code: Rule ChordOrText() {
  		return Sequence(
  				String("\""),
  				OptionalS(FirstOfS(Chord(), TextExpression())),
  				ZeroOrMoreS(SequenceS(ChordOrTextNewline(),
  						FirstOfS(Chord(), TextExpression())
  						)),
  				String("\"")
  		).label(ChordOrText);
  	}
docs: chord-or-text ::= %x22 (chord / text-expression)
  *(chord-newline (chord / text-expression)) %x22<p>
  <tt>".."</tt>