Version: 1.0


yaf::Function - generic representation of a callable entity.
Similar to Boost.Function and Loki::Function, but with only two standalone header files.

Author:
    Zurab Khetsuriani (zura.khetsuriani 'at gmail.com)

License:
    Boost Software License - Version 1.0 (See BOOST_LICENSE_1_0.txt)
    
Files:
    Function.h      - public header file, the only file used in the client code.
    Function_impl.h - private header file.
    main.cpp        - usage examples and tests.
    
Usage:

#include "Function.h"

yaf::Function<Signature> func;

Where Signature is any function signature with up to 7 parameters.
Given above, func can be assigned any callable entity with a corresponding signature, which are:
1. Free functions
2. Member functions (via constructor or yaf::mem_fun helper function)
3. Functors (objects with operator()), copied by value
 
When Signature has one or two parameters, yaf::Function<Signature> class is
publicly derived from std::unary_function or std::binary_function respectively.
 
Examples:

// free function
int get_sum(int a, int b)
{
	return a + b;
}


// functor type
struct MaxGetter {
	int operator()(int a, int b) const
	{
		return std::max(a, b);
	}
};


// some class
class A {
	int x;
public:
	// some non-const method (can be const as well)
	int get_mul(int a, int b)
	{
		x = a * b;
		return x;
	}
};



yaf::Function<int (int, int)> func;

func = get_sum;
int sum = func(1, 2);

MaxGetter max_getter_functor;
func = max_getter_functor;
int max = func(10, 15);

A a;
func = yaf::mem_fun(&a, &A::get_mul);
int mul = func(3, 4);

if (func) // if func is not empty, same as: !func.empty()
	func(1, 2);


yaf::Function<int (int, int)> func2;

// swap with func2 (has the same signature)
func.swap(func2);
yaf::swap(func, func2);

// assign
func = func2;


yaf::Function<int (int)> fempty; // empty yaf::Function

try {
	fempty(10);

} catch (const yaf::bad_function_call& e) {
	std::cerr << "Exception: " << e.what() << std::endl;
}