bref::Function Class Reference

Polymorphic Function Object Wrapper. More...

#include <Function.hpp>

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Detailed Description

Polymorphic Function Object Wrapper.

The Function class is a personal challenge to implement the following proposal to add a Polymorphic Function Object Wrapper to the C++ Standard Library. It's based on the Boost.Function library and have the added functionnality of bounded pointer-to-member function. You're not asked to understand the implementation, just invited to look into it's powerful features.

The implementation try to limit the size of the Function to be as small as possible, and with a small use of allocation (only used when there was no other way to do).

A function handle between 0 and 10 parameters, but this number can easily be extented to a larger number.

If you want to understand the Function class usage you should probably look into:

• Boost.Function - http://www.boost.org/doc/libs/1_49_0/doc/html/function.html
• std::function
• http://www.codeproject.com/Articles/11015/The-Impossibly-Fast-C-Delegates where the idea of embedding a bounded pointer come from.

An finally http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1402.html which was what I tried to implement. With a difference in the names used:

• reference_wrapper -> ReferenceWrapper
• ref -> ref
• cref -> cref
• bad_function_call -> BadFunctionCallException

Warning:

Calling a null function (not bounded to anything) will throw a bref::BadFunctionCallException.

A list of things Function can bind:

• a pointer to function

  int add(int a, int b)
  {
    return a + b;
  }
  
  bref::Function<int (int, int)> addFunction(&add);
  std::cout << addFunction(4, 12) << std::endl; // print 16
  

• a function object aka Functor

  struct Adder
  {
    int initValue;
    Adder(int val) : initValue(val)
    { }
  
    int operator()(int p) {
      return initValue + p;
    }
  };
  
  bref::Function<int (int)> addFunction(Adder(4));
  std::cout << addFunction(12) << std::endl; // print 16
  

• A pointer-to-member function

  struct Car
  {
    int initValue;
  
    void vroom(const std::string & id) {
      std::cout << id << " vrooOOOo00ooommm !!!" << std::endl;
    }
  };
  
  bref::Function<void (Car *, const std::string &)> addFunction(&Car::vroom);
  Car                                              c;
  
  addFunction(&c, "Flash Mc Queen");
  

• A bounded pointer-to-member function

    Car c;
    bref::Function<void (const std::string &)> f(&c, &Car::vroom);
    bref::Function<void (const std::string &)> f2;
  
    f2.bind(&c, &Car::vroom);
    f("Martin");
    f2("Martin");
  

You can check for emptiness with a boolean conversion operator or the empty() method.

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The documentation for this class was generated from the following file:

• /Users/giersc_v/projets/zia/api/include/bref/Function.hpp