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.fun;
  
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlSpecialOperator;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  
  /**
   * SqlColumnListConstructor defines the non-standard constructor used to pass a
   * COLUMN_LIST parameter to a UDX.
   */
  public class SqlColumnListConstructor extends SqlSpecialOperator {
    //~ Constructors -----------------------------------------------------------
  
    public SqlColumnListConstructor() {
      super(
          "COLUMN_LIST",
          SqlKind.COLUMN_LIST, MDX_PRECEDENCE,
          false,
          ReturnTypes.COLUMN_LIST,
          null,
          OperandTypes.ANY);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void unparse(
        SqlWriter writer,
        SqlCall call,
        int leftPrec,
        int rightPrec) {
      writer.keyword("ROW");
      final SqlWriter.Frame frame = writer.startList("(", ")");
      for (SqlNode operand : call.getOperandList()) {
        writer.sep(",");
        operand.unparse(writer, leftPrec, rightPrec);
      }
      writer.endList(frame);
    }
  }
  