///////////////////////////////////////////////////////////////
// enforce.cpp - Assert-like error handler                   //
//                                                           //
// Jim Fawcett, CSE687 - Object Oriented Design, Spring 2005 //
// Source: Andrei Alexandrescu and Petru Marginean           //
//         Enforcements, C/C++ User's Journal, June 2003     //
///////////////////////////////////////////////////////////////
// Note:                                                     //
// I have simply made some cosmetic changes.  The code is    //
// due, in total, to the efforts of Andrei and Petru.        //
///////////////////////////////////////////////////////////////

#ifdef TEST_ENFORCE 

// This file is just a test driver and is not needed for
// applications.  The compilation conditional above is included 
// just in case a user includes this file in a build.

#include "enforce.h"
#include <iostream>

int* simulateSuccess()
{
  static int i = 0;
  return &i;
}

int* simulateError()
{
  return 0;
}

void foo(int* pInt)
{
}

struct Widget
{
  void print()
  {
    std::cout << 1 << ". This is the Widget!" << std::endl;
  }
};

Widget* makeWidget()
{
  static Widget o;
  return &o;
}

//
int main()
{
  std::cout << "\n  Demonstrating Enforcer Module"
            << "\n ===============================\n\n";
  try
  {
    ENFORCE(simulateSuccess());

    // ENFORCE returns the value returned by its argument, e.g.,
    // the pointer to int returned by simulateSuccess()

    int* pInt 
      = ENFORCE(simulateSuccess())("You should not ")("see")(" this message.");

    // You can supply as many arguments in parens as you need to describe
    // the potential error.  These can be anything you would pass to cout.
    
    Widget* pObj
      = ENFORCE(makeWidget())("Hopefully you don't ")("see this either!");
    pObj->print();

    foo(
      ENFORCE(simulateError())(2)(". An exception will be thrown ")
      ("below.\n")
    );
  }
  catch (const std::exception& e)
  {
    std::cout << e.what() << "\n\n";
    std::cout.flush();
  }
  return 0;
}

#endif