pybind11/tests/test_docs_advanced_cast_custom.cpp
Tim Ohliger 1d09fc8300
Option for arg/return type hints and correct typing for std::filesystem::path (#5450)
* Added arg/return type handling.

* Added support for nested arg/return type in py::typing::List

* Added support for arg/return type in stl/filesystem

* Added tests for arg/return type in stl/filesystem and py::typing::List

* Added arg/return name to more py::typing classes

* Added arg/return type to Callable[...]

* Added tests for typing container classes (also nested)

* Changed typing classes to avoid using C++14 auto return type deduction.

* Fixed clang-tidy errors.

* Changed Enable to SFINAE

* Added test for Tuple[T, ...]

* Added RealNumber with custom caster for testing typing classes.

* Added tests for Set, Iterable, Iterator, Union, and Optional

* Added tests for Callable

* Fixed Callable with ellipsis test

* Changed TypeGuard/TypeIs to use return type (being the narrower type) + Tests

* Added test for use of fallback type name with stl vector

* Updated documentation.

* Fixed unnecessary constructor call in test.

* Fixed reference counting in example type caster.

* Fixed clang-tidy issues.

* Fix for clang-tidy

* Updated cast method to use pybind11 API rather than Python C API in custom caster example

* Updated load to use pybind11 API rather than Python C API in custom caster example

* Changed test of arg/return name to use pybind11 API instead of Python C API

* Updated code in adcanced/cast example and improved documentation text

* Fixed references in custom type caster docs

* Fixed wrong logical and operator in test

* Fixed wrong logical operator in doc example

* Added comment to test about `float` vs `float | int`

* Updated std::filesystem::path docs in cast/overview section

* Remove one stray dot.

---------

Co-authored-by: Ralf W. Grosse-Kunstleve <rgrossekunst@nvidia.com>
2024-12-08 11:30:49 -08:00

71 lines
2.7 KiB
C++

// #########################################################################
// PLEASE UPDATE docs/advanced/cast/custom.rst IF ANY CHANGES ARE MADE HERE.
// #########################################################################
#include "pybind11_tests.h"
namespace user_space {
struct Point2D {
double x;
double y;
};
Point2D negate(const Point2D &point) { return Point2D{-point.x, -point.y}; }
} // namespace user_space
namespace pybind11 {
namespace detail {
template <>
struct type_caster<user_space::Point2D> {
// This macro inserts a lot of boilerplate code and sets the default type hint to `tuple`
PYBIND11_TYPE_CASTER(user_space::Point2D, const_name("tuple"));
// `arg_name` and `return_name` may optionally be used to specify type hints separately for
// arguments and return values.
// The signature of our negate function would then look like:
// `negate(Sequence[float]) -> tuple[float, float]`
static constexpr auto arg_name = const_name("Sequence[float]");
static constexpr auto return_name = const_name("tuple[float, float]");
// C++ -> Python: convert `Point2D` to `tuple[float, float]`. The second and third arguments
// are used to indicate the return value policy and parent object (for
// return_value_policy::reference_internal) and are often ignored by custom casters.
// The return value should reflect the type hint specified by `return_name`.
static handle
cast(const user_space::Point2D &number, return_value_policy /*policy*/, handle /*parent*/) {
return py::make_tuple(number.x, number.y).release();
}
// Python -> C++: convert a `PyObject` into a `Point2D` and return false upon failure. The
// second argument indicates whether implicit conversions should be allowed.
// The accepted types should reflect the type hint specified by `arg_name`.
bool load(handle src, bool /*convert*/) {
// Check if handle is a Sequence
if (!py::isinstance<py::sequence>(src)) {
return false;
}
auto seq = py::reinterpret_borrow<py::sequence>(src);
// Check if exactly two values are in the Sequence
if (seq.size() != 2) {
return false;
}
// Check if each element is either a float or an int
for (auto item : seq) {
if (!py::isinstance<py::float_>(item) && !py::isinstance<py::int_>(item)) {
return false;
}
}
value.x = seq[0].cast<double>();
value.y = seq[1].cast<double>();
return true;
}
};
} // namespace detail
} // namespace pybind11
// Bind the negate function
TEST_SUBMODULE(docs_advanced_cast_custom, m) { m.def("negate", user_space::negate); }