code: Rule NonBracketChar() {
  		return ZeroOrMore(FirstOf(
  					WSP(),
  					CharRange('!','\\'),
  					CharRange('^','~'),
  					LatinExtendedAndOtherAlphabet()
  				)).label(NonBracketChar);
  	}
docs: all except <tt>]<tt>
  <p>
  non-bracket-char ::= *(WSP / %21-%5C / %5E-7E)