1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/* 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() = 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) = 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 <= 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;
};
// 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
|
