update fmt::join to support more character types#4686
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Yancey2023 wants to merge 3 commits intofmtlib:masterfrom
Open
update fmt::join to support more character types#4686Yancey2023 wants to merge 3 commits intofmtlib:masterfrom
Yancey2023 wants to merge 3 commits intofmtlib:masterfrom
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vitaut
requested changes
Feb 28, 2026
| // A loop is faster than memcpy on small sizes. | ||
| T* out = ptr_ + size; | ||
| for (size_t i = 0; i < count; ++i) out[i] = begin[i]; | ||
| for (size_t i = 0; i < count; ++i) out[i] = static_cast<T>(begin[i]); |
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This cast shouldn't be here because we shouldn't mix different code units.
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How can I fix the issues mentioned in my PR if I don't do this?
| template <typename Char> constexpr auto getsign(sign s) -> Char { | ||
| return static_cast<char>(((' ' << 24) | ('+' << 16) | ('-' << 8)) >> | ||
| (static_cast<int>(s) * 8)); | ||
| return static_cast<Char>(static_cast<char>( |
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Won't one cast be sufficient?
Author
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This does need to cast twice.
int -> char -> wchar_t
I have try to cast to wchar_t directly, but the result is error.
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| template <typename T, typename S, | ||
| typename Char = typename decltype(detail::to_string_view( | ||
| std::declval<S>()))::value_type, | ||
| FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)> | ||
| auto join(std::initializer_list<T> list, S&& sep) | ||
| -> join_view<const T*, const T*, Char> { | ||
| return {std::begin(list), std::end(list), detail::to_string_view(sep)}; | ||
| } |
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This one is a questionable API and we should probably deprecated it. At the very least let's not touch it here.
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This PR brings more character type support for
fmt::join.Besides, implicit conversions of different character types may generate errors, so CI cannot pass. I also fix it.