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#include <iostream>
#include <functional>
#include <sstream>
#include <vector>
#include <map>
#include <stdlib.h>
using namespace std;
/**
* Example function that adds numbers
* @param a A number
* @param b A different number
* @return Sum of both parameters
*/
int my_plus(int a, int b)
{
cout << "my_plus(" << a << ", " << b << ")" << endl;
return a + b;
}
/**
* Another example function that concatenates strings
* @param a A text
* @param b A different text
* @return Concattenation
*/
const string my_concat(const string &a, const string &b)
{
cout << "my_concat(" << a << ", " << b << ")" << endl;
return a + b;
}
/**
* Value class that can automatically convert objects between many
* different types
*/
class Value
{
private:
/**
* Internal representation
* @var _value
*/
string _value;
public:
/**
* Constructor based on string
* @param text
*/
Value(const string &text) : _value(text) {}
/**
* Constructor based on string
* @param text
*/
Value(const char *text) : _value(text) {}
/**
* Constructor based on int
* @param integer
*/
Value(int value)
{
ostringstream s;
s << value;
_value = s.str();
}
/**
* Destructor
*/
virtual ~Value() {}
/**
* Cast to integer
* @return Numeric representation
*/
operator int ()
{
return atoi(_value.c_str());
}
/**
* Cast to string
* @return String representation
*/
operator const string& ()
{
return _value;
}
};
/**
* Simple wrapper around a function
*/
class Function
{
private:
/**
* The actual function
*
* Note: there must be a much smarter way to achieve the same thing,
* we just want to have a single member that holds the function
*
* @var _function
*/
union F {
// union members
function<Value()> r0;
function<Value(Value&)> r1;
function<Value(Value&,Value&)> r2;
function<void()> v0;
function<void(Value&)> v1;
function<void(Value&,Value&)> v2;
// constructors
F() {}
F(function<Value()> &f) { r0 = f; }
F(function<Value(Value&)> &f) { r1 = f; }
F(function<Value(Value&,Value&)> &f) { r2 = f; }
F(function<void()> &f) { v0 = f; }
F(function<void(Value&)> &f) { v1 = f; }
F(function<void(Value&,Value&)> &f) { v2 = f; }
// destructor
~F();
// assignment operator
// F &operator=(function<Value()> &f) { r0 = f; return *this; }
// F &operator=(function<Value(Value&)> &f) { r1 = f; return *this; }
// F &operator=(function<Value(Value&,Value&)> &f) { r2 = f; return *this; }
} _function;
/**
* Is the object in a valid state
* @var bool
*/
bool _valid;
/**
* The number of arguments that the function required
* @var _argc
*/
int _argc;
/**
* Does the function return something?
* @var _return;
*/
bool _return;
public:
/**
* Contructor
* @param f
*/
Function(function<Value()> &f) : _function(f)
{
_argc = 0;
_return = true;
_valid = true;
}
/**
* Contructor
* @param f
*/
Function(function<Value(Value&)> &f) : _function(f)
{
_argc = 1;
_return = true;
}
/**
* Contructor
* @param f
*/
Function(function<Value(Value&,Value&)> &f) : _function(f)
{
_argc = 2;
_return = true;
}
/**
* Move constructor
* @param f
*/
Function(const Function &&f)
{
// copy params
_argc = f._argc;
_return = f._return;
switch (_argc) {
case 0: _function.r0 = f._function.r0; break;
case 1: _function.r1 = f._function.r1; break;
case 2: _function.r2 = f._function.r2; break;
}
}
/**
* Destructor
*/
virtual ~Function() {}
/**
* Operator to call the function
* @param args
*/
void operator()(vector<Value> args)
{
switch (_argc) {
case 0: _function.r0();
case 1: _function.r1(args[0]);
case 2: _function.r2(args[0], args[1]);
}
}
};
/**
* Class that stores pointers to functions
*/
class Functions
{
private:
/**
* Map of functions
* @var map
*/
map<string,Function> _functions;
public:
/**
* Constructor
*/
Functions() {}
/**
* Destructor
*/
virtual ~Functions() {}
/**
* Add a function
* @param name The function name
* @param func The function to call
*/
void add(const string &name, function<Value(Value&,Value&)> f)
{
_functions.insert(pair<string,Function>(name, Function(f)));
}
/**
* Call the functions
* @param args
*/
Value operator()(vector<Value> args)
{
for (auto it = _functions.begin(); it != _functions.end(); it++)
{
it->second(args);
}
return Value(123);
}
};
/**
* Main function
* @param argc
* @param argv
*/
int main(int argc, char *argv[])
{
// create a vector of arguments
vector<Value> arguments;
// fill the arguments
for (int i=1; i<argc-1; i++) arguments.push_back(argv[i]);
// now register all functions
Functions functions;
functions.add("plus", my_plus);
functions.add("concat", my_concat);
// call all functions
functions(arguments);
// done
return 0;
}
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