private Comparison.Op cmp_op() {
		switch (peekType()) {
		case LT:
			consume(LT);
			return Comparison.Op.LT;
		case LE:
			consume(LE);
			return Comparison.Op.LE;
		case EQ:
			consume(EQ);
			return Comparison.Op.EQ;
		case GE:
			consume(GE);
			return Comparison.Op.GE;
		case GT:
			consume(GT);
			return Comparison.Op.GT;
		case NE:
			consume(NE);
			return Comparison.Op.NE;
		default:
			throw new SyntaxError(peek());
		}
	}