Parser: use utils::regex_callback_extractor

parser.cpp

@@ -30,19 +30,12 @@ SOFTWARE.
 std::vector<Headline> Parser::extractHeadlines(std::string content) const
 {
 	std::vector<Headline> result;
-	std::string reg = R"(\[h(1|2|3)\](.*?)\[/h\1\])";
-	std::regex headerfinder(reg);
-	auto begin = std::sregex_iterator(content.begin(), content.end(), headerfinder);
-	auto end = std::sregex_iterator();
-
-	for(auto it = begin; it != end; it++)
-	{
-		auto smatch = *it;
+	utils::regex_callback_extractor(std::regex(R"(\[h(1|2|3)\](.*?)\[/h\1\])"), content, [&](std::smatch &smatch) {
 		Headline h;
 		h.level = utils::toUInt(smatch.str(1));
 		h.title = smatch.str(2);
 		result.push_back(h);
-	}
+	});
 	return result;
 }