gob_adapter's Introduction

gob_adapter

Overview

This is a library for using your own functions consisting of public functions of existing classes as if they were class functions of existing classes.
It can be used with C++11 or later.
It has the following features and limitations

Features

Can be encapsulated by classifying an ordinary function that uses the original class.
Does not modify the source code of the original class
"has-a" so there are no side effects on the original class (does not cause problems due to inheritance)
The use of arrow and dot operators is a little confusing, but it makes the difference between the original class function and a call to your own function clear.
Little impact from changes in the original class

Limitations

Not inherited, so only public functions of existing classes can be used.

How to install

Install in an appropriate way depending on your environment.

git clone or download zip, and extract into place
platformio.ini

lib_deps = https://github.com/GOB52/gob_adapter.git

How to use

#include <gob_adapter.hpp>

// Original class
class Original
{
  public:
    explicit Original(int v) : _v(v) {}
    int value() const { return _v; }
  private:
    int _v{};
};

// Extened class
// Add function to return squared value
class Extended : public goblib::plugin::Adapter<Original>
{
    using goblib::plugin::Adapter<Original>::_cls;
  public:
    using goblib::plugin::Adapter<Original>::Adapter; // for constructor

    int square() const { return _cls->value() * _cls->value(); }
};

Original org(52);
Extended  extended(org);

void foo()
{
    printf("Value:%d\nSquare:%d\n",
           extended->value(), // Call Original::value()
           extended.square()  // Call Extended::square()
           );

    Extended* ep = &extended;
    printf("Value:%d\nSquare:%d\n%d\n",
           (*ep)->value(), // Call Original::value()
           ep->square(),   // Call Extended::square()
           (*ep).square()  // Call Extended::square()
           );
}