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.SqlAsOperator;
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.type.InferTypes;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.ReturnTypes;
  
  /**
   * Operator that assigns an argument to a function call to a particular named
   * parameter.
   *
   * <p>Not an expression; just a holder to represent syntax until the validator
   * has chance to resolve arguments.
   *
   * <p>Sub-class of {@link SqlAsOperator} ("AS") out of convenience; to be
   * consistent with AS, we reverse the arguments.
   */
  class SqlArgumentAssignmentOperator extends SqlAsOperator {
    SqlArgumentAssignmentOperator() {
      super("=>", SqlKind.ARGUMENT_ASSIGNMENT, 20, true, ReturnTypes.ARG0,
          InferTypes.RETURN_TYPE, OperandTypes.ANY_IGNORE);
    }
  
    @Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
        int rightPrec) {
      // Arguments are held in reverse order to be consistent with base class (AS).
      call.operand(1).unparse(writer, leftPrec, getLeftPrec());
      writer.keyword(getName());
      call.operand(0).unparse(writer, getRightPrec(), rightPrec);
    }
  
    @Override public boolean argumentMustBeScalar(int ordinal) {
      return false;
    }
  }
  