diff --git a/CMakeLists.txt b/CMakeLists.txt
index c4437f4..5d8950e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
-set(BLT_VERSION 0.20.19)
+set(BLT_VERSION 0.20.20)
 set(BLT_TEST_VERSION 0.0.1)
 
 set(BLT_TARGET BLT)
diff --git a/include/blt/std/ranges.h b/include/blt/std/ranges.h
index c18756c..4721fbe 100644
--- a/include/blt/std/ranges.h
+++ b/include/blt/std/ranges.h
@@ -19,6 +19,13 @@
 namespace blt
 {
     
+    template<typename T>
+    struct enumerate_item
+    {
+        blt::size_t index;
+        T value;
+    };
+    
     template<typename Iter>
     class enumerate_base
     {
@@ -34,13 +41,15 @@ namespace blt
     class enumerate_base_fwd : public enumerate_base<Iter>
     {
         public:
-            explicit enumerate_base_fwd(Iter iter): enumerate_base<Iter>(std::move(iter)), index(0)
+            explicit enumerate_base_fwd(Iter iter, blt::size_t place = 0): enumerate_base<Iter>(std::move(iter)), index(place)
             {}
             
-            explicit enumerate_base_fwd(Iter iter, blt::size_t place): enumerate_base<Iter>(std::move(iter)), index(place)
-            {}
+            enumerate_item<blt::meta::deref_return_t<Iter>>* operator->() const
+            {
+                return &std::pair{index, *this->iter};
+            }
             
-            std::pair<blt::size_t, blt::meta::deref_return_t<Iter>> operator*() const
+            enumerate_item<blt::meta::deref_return_t<Iter>> operator*() const
             {
                 return {index, *this->iter};
             }
@@ -59,15 +68,15 @@ namespace blt
                 return tmp;
             }
             
-            bool operator==(const enumerate_base_fwd& other) const
-            {
-                return other.iter == this->iter;
-            }
-            
             friend bool operator==(const enumerate_base_fwd& a, const enumerate_base_fwd& b)
             {
                 return a.iter == b.iter;
             }
+            
+            friend bool operator!=(const enumerate_base_fwd& a, const enumerate_base_fwd& b)
+            {
+                return a.iter != b.iter;
+            }
         
         protected:
             blt::size_t index;
@@ -76,6 +85,7 @@ namespace blt
     template<typename Iter>
     class enumerate_base_bidirectional : public enumerate_base_fwd<Iter>
     {
+        public:
             using enumerate_base_fwd<Iter>::enumerate_base_fwd;
             
             enumerate_base_bidirectional& operator--()
@@ -93,11 +103,21 @@ namespace blt
             }
     };
     
+    template<typename Iter, typename Category = typename std::iterator_traits<Iter>::iterator_cateogry>
+    constexpr bool is_forward_only = std::is_same_v<Category, std::forward_iterator_tag>;
+    
+    template<typename Iter, typename Category = typename std::iterator_traits<Iter>::iterator_category>
+    constexpr bool is_bidirectional_or_better =
+            std::is_same_v<Category, std::bidirectional_iterator_tag> || std::is_same_v<Category, std::random_access_iterator_tag>;
+    
     template<typename Iter, typename = std::void_t<>>
-    class enumerate_wrapper;
+    class enumerate_wrapper
+    {
+            static_assert("Unsupported iterator type!");
+    };
     
     template<typename Iter>
-    class enumerate_wrapper<Iter, std::void_t<std::enable_if_t<std::is_same_v<typename Iter::iterator_category, std::forward_iterator_tag>, bool>>>
+    class enumerate_wrapper<Iter, std::enable_if_t<is_forward_only<Iter>, std::void_t<std::forward_iterator_tag>>> : public enumerate_base_fwd<Iter>
     {
         public:
             using iterator_category = std::forward_iterator_tag;
@@ -105,17 +125,22 @@ namespace blt
             using difference_type = typename std::iterator_traits<Iter>::difference_type;
             using pointer = typename std::iterator_traits<Iter>::pointer;
             using reference = typename std::iterator_traits<Iter>::reference;
-        public:
-            explicit enumerate_wrapper(Iter iter): iter(std::move(iter)), index(0)
-            {}
             
-            explicit enumerate_wrapper(Iter iter, blt::size_t place): iter(std::move(iter)), index(place)
-            {}
-        
-        
-        private:
-            Iter iter;
-            blt::size_t index;
+            using enumerate_base_fwd<Iter>::enumerate_base_fwd;
+    };
+    
+    template<typename Iter>
+    class enumerate_wrapper<Iter, std::enable_if_t<is_bidirectional_or_better<Iter>, std::void_t<std::bidirectional_iterator_tag>>>
+            : public enumerate_base_bidirectional<Iter>
+    {
+        public:
+            using iterator_category = std::forward_iterator_tag;
+            using value_type = typename std::iterator_traits<Iter>::value_type;
+            using difference_type = typename std::iterator_traits<Iter>::difference_type;
+            using pointer = typename std::iterator_traits<Iter>::pointer;
+            using reference = typename std::iterator_traits<Iter>::reference;
+            
+            using enumerate_base_bidirectional<Iter>::enumerate_base_bidirectional;
     };
     
     namespace itr
@@ -143,56 +168,6 @@ namespace blt
                 End end_;
         };
         
-        template<typename TYPE_ITR>
-        class iterator
-        {
-            public:
-                using iterator_category = std::forward_iterator_tag;
-                using value_type = typename std::iterator_traits<TYPE_ITR>::value_type;
-                using difference_type = typename std::iterator_traits<TYPE_ITR>::difference_type;
-                using pointer = typename std::iterator_traits<TYPE_ITR>::pointer;
-                using reference = typename std::iterator_traits<TYPE_ITR>::reference;
-                using const_reference = const reference;
-            private:
-                blt::size_t index;
-                TYPE_ITR current;
-            public:
-                explicit iterator(TYPE_ITR current, blt::size_t index): index(index), current(std::move(current))
-                {}
-                
-                auto iter()
-                {
-                    return current;
-                }
-                
-                iterator& operator++()
-                {
-                    ++index;
-                    ++current;
-                    return *this;
-                }
-                
-                bool operator==(iterator other) const
-                {
-                    return current == other.current;
-                }
-                
-                bool operator!=(iterator other) const
-                {
-                    return current != other.current;
-                }
-                
-                std::pair<blt::size_t, blt::meta::deref_return_t<TYPE_ITR>> operator*() const
-                {
-                    return {index, *current};
-                };
-                
-                std::pair<blt::size_t, blt::meta::deref_return_t<TYPE_ITR>> operator*()
-                {
-                    return {index, *current};
-                };
-        };
-        
         // TODO: cleanup! all of this! add support for reversing
         template<typename C1_TYPE, typename C2_TYPE>
         class pair_iterator
@@ -242,56 +217,6 @@ namespace blt
                 C1_TYPE current_c1_iter;
                 C2_TYPE current_c2_iter;
         };
-        
-        template<typename TYPE_ITR>
-        class reverse_iterator
-        {
-            public:
-                using iterator_category = std::forward_iterator_tag;
-                using value_type = typename std::iterator_traits<TYPE_ITR>::value_type;
-                using difference_type = typename std::iterator_traits<TYPE_ITR>::difference_type;
-                using pointer = typename std::iterator_traits<TYPE_ITR>::pointer;
-                using reference = typename std::iterator_traits<TYPE_ITR>::reference;
-                using const_reference = const reference;
-            private:
-                blt::size_t index;
-                TYPE_ITR current;
-            public:
-                explicit reverse_iterator(TYPE_ITR current, blt::size_t index): index(index), current(std::move(current))
-                {}
-                
-                auto iter()
-                {
-                    return current;
-                }
-                
-                reverse_iterator& operator++()
-                {
-                    --index;
-                    --current;
-                    return *this;
-                }
-                
-                bool operator==(reverse_iterator other) const
-                {
-                    return current == other.current;
-                }
-                
-                bool operator!=(reverse_iterator other) const
-                {
-                    return current != other.current;
-                }
-                
-                std::pair<blt::size_t, const_reference> operator*() const
-                {
-                    return {index, *current};
-                };
-                
-                std::pair<blt::size_t, reference> operator*()
-                {
-                    return {index, *current};
-                };
-        };
     }
     
     template<typename Begin, typename End>
@@ -306,60 +231,106 @@ namespace blt
         return itr::itr_container{std::reverse_iterator(std::forward<Begin>(end)), std::reverse_iterator(std::forward<End>(begin))};
     }
     
-    template<typename TYPE_ITR, template<typename> typename iterator = itr::iterator>
-    class enumerator
+    template<typename Iter>
+    class enumerator_base
     {
         public:
-            explicit enumerator(TYPE_ITR begin, TYPE_ITR end): begin_(std::move(begin), 0), end_(std::move(end), 0)
+            explicit enumerator_base(Iter begin, Iter end): begin_(std::move(begin)), end_(std::move(end))
             {}
             
-            explicit enumerator(TYPE_ITR begin, TYPE_ITR end, blt::size_t i_begin, blt::size_t i_end):
-                    begin_(std::move(begin), i_begin), end_(std::move(end), i_end)
+            explicit enumerator_base(Iter begin, Iter end, blt::size_t begin_index, blt::size_t end_index):
+                    begin_(std::move(begin), begin_index), end_(std::move(end), end_index)
             {}
             
-            itr::iterator<TYPE_ITR> begin()
+            auto begin()
             {
                 return begin_;
             }
             
-            itr::iterator<TYPE_ITR> end()
+            auto end()
             {
                 return end_;
             }
         
-        private:
-            iterator<TYPE_ITR> begin_;
-            iterator<TYPE_ITR> end_;
+        protected:
+            enumerate_wrapper<Iter> begin_;
+            enumerate_wrapper<Iter> end_;
     };
     
+    template<typename Iter, typename = std::void_t<>>
+    class enumerator
+    {
+            static_assert("Unsupported iterator type!");
+    };
+    
+    template<typename Iter>
+    class enumerator<Iter, std::enable_if_t<is_forward_only<Iter>, std::void_t<std::forward_iterator_tag>>> : public enumerator_base<Iter>
+    {
+        public:
+            using enumerator_base<Iter>::enumerator_base;
+    };
+    
+    template<typename Iter>
+    class enumerator<Iter, std::enable_if_t<is_bidirectional_or_better<Iter>, std::void_t<std::bidirectional_iterator_tag>>>
+            : public enumerator_base<Iter>
+    {
+        public:
+            //using enumerator_base<Iter>::enumerator_base;
+            
+            explicit enumerator(Iter begin, Iter end, blt::size_t container_size):
+                    enumerator_base<Iter>(std::move(begin), std::move(end)), container_size(container_size)
+            {}
+            
+            explicit enumerator(Iter begin, Iter end, blt::size_t begin_index, blt::size_t end_index):
+                    enumerator_base<Iter>(std::move(begin), std::move(end), begin_index, end_index), container_size(end_index - begin_index)
+            {}
+            
+            enumerator rev()
+            {
+                return enumerator<Iter>{std::reverse_iterator{this->end_}, std::reverse_iterator{this->begin_}, container_size - 1, 0ul};
+            }
+        
+        protected:
+            blt::size_t container_size;
+    };
+    
+    template<typename Iter>
+    enumerator(Iter, Iter) -> enumerator<Iter>;
+    
+    template<typename Iter>
+    enumerator(Iter, Iter, blt::size_t) -> enumerator<Iter>;
+    
+    template<typename Iter>
+    enumerator(Iter, Iter, blt::size_t, blt::size_t) -> enumerator<Iter>;
+    
     template<typename T>
     static inline auto enumerate(const T& container)
     {
-        return enumerator{container.begin(), container.end()};
+        return enumerator{container.begin(), container.end(), container.size()};
     }
     
     template<typename T, blt::size_t size>
     static inline auto enumerate(const T(& container)[size])
     {
-        return enumerator{&container[0], &container[size]};
+        return enumerator{&container[0], &container[size], size};
     }
     
     template<typename T, blt::size_t size>
     static inline auto enumerate(T(& container)[size])
     {
-        return enumerator{&container[0], &container[size]};
+        return enumerator{&container[0], &container[size], size};
     }
     
     template<typename T>
     static inline auto enumerate(T& container)
     {
-        return enumerator{container.begin(), container.end()};
+        return enumerator{container.begin(), container.end(), container.size()};
     }
     
     template<typename T>
     static inline auto enumerate(T&& container)
     {
-        return enumerator{container.begin(), container.end()};
+        return enumerator{container.begin(), container.end(), container.size()};
     }
     
     template<typename C1_ITER, typename C2_ITER, template<typename, typename> typename iterator = itr::pair_iterator>
diff --git a/src/blt/parse/argparse.cpp b/src/blt/parse/argparse.cpp
index e42d85c..d6c34cf 100644
--- a/src/blt/parse/argparse.cpp
+++ b/src/blt/parse/argparse.cpp
@@ -122,10 +122,10 @@ namespace blt
     {
         std::string result = "[";
         
-        for (const auto& value : blt::enumerate(vec))
+        for (const auto& [index, value] : blt::enumerate(vec))
         {
-            result += to_string(value.second);
-            if (value.first != vec.size() - 1)
+            result += to_string(value);
+            if (index != vec.size() - 1)
                 result += ", ";
         }
         result += "]";
diff --git a/src/blt/parse/obj_loader.cpp b/src/blt/parse/obj_loader.cpp
index 0a012e2..d211be7 100644
--- a/src/blt/parse/obj_loader.cpp
+++ b/src/blt/parse/obj_loader.cpp
@@ -141,10 +141,9 @@ namespace blt::parse
     obj_model_t obj_loader::parseFile(std::string_view file)
     {
         auto lines = blt::fs::getLinesFromFile(std::string(file));
-        for (auto line_e : blt::enumerate(lines))
+        for (const auto& [index, line] : blt::enumerate(lines))
         {
-            auto& line = line_e.second;
-            current_line = line_e.first;
+            current_line = index;
             char_tokenizer token(line);
             if (!token.has_next() || token.read_fully().empty())
                 continue;
@@ -220,9 +219,9 @@ namespace blt::parse
     
     void obj_loader::handle_face_vertex(const std::vector<std::string>& face_list, int32_t* arr)
     {
-        for (const auto& pair : blt::enumerate(face_list))
+        for (const auto& [e_index, value] : blt::enumerate(face_list))
         {
-            auto indices = blt::string::split(pair.second, '/');
+            auto indices = blt::string::split(value, '/');
             BLT_ASSERT(indices.size() == 3 && "Must have vertex, uv, and normal indices!!");
             
             auto vi = get<std::int32_t>(indices[0]) - 1;
@@ -242,14 +241,14 @@ namespace blt::parse
                 BLT_DEBUG("Vertex: (%f, %f, %f), UV: (%f, %f), Normal: (%f, %f, %f)", vertices[vi].x(), vertices[vi].y(), vertices[vi].z(),
                           uvs[ui].x(), uvs[ui].y(), normals[ni].x(), normals[ni].y(), normals[ni].z());
                 vertex_map.insert({face, index});
-                arr[pair.first] = index;
+                arr[e_index] = index;
             } else
             {
                 BLT_TRACE("Using cached data; %d; map size: %d", loc->second, vertex_data.size());
                 //const auto& d = vertex_data[loc->second];
                 BLT_TRACE("Vertex: (%f, %f, %f), UV: (%f, %f), Normal: (%f, %f, %f)", d.vertex.x(), d.vertex.y(), d.vertex.z(),
                           d.uv.x(), d.uv.y(), d.normal.x(), d.normal.y(), d.normal.z());
-                arr[pair.first] = loc->second;
+                arr[e_index] = loc->second;
             }
         }
     }