float TreeInfer(float* x, Node* nodes) {
   int idx = 0;
   idx = nodes->children[x[nodes[idx].fIdx] > nodes[idx].threshold];
   idx = nodes->children[x[nodes[idx].fIdx] > nodes[idx].threshold];
   ...
   return nodes[idx].score;
}

#include <pybind11/pybind11.h>
namespace py = pybind11;

struct Pet {
    Pet(const std::string &name) : name(name) { }
    void setName(const std::string &name_) { name = name_; }
    const std::string &getName() const { return name; }

    std::string name;
};

PYBIND11_MODULE(example, m) {
    py::class_<Pet>(m, "Pet")
        .def(py::init<const std::string &>())
        .def("setName", &Pet::setName)
        .def("getName", &Pet::getName);
}

#include <pybind11/pybind11.h>

int add(int i, int j) {
  return i + j;
}

PYBIND11_MODULE(example, m) {
  //m.def("add", &add, "A function which adds two numbers");
  // 变为关键字参数
  m.def("add", &add, "A function which adds two numbers", py::arg("i"), py::arg("j"));
}
// python调用：example.add(i=1,  j=2)

PYBIND11_MODULE(example, m) {
  // 设置参数默认值
  m.def("add", &add, "A function which adds two numbers", py::arg("i") = 1, py::arg("j") = 2);
}

py::class_<Pet>(m, "Pet")
    .def(py::init<const std::string &>())
    .def("setName", &Pet::setName)
    .def("getName", &Pet::getName)
    .def("__repr__",
        [](const Pet &a) {
            return "<example.Pet named '" + a.name + "'>";
        }
    );

PYBIND11_MODULE(example, m) {
    py::class_<Pet>(m, "Pet")
        .def(py::init<const std::string &>())
        .def("setName", &Pet::setName)
        .def("getName", &Pet::getName)
        .def_readwrite("name", &Pet::name); //公有非const成员变量
}
// Python中调用：
// >>> p = example.Pet("Molly")
// >>> p.name
// >>> p.name = "Charly"

py::class_<Pet>(m, "Pet")
  .def(py::init<const std::string &>())
  .def_property("name", &Pet::getName, &Pet::setName);
  ...

// py::dynamic_attr()支持动态属性
py::class_<Pet>(m, "Pet", py::dynamic_attr())
    .def(py::init<>())
    .def_readwrite("name", &Pet::name);

// Python中动态向Pet添加属性
// >>> p = example.Pet()
// >>> p.name = "charly"
// >>> p.age = 2 # 动态添加age属性

struct Pet {
    Pet(const std::string &name) : name(name) { }
    std::string name;
};

struct Dog : Pet {
    Dog(const std::string &name) : Pet(name) { }
    std::string bark() const { return "woof!"; }
};

py::class_<Pet>(m, "Pet")
   .def(py::init<const std::string &>())
   .def_readwrite("name", &Pet::name);

// Method 1: template parameter:
py::class_<Dog, Pet /* <- specify C++ parent type */>(m, "Dog")
    .def(py::init<const std::string &>())
    .def("bark", &Dog::bark);

py::class_<Pet> pet(m, "Pet");
pet.def(py::init<const std::string &>())
   .def_readwrite("name", &Pet::name);

// Method 2: pass parent class_ object:
py::class_<Dog>(m, "Dog", pet /* <- specify Python parent type */)
    .def(py::init<const std::string &>())
    .def("bark", &Dog::bark);

struct PolymorphicPet {
    virtual ~PolymorphicPet() = default;
};

struct PolymorphicDog : PolymorphicPet {
    std::string bark() const { return "woof!"; }
};

// Same binding code
py::class_<PolymorphicPet>(m, "PolymorphicPet");
py::class_<PolymorphicDog, PolymorphicPet>(m, "PolymorphicDog")
    .def(py::init<>())
    .def("bark", &PolymorphicDog::bark);

// Again, return a base pointer to a derived instance
m.def("pet_store2", []() { return std::unique_ptr<PolymorphicPet>(new PolymorphicDog); });

// Python中调用
// >>> p = example.pet_store2()
// >>> type(p)
// PolymorphicDog  # automatically downcast
// >>> p.bark()
// u'woof!'

struct Pet {
    Pet(const std::string &name, int age) : name(name), age(age) { }

    void set(int age_) { age = age_; }
    void set(const std::string &name_) { name = name_; }

    std::string name;
    int age;
};

// 方法1：指定方法指针类型，C++11+支持
py::class_<Pet>(m, "Pet")
   .def(py::init<const std::string &, int>())
   .def("set", (void (Pet::*)(int)) &Pet::set, "Set the pet's age")
   .def("set", (void (Pet::*)(const std::string &)) &Pet::set, "Set the pet's name");
// 方法2：py::overload_cast自动推导返回值类型， C++14+支持
py::class_<Pet>(m, "Pet")
    .def("set", py::overload_cast<int>(&Pet::set), "Set the pet's age")
    .def("set", py::overload_cast<const std::string &>(&Pet::set), "Set the pet's name");

struct Pet {
    enum Kind {
        Dog = 0,
        Cat
    };

    Pet(const std::string &name, Kind type) : name(name), type(type) { }

    std::string name;
    Kind type;
};

py::class_<Pet> pet(m, "Pet");

pet.def(py::init<const std::string &, Pet::Kind>())
    .def_readwrite("name", &Pet::name)
    .def_readwrite("type", &Pet::type);

py::enum_<Pet::Kind>(pet, "Kind")
    .value("Dog", Pet::Kind::Dog)
    .value("Cat", Pet::Kind::Cat)
    .export_values();

// Python 调用：
// >>> p = Pet('Lucy', Pet.Cat)
// >>> p.type
// Kind.Cat
// >>> int(p.type)
// 1L

class Animal {
public:
    virtual ~Animal() { }
    // 纯虚函数， 有纯虚函数的类无法实例化， 因此无法定义构造函数
    virtual std::string go(int n_times) = 0;
};

class Dog : public Animal {
public:
    std::string go(int n_times) override {
        std::string result;
        for (int i=0; i<n_times; ++i)
            result += "woof! ";
        return result;
    }
};

// 传入基类指针，调用实际对象的go方法
std::string call_go(Animal *animal) {
    return animal->go(3);
}

// Bad binding! 无法扩展，因为此处Animal类没有构造函数
PYBIND11_MODULE(example, m) {
    py::class_<Animal>(m, "Animal")
        .def("go", &Animal::go);

    py::class_<Dog, Animal>(m, "Dog")
        .def(py::init<>());

    m.def("call_go", &call_go);
}

class PyAnimal : public Animal {
public:
    /* Inherit the constructors */
    using Animal::Animal;

    /* Trampoline (need one for each virtual function) */
    std::string go(int n_times) override {
        /* 对纯虚函数使用此宏 */
        /* 对有默认实现的虚函数，使用PYBIND11_OVERLOAD*/
        PYBIND11_OVERLOAD_PURE(
            std::string, /* Return type */
            Animal,      /* Parent class */
            go,          /* Name of function in C++ (must match Python name) */
            n_times      /* Argument(s) */
        );
    }
};

PYBIND11_MODULE(example, m) {
    py::class_<Animal, PyAnimal /* <--- trampoline*/>(m, "Animal")
        .def(py::init<>())
        .def("go", &Animal::go);

    py::class_<Dog, Animal>(m, "Dog")
        .def(py::init<>());

    m.def("call_go", &call_go);
}
/*
Python中进行扩展和调用：
>>> from example import *
>>> d = Dog()
>>> call_go(d)
u'woof! woof! woof! '
>>> class Cat(Animal):
...     def go(self, n_times):
...             return "meow! " * n_times
...
>>> class Dachshund(Dog):
...        def __init__(self, name):
...            Dog.__init__(self) # init c++ part
...            self.name = name
...        def bark(self):
...            return "yap!"
>>> c = Cat()
>>> call_go(c)
u'meow! meow! meow! '
*/

class Animal {
public:
    virtual std::string go(int n_times) = 0;
    virtual std::string name() { return "unknown"; }
};
class Dog : public Animal {
public:
    std::string go(int n_times) override {
        std::string result;
        for (int i=0; i<n_times; ++i)
            result += bark() + " ";
        return result;
    }
    virtual std::string bark() { return "woof!"; }
};

// 定义两个跳转类， 覆写虚函数
class PyAnimal : public Animal {
public:
    using Animal::Animal; // Inherit constructors
    std::string go(int n_times) override { PYBIND11_OVERLOAD_PURE(std::string, Animal, go, n_times); }
    std::string name() override { PYBIND11_OVERLOAD(std::string, Animal, name, ); }
};
class PyDog : public Dog {
public:
    using Dog::Dog; // Inherit constructors
    std::string go(int n_times) override { PYBIND11_OVERLOAD(std::string, Dog, go, n_times); }
    std::string name() override { PYBIND11_OVERLOAD(std::string, Dog, name, ); }
    std::string bark() override { PYBIND11_OVERLOAD(std::string, Dog, bark, ); }
};

class Example {
private:
    Example(int); // private constructor
public:
    // Factory function - returned by value:
    static Example create(int a) { return Example(a); }

    // These constructors are publicly callable:
    Example(double);
    Example(int, int);
    Example(std::string);
};

py::class_<Example>(m, "Example")
    // Bind the factory function as a constructor:
    .def(py::init(&Example::create))
    // Bind a lambda function returning a pointer wrapped in a holder:
    .def(py::init([](std::string arg) {
        return std::unique_ptr<Example>(new Example(arg));
    }))
    // Return a raw pointer:
    .def(py::init([](int a, int b) { return new Example(a, b); }))
    // You can mix the above with regular C++ constructor bindings as well:
    .def(py::init<double>())
    ;

#include <pybind11/factory.h>
class Example {
public:
    // ...
    virtual ~Example() = default;
};
class PyExample : public Example {
public:
    using Example::Example;
    // 第一种方式：跳转类以右值引用方式接收基类
    PyExample(Example &&base) : Example(std::move(base)) {}
};
py::class_<Example, PyExample>(m, "Example")
    // Returns an Example pointer.  If a PyExample is needed, the Example instance will be moved via the extra constructor in PyExample, above.
    .def(py::init([]() { return new Example(); }))
    // 第二种方式：提供两个工厂函数
    .def(py::init([]() { return new Example(); } /* no alias needed */,
                  []() { return new PyExample(); } /* alias needed */))
    // *Always* returns an alias instance (like py::init_alias<>())
    .def(py::init([]() { return new PyExample(); }))
    ;

py::class_ <MyType, BaseType1, BaseType2, BaseType3>(m, "MyType")
...