From baf6d06cc29fbb5975009d091d8f481fd452883d Mon Sep 17 00:00:00 2001
From: Andrey Semashev <andrey.semashev@gmail.com>
Date: Wed, 5 Feb 2025 00:24:07 +0300
Subject: [PATCH] Modernized iterator_traits.hpp.

Added *_t type traits and removed an oudated macro that was used with
ancient compilers.
---
 include/boost/iterator/iterator_traits.hpp | 41 +++++++++++++---------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/include/boost/iterator/iterator_traits.hpp b/include/boost/iterator/iterator_traits.hpp
index 6582a68..0437a64 100644
--- a/include/boost/iterator/iterator_traits.hpp
+++ b/include/boost/iterator/iterator_traits.hpp
@@ -3,49 +3,56 @@
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 #ifndef ITERATOR_TRAITS_DWA200347_HPP
-# define ITERATOR_TRAITS_DWA200347_HPP
-
-# include <boost/detail/workaround.hpp>
+#define ITERATOR_TRAITS_DWA200347_HPP
 
 #include <iterator>
 
 namespace boost {
 namespace iterators {
 
-// Macro for supporting old compilers, no longer needed but kept
-// for backwards compatibility (it was documented).
-#define BOOST_ITERATOR_CATEGORY iterator_category
+template< typename Iterator >
+using iterator_value_t = typename std::iterator_traits< Iterator >::value_type;
 
-
-template <class Iterator>
+template< typename Iterator >
 struct iterator_value
 {
-    typedef typename std::iterator_traits<Iterator>::value_type type;
+    using type = iterator_value_t< Iterator >;
 };
 
-template <class Iterator>
+template< typename Iterator >
+using iterator_reference_t = typename std::iterator_traits< Iterator >::reference;
+
+template< typename Iterator >
 struct iterator_reference
 {
-    typedef typename std::iterator_traits<Iterator>::reference type;
+    using type = iterator_reference_t< Iterator >;
 };
 
+template< typename Iterator >
+using iterator_pointer_t = typename std::iterator_traits< Iterator >::pointer;
 
-template <class Iterator>
+template< typename Iterator >
 struct iterator_pointer
 {
-    typedef typename std::iterator_traits<Iterator>::pointer type;
+    using type = iterator_pointer_t< Iterator >;
 };
 
-template <class Iterator>
+template< typename Iterator >
+using iterator_difference_t = typename std::iterator_traits< Iterator >::difference_type;
+
+template< typename Iterator >
 struct iterator_difference
 {
-    typedef typename std::iterator_traits<Iterator>::difference_type type;
+    using type = iterator_difference_t< Iterator >;
 };
 
-template <class Iterator>
+template< typename Iterator >
+using iterator_category_t = typename std::iterator_traits< Iterator >::iterator_category;
+
+template< typename Iterator >
 struct iterator_category
 {
-    typedef typename std::iterator_traits<Iterator>::iterator_category type;
+    using type = iterator_category_t< Iterator >;
 };
 
 } // namespace iterators