The available binary operators are *, /, %, +, -, <<, >>, &, |, and ^ (in this man-page they are generically indicated as the `@' operator). In addition, overloaded operator<< and operator>> for stream insertion and extraction are frequently defined.
If a class Derived supports copy and/or move construction and if it offers a swap member (void Derived::swap(Derived &rhs)), and is publicly derived from FBB::BinopsBase<Derived> then once Derived defines a member
void Class::operator@=(Rhs const &rhs) &&
defining the compound @-operator for anonymous, temporary Derived
objects and a Rhs type for its right-hand side operand the following
operators are also available:
Derived &operator@=(Rhs const &rhs) &
Derived operator@(Derived &&lhs, Rhs const &rhs);
Derived operator@(Derived const &lhs, Rhs const &rhs);
A similar procedure applies to the insertion and extraction operators. Insertion and extraction operators become available once BinopsBase<Derived> is declared a friend class of Derived. To make the insertion operator available a private member
void Derived::insert(std::ostream &out) const
must then also be defined, inserting the calling object into
out. Analogously, to make the extraction operator available a private
member
void Derived::extract(std::istream &in)
must be defined extrating the calling object from in.
--
For each defined Derived &&operator@=(Rhs const &rhs) &&, defined in the class Derived the following operators are automatically also available:
Derived operator@(Derived &&lhs, Rhs const &rhs);
Derived operator@(Derived const &lhs, Rhs const &rhs);
and
Derived &operator@=(Rhs const &rhs) &;
The insertion operator becomew available once
void Derived::insert(std::ostream &out) const
(inserting the calling object into out) has been defined. Analogously,
the extraction operator becomes available after defining a private member
void Derived::extract(std::istream &in)
(extracting the calling object from in).
To make the insertion and/or extraction operators available the class Derived must also declare
friend FBB::BinopsBase<Derived>;
#include <iostream>
#include <bobcat/binopsbase>
class Demo1: public FBB::BinopsBase<Demo1>
{
friend FBB::BinopsBase<Demo1>; // for insert/extract
public:
void swap(Demo1 &other)
{}
Demo1 &&operator+=(Demo1 const &rhs) &&
{
std::cout << "adding two Demo1 objects\n";
return std::move(*this);
}
// Explicit definitions take precedence over functions templates
// instantiated from definitions in bobcat/binopsbase.
// Demo1 &operator+=(Demo1 const &rhs) &
// {
// std::cout << "adding (self-defined) two Demo1 objects\n";
// return *this;
// }
Demo1 &&operator-=(Demo1 const &rhs) &&
{
std::cout << "subtracting two Demo1 objects\n";
return std::move(*this);
}
Demo1 &&operator<<=(Demo1 const &rhs) &&
{
std::cout << "shiftleft on two Demo1 objects\n";
return std::move(*this);
}
Demo1 &&operator<<=(size_t rhs) &&
{
std::cout << "shiftleft Demo1 object size_t bits\n";
return std::move(*this);
}
void insert(std::ostream &out) const // requires friend
{
out << "inerting a Demo1 object\n";
}
void extract(std::istream &in) // requires friend
{
std::cout << "extracting a Demo1 object\n";
}
};
class Demo2: public FBB::BinopsBase<Demo2>
{
public:
void swap(Demo2 &other)
{}
Demo2 &&operator+=(Demo2 const &rhs) &&
{
std::cout << "adding two Demo2 objects\n";
return std::move(*this);
}
Demo2 &operator+=(Demo2 const &rhs) &
{
std::cout << "adding (self-defined) two Demo2 objects";
return *this;
}
Demo2 &&operator^=(Demo2 const &rhs) &&
{
std::cout << "xor-ing two Demo2 objects\n";
return std::move(*this);
}
Demo2 &&operator|=(Demo2 const &rhs) &&
{
std::cout << "or-ing two Demo2 objects\n";
return std::move(*this);
}
};
int main()
{
Demo1 d1a, d1b;
Demo1 d1c = d1a + d1b;
d1a += d1b;
d1c = Demo1{} + d1b;
std::cout << "Here we are " << d1c << '\n';
std::cin >> d1c;
d1a <<= d1a;
d1a <<= 5;
Demo2 d2a, d2b;
Demo2 d2c = d2a + d2b;
d2a ^= d2b;
d2c = Demo2{} ^ d2b;
d2c = d2c | d2b;
}