probably going to revert all of this.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
-set(BLT_VERSION 1.1.1)
+set(BLT_VERSION 1.1.2)
 
 set(BLT_TARGET BLT)
 

include/blt/iterator/common.h

@@ -25,16 +25,16 @@
 namespace blt::iterator
 {
     template<typename Derived>
-    struct wrapper_base
+    struct base_wrapper
     {
-        wrapper_base operator++(int)
+        base_wrapper operator++(int)
         {
             auto tmp = *this;
             ++*this;
             return tmp;
         }
         
-        wrapper_base operator--(int)
+        base_wrapper operator--(int)
         {
             static_assert(std::is_same_v<typename Derived::iterator_category, std::bidirectional_iterator_tag> ||
                           std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
@@ -51,80 +51,75 @@ namespace blt::iterator
             return *(*this + n);
         }
         
-        friend wrapper_base operator+(const wrapper_base& a, blt::ptrdiff_t n)
+        friend base_wrapper operator+(blt::ptrdiff_t n, const base_wrapper& a)
         {
-            static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
+            return a + n;
-                          "Iterator must allow random access");
-            auto copy = a;
-            copy += n;
-            return copy;
         }
         
-        friend wrapper_base operator+(blt::ptrdiff_t n, const wrapper_base& a)
+        friend bool operator<(const base_wrapper& a, const base_wrapper& b)
-        {
-            static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
-                          "Iterator must allow random access");
-            auto copy = a;
-            copy += n;
-            return copy;
-        }
-        
-        friend wrapper_base operator-(const wrapper_base& a, blt::ptrdiff_t n)
-        {
-            static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
-                          "Iterator must allow random access");
-            auto copy = a;
-            copy -= n;
-            return copy;
-        }
-        
-        friend wrapper_base operator-(blt::ptrdiff_t n, const wrapper_base& a)
-        {
-            static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
-                          "Iterator must allow random access");
-            auto copy = a;
-            copy -= n;
-            return copy;
-        }
-        
-        friend bool operator<(const wrapper_base& a, const wrapper_base& b)
         {
             static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
                           "Iterator must allow random access");
             return b - a > 0;
         }
         
-        friend bool operator>(const wrapper_base& a, const wrapper_base& b)
+        friend bool operator>(const base_wrapper& a, const base_wrapper& b)
         {
             static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
                           "Iterator must allow random access");
             return b < a;
         }
         
-        friend bool operator>=(const wrapper_base& a, wrapper_base& b)
+        friend bool operator>=(const base_wrapper& a, base_wrapper& b)
         {
             static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
                           "Iterator must allow random access");
             return !(a < b); // NOLINT
         }
         
-        friend bool operator<=(const wrapper_base& a, const wrapper_base& b)
+        friend bool operator<=(const base_wrapper& a, const base_wrapper& b)
         {
             static_assert(std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>,
                           "Iterator must allow random access");
             return !(a > b); // NOLINT
         }
         
-        friend bool operator==(const wrapper_base& a, const wrapper_base& b)
+        friend bool operator==(const base_wrapper& a, const base_wrapper& b)
         {
             return a.base() == b.base();
         }
         
-        friend bool operator!=(const wrapper_base& a, const wrapper_base& b)
+        friend bool operator!=(const base_wrapper& a, const base_wrapper& b)
         {
             return !(a.base() == b.base()); // NOLINT
         }
     };
+    
+    template<typename Iter, typename Derived>
+    struct passthrough_wrapper : public base_wrapper<Derived>
+    {
+        public:
+            explicit passthrough_wrapper(Iter iter): iter(std::move(iter))
+            {}
+            
+            meta::deref_return_t<Iter> operator*() const
+            {
+                return *iter;
+            }
+            
+            auto base() const
+            {
+                return iter;
+            }
+            
+            friend blt::ptrdiff_t operator-(const passthrough_wrapper& a, const passthrough_wrapper& b)
+            {
+                return a.base() - b.base();
+            }
+        
+        protected:
+            Iter iter;
+    };
 }
 
 #endif //BLT_ITERATOR_ITER_COMMON

include/blt/iterator/zip.h

@@ -29,7 +29,7 @@ namespace blt
     namespace iterator
     {
         template<typename... Iter>
-        class zip_wrapper : public wrapper_base<zip_wrapper<Iter...>>
+        struct zip_wrapper : public base_wrapper<zip_wrapper<Iter...>>
         {
             public:
                 using iterator_category = meta::lowest_iterator_category_t<Iter...>;
@@ -58,16 +58,18 @@ namespace blt
                     return *this;
                 }
                 
-                zip_wrapper& operator+=(blt::ptrdiff_t n)
+                friend zip_wrapper operator+(const zip_wrapper& a, blt::ptrdiff_t n)
                 {
-                    std::apply([n](auto& ... i) { ((i += n), ...); }, this->iter);
+                    static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
-                    return *this;
+                                  "Iterator must allow random access");
+                    return std::apply([n](auto& ... i) { return zip_wrapper((i + n)...); }, a.iter);
                 }
                 
-                zip_wrapper& operator-=(blt::ptrdiff_t n)
+                friend zip_wrapper operator-(const zip_wrapper& a, blt::ptrdiff_t n)
                 {
-                    std::apply([n](auto& ... i) { ((i -= n), ...); }, this->iter);
+                    static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
-                    return *this;
+                                  "Iterator must allow random access");
+                    return std::apply([n](auto& ... i) { return zip_wrapper((i - n)...); }, a.iter);
                 }
                 
                 friend blt::ptrdiff_t operator-(const zip_wrapper& a, const zip_wrapper& b)
@@ -93,112 +95,78 @@ namespace blt
                 }
         };
         
-        BLT_META_MAKE_FUNCTION_CHECK(base);
+        template<typename Iter, bool checked>
-        
+        struct skip_wrapper : public passthrough_wrapper<Iter, skip_wrapper<Iter, checked>>
-        template<typename Iter>
-        auto get_base(Iter iter)
         {
-            if constexpr (has_func_base_v<Iter>)
-            {
-                return std::move(iter).base();
-            } else
-            {
-                return std::move(iter);
-            }
-        }
-        
-        template<typename Derived>
-        class take_impl
-        {
-            private:
-                template<bool check>
-                auto take_base(blt::size_t n)
-                {
-                    static_assert(!std::is_same_v<typename Derived::iterator_category, std::input_iterator_tag>,
-                                  "Cannot .take() on an input iterator!");
-                    auto* d = static_cast<Derived*>(this);
-                    auto begin = d->begin();
-                    auto end = d->end();
-                    
-                    // take variant for forward and bidirectional iterators
-                    if constexpr (std::is_same_v<typename Derived::iterator_category, std::forward_iterator_tag> ||
-                                  std::is_same_v<typename Derived::iterator_category, std::bidirectional_iterator_tag>)
-                    {
-                        // with these guys we have to loop forward to move the iterators. an unfortunate inefficiency
-                        auto new_end = begin;
-                        for (blt::size_t i = 0; i < n; i++)
-                        {
-                            if constexpr (check)
-                            {
-                                if (new_end == end)
-                                    break;
-                            }
-                            ++new_end;
-                        }
-                        return Derived{get_base(std::move(begin)), get_base(std::move(new_end))};
-                    } else if constexpr (std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>)
-                    {
-                        // random access iterators can have math directly applied to them.
-                        if constexpr (check)
-                        {
-                            return Derived{get_base(begin),
-                                           get_base(begin + std::min(static_cast<blt::ptrdiff_t>(n), std::distance(begin, end)))};
-                        } else
-                        {
-                            return Derived{get_base(begin), get_base(begin + n)};
-                        }
-                    }
-                }
-            
             public:
-                auto take(blt::size_t n)
+                using iterator_category = typename std::iterator_traits<Iter>::iterator_category;
-                { return take_base<false>(n); }
+                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;
                 
-                auto take_or(blt::size_t n)
+                explicit skip_wrapper(Iter iter, blt::size_t n): passthrough_wrapper<Iter, skip_wrapper<Iter, checked>>(std::move(iter)), skip(n)
-                { return take_base<true>(n); }
+                {}
-        };
                 
-        template<typename Derived>
+                skip_wrapper& operator++()
-        class skip_impl
                 {
+                    if constexpr (std::is_same_v<iterator_category, std::random_access_iterator_tag>)
+                    {
+                        if (skip > 0)
+                        {
+                            this->base() += skip;
+                            skip = 0;
+                        }
+                    } else
+                    {
+                        while (skip > 0)
+                        {
+                            ++this->base();
+                            --skip;
+                        }
+                    }
+                    
+                    ++this->base();
+                    return *this;
+                }
+                
+                skip_wrapper& operator--()
+                {
+                    if constexpr (std::is_same_v<iterator_category, std::random_access_iterator_tag>)
+                    {
+                        if (skip > 0)
+                        {
+                            this->base() -= skip;
+                            skip = 0;
+                        }
+                    } else
+                    {
+                        while (skip > 0)
+                        {
+                            --this->base();
+                            --skip;
+                        }
+                    }
+                    --this->base();
+                    return *this;
+                }
+                
+                friend skip_wrapper operator+(const skip_wrapper& a, blt::ptrdiff_t n)
+                {
+                    static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
+                                  "Iterator must allow random access");
+                    return {a.base() + static_cast<blt::ptrdiff_t>(a.skip) + n, 0};
+                }
+                
+                friend skip_wrapper operator-(const skip_wrapper& a, blt::ptrdiff_t n)
+                {
+                    static_assert(std::is_same_v<iterator_category, std::random_access_iterator_tag>,
+                                  "Iterator must allow random access");
+                    return {a.base() - static_cast<blt::ptrdiff_t>(a.skip) - n, 0};
+                }
+            
             private:
-                template<bool check>
+                blt::size_t skip;
-                auto skip_base(blt::size_t n)
-                {
-                    auto* d = static_cast<Derived*>(this);
-                    auto begin = d->begin();
-                    auto end = d->end();
-                    
-                    if constexpr (std::is_same_v<typename Derived::iterator_category, std::random_access_iterator_tag>)
-                    {
-                        if constexpr (check)
-                        {
-                            return Derived{begin + std::min(static_cast<blt::ptrdiff_t>(n), std::distance(begin, end))};
-                        } else
-                        {
-                            return Derived{begin + n, end};
-                        }
-                    } else
-                    {
-                        for (blt::size_t i = 0; i < n; i++)
-                        {
-                            if constexpr (check)
-                            {
-                                if (begin == end)
-                                    break;
-                            }
-                            ++begin;
-                        }
-                        return Derived{begin, end};
-                    }
-                }
-            
-            public:
-                void skip(blt::size_t n)
-                { return skip_base<false>(n); }
-                
-                void skip_or(blt::size_t n)
-                { return skip_base<true>(n); }
         };
     }
     
@@ -221,7 +189,7 @@ namespace blt
     class zip_iterator_storage_rev;
     
     template<typename... Iter>
-    class zip_iterator_storage : public iterator::take_impl<zip_iterator_storage<Iter...>>
+    class zip_iterator_storage
     {
         public:
             using iterator_category = meta::lowest_iterator_category_t<Iter...>;
@@ -243,12 +211,9 @@ namespace blt
             }
             
             auto skip(blt::size_t n)
-            {
-                if constexpr (std::is_same_v<iterator_category, std::input_iterator_tag>)
             {
             
             }
-            }
             
             auto begin() const
             {
@@ -266,7 +231,7 @@ namespace blt
     };
     
     template<typename... Iter>
-    class zip_iterator_storage_rev : public iterator::take_impl<zip_iterator_storage_rev<Iter...>>
+    class zip_iterator_storage_rev
     {
         public:
             using iterator_category = meta::lowest_iterator_category_t<Iter...>;
@@ -329,7 +294,7 @@ namespace blt
     template<typename... Container>
     auto zip(Container& ... container)
     {
-        return blt::zip_iterator_storage{iterator_pair{container.begin(), container.end()}...};
+        return zip_iterator_storage{iterator_pair{container.begin(), container.end()}...};
     }
 }