content: /*
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * Licensed 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 com.alibaba.graphscope.gremlin.antlr4x.visitor;
  
  import org.apache.calcite.rex.RexCall;
  import org.apache.calcite.rex.RexLiteral;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.sql.SqlKind;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.javatuples.Pair;
  
  import java.util.List;
  
  public class Utils {
      public static Pair<RexNode, @Nullable String> convertExprToPair(RexNode rex) {
          if (rex.getKind() == SqlKind.AS) {
              List<RexNode> operands = ((RexCall) rex).getOperands();
              return Pair.with(
                      operands.get(0),
                      (String)
                              com.alibaba.graphscope.common.ir.tools.Utils.getValuesAsList(
                                              ((RexLiteral) operands.get(1)).getValue())
                                      .get(0));
          }
          return Pair.with(rex, null);
      }
  }
  