From 98f793118d71f7f4c81c3a96878fb0e05efa51fb Mon Sep 17 00:00:00 2001
From: Matthias Moulin <matthias.moulin@gmail.com>
Date: Thu, 23 May 2024 20:10:26 +0200
Subject: [PATCH] Added range_format::string formatter

Either the basic_string_view<Char> range constructor or a user-defined conversion operator will be used.
---
 include/fmt/ranges.h | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index 57ccb6a0ae3d8..3b5d7d76b56bb 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -515,7 +515,8 @@ struct formatter<
     enable_if_t<conjunction<
         bool_constant<range_format_kind<R, Char>::value !=
                           range_format::disabled &&
-                      range_format_kind<R, Char>::value != range_format::map>
+                      range_format_kind<R, Char>::value != range_format::map &&
+                      range_format_kind<R, Char>::value != range_format::string>
 // Workaround a bug in MSVC 2015 and earlier.
 #if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
         ,
@@ -604,6 +605,28 @@ struct formatter<
   }
 };
 
+// A string formatter.
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<range_format_kind<R, Char>::value == range_format::string>> {
+ private:
+  using range_type = detail::maybe_const_range<R>;
+  formatter<detail::std_string_view<Char>, Char> range_formatter_;
+
+ public:
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return range_formatter_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return range_formatter_.format(detail::std_string_view<Char>(range), ctx);
+  }
+};
+
 template <typename It, typename Sentinel, typename Char = char>
 struct join_view : detail::view {
   It begin;