TupleOfFunctions, C++ (gcc)

TupleOfFunctions

#include <iostream>
#include <utility>

template <typename T, typename U>
struct PairOfFunctions: std::pair<T, U> {
    using std::pair<T, U>::pair;

template <typename... Args>
    auto operator() (Args&&... args) {
        return std::pair<T, U>::second(std::pair<T, U>::first(args...));
    }
};

template<typename...>
struct TupleOfFunctions;

template<typename T, typename... U>
struct TupleOfFunctions<T, U...>: PairOfFunctions<T, TupleOfFunctions<U...> >{
    using PairOfFunctions<T, TupleOfFunctions<U...> >::PairOfFunctions;
    TupleOfFunctions(T t, U... u):PairOfFunctions<T, TupleOfFunctions<U...> >(t, TupleOfFunctions<U...>(u...)){}
};

template<>
struct TupleOfFunctions<>{
    template <typename T>
    T operator() (T t) { // not sure if this is optimal
        return t;
    }
};

// My universal helper
template<template <typename...> class T, typename... Args>
auto mk(Args... args){
    return T<Args...>{args...};
}

int main()
{
    auto a = mk<TupleOfFunctions>(
        [](int a) {return a*2;},
        [](int a) {return a + 10;},
        [](int a) {return a / 2;}
    );
    std::cout << a(4) << '\n'; // (4 * 2 + 10) / 2
}


run \| edit \| history \| help	0

Please log in to post a comment.

stackse - search stackoverflow differently