The Big Programming Thread - Page 636

   Stash operator+(const Stash& stashB)
   {
      Stash stash;
      stash.item1 = this->item1 + stashB.item1;
      stash.item2 = this->item2 + stashB.item2;
      stash.item3 = this->item3 + stashB.item3;
      stash.item4 = this->item4 + stashB.item4;
      return stash;
   }

 stashA= stashB + stashC;

std::map<std::pair<int, int>, int>

int MatrixElement::operator[](std::pair<int, int>)
{
//dont know how to make the function accept variables, since
//	return map[int, int];
//	return map[std::pair<int, int>];
//	return map[std::make_pair(int int)]
// dont work.
}

use Phamda\Phamda as P;

// Add function is roughly equivalent to basic addition operator:
P::add(15, 27); // => 42

// But it is also has automatic partial application:
$addFour = P::add(4); // Create a new function
$addFour(5); // => 9
$addFour(16); // => 20

$div15 = P::divide(15); // Create a new function that uses 15 as dividend
$div15(3); // => 5

$_ = P::_(); // Create / retrieve a singleton placeholder object

$divBy5 = P::divide($_, 5); // Create a new function that uses 5 as divisor
$divBy5(20); // => 4

std::map<std::pair<int, int>, int>

int MatrixElement::operator[](std::pair<int, int>)
{
//dont know how to make the function accept variables, since
//	return map[int, int];
//	return map[std::pair<int, int>];
//	return map[std::make_pair(int int)]
// dont work.
}

int& MatrixElement::operator[](std::pair<int, int> const& key)
{
    return map[key];
}

UPDATE table SET column = column * 10
WHERE foreign_id < 123123

struct Proxy
{
    explicit Proxy(MatrixElement& element, int x): element(element), x(x) { }
    
    int& operator[](int y)
    {
        return element.map[std::make_pair(x, y)];
    }
    
private:
    MatrixElement& element;
    int x;
};

Proxy MatrixElement::operator[](int x)
{
    return Proxy(*this, x);
}