From ec2daddf475a904713cfdd6f785d63a90fe0313d Mon Sep 17 00:00:00 2001
From: Marc Chevrier <marc.chevrier@gmail.com>
Date: Sat, 14 Mar 2026 11:55:55 +0100
Subject: [PATCH] cmext/algorithm: add helpers functions cm::keys and
 cm::values

---
 Help/dev/source.rst           |  8 ++++
 Utilities/std/cmext/algorithm | 82 +++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/Help/dev/source.rst b/Help/dev/source.rst
index 47336456f1..ec4e12c0e0 100644
--- a/Help/dev/source.rst
+++ b/Help/dev/source.rst
@@ -247,6 +247,14 @@ These are:
   * ``cm::contains``:
     Checks if element or key is contained in container.
 
+  * ``cm::keys``
+    Extract keys from associative container or sequence container with tuple as
+    element
+
+  * ``cm::values``
+    Extract values from associative container or sequence container with tuple as
+    element
+
 * ``<cmext/enum_set>``
 
   * ``cm::enum_set``:
diff --git a/Utilities/std/cmext/algorithm b/Utilities/std/cmext/algorithm
index cc85b0ae25..327a7721f1 100644
--- a/Utilities/std/cmext/algorithm
+++ b/Utilities/std/cmext/algorithm
@@ -10,6 +10,7 @@
 #include <memory>
 #include <utility>
 
+#include <cm/ranges>
 #include <cm/type_traits>
 #include <cmext/iterator>
 #include <cmext/type_traits>
@@ -251,4 +252,85 @@ bool contains(Range const& range, Key const& key)
 }
 #endif
 
+template <
+  typename Range,
+  cm::enable_if_t<cm::is_associative_container<Range>::value ||
+                    cm::is_unordered_associative_container<Range>::value,
+                  int> = 0>
+std::vector<typename Range::key_type> keys(Range const& range)
+{
+#if defined(CMake_HAVE_CXX_RANGES)
+#  if __cplusplus >= 202302L || (defined(_MSVC_LANG) && _MSVC_LANG >= 202302L)
+  return std::vector<std::string_view>{ std::from_range,
+                                        std::views::keys(range) };
+#  else
+  auto view = std::views::keys(range);
+  return std::vector<std::string_view>{ view.begin(), view.end() };
+#  endif
+#else
+  return cm::views::keys(range);
+#endif
+}
+
+template <
+  typename Range,
+  cm::enable_if_t<cm::is_associative_container<Range>::value ||
+                    cm::is_unordered_associative_container<Range>::value,
+                  int> = 0>
+std::vector<typename Range::mapped_type> values(Range const& range)
+{
+#if defined(CMake_HAVE_CXX_RANGES)
+#  if __cplusplus >= 202302L || (defined(_MSVC_LANG) && _MSVC_LANG >= 202302L)
+  return std::vector<std::string_view>{ std::from_range,
+                                        std::views::values(range) };
+#  else
+  auto view = std::views::values(range);
+  return std::vector<std::string_view>{ view.begin(), view.end() };
+#  endif
+#else
+  return cm::views::values(range);
+#endif
+}
+
+// sequence containers with std::pair<> or std::tuple<> as elements
+template <typename Range,
+          cm::enable_if_t<cm::is_sequence_container<Range>::value &&
+                            cm::is_tuple<1, typename Range::value_type>::value,
+                          int> = 0>
+std::vector<typename std::tuple_element<0, typename Range::value_type>::type>
+keys(Range const& range)
+{
+#if defined(CMake_HAVE_CXX_RANGES)
+#  if __cplusplus >= 202302L || (defined(_MSVC_LANG) && _MSVC_LANG >= 202302L)
+  return std::vector<std::string_view>{ std::from_range,
+                                        std::views::keys(range) };
+#  else
+  auto view = std::views::keys(range);
+  return std::vector<std::string_view>{ view.begin(), view.end() };
+#  endif
+#else
+  return cm::views::keys(range);
+#endif
+}
+
+template <typename Range,
+          cm::enable_if_t<cm::is_sequence_container<Range>::value &&
+                            cm::is_tuple<2, typename Range::value_type>::value,
+                          int> = 0>
+std::vector<typename std::tuple_element<1, typename Range::value_type>::type>
+keys(Range const& range)
+{
+#if defined(CMake_HAVE_CXX_RANGES)
+#  if __cplusplus >= 202302L || (defined(_MSVC_LANG) && _MSVC_LANG >= 202302L)
+  return std::vector<std::string_view>{ std::from_range,
+                                        std::views::values(range) };
+#  else
+  auto view = std::views::values(range);
+  return std::vector<std::string_view>{ view.begin(), view.end() };
+#  endif
+#else
+  return cm::views::values(range);
+#endif
+}
+
 } // namespace cm