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[toc] / antlr4-cpp-runtime-4.9.2-source / runtime / src / tree / ParseTreeListener.h

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/tree/ParseTreeListener.h b/antlr4-cpp-runtime-4.9.2-source/runtime/src/tree/ParseTreeListener.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 "antlr4-common.h"
+
+namespace antlr4 {
+namespace tree {
+
+  /** This interface describes the minimal core of methods triggered
+   *  by {@link ParseTreeWalker}. E.g.,
+   *
+   *   ParseTreeWalker walker = new ParseTreeWalker();
+   *           walker.walk(myParseTreeListener, myParseTree); <-- triggers events in your listener
+   *
+   *  If you want to trigger events in multiple listeners during a single
+   *  tree walk, you can use the ParseTreeDispatcher object available at
+   *
+   *           https://github.com/antlr/antlr4/issues/841
+   */
+  class ANTLR4CPP_PUBLIC ParseTreeListener {
+  public:
+    virtual ~ParseTreeListener();
+
+    virtual void visitTerminal(TerminalNode *node) = 0;
+    virtual void visitErrorNode(ErrorNode *node) = 0;
+    virtual void enterEveryRule(ParserRuleContext *ctx) = 0;
+    virtual void exitEveryRule(ParserRuleContext *ctx) = 0;
+
+    bool operator == (const ParseTreeListener &other) {
+      return this == &other;
+    }
+  };
+
+} // namespace tree
+} // namespace antlr4