private SimpleExpression parseSimpleExpression() {
		//System.out.println("parseSimpleExpression");
		SimpleExpression node = new SimpleExpression();
		SignedTerm sTerm = new SignedTerm();
		if(nextIs("plus") || nextIs("minus")){
			sTerm.setOp(new Operator(acceptIt()));
		}
		sTerm.setTerm(parseTerm());
		node.getTerms().add(sTerm);
		while (nextIs("plus") || nextIs("minus") || nextIs("or")) {
			sTerm = new SignedTerm();
			sTerm.setOp(new Operator(acceptIt()));
			sTerm.setTerm(parseTerm());
			node.getTerms().add(sTerm);
		}
		return node;
	}