SqlColumnListConstructor.java

/*
 * 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);
  }
}