code: Rule IfieldArea() {
  		return Sequence(String("[A:"),
  				ZeroOrMore(WSP()).suppressNode(),
  				TexTextIfield(),
  				String("]"))
  			.label(IfieldArea);
  	}
docs: ifield-area ::= %5B.%41.%3A *WSP tex-text-ifield %5D<p>
  <tt>[A:..]</tt>