// function template to export a compile-time string to runtime:
template<int MaxSize>
consteval auto toRuntimeString(std::string s)
{ // ensure the size of the exported array is large enough:
assert(s.size() <= MaxSize);
// create a compile-time array and copy all characters into it:
std::array<char, MaxSize+1> arr{}; // ensure all elems are initialized
for (int i = 0; i < s.size(); ++i) {
arr[i] = s[i];
}
// return the compile-time array and the string size:
return std::pair{arr, s.size()};
}
// function to import an exported compile-time string at runtime:
std::string fromComptimeString(const auto& dataAndSize)
{ // init string with exported array of chars and size:
return std::string{dataAndSize.first.data(),
dataAndSize.second};
}
// test the functions:
consteval auto comptimeMaxStr()
{
std::string s = "max int is " + asString(std::numeric_limits<int>::max())
+ " (" + asString(std::numeric_limits<int>::digits + 1)
+ " bits)";
return toRuntimeString<100>(s);
}
int main()
{
std::string s = fromComptimeString(comptimeMaxStr());
std::cout << s << '\n';
}
