External/fmt
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tiptoeing into class template argument deduction.

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Signed-off-by: Daniela Engert <dani@ngrt.de>
This commit is contained in:
Daniela Engert 2018-10-07 10:21:15 +02:00
parent 041bf83d9b
commit 604b4c41f2
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2 changed files with 45 additions and 0 deletions
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19
include/fmt/core.h
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@ -139,6 +139,13 @@
# endif
#endif
#if FMT_HAS_FEATURE(__cpp_deduction_guides) || \
(defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1914)
# define FMT_HAS_CTAD 1
#else
# define FMT_HAS_CTAD 0
#endif
#ifndef FMT_BEGIN_NAMESPACE
# if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
FMT_MSC_VER >= 1900
@ -434,6 +441,18 @@ class basic_string_view {
typedef basic_string_view<char> string_view;
typedef basic_string_view<wchar_t> wstring_view;
#if FMT_HAS_CTAD
template<typename Char>
basic_string_view(const Char *, size_t) -> basic_string_view<Char>;
template<typename Char>
basic_string_view(const Char *) -> basic_string_view<Char>;
template<typename Char, typename Alloc>
basic_string_view(const std::basic_string<Char, Alloc> &) -> basic_string_view<Char>;
#ifdef FMT_STRING_VIEW
template<typename Char>
basic_string_view(FMT_STRING_VIEW<Char>) -> basic_string_view<Char>;
#endif
#endif
// A base class for compile-time strings. It is defined in the fmt namespace to
// make formatting functions visible via ADL, e.g. format(fmt("{}"), 42).

26
test/core-test.cc
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@ -32,6 +32,7 @@ using fmt::basic_format_arg;
using fmt::internal::basic_buffer;
using fmt::internal::value;
using fmt::string_view;
using fmt::wstring_view;
using testing::_;
using testing::StrictMock;
@ -437,6 +438,31 @@ TEST(StringViewTest, Compare) {
check_op<std::greater_equal>();
}
#if FMT_HAS_CTAD
TEST(BasicStringViewTest, ClassTemplateArgumentDeduction) {
// Test that basic_string_view<Char> is correctly deduced
char str[] = "some string";
const std::size_t slen = strlen(str);
const string_view sv(str);
EXPECT_EQ(sv, fmt::basic_string_view(str));
EXPECT_EQ(sv, fmt::basic_string_view(str, slen));
EXPECT_EQ(sv, fmt::basic_string_view(std::string(str)));
#ifdef FMT_STRING_VIEW
EXPECT_EQ(sv, fmt::basic_string_view(FMT_STRING_VIEW<char>(str)));
#endif
// wide character types
const wchar_t *wstr = L"some string";
EXPECT_EQ(wstring_view(wstr), fmt::basic_string_view(wstr));
const char16_t *c16str = u"some string";
EXPECT_EQ(fmt::basic_string_view<char16_t>(c16str), fmt::basic_string_view(c16str));
const char32_t *c32str = U"some string";
EXPECT_EQ(fmt::basic_string_view<char32_t>(c32str), fmt::basic_string_view(c32str));
}
#endif
enum basic_enum {};
TEST(CoreTest, ConvertToInt) {