static Exp nlLogic_parseExpression(S s) {
  L<S> tok = javaTokPlusBrackets(s);
  L<S> l = splitAtTokens(tok, ll("&", "", "&"));
  if (l(l) == 2) // TODO
    ret And(parseExpression(first(l)), nlLogic_parseExpression(second(l)));
  if (l(tok) == 5 && isIdentifier(tok.get(1)) && isRoundBracketed(tok.get(3)))
    ret Func(tok.get(1), nlLogic_parseExpression(deRoundBracket(tok.get(3))));
  l = splitAtTokens(tok, ll("="));
  if (l(l) == 2)
    ret Eq(nlLogic_parseExpression(first(l)), nlLogic_parseExpression(second(l)));
  ret Sentence(tok);
}