static_cast<py::str (ExampleMandA::*)(float, int)>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int, float) const>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(float, int) const>(&ExampleMandA::overloaded))
.def("overloaded", static_cast<py::str (ExampleMandA::*)(int, float)>(&ExampleMandA::overloaded))
.def("overloaded", static_cast<py::str (ExampleMandA::*)(float, int)>(&ExampleMandA::overloaded))
.def("overloaded", static_cast<py::str (ExampleMandA::*)(int, int)>(&ExampleMandA::overloaded))
.def("overloaded", static_cast<py::str (ExampleMandA::*)(float, float)>(&ExampleMandA::overloaded))
.def("overloaded_float", static_cast<py::str (ExampleMandA::*)(float, float)>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int, float) const>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(float, int) const>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(int, int) const>(&ExampleMandA::overloaded))
.def("overloaded_const", static_cast<py::str (ExampleMandA::*)(float, float) const>(&ExampleMandA::overloaded))
#endif
.def("__str__", &ExampleMandA::toString)
.def_readwrite("value", &ExampleMandA::value);
@@ -220,22 +247,25 @@ test_initializer methods_and_attributes([](py::module &m) {
.def(py::init());
#endif
// Test converting. The ArgAlwaysConverts is just there to make the first no-conversion pass
// fail so that our call always ends up happening via the second dispatch (the one that allows
// some conversion).
class ArgInspector {
public:
ArgInspector1 f(ArgInspector1 a) { return a; }
std::string g(ArgInspector1 a, const ArgInspector1 &b, int c, ArgInspector2 *d) {
ArgInspector1 f(ArgInspector1 a, ArgAlwaysConverts) { return a; }
std::string g(ArgInspector1 a, const ArgInspector1 &b, int c, ArgInspector2 *d, ArgAlwaysConverts) {
return a.arg + "\n" + b.arg + "\n" + std::to_string(c) + "\n" + d->arg;
}
static ArgInspector2 h(ArgInspector2 a) { return a; }
static ArgInspector2 h(ArgInspector2 a, ArgAlwaysConverts) { return a; }
};
py::class_<ArgInspector>(m, "ArgInspector")
.def(py::init<>())
.def("f", &ArgInspector::f)
.def("g", &ArgInspector::g, "a"_a.noconvert(), "b"_a, "c"_a.noconvert()=13, "d"_a=ArgInspector2())
.def_static("h", &ArgInspector::h, py::arg().noconvert())
.def("f", &ArgInspector::f, py::arg(), py::arg() = ArgAlwaysConverts())
.def("g", &ArgInspector::g, "a"_a.noconvert(), "b"_a, "c"_a.noconvert()=13, "d"_a=ArgInspector2(), py::arg() = ArgAlwaysConverts())
.def_static("h", &ArgInspector::h, py::arg().noconvert(), py::arg() = ArgAlwaysConverts())
;
m.def("arg_inspect_func", [](ArgInspector2 a, ArgInspector1 b) { return a.arg + "\n" + b.arg; },
py::arg().noconvert(false), py::arg_v(nullptr, ArgInspector1()).noconvert(true));
m.def("arg_inspect_func", [](ArgInspector2 a, ArgInspector1 b, ArgAlwaysConverts) { return a.arg + "\n" + b.arg; },
py::arg().noconvert(false), py::arg_v(nullptr, ArgInspector1()).noconvert(true), py::arg() = ArgAlwaysConverts());
m.def("floats_preferred", [](double f) { return 0.5 * f; }, py::arg("f"));
m.def("floats_only", [](double f) { return 0.5 * f; }, py::arg("f").noconvert());