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

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/tree/ParseTree.h b/antlr4-cpp-runtime-4.9.2-source/runtime/src/tree/ParseTree.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 "support/Any.h"
+
+namespace antlr4 {
+namespace tree {
+
+  /// An interface to access the tree of <seealso cref="RuleContext"/> objects created
+  /// during a parse that makes the data structure look like a simple parse tree.
+  /// This node represents both internal nodes, rule invocations,
+  /// and leaf nodes, token matches.
+  ///
+  /// The payload is either a <seealso cref="Token"/> or a <seealso cref="RuleContext"/> object.
+  // ml: This class unites 4 Java classes: RuleNode, ParseTree, SyntaxTree and Tree.
+  class ANTLR4CPP_PUBLIC ParseTree {
+  public:
+    ParseTree();
+    ParseTree(ParseTree const&) = delete;
+    virtual ~ParseTree() {}
+
+    ParseTree& operator=(ParseTree const&) = delete;
+
+    /// The parent of this node. If the return value is null, then this
+    /// node is the root of the tree.
+    ParseTree *parent;
+
+    /// If we are debugging or building a parse tree for a visitor,
+    /// we need to track all of the tokens and rule invocations associated
+    /// with this rule's context. This is empty for parsing w/o tree constr.
+    /// operation because we don't the need to track the details about
+    /// how we parse this rule.
+    // ml: memory is not managed here, but by the owning class. This is just for the structure.
+    std::vector<ParseTree *> children;
+
+    /// Print out a whole tree, not just a node, in LISP format
+    /// {@code (root child1 .. childN)}. Print just a node if this is a leaf.
+    virtual std::string toStringTree(bool pretty = false) = 0;
+    virtual std::string toString() = 0;
+
+    /// Specialize toStringTree so that it can print out more information
+    /// based upon the parser.
+    virtual std::string toStringTree(Parser *parser, bool pretty = false) = 0;
+
+    virtual bool operator == (const ParseTree &other) const;
+
+    /// The <seealso cref="ParseTreeVisitor"/> needs a double dispatch method.
+    // ml: This has been changed to use Any instead of a template parameter, to avoid the need of a virtual template function.
+    virtual antlrcpp::Any accept(ParseTreeVisitor *visitor) = 0;
+
+    /// Return the combined text of all leaf nodes. Does not get any
+    /// off-channel tokens (if any) so won't return whitespace and
+    /// comments if they are sent to parser on hidden channel.
+    virtual std::string getText() = 0;
+
+    /**
+     * Return an {@link Interval} indicating the index in the
+     * {@link TokenStream} of the first and last token associated with this
+     * subtree. If this node is a leaf, then the interval represents a single
+     * token and has interval i..i for token index i.
+     *
+     * <p>An interval of i..i-1 indicates an empty interval at position
+     * i in the input stream, where 0 &lt;= i &lt;= the size of the input
+     * token stream.  Currently, the code base can only have i=0..n-1 but
+     * in concept one could have an empty interval after EOF. </p>
+     *
+     * <p>If source interval is unknown, this returns {@link Interval#INVALID}.</p>
+     *
+     * <p>As a weird special case, the source interval for rules matched after
+     * EOF is unspecified.</p>
+     */
+    virtual misc::Interval getSourceInterval() = 0;
+  };
+
+  // A class to help managing ParseTree instances without the need of a shared_ptr.
+  class ANTLR4CPP_PUBLIC ParseTreeTracker {
+  public:
+    template<typename T, typename ... Args>
+    T* createInstance(Args&& ... args) {
+      static_assert(std::is_base_of<ParseTree, T>::value, "Argument must be a parse tree type");
+      T* result = new T(args...);
+      _allocated.push_back(result);
+      return result;
+    }
+
+    void reset() {
+      for (auto * entry : _allocated)
+        delete entry;
+      _allocated.clear();
+    }
+
+  private:
+    std::vector<ParseTree *> _allocated;
+  };
+
+
+} // namespace tree
+} // namespace antlr4