static IfThen nlLogic_parseRule(S s) {
  new IfThen rule;
  L<S> tok = javaTokPlusBrackets2(s);
  if (isSquareBracketed(get(tok, 1))) {
    L<S> tokOptions = javaTokPlusBrackets2(deSquareBracket(get(tok, 1)));
    new Matches m;
    for (S option : tok_splitAtComma(tokOptions)) {
      if (startsWith_trim(option, "id: ", m))
        rule.globalID = m.rest();
      else
        rule.options.add(m.rest());
    }
    tok = dropFirst(2, tok);
  }
  
  L<S> l = splitAtDoubleArrow(tok);
  if (l(l) != 2) null;
  rule.in = nlLogic_parseExpression(first(l));
  rule.out = nlLogic_parseExpression(second(l));
  ret rule;
}