Output Ranges for Functionality & Additional Safety

include/fmt/color.h

@@ -538,6 +538,86 @@ inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                       fmt::make_format_args<buffer_context<Char>>(args...));
 }
 
+#if FMT_OUTPUT_RANGES
+/**
+  Formats a string with the given text_style and writes the output to ``out``.
+ */
+template <typename Output, typename Char,
+          FMT_ENABLE_IF(std::ranges::output_range<Output, Char> ||
+                        std::output_iterator<remove_cvref_t<Output>, Char>)>
+auto vformat_to(Output&& out, const text_style& ts,
+                basic_string_view<Char> format_str,
+                basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  auto&& buf = detail::get_appendable_buffer<Char>(std::forward<Output>(out));
+  detail::vformat_to(buf, ts, format_str, args);
+  return detail::get_iterator(buf, out);
+}
+
+/**
+  \rst
+  Formats arguments with the given text_style, writes the result to the output
+  iterator or range ``out`` and returns the iterator past the end of the output
+  range.
+
+  **Example**::
+
+    std::vector<char> out;
+    fmt::format_to(std::back_inserter(out),
+                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+  \endrst
+*/
+template <typename Output, typename S, typename... Args,
+          bool enable =
+              (std::ranges::output_range<Output, char_t<S>> ||
+               std::output_iterator<remove_cvref_t<Output>,
+                                    char_t<S>>)&&detail::is_string<S>::value,
+          FMT_ENABLE_IF(enable)>
+inline auto format_to(Output&& out, const text_style& ts, const S& format_str,
+                      Args&&... args) {
+  return vformat_to(std::forward<Output>(out), ts,
+                    detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+}
+
+/**
+  Formats a string with the given text_style and writes the output to ``out``.
+ */
+template <typename Output, typename Char,
+          FMT_ENABLE_IF(std::ranges::output_range<Output, Char> ||
+                        std::output_iterator<remove_cvref_t<Output>, Char>)>
+auto vformat_into(
+    Output&& out, const text_style& ts, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  auto&& buf = detail::get_buffer<Char>(std::forward<Output>(out));
+  detail::vformat_to(buf, ts, format_str, args);
+  return detail::get_iterator(buf, out);
+}
+
+/**
+  \rst
+  Formats arguments with the given text_style, writes the result to the output
+  iterator ``out`` and returns the iterator past the end of the output range.
+
+  **Example**::
+
+    std::vector<char> out;
+    fmt::format_to(std::back_inserter(out),
+                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+  \endrst
+*/
+template <typename Output, typename S, typename... Args,
+          bool enable =
+              (std::ranges::output_range<Output, char_t<S>> ||
+               std::output_iterator<remove_cvref_t<Output>,
+                                    char_t<S>>)&&detail::is_string<S>::value,
+          FMT_ENABLE_IF(enable)>
+inline auto format_into(Output&& out, const text_style& ts, const S& format_str,
+                        Args&&... args) {
+  return vformat_into(
+      std::forward<Output>(out), ts, detail::to_string_view(format_str),
+      fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+}
+#else
 /**
   Formats a string with the given text_style and writes the output to ``out``.
  */
@@ -573,6 +653,7 @@ inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
   return vformat_to(out, ts, detail::to_string_view(format_str),
                     fmt::make_format_args<buffer_context<char_t<S>>>(args...));
 }
+#endif
 
 template <typename T, typename Char>
 struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {

include/fmt/compile.h

@@ -471,6 +471,39 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
   }
 }
 
+#  if FMT_OUTPUT_RANGES
+template <typename Output, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR auto format_to(Output&& out, const S&, Args&&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format_to(
+        std::forward<Output>(out),
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format_to(std::forward<Output>(out), compiled,
+                          std::forward<Args>(args)...);
+  }
+}
+
+template <typename Output, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR auto format_into(Output&& out, const S&, Args&&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format_into(
+        std::forward<Output>(out),
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format_into(std::forward<Output>(out), compiled,
+                            std::forward<Args>(args)...);
+  }
+}
+#  else
 template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
@@ -484,6 +517,7 @@ FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
     return fmt::format_to(out, compiled, std::forward<Args>(args)...);
   }
 }
+#  endif
 #endif
 
 template <typename OutputIt, typename S, typename... Args,