boost::urls::unreserved_chars
The unreserved character set
Synopsis
Declared in header <boost/url/rfc/unreserved_chars.hpp>
Character sets are used with rules and
the functions grammar::find_if and grammar::find_if_not .
system::result< decode_view > rv = grammar::parse( "Program%20Files", pct_encoded_rule( unreserved_chars ) );
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"