<boost/url/rfc/uri_rule.hpp>
constexpr /* implementation-defined */ uri_rule = {};
using value_type = url_view;
Rules are used with the function grammar::parse.
system::result< url_view > rv = grammar::parse( "https://www.example.com/index.htm?id=guest#s1", uri_rule );
URI = scheme ":" hier-part [ "?" query ] [ "#" fragment ]