regex_searcher.cpp

#include <iostream>
#include <regex>


template<typename StringT>
struct regex_searcher_t {
    
    using IterT = decltype(std::begin(std::declval<const StringT&>()));
//    using CharT = typename std::decay<decltype(*std::declval<IterT>())>::type;
    using CharT = typename std::iterator_traits<IterT>::value_type;
    
    const std::basic_regex<CharT> _r;
    const std::regex_iterator<IterT> _it;
    
    
    regex_searcher_t(const StringT& s, const std::basic_regex<CharT>& r) : _r(r), _it(std::begin(s), std::end(s), _r) {}
    
    decltype(_it) begin() {
        return _it;
    }
    
    decltype(_it) end() {
        return decltype(_it)();
    }
};

template<typename StringT>
regex_searcher_t<StringT> regex_searcher(const StringT& s, const std::basic_regex<typename std::decay<decltype(*std::begin(std::declval<StringT&>()))>::type>& r) {
    return regex_searcher_t<StringT>(s, r);
}

int main(int argc, const char **argv) {
    
//    std::cmatch m;
//    if (std::regex_search("foobar", m, std::regex(R"(..)"))) {
//        std::cout << "m[0] = " << m[0] << std::endl;
//    }

//    const char *foo = "abcdef";
//    std::regex r(R"(..)");
//    std::regex_iterator<char*>(foo, foo+strlen(foo), r);

    std::string ss = "foobar";
    for (const auto& m : regex_searcher(ss, std::regex(R"(..)"))) {
        std::cout << "found match m[0] = " << m[0] << std::endl;
    }
    
    return 0;
}