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[toc] / antlr4-cpp-runtime-4.9.2-source / runtime / src / atn / LexerAction.h

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/atn/LexerAction.h b/antlr4-cpp-runtime-4.9.2-source/runtime/src/atn/LexerAction.h
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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 "atn/LexerActionType.h"
+#include "antlr4-common.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