Remove char_traits (#1117)

include/fmt/format-inl.h

@@ -254,21 +254,12 @@ template <> FMT_FUNC int count_digits<4>(internal::uintptr_t n) {
 }
 
 template <typename T>
-int char_traits<char>::format_float(char* buf, std::size_t size,
+int format_float(char* buf, std::size_t size, const char* format, int precision,
-                                    const char* format, int precision,
+                 T value) {
-                                    T value) {
   return precision < 0 ? FMT_SNPRINTF(buf, size, format, value)
                        : FMT_SNPRINTF(buf, size, format, precision, value);
 }
 
-template <typename T>
-int char_traits<wchar_t>::format_float(wchar_t* buf, std::size_t size,
-                                       const wchar_t* format, int precision,
-                                       T value) {
-  return precision < 0 ? FMT_SWPRINTF(buf, size, format, value)
-                       : FMT_SWPRINTF(buf, size, format, precision, value);
-}
-
 template <typename T>
 const char basic_data<T>::DIGITS[] =
     "0001020304050607080910111213141516171819"
@@ -758,8 +749,8 @@ void sprintf_format(Double value, internal::buffer<char>& buf,
   for (;;) {
     std::size_t buffer_size = buf.capacity();
     start = &buf[0];
-    int result = internal::char_traits<char>::format_float(
+    int result =
-        start, buffer_size, format, spec.precision, value);
+        format_float(start, buffer_size, format, spec.precision, value);
     if (result >= 0) {
       unsigned n = internal::to_unsigned(result);
       if (n < buf.capacity()) {

include/fmt/format.h

@@ -552,40 +552,6 @@ typedef basic_memory_buffer<wchar_t> wmemory_buffer;
 
 namespace internal {
 
-template <typename Char> struct char_traits;
-
-template <> struct char_traits<char> {
-  // Formats a floating-point number.
-  template <typename T>
-  FMT_API static int format_float(char* buffer, std::size_t size,
-                                  const char* format, int precision, T value);
-};
-
-template <> struct char_traits<wchar_t> {
-  template <typename T>
-  FMT_API static int format_float(wchar_t* buffer, std::size_t size,
-                                  const wchar_t* format, int precision,
-                                  T value);
-};
-
-#if FMT_USE_EXTERN_TEMPLATES
-extern template int char_traits<char>::format_float<double>(char* buffer,
-                                                            std::size_t size,
-                                                            const char* format,
-                                                            int precision,
-                                                            double value);
-extern template int char_traits<char>::format_float<long double>(
-    char* buffer, std::size_t size, const char* format, int precision,
-    long double value);
-
-extern template int char_traits<wchar_t>::format_float<double>(
-    wchar_t* buffer, std::size_t size, const wchar_t* format, int precision,
-    double value);
-extern template int char_traits<wchar_t>::format_float<long double>(
-    wchar_t* buffer, std::size_t size, const wchar_t* format, int precision,
-    long double value);
-#endif
-
 // A workaround for std::string not having mutable data() until C++17.
 template <typename Char> inline Char* get_data(std::basic_string<Char>& s) {
   return &s[0];

src/format.cc

@@ -28,16 +28,6 @@ template FMT_API void internal::buffer<char>::append(const char*, const char*);
 template FMT_API void internal::arg_map<format_context>::init(
     const basic_format_args<format_context>& args);
 
-template FMT_API int internal::char_traits<char>::format_float(char*,
-                                                               std::size_t,
-                                                               const char*, int,
-                                                               double);
-
-template FMT_API int internal::char_traits<char>::format_float(char*,
-                                                               std::size_t,
-                                                               const char*, int,
-                                                               long double);
-
 template FMT_API std::string internal::vformat<char>(
     string_view, basic_format_args<format_context>);
 
@@ -60,12 +50,6 @@ template FMT_API void internal::buffer<wchar_t>::append(const wchar_t*,
 template FMT_API void internal::arg_map<wformat_context>::init(
     const basic_format_args<wformat_context>&);
 
-template FMT_API int internal::char_traits<wchar_t>::format_float(
-    wchar_t*, std::size_t, const wchar_t*, int, double);
-
-template FMT_API int internal::char_traits<wchar_t>::format_float(
-    wchar_t*, std::size_t, const wchar_t*, int, long double);
-
 template FMT_API std::wstring internal::vformat<wchar_t>(
     wstring_view, basic_format_args<wformat_context>);
 FMT_END_NAMESPACE

test/format-test.cc

@@ -2538,3 +2538,8 @@ TEST(FormatTest, EmphasisNonHeaderOnly) {
   EXPECT_EQ(fmt::format(fmt::emphasis::bold, "bold error"),
             "\x1b[1mbold error\x1b[0m");
 }
+
+TEST(FormatTest, CharTraitsIsNotAmbiguous) {
+  using namespace std;
+  char_traits<char>::char_type c;
+}