composed.hpp

#pragma once
 
#include <functional>
 
namespace dl::utils {
    template <class F, class... Fs>
    auto composed(F&& arg, Fs&&... args) {
        return [fun = std::forward<F>(arg), ... functions = std::forward<Fs>(args)]<class X>(X&& x) mutable {
            if constexpr (sizeof...(Fs)) {
                return composed(std::forward<Fs>(functions)...)(std::invoke(std::forward<F>(fun), std::forward<X>(x)));
            } else {
                return std::invoke(std::forward<F>(fun), std::forward<X>(x));
            }
        };
    }
} // namespace dl::utils