[#748253C08DC3B24AD30AEC881354E7D8943C39A4]
Constructor
constexpr lut_chars(char const* s) noexcept;
This function constructs a character set which has as members, all of the characters present in the null-terminated string `s`.
constexpr lut_chars digits = "0123456789";
Linear in `::strlen(s)`, or constant if `s` is a constant expression.
Throws nothing.