main.cpp

/**
 * This file contains the pybind11 reference implementation for the stugen tests,
 * and was originally inspired by:
 *
 * https://github.com/sizmailov/pybind11-mypy-demo
 *
 * Copyright (c) 2016 The Pybind Development Team, All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * You are under no obligation whatsoever to provide any bug fixes, patches, or
 * upgrades to the features, functionality or performance of the source code
 * ("Enhancements") to anyone; however, if you choose to make your Enhancements
 * available either publicly, or directly to the author of this software, without
 * imposing a separate written license agreement for such Enhancements, then you
 * hereby grant the following license: a non-exclusive, royalty-free perpetual
 * license to install, use, modify, prepare derivative works, incorporate into
 * other computer software, distribute, and sublicense such enhancements or
 * derivative works thereof, in binary and source code form.
 */

#include <cmath>
#include <filesystem>
#include <optional>
#include <utility>
#include <vector>

#include <pybind11/pybind11.h>
#include <pybind11/stl.h>
#include <pybind11/stl/filesystem.h>

namespace py = pybind11;

// ----------------------------------------------------------------------------
// Dedicated test cases
// ----------------------------------------------------------------------------

std::vector<float> funcReturningVector()
{
  return std::vector<float>{1.0, 2.0, 3.0};
}

std::pair<int, float> funcReturningPair()
{
  return std::pair{42, 1.0};
}

std::optional<int> funcReturningOptional()
{
  return std::nullopt;
}

std::filesystem::path funcReturningPath()
{
  return std::filesystem::path{"foobar"};
}

namespace dummy_sub_namespace {
  struct HasNoBinding{};
}

// We can enforce the case of an incomplete signature by referring to a type in
// some namespace that doesn't have a pybind11 binding.
dummy_sub_namespace::HasNoBinding funcIncompleteSignature()
{
  return dummy_sub_namespace::HasNoBinding{};
}

struct TestStruct
{
  int field_readwrite;
  int field_readwrite_docstring;
  int field_readonly;
};

struct StaticMethods
{
  static int some_static_method(int a, int b) { return 42; }
  static int overloaded_static_method(int value) { return 42; }
  static double overloaded_static_method(double value) { return 1.0; }
};

// Bindings

void bind_test_cases(py::module& m) {
  m.def("func_returning_vector", &funcReturningVector);
  m.def("func_returning_pair", &funcReturningPair);
  m.def("func_returning_optional", &funcReturningOptional);
  m.def("func_returning_path", &funcReturningPath);

  m.def("func_incomplete_signature", &funcIncompleteSignature);

  py::class_<TestStruct>(m, "TestStruct")
      .def_readwrite("field_readwrite", &TestStruct::field_readwrite)
      .def_readwrite("field_readwrite_docstring", &TestStruct::field_readwrite_docstring, "some docstring")
      .def_property_readonly(
          "field_readonly",
          [](const TestStruct& x) {
            return x.field_readonly;
          },
          "some docstring");

  // Static methods
  py::class_<StaticMethods> pyStaticMethods(m, "StaticMethods");

  pyStaticMethods
    .def_static(
      "some_static_method",
      &StaticMethods::some_static_method, R"#(None)#", py::arg("a"), py::arg("b"))
    .def_static(
      "overloaded_static_method",
      py::overload_cast<int>(&StaticMethods::overloaded_static_method), py::arg("value"))
    .def_static(
      "overloaded_static_method",
      py::overload_cast<double>(&StaticMethods::overloaded_static_method), py::arg("value"));
}

// ----------------------------------------------------------------------------
// Original demo
// ----------------------------------------------------------------------------

namespace demo {

int answer() {
  return 42;
}

int sum(int a, int b) {
  return a + b;
}

double midpoint(double left, double right){
  return left + (right - left)/2;
}

double weighted_midpoint(double left, double right, double alpha=0.5) {
  return left + (right - left) * alpha;
}

struct Point {

  enum class LengthUnit {
    mm=0,
    pixel,
    inch
  };

  enum class AngleUnit {
    radian=0,
    degree
  };

  Point() : Point(0, 0) {}
  Point(double x, double y) : x(x), y(y) {}

  static const Point origin;
  static const Point x_axis;
  static const Point y_axis;

  static LengthUnit length_unit;
  static AngleUnit angle_unit;

  double length() const {
    return std::sqrt(x * x + y * y);
  }

  double distance_to(double other_x, double other_y) const {
    double dx = x - other_x;
    double dy = y - other_y;
    return std::sqrt(dx*dx + dy*dy);
  }

  double distance_to(const Point& other) const {
    return distance_to(other.x, other.y);
  }

  std::vector<double> as_vector()
  {
    return std::vector<double>{x, y};
  }

  double x, y;
};

const Point Point::origin = Point(0, 0);
const Point Point::x_axis = Point(1, 0);
const Point Point::y_axis = Point(0, 1);

Point::LengthUnit Point::length_unit = Point::LengthUnit::mm;
Point::AngleUnit Point::angle_unit = Point::AngleUnit::radian;

} // namespace: demo

// Bindings

void bind_demo(py::module& m) {

  using namespace demo;

  // Functions
  m.def("answer", &answer, "answer docstring, with end quote\""); // tests explicit docstrings
  m.def("sum", &sum, "multiline docstring test, edge case quotes \"\"\"'''");
  m.def("midpoint", &midpoint, py::arg("left"), py::arg("right"));
  m.def("weighted_midpoint", weighted_midpoint, py::arg("left"), py::arg("right"), py::arg("alpha")=0.5);

  // Classes
  py::class_<Point> pyPoint(m, "Point");
  py::enum_<Point::LengthUnit> pyLengthUnit(pyPoint, "LengthUnit");
  py::enum_<Point::AngleUnit> pyAngleUnit(pyPoint, "AngleUnit");

  pyPoint
    .def(py::init<>())
    .def(py::init<double, double>(), py::arg("x"), py::arg("y"))
    .def("distance_to", py::overload_cast<double, double>(&Point::distance_to, py::const_), py::arg("x"), py::arg("y"))
    .def("distance_to", py::overload_cast<const Point&>(&Point::distance_to, py::const_), py::arg("other"))
    .def("as_list", &Point::as_vector)
    .def_readwrite("x", &Point::x, "some docstring")
    .def_property("y",
        [](Point& self){ return self.y; },
        [](Point& self, double value){ self.y = value; }
    )
    .def_property_readonly("length", &Point::length)
    .def_property_readonly_static("x_axis", [](py::object cls){return Point::x_axis;})
    .def_property_readonly_static("y_axis", [](py::object cls){return Point::y_axis;}, "another docstring")
    .def_readwrite_static("length_unit", &Point::length_unit)
    .def_property_static("angle_unit",
        [](py::object& /*cls*/){ return Point::angle_unit; },
        [](py::object& /*cls*/, Point::AngleUnit value){ Point::angle_unit = value; }
     );

  pyPoint.attr("origin") = Point::origin;

  pyLengthUnit
    .value("mm", Point::LengthUnit::mm)
    .value("pixel", Point::LengthUnit::pixel)
    .value("inch", Point::LengthUnit::inch);

  pyAngleUnit
    .value("radian", Point::AngleUnit::radian)
    .value("degree", Point::AngleUnit::degree);

  // Module-level attributes
  m.attr("PI") = std::acos(-1);
  m.attr("__version__") = "0.0.1";
}

// ----------------------------------------------------------------------------
// Module entry point
// ----------------------------------------------------------------------------

PYBIND11_MODULE(pybind11_fixtures, m) {
  bind_test_cases(m);

  auto demo = m.def_submodule("demo");
  bind_demo(demo);
}