Return the union of two character sets.
Declared in file <boost/url/grammar/lut_chars.hpp> at line 291
This function returns a new character set which contains all of the characters in `cs0` as well as all of the characters in `cs`.
This creates a character set which includes all letters and numbers
constexpr lut_chars alpha_chars(
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz");
constexpr lut_chars alnum_chars = alpha_chars + "0123456789";
Constant.