jaroslawwiosna / generic-cpp Goto Github PK

template <typename T>
concept Foldable2 = requires(T a) {
    {a.begin()} -> std::same_as<std::iterator_traits<T> >;
    {a.end()} -> std::same_as<std::iterator_traits<T> >;
};

template<Monoid M, Foldable2 T>
M fold(T<M> t) {
    auto result = M::mempty();
    for (auto it = t.begin(); it != t.end(); ++it)
        result = M::mappend(result, *it);
    }
    return result;
}