content: /*
   * 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.calcite.sql;
  
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  
  import com.google.common.collect.ImmutableSet;
  
  import java.util.Set;
  
  /**
   * An operator describing a LATERAL specification.
   */
  public class SqlLateralOperator extends SqlSpecialOperator {
    //~ Constructors -----------------------------------------------------------
  
    public SqlLateralOperator(SqlKind kind) {
      super(kind.name(), kind, 200, true, ReturnTypes.ARG0, null,
          OperandTypes.ANY);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
        int rightPrec) {
      final Set<SqlKind> specialOperandKinds =
          ImmutableSet.of(SqlKind.COLLECTION_TABLE, SqlKind.SELECT, SqlKind.AS, SqlKind.UNNEST);
      if (call.operandCount() == 1
          && specialOperandKinds.contains(call.operand(0).getKind())) {
        // Do not create ( ) around the following TABLE clause.
        writer.keyword(getName());
        call.operand(0).unparse(writer, 0, 0);
      } else {
        SqlUtil.unparseFunctionSyntax(this, writer, call, false);
      }
    }
  }
  