83 lines
3.2 KiB
C++
83 lines
3.2 KiB
C++
/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
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* Use of this file is governed by the BSD 3-clause license that
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* can be found in the LICENSE.txt file in the project root.
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*/
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#pragma once
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#include "RuleContext.h"
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#include "atn/LexerAction.h"
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namespace antlr4 {
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namespace atn {
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/// <summary>
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/// This implementation of <seealso cref="LexerAction"/> is used for tracking input offsets
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/// for position-dependent actions within a <seealso cref="LexerActionExecutor"/>.
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///
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/// <para>This action is not serialized as part of the ATN, and is only required for
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/// position-dependent lexer actions which appear at a location other than the
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/// end of a rule. For more information about DFA optimizations employed for
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/// lexer actions, see <seealso cref="LexerActionExecutor#append"/> and
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/// <seealso cref="LexerActionExecutor#fixOffsetBeforeMatch"/>.</para>
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///
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/// @author Sam Harwell
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/// @since 4.2
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/// </summary>
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class ANTLR4CPP_PUBLIC LexerIndexedCustomAction final : public LexerAction {
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public:
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/// <summary>
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/// Constructs a new indexed custom action by associating a character offset
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/// with a <seealso cref="LexerAction"/>.
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///
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/// <para>Note: This class is only required for lexer actions for which
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/// <seealso cref="LexerAction#isPositionDependent"/> returns {@code true}.</para>
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/// </summary>
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/// <param name="offset"> The offset into the input <seealso cref="CharStream"/>, relative to
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/// the token start index, at which the specified lexer action should be
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/// executed. </param>
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/// <param name="action"> The lexer action to execute at a particular offset in the
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/// input <seealso cref="CharStream"/>. </param>
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LexerIndexedCustomAction(int offset, Ref<LexerAction> const& action);
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/// <summary>
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/// Gets the location in the input <seealso cref="CharStream"/> at which the lexer
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/// action should be executed. The value is interpreted as an offset relative
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/// to the token start index.
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/// </summary>
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/// <returns> The location in the input <seealso cref="CharStream"/> at which the lexer
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/// action should be executed. </returns>
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int getOffset() const;
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/// <summary>
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/// Gets the lexer action to execute.
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/// </summary>
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/// <returns> A <seealso cref="LexerAction"/> object which executes the lexer action. </returns>
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Ref<LexerAction> getAction() const;
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/// <summary>
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/// {@inheritDoc}
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/// </summary>
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/// <returns> This method returns the result of calling <seealso cref="#getActionType"/>
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/// on the <seealso cref="LexerAction"/> returned by <seealso cref="#getAction"/>. </returns>
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virtual LexerActionType getActionType() const override;
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/// <summary>
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/// {@inheritDoc} </summary>
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/// <returns> This method returns {@code true}. </returns>
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virtual bool isPositionDependent() const override;
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virtual void execute(Lexer *lexer) override;
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virtual size_t hashCode() const override;
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virtual bool operator == (const LexerAction &obj) const override;
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virtual std::string toString() const override;
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private:
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const int _offset;
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const Ref<LexerAction> _action;
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};
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} // namespace atn
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} // namespace antlr4
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