cpp/third_party/antlr4-cpp-runtime-4/runtime/src/atn/LexerCustomAction.h

/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

#pragma once

#include "atn/LexerAction.h"
#include "atn/LexerActionType.h"

namespace antlr4 {
namespace atn {

  /// <summary>
  /// Executes a custom lexer action by calling <seealso cref="Recognizer#action"/> with the
  /// rule and action indexes assigned to the custom action. The implementation of
  /// a custom action is added to the generated code for the lexer in an override
  /// of <seealso cref="Recognizer#action"/> when the grammar is compiled.
  ///
  /// <para>This class may represent embedded actions created with the <code>{...}</code>
  /// syntax in ANTLR 4, as well as actions created for lexer commands where the
  /// command argument could not be evaluated when the grammar was compiled.</para>
  ///
  /// @author Sam Harwell
  /// @since 4.2
  /// </summary>
  class ANTLR4CPP_PUBLIC LexerCustomAction final : public LexerAction {
  public:
    /// <summary>
    /// Constructs a custom lexer action with the specified rule and action
    /// indexes.
    /// </summary>
    /// <param name="ruleIndex"> The rule index to use for calls to
    /// <seealso cref="Recognizer#action"/>. </param>
    /// <param name="actionIndex"> The action index to use for calls to
    /// <seealso cref="Recognizer#action"/>. </param>
    LexerCustomAction(size_t ruleIndex, size_t actionIndex);

    /// <summary>
    /// Gets the rule index to use for calls to <seealso cref="Recognizer#action"/>.
    /// </summary>
    /// <returns> The rule index for the custom action. </returns>
    size_t getRuleIndex() const;

    /// <summary>
    /// Gets the action index to use for calls to <seealso cref="Recognizer#action"/>.
    /// </summary>
    /// <returns> The action index for the custom action. </returns>
    size_t getActionIndex() const;

    /// <summary>
    /// {@inheritDoc}
    /// </summary>
    /// <returns> This method returns <seealso cref="LexerActionType#CUSTOM"/>. </returns>
    virtual LexerActionType getActionType() const override;

    /// <summary>
    /// Gets whether the lexer action is position-dependent. Position-dependent
    /// actions may have different semantics depending on the <seealso cref="CharStream"/>
    /// index at the time the action is executed.
    ///
    /// <para>Custom actions are position-dependent since they may represent a
    /// user-defined embedded action which makes calls to methods like
    /// <seealso cref="Lexer#getText"/>.</para>
    /// </summary>
    /// <returns> This method returns {@code true}. </returns>
    virtual bool isPositionDependent() const override;

    /// <summary>
    /// {@inheritDoc}
    ///
    /// <para>Custom actions are implemented by calling <seealso cref="Lexer#action"/> with the
    /// appropriate rule and action indexes.</para>
    /// </summary>
    virtual void execute(Lexer *lexer) override;

    virtual size_t hashCode() const override;
    virtual bool operator == (const LexerAction &obj) const override;
    virtual std::string toString() const override;

  private:
    const size_t _ruleIndex;
    const size_t _actionIndex;
  };

} // namespace atn
} // namespace antlr4