cpp/third_party/antlr4-cpp-runtime-4/runtime/src/tree/ParseTreeProperty.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 "antlr4-common.h"

namespace antlr4 {
namespace tree {

  /// <summary>
  /// Associate a property with a parse tree node. Useful with parse tree listeners
  /// that need to associate values with particular tree nodes, kind of like
  /// specifying a return value for the listener event method that visited a
  /// particular node. Example:
  ///
  /// <pre>
  /// ParseTreeProperty&lt;Integer&gt; values = new ParseTreeProperty&lt;Integer&gt;();
  /// values.put(tree, 36);
  /// int x = values.get(tree);
  /// values.removeFrom(tree);
  /// </pre>
  ///
  /// You would make one decl (values here) in the listener and use lots of times
  /// in your event methods.
  /// </summary>
  template<typename V>
  class ANTLR4CPP_PUBLIC ParseTreeProperty {
  public:
    virtual ~ParseTreeProperty() {}
    virtual V get(ParseTree *node) {
      return _annotations[node];
    }
    virtual void put(ParseTree *node, V value) {
      _annotations[node] = value;
    }
    virtual V removeFrom(ParseTree *node) {
      auto value = _annotations[node];
      _annotations.erase(node);
      return value;
    }

  protected:
    std::map<ParseTree*, V> _annotations;
  };

} // namespace tree
} // namespace antlr4