Merge pull request #61 from aminroosta/lvalue_functors

Support lvalue functors

Author: aminroosta

hdr/sqlite_modern_cpp.h

@@ -280,7 +280,7 @@ namespace sqlite {
 
 		template <typename Function>
 		typename std::enable_if<!is_sqlite_value<Function>::value, void>::type operator>>(
-			Function func) {
+			Function&& func) {
 			typedef utility::function_traits<Function> traits;
 
 			this->_extract([&func, this]() {
@@ -359,7 +359,7 @@ namespace sqlite {
 		>
 			static typename std::enable_if<(sizeof...(Values) < Boundary), void>::type run(
 				database_binder& db,
-				Function&        function,
+				Function&&       function,
 				Values&&...      values
 				) {
 			nth_argument_type<Function, sizeof...(Values)> value{};
@@ -375,7 +375,7 @@ namespace sqlite {
 		>
 			static typename std::enable_if<(sizeof...(Values) == Boundary), void>::type run(
 				database_binder&,
-				Function&        function,
+				Function&&       function,
 				Values&&...      values
 				) {
 			function(std::move(values)...);

hdr/sqlite_modern_cpp/extensions/boost_json_spirit.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <tuple>
+#include<type_traits>
 
 namespace sqlite {
 	namespace utility {
@@ -9,7 +10,7 @@ namespace sqlite {
 
 		template <typename Function>
 		struct function_traits : public function_traits<
-			decltype(&Function::operator())
+			decltype(&std::remove_reference<Function>::type::operator())
 		> { };
 
 		template <

hdr/sqlite_modern_cpp/extensions/boost_uuid.h

@@ -0,0 +1,62 @@
+#include<iostream>
+#include<sqlite_modern_cpp.h>
+#include<string>
+#include<vector>
+using namespace  sqlite;
+using namespace std;
+
+template<typename Target, typename... AttrTypes>
+struct builder {
+    vector<Target> results;
+
+    void operator()(AttrTypes... args) {
+      results.emplace_back(std::forward<AttrTypes&&>(args)...);
+    };
+};
+
+
+struct user {
+	int age;
+	string name;
+	double weight;
+	
+	user(int age, string name, double weight) : age(age), name(name), weight(weight) { }
+
+    static std::vector<user> all(sqlite::database& db) {
+	  builder<user, int, std::string, double> person_builder;
+      db << "SELECT * FROM user;"
+        >> person_builder;
+      return std::move(person_builder.results); // move to avoid copying data ;-)
+    };
+};
+
+int main() {
+
+	try {
+		database db(":memory:");
+
+		db <<
+			"create table if not exists user ("
+			"   age int,"
+			"   name text,"
+			"   weight real"
+			");";
+
+		db << "insert into user (age,name,weight) values (?,?,?);" << 20 << u"chandler" << 83.25;
+		db << "insert into user (age,name,weight) values (?,?,?);" << 21 << u"monika" << 86.25;
+		db << "insert into user (age,name,weight) values (?,?,?);" << 22 << u"ross" << 88.25;
+
+		auto users = user::all(db);
+		
+		for(auto u : users)
+			cout << u.age << ' ' << u.name << ' ' << u.weight << endl;
+        if(users.size() != 3)
+			exit(EXIT_FAILURE);
+	}
+	catch (exception& e) {
+		cerr << e.what() << endl;
+		exit(EXIT_FAILURE);
+	}
+
+  return 0;
+}