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
|
/********************* */
/*! \file node_algorithm.h
** \verbatim
** Top contributors (to current version):
** Morgan Deters, Andrew Reynolds, Tim King
** This file is part of the CVC4 project.
** Copyright (c) 2009-2018 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Common algorithms on nodes
**
** This file implements common algorithms applied to nodes, such as checking if
** a node contains a free or a bound variable. This file should generally only
** be included in source files.
**/
#include "cvc4_private.h"
#ifndef __CVC4__EXPR__NODE_ALGORITHM_H
#define __CVC4__EXPR__NODE_ALGORITHM_H
#include <unordered_map>
#include <vector>
#include "expr/node.h"
namespace CVC4 {
namespace expr {
/**
* Check if the node n has a subterm t.
* @param n The node to search in
* @param t The subterm to search for
* @param strict If true, a term is not considered to be a subterm of itself
* @return true iff t is a subterm in n
*/
bool hasSubterm(TNode n, TNode t, bool strict = false);
/**
* Check if the node n has >1 occurrences of a subterm t.
*/
bool hasSubtermMulti(TNode n, TNode t);
/**
* Returns true iff the node n contains a bound variable, that is a node of
* kind BOUND_VARIABLE. This bound variable may or may not be free.
* @param n The node under investigation
* @return true iff this node contains a bound variable
*/
bool hasBoundVar(TNode n);
/**
* Returns true iff the node n contains a free variable, that is, a node
* of kind BOUND_VARIABLE that is not bound in n.
* @param n The node under investigation
* @return true iff this node contains a free variable.
*/
bool hasFreeVar(TNode n);
/**
* Get the free variables in n, that is, the subterms of n of kind
* BOUND_VARIABLE that are not bound in n, adds these to fvs.
* @param n The node under investigation
* @param fvs The set which free variables are added to
* @param computeFv If this flag is false, then we only return true/false and
* do not add to fvs.
* @return true iff this node contains a free variable.
*/
bool getFreeVariables(TNode n,
std::unordered_set<Node, NodeHashFunction>& fvs,
bool computeFv = true);
/**
* For term n, this function collects the symbols that occur as a subterms
* of n. A symbol is a variable that does not have kind BOUND_VARIABLE.
* @param n The node under investigation
* @param syms The set which the symbols of n are added to
*/
void getSymbols(TNode n, std::unordered_set<Node, NodeHashFunction>& syms);
/** Same as above, with a visited cache */
void getSymbols(TNode n,
std::unordered_set<Node, NodeHashFunction>& syms,
std::unordered_set<TNode, TNodeHashFunction>& visited);
/**
* Substitution of Nodes in a capture avoiding way.
*/
Node substituteCaptureAvoiding(TNode n, Node src, Node dest);
/**
* Simultaneous substitution of Nodes in a capture avoiding way. Elements in
* source will be replaced by their corresponding element in dest. Both
* vectors should have the same size.
*/
Node substituteCaptureAvoiding(TNode n,
std::vector<Node>& src,
std::vector<Node>& dest);
} // namespace expr
} // namespace CVC4
#endif
|
