diff --git a/bin/main.cpp b/bin/main.cpp
index 7f5b6c2..2736396 100644
--- a/bin/main.cpp
+++ b/bin/main.cpp
@@ -1,30 +1,55 @@
 #include <iostream>
 
+#include <map>
+#include <vector>
+
 #include "string/string.hpp"
 #include "range/range.hpp"
 #include "container/container.hpp"
+#include "logger/logger.hpp"
 
 int main(int argc, char *argv[])
 {
-  {// ex: split_str
-    std::string str { "asdf,qwer,zxcv" };
-    hack::string::v_str v = hack::string::split_str(str, ',');
-    for (const auto& c : v) std::cout << c << std::endl;
-  }
+  // {// ex: split_str
+  //   std::string str { "asdf,qwer,zxcv" };
+  //   hack::string::v_str v = hack::string::split_str(str, ',');
+  //   for (const auto& c : v) std::cout << c << std::endl;
+  // }
+  //
+  // {// ex: within
+  //   std::cout << std::boolalpha << hack::range::within(12, 34, 12, 23, 31, 17, 22, 33) << std::endl;
+  // }
+  // 
+  // {// ex: v_multiset
+  //   std::vector<std::string> v;
+  //   hack::container::v_multiset(v, "asdf", "qwer", "zcv");
+  //   for(const auto& c : v) std::cout << c << std::endl;
+  // }
+  //
+  // {// ex: s_multiset
+  //   std::set<int> s;
+  //   hack::container::s_multiset(s, 1, 2, 3, 3, 2, 1);
+  //   for(const auto& c : s) std::cout << c << std::endl;
+  // }
 
-  {// ex: within
-    std::cout << std::boolalpha << hack::range::within(12, 34, 12, 23, 31, 17, 22, 33) << std::endl;
-  }
-  
-  {// ex: v_multiset
-    std::vector<std::string> v;
-    hack::container::v_multiset(v, "asdf", "qwer", "zcv");
-    for(const auto& c : v) std::cout << c << std::endl;
-  }
+  {// ex: log
+    hack::log()(1234, "run in main", 1234);
+    hack::warn(" # ")(1234, "run in main", 1234);
+    hack::error(" - ")(1234, "run in main", 1234);
 
-  {// ex: s_multiset
-    std::set<int> s;
-    hack::container::s_multiset(s, 1, 2, 3, 3, 2, 1);
-    for(const auto& c : s) std::cout << c << std::endl;
+    std::string str { "hi" };
+    hack::log()(str);
+
+    std::vector<std::string> vs { "asdf", "qwer", "zxcv" };
+    hack::log()("vector", vs, 1, 2, 'a');
+    
+    std::list<std::string> ls {  "asdf", "qwer", "zxcv" };
+    hack::log()(vs, ls);
+
+    std::map<int, std::string> m { { 1, "asdf" }, { 2, "qwer" }, { 3, "zxcv" } };
+    hack::log()(vs, ls, m);
+
+    std::tuple<int, std::string, bool> tp { 1, "tuple test", false };
+    hack::log()(tp);
   }
 }
diff --git a/bin/meson.build b/bin/meson.build
index 727a5f2..312c7e2 100644
--- a/bin/meson.build
+++ b/bin/meson.build
@@ -1,6 +1,9 @@
+deps += view_dep
+deps += iterators_dep
 deps += string_dep
 deps += range_dep
-deps += range_dep
+deps += container_dep
+deps += logger_dep
 
 executable(
   'hack', 'main.cpp', 
diff --git a/meson.build b/meson.build
index 788e89d..d1d1702 100644
--- a/meson.build
+++ b/meson.build
@@ -3,7 +3,7 @@ project(
   'hack', 
   'cpp', 
   version : '0.0.1', 
-  default_options : ['cpp_std=c++20']
+  default_options : ['cpp_std=c++2a']
 )
 
 add_project_arguments (
diff --git a/src/container/container.hpp b/src/container/container.hpp
index 92282de..fbb47b6 100644
--- a/src/container/container.hpp
+++ b/src/container/container.hpp
@@ -6,7 +6,7 @@
 namespace hack::container
 {
   template<typename Range, typename... Args>
-  void v_multiset(Range& r, Args... args)
+  void vector_multiset(Range& r, Args... args)
   {
     constexpr std::size_t t = sizeof... (args);
     r.reserve(t);
@@ -14,7 +14,7 @@ namespace hack::container
   }
 
   template<typename Range, typename... Args>
-  void s_multiset(Range& r, Args... args)
+  void set_multiset(Range& r, Args... args)
   {
     (r.insert(args), ...);
   }
diff --git a/src/iterators/associative_ostream_iterator.hpp b/src/iterators/associative_ostream_iterator.hpp
new file mode 100644
index 0000000..0a550e2
--- /dev/null
+++ b/src/iterators/associative_ostream_iterator.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <iostream>
+
+namespace hack::iterators
+{
+  template<typename T>
+  class associative_ostream_iterator : public std::iterator<std::output_iterator_tag, void, void, void, void>
+  {
+    using traits = std::char_traits<char>;
+    using ostream_type = std::basic_ostream<char, traits>;
+
+    private:
+      std::basic_ostream<char, traits>* os;
+      const std::string devider = ", ";
+      std::size_t size;
+
+    public:
+      associative_ostream_iterator(std::size_t size, ostream_type& s) : os { &s }, size { size } { }
+
+      auto& operator=(T const& item)
+      {
+        --size;
+        const auto& [key, value] = item;
+        *os << "{ " << key << ":" << value << " }" << (size != 0 ? devider : "");
+        return *this;
+      }
+
+      auto& operator*()
+      {
+        return *this;
+      }
+
+      auto& operator++()
+      {
+        return *this;
+      }
+  };
+}
diff --git a/src/iterators/meson.build b/src/iterators/meson.build
new file mode 100644
index 0000000..8457fbe
--- /dev/null
+++ b/src/iterators/meson.build
@@ -0,0 +1,14 @@
+headers = ['sequence_ostream_iterator.hpp', 'associative_ostream_iterator.hpp']
+sources = []
+
+lib = library(
+  'iterators',
+  include_directories : inc,
+  install : true,
+  sources: [headers, sources]
+)
+
+iterators_dep = declare_dependency(
+  include_directories: inc,
+  link_with: lib
+)
diff --git a/src/iterators/sequence_ostream_iterator.hpp b/src/iterators/sequence_ostream_iterator.hpp
new file mode 100644
index 0000000..596ebef
--- /dev/null
+++ b/src/iterators/sequence_ostream_iterator.hpp
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <iostream>
+
+namespace hack::iterators
+{
+  template<typename T>
+  class sequence_ostream_iterator : public std::iterator<std::output_iterator_tag, void, void, void, void>
+  {
+    using traits = std::char_traits<char>;
+    using ostream_type = std::basic_ostream<char, traits>;
+
+    private:
+      std::basic_ostream<char, traits>* os;
+      const std::string devider = ", ";
+      std::size_t size;
+
+    public:
+      sequence_ostream_iterator(std::size_t size, ostream_type& s) : os { &s }, size { size } { }
+
+      auto& operator=(T const& item)
+      {
+        --size;
+        *os << item << (size != 0 ? devider : "");
+        return *this;
+      }
+
+      auto& operator*()
+      {
+        return *this;
+      }
+
+      auto& operator++()
+      {
+        return *this;
+      }
+  };
+}
diff --git a/src/logger/logger.cpp b/src/logger/logger.cpp
new file mode 100644
index 0000000..3981011
--- /dev/null
+++ b/src/logger/logger.cpp
@@ -0,0 +1,24 @@
+#include "logger.hpp"
+
+namespace hack
+{
+  std::string log::devider = " ";
+  int log::count = 0;
+
+  log::log(const std::string devider, std::experimental::source_location location) : location { location }
+  {
+    this->devider = devider;
+  }
+
+  warn::warn(const std::string devider, std::experimental::source_location location) : location { location }
+  {
+   this->devider = devider;
+  }
+
+  error::error(const std::string devider, std::experimental::source_location location) : location { location }
+  {
+   this->devider = devider;
+  }
+
+  void log::print() { std::cout << std::endl; }
+}
diff --git a/src/logger/logger.hpp b/src/logger/logger.hpp
new file mode 100644
index 0000000..4aa52fb
--- /dev/null
+++ b/src/logger/logger.hpp
@@ -0,0 +1,179 @@
+#pragma once
+
+#include <iostream>
+#include <experimental/source_location>
+#include <vector>
+#include <list>
+#include <map>
+#include <unordered_map>
+
+#include "view/color.hpp"
+#include "iterators/sequence_ostream_iterator.hpp"
+#include "iterators/associative_ostream_iterator.hpp"
+
+namespace hack
+{
+  template<typename T>
+  concept is_sequence_container = std::same_as<T, std::vector<typename T::value_type>> || 
+    std::same_as<T, std::list<typename T::value_type>>;
+
+  template<typename T>
+  concept is_tuple = requires (T t)
+  { 
+    std::tuple_cat(t, std::make_tuple(1, "tuple"));
+  };
+
+  template<class T>
+  concept is_string = std::is_convertible_v<T, std::string_view>;
+
+  template<class T>
+  concept is_map = std::same_as<T, std::map<typename T::key_type, typename T::mapped_type, typename T::key_compare, typename T::allocator_type>> ||
+    std::same_as<T, std::unordered_map<typename T::key_type, typename T::mapped_type, typename T::hasher, typename T::key_equal, typename T::allocator_type>>;
+
+  class log
+  {
+    public:
+      log(const std::string devider = ", ", std::experimental::source_location location = std::experimental::source_location::current()); 
+      log(log&) = delete;
+      log(log&&) = delete;
+
+    public:
+      template<typename... Args>
+      void operator() (const Args&... args)
+      {
+        std::cout << make_type_view
+                  << location.file_name() << ":" << view::color::reset 
+                  << view::color::italic << view::color::yellow << location.function_name() << "()" << view::color::reset
+                  << view::color::bold << view::color::blue << "[" << location.line() << "]" << view::color::reset << ": ";
+        count = sizeof...(Args);
+        print(args...);
+      }
+
+    private:
+      std::experimental::source_location location;
+      static int count;
+      static std::string devider;
+
+    private:
+      static void print();
+
+      static std::ostream& make_type_view(std::ostream &os)
+      {
+        os << view::color::bold << view::color::green << "[ok]" << view::color::reset << view::color::green;
+        return os;
+      }
+
+      template<typename T, typename... Args>
+      static void print(const T& data, const Args&... args)
+      {
+        count--;
+        print_t(data);
+        print(args...);
+      }
+
+      template<is_string T>
+      static void print_t(const T& data)
+      {
+        std::cout << data << (count != 0 ? devider : "");
+      }
+
+      template<std::integral T>
+      static void print_t(const T& data)
+      {
+        std::cout << data << (count != 0 ? devider : "");
+      }
+
+      template<is_sequence_container T>
+      static void print_t(const T& data)
+      {
+        std::cout << "{ ";
+        std::copy(data.cbegin(), data.cend(), iterators::sequence_ostream_iterator<typename T::value_type>(data.size(), std::cout));
+        std::cout << " }" << (count != 0 ? devider : "");
+      }
+
+      template<is_map T>
+      static void print_t(const T& data)
+      {
+        std::cout << "{";
+        std::copy(data.cbegin(), data.cend(), iterators::associative_ostream_iterator<typename T::value_type>(data.size(), std::cout));
+        std::cout << "}" << (count != 0 ? devider : "");
+      }
+
+      template<is_tuple T, typename std::size_t... idx>
+      static void print_t(const T& data)
+      {
+        print_t(data, std::make_index_sequence<std::tuple_size<T>::value>{});
+      }
+
+      template<typename T, typename std::size_t... idx>
+      static void print_t(const T& data, std::index_sequence<idx...>)
+      {
+        std::cout << "{ ";
+        ((std::cout << std::get<idx>(data) << (idx != std::tuple_size<T>::value - 1 ? devider : "")), ...);
+        std::cout << " }" << (count != 0 ? devider : "");
+      }
+
+      friend class warn;
+      friend class error;
+  };
+
+  class warn : public log
+  {
+    public:
+      warn(const std::string devider = ", ", std::experimental::source_location location = std::experimental::source_location::current()); 
+      warn(log&) = delete;
+      warn(log&&) = delete;
+
+    public:
+      template<typename... Args>
+      void operator() (const Args&... args)
+      {
+        std::cout << make_type_view
+                  << location.file_name() << ":" << view::color::reset 
+                  << view::color::italic << view::color::yellow << location.function_name() << "()" << view::color::reset
+                  << view::color::bold << view::color::blue << "[" << location.line() << "]" << view::color::reset << ": ";
+        count = sizeof...(Args);
+        print(args...);
+      }
+
+    private:
+      std::experimental::source_location location;
+
+    private:
+      static std::ostream& make_type_view(std::ostream &os)
+      {
+        os << view::color::bold << view::color::yellow << "[WARN]" << view::color::reset << view::color::yellow;
+        return os;
+      }
+  };
+
+  class error : public log
+  {
+    public:
+      error(const std::string devider = ", ", std::experimental::source_location location = std::experimental::source_location::current()); 
+      error(log&) = delete;
+      error(log&&) = delete;
+
+    public:
+      template<typename... Args>
+      void operator() (const Args&... args)
+      {
+        std::cout << make_type_view
+                  << location.file_name() << ":" << view::color::reset 
+                  << view::color::italic << view::color::yellow << location.function_name() << "()" << view::color::reset
+                  << view::color::bold << view::color::blue << "[" << location.line() << "]" << view::color::reset << ": ";
+        count = sizeof...(Args);
+        print(args...);
+      }
+
+    private:
+      std::experimental::source_location location;
+
+    private:
+      static std::ostream& make_type_view(std::ostream &os)
+      {
+        os << view::color::bold <<  view::color::red << "[ERROR]" << view::color::reset << view::color::red;
+        return os;
+      }
+  };
+}
diff --git a/src/logger/meson.build b/src/logger/meson.build
new file mode 100644
index 0000000..7a05b37
--- /dev/null
+++ b/src/logger/meson.build
@@ -0,0 +1,14 @@
+headers = ['logger.hpp']
+sources = ['logger.cpp']
+
+lib = library(
+  'logger',
+  include_directories : inc,
+  install : true,
+  sources: [headers, sources]
+)
+
+logger_dep = declare_dependency(
+  include_directories: inc,
+  link_with: lib
+)
diff --git a/src/meson.build b/src/meson.build
index 2e0df30..8a3b66e 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,5 +1,8 @@
 inc += include_directories('.')
 
+subdir('view')
+subdir('iterators')
 subdir('string')
 subdir('range')
 subdir('container')
+subdir('logger')
diff --git a/src/view/color.hpp b/src/view/color.hpp
new file mode 100644
index 0000000..3f3d37d
--- /dev/null
+++ b/src/view/color.hpp
@@ -0,0 +1,72 @@
+#pragma once
+
+#include <iostream>
+
+namespace hack::view::color
+{
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& reset(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[0m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& bold(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[1m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& italic(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[3m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& black(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[30m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& red(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[31m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& green(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[32m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& yellow(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[33m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& blue(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[34m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& magenta(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[35m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& cyan(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[36m";
+  }
+
+  template<typename CharT, typename Traits>
+  std::basic_ostream<CharT, Traits>& white(std::basic_ostream<CharT, Traits> &os)
+  {
+    return os << "\033[37m";
+  }
+} 
diff --git a/src/view/meson.build b/src/view/meson.build
new file mode 100644
index 0000000..22e3044
--- /dev/null
+++ b/src/view/meson.build
@@ -0,0 +1,14 @@
+headers = ['color.hpp']
+sources = []
+
+lib = library(
+  'view',
+  include_directories : inc,
+  install : true,
+  sources: [headers, sources]
+)
+
+view_dep = declare_dependency(
+  include_directories: inc,
+  link_with: lib
+)
diff --git a/tests/container.cpp b/tests/container.cpp
index 7895080..612aff3 100644
--- a/tests/container.cpp
+++ b/tests/container.cpp
@@ -5,6 +5,6 @@
 TEST(v_multiset, check)
 {
   std::vector<int> v;
-  hack::container::v_multiset(v, 1, 2, 3);
+  hack::container::vector_multiset(v, 1, 2, 3);
   ASSERT_EQ(v.at(0), 1);
 }