static addUnaryOp(op_name) {
		Jsep.max_unop_len = Math.max(op_name.length, Jsep.max_unop_len);
		Jsep.unary_ops[op_name] = 1;
		return Jsep;
	}
@method addUnaryOp
@param {string} op_name The name of the unary op to add
@returns {Jsep}