twalthr commented on a change in pull request #7664: [FLINK-11449][table] Uncouple the Expression class from RexNodes. URL: https://github.com/apache/flink/pull/7664#discussion_r255060144
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/expressions/TableSymbol.java ########## @@ -0,0 +1,26 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.table.expressions; + +/** + * The base interface for all symbol, such as time interval unit, time point unit + * are all defined based on TableSymbol. + */ +public interface TableSymbol { Review comment: Not sure if this is possible in Java but can we enforce subclasses to be of type enum? Maybe by converting this interface to a class extending enum? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
