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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"
#include "tree/ParseTreeType.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 const&) = delete;
virtual ~ParseTree() = default;
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 = nullptr;
/// 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;
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 std::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 <= i <= 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;
ParseTreeType getTreeType() const { return _treeType; }
protected:
explicit ParseTree(ParseTreeType treeType) : _treeType(treeType) {}
private:
const ParseTreeType _treeType;
};
// 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