Method pointer with boost::bind and map - c++

Question

Is there a nicer way of doing this
auto commodityOneLeg = boost::bind(&VegaFactory::load_commodity_one_leg,this,conn,_1);
std::map<std::string,decltype(commodityOneLeg)> methods;
methods.insert(std::make_pair("COMMODITYONELEG",commodityOneLeg));
methods.insert(std::make_pair("FXOPTION",boost::bind(&VegaFactory::load_fx_index,this,conn,_1)));
methods.insert(std::make_pair("FXBARROPT",boost::bind(&VegaFactory::load_fx_bar_opt,this,conn,_1)));
methods.insert(std::make_pair("COMMODITYINDEX",boost::bind(&VegaFactory::load_fx_index,this,conn,_1)));
auto f = methods.find(trade_table);
if(f != methods.end()) {
fx_opt = (f->second)(t_id);
}
Is there a way of declaring the type of std:map<> without having to declare a mapping first on the previous line? I guess I mean aesthetically - Code should look neat right?
Is there a cleaner/simpler way to do this c++ string switch statement overall when the input is a 'trade type' string.
Edit
To clarify further. I can manually write out the type of the boost:bind type but that seems excessive. And this is probably a really good example of where auto and decltype can be used to simplify the code.
However having to declare one entry in the map one way and the others in a different way just looks wrong; so that's what I want to address

Answer 1

IMHO using Boost.Signals2 is a more clear way. There is also the Boost.Signals library but it is deprecated starting from Boost 1.54. The following code demonstrates it. I think something similar is possible to implement using the Boost.Function library too.
#include <boost/signals2.hpp>
#include <map>
#include <string>
typedef boost::signals2::signal<bool (int)> CSignal;
typedef CSignal::slot_type CSignalSlotType;
typedef std::map<std::string, CSignalSlotType> CMethodMap;
bool Func1(int a, int b) {
return a == b;
}
bool Func2(int a, int b) {
return a < b;
}
int main(int, char *[]) {
CMethodMap methods;
methods.insert(std::make_pair("Func1", boost::bind(&Func1, 1, _1)));
methods.insert(std::make_pair("Func2", boost::bind(&Func2, 2, _1)));
auto it = methods.find("Func1");
if(it != methods.end()) {
CSignal signal;
signal.connect(it->second);
auto rt = signal(2);
if (rt) {
const bool result = *rt;
}
}
return 0;
}
Here is a sample code using the Boost.Function. It looks even simpler but I used to use the Signals2 library.
#include <map>
#include <string>
#include <boost/function.hpp>
#include <boost/bind.hpp>
typedef boost::function<bool (int)> CFunction;
typedef std::map<std::string, CFunction> CMethodMap;
bool Func1(int a, int b) {
return a == b;
}
bool Func2(int a, int b) {
return a < b;
}
int main(int, char *[]) {
CMethodMap methods;
methods.insert(std::make_pair("Func1", boost::bind(&Func1, 1, _1)));
methods.insert(std::make_pair("Func2", boost::bind(&Func2, 2, _1)));
auto it = methods.find("Func1");
if(it != methods.end()) {
auto &f = it->second;
const bool result = f(2);
}
return 0;
}