/**
 *   Copyright 2011-2015 Quickstep Technologies LLC.
 *   Copyright 2015 Pivotal Software, Inc.
 *   Copyright 2016, Quickstep Research Group, Computer Sciences Department,
 *     University of Wisconsin—Madison.
 *
 *   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.
 **/

#ifndef QUICKSTEP_PARSER_PARSE_EXPRESSION_HPP_
#define QUICKSTEP_PARSER_PARSE_EXPRESSION_HPP_

#include <string>

#include "parser/ParseTreeNode.hpp"
#include "utility/Macros.hpp"

namespace quickstep {

/** \addtogroup Parser
 *  @{
 */

/**
 * @brief The parsed representation of an expression.
 **/
class ParseExpression : public ParseTreeNode {
 public:
  enum ExpressionType {
    kAttribute,
    kBinaryExpression,
    kExtract,
    kFunctionCall,
    kScalarLiteral,
    kSearchedCaseExpression,
    kSimpleCaseExpression,
    kSubqueryExpression,
    kUnaryExpression,
  };

  /**
   * @brief Virtual destructor.
   **/
  ~ParseExpression() override {
  }

  /**
   * @return The expression type.
   */
  virtual ExpressionType getExpressionType() const = 0;

  /**
   * @brief Get a human-readable representation of this expression.
   *
   * @return The human-readable form of this expression.
   **/
  virtual std::string generateName() const = 0;

 protected:
  ParseExpression(const int line_number, const int column_number)
      : ParseTreeNode(line_number, column_number) {
  }

 private:
  DISALLOW_COPY_AND_ASSIGN(ParseExpression);
};


}  // namespace quickstep

#endif /* QUICKSTEP_PARSER_PARSE_EXPRESSION_HPP_ */