Use grouping() from locale for specifier 'n'

test/format-test.cc

@@ -1475,11 +1475,7 @@ TEST(FormatterTest, FormatOct) {
 }
 
 TEST(FormatterTest, FormatIntLocale) {
-  EXPECT_EQ("123", format("{:n}", 123));
-  EXPECT_EQ("1,234", format("{:n}", 1234));
-  EXPECT_EQ("1,234,567", format("{:n}", 1234567));
-  EXPECT_EQ("4,294,967,295",
-            format("{:n}", max_value<uint32_t>()));
+  EXPECT_EQ("1234", format("{:n}", 1234));
 }
 
 struct ConvertibleToLongLong {

test/locale-test.cc

@@ -8,13 +8,37 @@
 #include "fmt/locale.h"
 #include "gmock.h"
 
+using fmt::internal::max_value;
+
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
 template <typename Char> struct numpunct : std::numpunct<Char> {
  protected:
   Char do_decimal_point() const FMT_OVERRIDE { return '?'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\03"; }
   Char do_thousands_sep() const FMT_OVERRIDE { return '~'; }
 };
 
+template <typename Char> struct no_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return ""; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
+template <typename Char> struct special_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\03\02"; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
+template <typename Char> struct small_grouping : std::numpunct<Char> {
+ protected:
+  Char do_decimal_point() const FMT_OVERRIDE { return '.'; }
+  std::string do_grouping() const FMT_OVERRIDE { return "\01"; }
+  Char do_thousands_sep() const FMT_OVERRIDE { return ','; }
+};
+
 TEST(LocaleTest, DoubleDecimalPoint) {
   std::locale loc(std::locale(), new numpunct<char>());
   EXPECT_EQ("1?23", fmt::format(loc, "{:n}", 1.23));
@@ -29,24 +53,44 @@ TEST(LocaleTest, DoubleDecimalPoint) {
 
 TEST(LocaleTest, Format) {
   std::locale loc(std::locale(), new numpunct<char>());
-  EXPECT_EQ("1,234,567", fmt::format(std::locale(), "{:n}", 1234567));
+  EXPECT_EQ("1234567", fmt::format(std::locale(), "{:n}", 1234567));
   EXPECT_EQ("1~234~567", fmt::format(loc, "{:n}", 1234567));
   fmt::format_arg_store<fmt::format_context, int> as{1234567};
   EXPECT_EQ("1~234~567", fmt::vformat(loc, "{:n}", fmt::format_args(as)));
   std::string s;
   fmt::format_to(std::back_inserter(s), loc, "{:n}", 1234567);
   EXPECT_EQ("1~234~567", s);
+
+  std::locale no_grouping_loc(std::locale(), new no_grouping<char>());
+  EXPECT_EQ("1234567", fmt::format(no_grouping_loc, "{:n}", 1234567));
+
+  std::locale special_grouping_loc(std::locale(), new special_grouping<char>());
+  EXPECT_EQ("1,23,45,678", fmt::format(special_grouping_loc, "{:n}", 12345678));
+
+  std::locale small_grouping_loc(std::locale(), new small_grouping<char>());
+  EXPECT_EQ("4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, "{:n}", max_value<uint32_t>()));
 }
 
 TEST(LocaleTest, WFormat) {
   std::locale loc(std::locale(), new numpunct<wchar_t>());
-  EXPECT_EQ(L"1,234,567", fmt::format(std::locale(), L"{:n}", 1234567));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale(), L"{:n}", 1234567));
   EXPECT_EQ(L"1~234~567", fmt::format(loc, L"{:n}", 1234567));
   fmt::format_arg_store<fmt::wformat_context, int> as{1234567};
   EXPECT_EQ(L"1~234~567", fmt::vformat(loc, L"{:n}", fmt::wformat_args(as)));
-  auto sep =
-      std::use_facet<std::numpunct<wchar_t>>(std::locale("C")).thousands_sep();
-  auto result = sep == ',' ? L"1,234,567" : L"1234567";
-  EXPECT_EQ(result, fmt::format(std::locale("C"), L"{:n}", 1234567));
+  EXPECT_EQ(L"1234567", fmt::format(std::locale("C"), L"{:n}", 1234567));
+
+  std::locale no_grouping_loc(std::locale(), new no_grouping<wchar_t>());
+  EXPECT_EQ(L"1234567", fmt::format(no_grouping_loc, L"{:n}", 1234567));
+
+  std::locale special_grouping_loc(std::locale(),
+                                   new special_grouping<wchar_t>());
+  EXPECT_EQ(L"1,23,45,678",
+            fmt::format(special_grouping_loc, L"{:n}", 12345678));
+
+  std::locale small_grouping_loc(std::locale(), new small_grouping<wchar_t>());
+  EXPECT_EQ(L"4,2,9,4,9,6,7,2,9,5",
+            fmt::format(small_grouping_loc, L"{:n}", max_value<uint32_t>()));
 }
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR

test/std-format-test.cc

@@ -61,11 +61,11 @@ TEST(StdFormatTest, Int) {
   string s0 = format("{}", 42);                       // s0 == "42"
   string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);  // s1 == "101010 42 52 2a"
   string s2 = format("{0:#x} {0:#X}", 42);            // s2 == "0x2a 0X2A"
-  string s3 = format("{:n}", 1234);  // s3 == "1,234" (depends on the locale)
+  string s3 = format("{:n}", 1234);  // s3 == "1234" (depends on the locale)
   EXPECT_EQ(s0, "42");
   EXPECT_EQ(s1, "101010 42 52 2a");
   EXPECT_EQ(s2, "0x2a 0X2A");
-  EXPECT_EQ(s3, "1,234");
+  EXPECT_EQ(s3, "1234");
 }
 
 #include <format>