Add join argument allowing formating list of values separated by a (#466)
Add join argument allowing formating list of values separated by a
string. Each value is formated according the format specifier.
diff --git a/fmt/format.h b/fmt/format.h
index 1f5fa26..ea49eef 100644
--- a/fmt/format.h
+++ b/fmt/format.h
@@ -3865,6 +3865,66 @@
}
write(writer_, start, s);
}
+
+template <typename Char, typename It>
+struct ArgJoin {
+ It first;
+ It last;
+ BasicCStringRef<Char> sep;
+
+ ArgJoin(It first, It last, const BasicCStringRef<Char>& sep) :
+ first(first),
+ last(last),
+ sep(sep) {}
+};
+
+template <typename It>
+ArgJoin<char, It> join(It first, It last, const BasicCStringRef<char>& sep) {
+ return ArgJoin<char, It>(first, last, sep);
+}
+
+template <typename It>
+ArgJoin<wchar_t, It> join(It first, It last, const BasicCStringRef<wchar_t>& sep) {
+ return ArgJoin<wchar_t, It>(first, last, sep);
+}
+
+#if FMT_HAS_GXX_CXX11
+template <typename Range>
+auto join(const Range& range, const BasicCStringRef<char>& sep)
+ -> ArgJoin<char, decltype(std::begin(range))> {
+ return join(std::begin(range), std::end(range), sep);
+}
+
+template <typename Range>
+auto join(const Range& range, const BasicCStringRef<wchar_t>& sep)
+ -> ArgJoin<wchar_t, decltype(std::begin(range))> {
+ return join(std::begin(range), std::end(range), sep);
+}
+#endif
+
+template <typename ArgFormatter, typename Char, typename It>
+void format_arg(fmt::BasicFormatter<Char, ArgFormatter> &f,
+ const Char *&format_str, const ArgJoin<Char, It>& e) {
+ const Char* end = format_str;
+ if (*end == ':')
+ ++end;
+ while (*end && *end != '}')
+ ++end;
+ if (*end != '}')
+ FMT_THROW(FormatError("missing '}' in format string"));
+
+ It it = e.first;
+ if (it != e.last) {
+ const Char* save = format_str;
+ f.format(format_str, internal::MakeArg<fmt::BasicFormatter<Char, ArgFormatter> >(*it++));
+ while (it != e.last) {
+ f.writer().write(e.sep);
+ format_str = save;
+ f.format(format_str, internal::MakeArg<fmt::BasicFormatter<Char, ArgFormatter> >(*it++));
+ }
+ }
+ format_str = end + 1;
+}
} // namespace fmt
#if FMT_USE_USER_DEFINED_LITERALS
diff --git a/test/format-test.cc b/test/format-test.cc
index 6d4a8fc..e0d3ea7 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1552,6 +1552,27 @@
EXPECT_EQ(L"abc1", format(L"{}c{}", L"ab", 1));
}
+TEST(FormatTest, JoinArg) {
+ using fmt::join;
+ int v1[3] = { 1, 2, 3 };
+ std::vector<float> v2;
+ v2.push_back(1.2);
+ v2.push_back(3.4);
+
+ EXPECT_EQ("(1, 2, 3)", format("({})", join(v1 + 0, v1 + 3, ", ")));
+ EXPECT_EQ("(1)", format("({})", join(v1 + 0, v1 + 1, ", ")));
+ EXPECT_EQ("()", format("({})", join(v1 + 0, v1 + 0, ", ")));
+ EXPECT_EQ("(001, 002, 003)", format("({:03})", join(v1 + 0, v1 + 3, ", ")));
+ EXPECT_EQ("(+01.20, +03.40)", format("({:+06.2f})", join(v2.begin(), v2.end(), ", ")));
+
+ EXPECT_EQ(L"(1, 2, 3)", format(L"({})", join(v1 + 0, v1 + 3, L", ")));
+
+#if FMT_HAS_GXX_CXX11
+ EXPECT_EQ("(1, 2, 3)", format("({})", join(v1, ", ")));
+ EXPECT_EQ("(+01.20, +03.40)", format("({:+06.2f})", join(v2, ", ")));
+#endif
+}
+
template <typename T>
std::string str(const T &value) {
return fmt::format("{}", value);
