HuaHuaY commented on PR #572:
URL: https://github.com/apache/iceberg-cpp/pull/572#issuecomment-3950201156
> > Can we implement this by SFINAE or concept instead of using macro?
>
> I tried, but it still requires relying on the _LIBCPP_VERSION macro, I
would appreciate your suggestions if there is a better solution.
For examples,
```cpp
#include <charconv>
#include <string_view>
#include <utility>
#include <iostream>
template <typename T>
concept FromChars = requires(const char* p, T& v) { std::from_chars(p, p,
v); };
template <typename T>
requires std::is_arithmetic_v<T> && (!std::same_as<T, bool>)
&& FromChars<T>
static T ParseNumber(std::string_view str) {
T value = 0;
auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(),
value);
if (ec == std::errc()) [[likely]] {
return value;
}
std::unreachable();
}
template <typename T>
requires std::floating_point<T> && (!FromChars<T>)
static T ParseNumber(std::string_view str) {
char* end = nullptr;
return std::strtod(str.data(), &end);
}
int main() {
auto v = ParseNumber<double>("123.12");
std::cout << v << std::endl;
}
```
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