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/* 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 "antlr4-common.h"
#include "atn/LexerActionType.h"
namespace antlr4 {
namespace atn {
/// <summary>
/// Represents a single action which can be executed following the successful
/// match of a lexer rule. Lexer actions are used for both embedded action
/// syntax and ANTLR 4's new lexer command syntax.
///
/// @author Sam Harwell
/// @since 4.2
/// </summary>
class ANTLR4CPP_PUBLIC LexerAction {
public:
virtual ~LexerAction();
/// <summary>
/// Gets the serialization type of the lexer action.
/// </summary>
/// <returns> The serialization type of the lexer action. </returns>
virtual LexerActionType getActionType() const = 0;
/// <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>Many lexer commands, including {@code type}, {@code skip}, and
/// {@code more}, do not check the input index during their execution.
/// Actions like this are position-independent, and may be stored more
/// efficiently as part of the <seealso
/// cref="LexerATNConfig#lexerActionExecutor"/>.</para>
/// </summary>
/// <returns> {@code true} if the lexer action semantics can be affected by
/// the position of the input <seealso cref="CharStream"/> at the time it is
/// executed; otherwise, {@code false}. </returns>
virtual bool isPositionDependent() const = 0;
/// <summary>
/// Execute the lexer action in the context of the specified <seealso
/// cref="Lexer"/>.
///
/// <para>For position-dependent actions, the input stream must already be
/// positioned correctly prior to calling this method.</para>
/// </summary>
/// <param name="lexer"> The lexer instance. </param>
virtual void execute(Lexer* lexer) = 0;
virtual size_t hashCode() const = 0;
virtual bool operator==(const LexerAction& obj) const = 0;
virtual bool operator!=(const LexerAction& obj) const {
return !(*this == obj);
}
virtual std::string toString() const = 0;
};
} // namespace atn
} // namespace antlr4
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