fortran - Fortran 2003 的完整面向对象示例？

Question

任何人都可以给我一个例子，说明一个简单的 Fortran 2003 面向对象的布局应该如何等效于此 C++ 代码:

stefanos-imac:tmp borini$ more Animal.h 
class Animal {
    public:
        Animal(int age);
        ~Animal();
        virtual void speak();
        int getAge();
    private:
        int age;
};

stefanos-imac:tmp borini$ more Animal.cpp 
#include <Animal.h>
#include <iostream>
Animal::Animal(int age) {
    std::cout << "init animal" << age << std::endl;
    this->age = age;
}
Animal::~Animal() {
    std::cout << "dtor animal" << std::endl;
}
void Animal::speak() {
    std::cout << "speak not reimplemented" << std::endl;
}
int Animal::getAge() {
    return this->age;
}
stefanos-imac:tmp borini$ more Cat.h 
#include <Animal.h>
class Cat : public Animal {
    public:
        Cat(int age);
        ~Cat();
        virtual void speak();
};
stefanos-imac:tmp borini$ more Cat.cpp 
#include <Cat.h>
#include <iostream>
Cat::Cat(int age) : Animal(age) {
    std::cout << "init cat" << std::endl;
}
Cat::~Cat() { 
    std::cout << "dtor cat" << std::endl;
}
void Cat::speak() {
    std::cout << "meow" << std::endl;
}
stefanos-imac:tmp borini$ more main.cpp 
#include <iostream>
#include <Cat.h>

int main() {
    Cat c(10);

    std::cout << c.getAge() <<std::endl;
    c.speak();
}

我的代码有问题，请参阅以下内容

stefanos-imac:oop borini$ more Animal.f90 
module AnimalModule
   implicit none
   private
   public :: AnimalType

   type :: AnimalType
      private
      integer :: age
   contains
      procedure :: getAge 
      procedure :: speak
      final :: dtor
   end type

   interface AnimalType
      module procedure ctor
   end interface
contains 
   subroutine ctor(self, age)
      type(AnimalType), intent(inout) :: self
      integer :: age
      print *, "Constructor Animal"
      self%age = age
   end subroutine 
   subroutine dtor(self)
      type(AnimalType), intent(inout) :: self
      print *, "Destroying animal"
   end subroutine 

   function getAge(self)
      class(AnimalType), intent(inout) :: self
      integer :: getAge
      getAge = self%age
   end function
   subroutine speak(self)
      class(AnimalType), intent(in) :: self

      print *, "Animal::speak not overridden"
   end subroutine
end

stefanos-imac:oop borini$ more Cat.f90 
module CatModule
   use AnimalModule
   implicit none
   private

   type, extends(AnimalType) :: CatType
      private
   contains
      procedure :: speak 
      final :: dtor
   end type

   interface CatType
      module procedure ctor
   end interface

contains 
   subroutine ctor(self, age)
      type(CatType), intent(inout) :: self
      integer, intent(in) :: age
      print *, "Constructor Cat"
      self%AnimalType = AnimalType(age)
   end subroutine 
   subroutine dtor(self)
      type(CatType), intent(inout) :: self
      print *, "Destroying Cat"
   end subroutine 
   subroutine speak(self)
      class(CatType), intent(in) :: self

      print *, "Meow"
   end subroutine
end

stefanos-imac:oop borini$ ifort Animal.f90 Cat.f90 
Cat.f90(10): error #8341: Final subroutines are not inherited through type extension and cannot be overridden.   [DTOR]
      final :: dtor
---------------^
Cat.f90(22): error #6292: The parent type of this field is use associated with the PRIVATE fields attribute   [AGE]
      self%AnimalType = AnimalType(age)
-----------------------------------^
compilation aborted for Cat.f90 (code 1)
stefanos-imac:oop borini$ 

特别是，我不清楚如何初始化基类，以及如何为派生类定义析构函数。

谢谢

Answer 1

   subroutine ctor(self, age)
      type(CatType), intent(inout) :: self
      integer, intent(in) :: age
      print *, "Constructor Cat"
      self%AnimalType = AnimalType(age)
   end subroutine

这是错误的。 CatType 没有 AnimalType 组件。它扩展了 AnimalType 类型。 ctor 是一个子例程，您可以将它用作函数。我建议您将构造函数(但它更多只是初始化，而不是分配)定义为函数，但也可以使用子例程。你可以像你一样使用接口(interface) block 来实现与类名相同的名称，但你必须保持一致并使用 CALL，如果你将它定义为子例程。

在派生类的构造函数中，您可以只设置正确的组件，或者使用基类的构造函数。然后不要忘记为您的类型编写正确的工作用户定义的分配。