Head

GCC Code Coverage Report

Directory:	.		Exec	Total	Coverage
File:	src/theory/strings/skolem_cache.cpp	Lines:	122	134	91.0 %
Date:	2021-05-24	Branches:	283	581	48.7 %


/******************************************************************************
 * Top contributors (to current version):
 *   Andrew Reynolds, Andres Noetzli, Yoni Zohar
 *
 * This file is part of the cvc5 project.
 *
 * Copyright (c) 2009-2021 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.
 * ****************************************************************************
 *
 * Implementation of a cache of skolems for theory of strings.
 */

#include "theory/strings/skolem_cache.h"

#include "expr/attribute.h"
#include "expr/bound_var_manager.h"
#include "expr/skolem_manager.h"
#include "theory/rewriter.h"
#include "theory/strings/arith_entail.h"
#include "theory/strings/theory_strings_utils.h"
#include "theory/strings/word.h"
#include "util/rational.h"

using namespace cvc5::kind;

namespace cvc5 {
namespace theory {
namespace strings {

/**
 * A bound variable corresponding to the universally quantified integer
 * variable used to range over the valid positions in a string, used
 * for axiomatizing the behavior of some term.
 */
struct IndexVarAttributeId
{
};
typedef expr::Attribute<IndexVarAttributeId, Node> IndexVarAttribute;

SkolemCache::SkolemCache(bool useOpts) : d_useOpts(useOpts)
{
  NodeManager* nm = NodeManager::currentNM();
  d_strType = nm->stringType();
  d_zero = nm->mkConst(Rational(0));
}

Node SkolemCache::mkSkolemCached(Node a, Node b, SkolemId id, const char* c)
{
  return mkTypedSkolemCached(d_strType, a, b, id, c);
}

Node SkolemCache::mkSkolemCached(Node a, SkolemId id, const char* c)
{
  return mkSkolemCached(a, Node::null(), id, c);
}

Node SkolemCache::mkTypedSkolemCached(
    TypeNode tn, Node a, Node b, SkolemId id, const char* c)
{
  Trace("skolem-cache") << "mkTypedSkolemCached start: (" << id << ", " << a
                        << ", " << b << ")" << std::endl;
  SkolemId idOrig = id;
  // do not rewrite beforehand if we are not using optimizations, this is so
  // that the proof checker does not depend on the rewriter.
  if (d_useOpts)
  {
    a = a.isNull() ? a : Rewriter::rewrite(a);
    b = b.isNull() ? b : Rewriter::rewrite(b);
  }
  std::tie(id, a, b) = normalizeStringSkolem(id, a, b);

  // optimization: if we aren't asking for the purification skolem for constant
  // a, and the skolem is equivalent to a, then we just return a.
  if (d_useOpts && idOrig != SK_PURIFY && id == SK_PURIFY && a.isConst())
  {
    Trace("skolem-cache") << "...optimization: return constant " << a
                          << std::endl;
    return a;
  }

  std::map<SkolemId, Node>::iterator it = d_skolemCache[a][b].find(id);
  if (it != d_skolemCache[a][b].end())
  {
    Trace("skolem-cache") << "...return existing " << it->second << std::endl;
    // already cached
    return it->second;
  }

  NodeManager* nm = NodeManager::currentNM();
  SkolemManager* sm = nm->getSkolemManager();
  Node sk;
  switch (id)
  {
    // exists k. k = a
    case SK_PURIFY:
    {
      // for sequences of Booleans, we may purify Boolean terms, in which case
      // they must be Boolean term variables.
      int flags = a.getType().isBoolean() ? NodeManager::SKOLEM_BOOL_TERM_VAR
                                          : NodeManager::SKOLEM_DEFAULT;
      sk = sm->mkPurifySkolem(a, c, "string purify skolem", flags);
    }
    break;
    // these are eliminated by normalizeStringSkolem
    case SK_ID_V_SPT:
    case SK_ID_V_SPT_REV:
    case SK_ID_VC_SPT:
    case SK_ID_VC_SPT_REV:
    case SK_FIRST_CTN_POST:
    case SK_ID_C_SPT:
    case SK_ID_C_SPT_REV:
    case SK_ID_DC_SPT:
    case SK_ID_DC_SPT_REM:
    case SK_ID_DEQ_X:
    case SK_ID_DEQ_Y:
    case SK_FIRST_CTN_PRE:
    case SK_PREFIX:
    case SK_SUFFIX_REM:
      Unhandled() << "Expected to eliminate Skolem ID " << id << std::endl;
      break;
    case SK_NUM_OCCUR:
    case SK_OCCUR_INDEX:
    default:
    {
      Notice() << "Don't know how to handle Skolem ID " << id << std::endl;
      Node v = nm->mkBoundVar(tn);
      Node cond = nm->mkConst(true);
      sk = sm->mkSkolem(v, cond, c, "string skolem");
    }
    break;
  }
  Trace("skolem-cache") << "...returned " << sk << std::endl;
  d_allSkolems.insert(sk);
  d_skolemCache[a][b][id] = sk;
  return sk;
}
Node SkolemCache::mkTypedSkolemCached(TypeNode tn,
                                      Node a,
                                      SkolemId id,
                                      const char* c)
{
  return mkTypedSkolemCached(tn, a, Node::null(), id, c);
}

Node SkolemCache::mkSkolemSeqNth(TypeNode seqType, const char* c)
{
  // Note this method is static and does not rely on any local caching.
  // It is used by expand definitions and by (dynamic) reductions, thus
  // it is centrally located here.
  Assert(seqType.isSequence());
  NodeManager* nm = NodeManager::currentNM();
  SkolemManager* sm = nm->getSkolemManager();
  std::vector<TypeNode> argTypes;
  argTypes.push_back(seqType);
  argTypes.push_back(nm->integerType());
  TypeNode elemType = seqType.getSequenceElementType();
  TypeNode ufType = nm->mkFunctionType(argTypes, elemType);
  return sm->mkSkolemFunction(SkolemFunId::SEQ_NTH_OOB, ufType);
}

Node SkolemCache::mkSkolem(const char* c)
{
  // TODO: eliminate this
  SkolemManager* sm = NodeManager::currentNM()->getSkolemManager();
  Node n = sm->mkDummySkolem(c, d_strType, "string skolem");
  d_allSkolems.insert(n);
  return n;
}

bool SkolemCache::isSkolem(Node n) const
{
  return d_allSkolems.find(n) != d_allSkolems.end();
}

std::tuple<SkolemCache::SkolemId, Node, Node>
SkolemCache::normalizeStringSkolem(SkolemId id, Node a, Node b)
{

  NodeManager* nm = NodeManager::currentNM();

  // eliminate in terms of prefix/suffix_rem
  if (id == SK_FIRST_CTN_POST)
  {
    // SK_FIRST_CTN_POST(x, y) --->
    //   SK_SUFFIX_REM(x, (+ (str.len SK_FIRST_CTN_PRE(x, y)) (str.len y)))
    id = SK_SUFFIX_REM;
    Node pre = mkSkolemCached(a, b, SK_FIRST_CTN_PRE, "pre");
    b = nm->mkNode(
        PLUS, nm->mkNode(STRING_LENGTH, pre), nm->mkNode(STRING_LENGTH, b));
  }
  else if (id == SK_ID_V_SPT || id == SK_ID_C_SPT)
  {
    // SK_ID_*_SPT(x, y) ---> SK_SUFFIX_REM(x, (str.len y))
    id = SK_SUFFIX_REM;
    b = nm->mkNode(STRING_LENGTH, b);
  }
  else if (id == SK_ID_V_SPT_REV || id == SK_ID_C_SPT_REV)
  {
    // SK_ID_*_SPT_REV(x, y) ---> SK_PREFIX(x, (- (str.len x) (str.len y)))
    id = SK_PREFIX;
    b = nm->mkNode(
        MINUS, nm->mkNode(STRING_LENGTH, a), nm->mkNode(STRING_LENGTH, b));
  }
  else if (id == SK_ID_VC_SPT)
  {
    // SK_ID_VC_SPT(x, y) ---> SK_SUFFIX_REM(x, 1)
    id = SK_SUFFIX_REM;
    b = nm->mkConst(Rational(1));
  }
  else if (id == SK_ID_VC_SPT_REV)
  {
    // SK_ID_VC_SPT_REV(x, y) ---> SK_PREFIX(x, (- (str.len x) 1))
    id = SK_PREFIX;
    b = nm->mkNode(
        MINUS, nm->mkNode(STRING_LENGTH, a), nm->mkConst(Rational(1)));
  }
  else if (id == SK_ID_DC_SPT)
  {
    // SK_ID_DC_SPT(x, y) ---> SK_PREFIX(x, 1)
    id = SK_PREFIX;
    b = nm->mkConst(Rational(1));
  }
  else if (id == SK_ID_DC_SPT_REM)
  {
    // SK_ID_DC_SPT_REM(x, y) ---> SK_SUFFIX_REM(x, 1)
    id = SK_SUFFIX_REM;
    b = nm->mkConst(Rational(1));
  }
  else if (id == SK_ID_DEQ_X)
  {
    // SK_ID_DEQ_X(x, y) ---> SK_PREFIX(y, (str.len x))
    id = SK_PREFIX;
    Node aOld = a;
    a = b;
    b = nm->mkNode(STRING_LENGTH, aOld);
  }
  else if (id == SK_ID_DEQ_Y)
  {
    // SK_ID_DEQ_Y(x, y) ---> SK_PREFIX(x, (str.len y))
    id = SK_PREFIX;
    b = nm->mkNode(STRING_LENGTH, b);
  }
  else if (id == SK_FIRST_CTN_PRE)
  {
    // SK_FIRST_CTN_PRE(x,y) ---> SK_PREFIX(x, indexof(x,y,0))
    id = SK_PREFIX;
    b = nm->mkNode(STRING_STRIDOF, a, b, d_zero);
  }

  if (id == SK_ID_V_UNIFIED_SPT || id == SK_ID_V_UNIFIED_SPT_REV)
  {
    bool isRev = (id == SK_ID_V_UNIFIED_SPT_REV);
    Node la = nm->mkNode(STRING_LENGTH, a);
    Node lb = nm->mkNode(STRING_LENGTH, b);
    Node ta = isRev ? utils::mkPrefix(a, nm->mkNode(MINUS, la, lb))
                    : utils::mkSuffix(a, lb);
    Node tb = isRev ? utils::mkPrefix(b, nm->mkNode(MINUS, lb, la))
                    : utils::mkSuffix(b, la);
    id = SK_PURIFY;
    // SK_ID_V_UNIFIED_SPT(x,y) --->
    //   ite(len(x) >= len(y), substr(x,0,str.len(y)), substr(y,0,str.len(x))
    a = nm->mkNode(ITE, nm->mkNode(GEQ, la, lb), ta, tb);
    b = Node::null();
  }

  // now, eliminate prefix/suffix_rem in terms of purify
  if (id == SK_PREFIX)
  {
    // SK_PREFIX(x,y) ---> SK_PURIFY(substr(x,0,y))
    id = SK_PURIFY;
    a = utils::mkPrefix(a, b);
    b = Node::null();
  }
  else if (id == SK_SUFFIX_REM)
  {
    // SK_SUFFIX_REM(x,y) ---> SK_PURIFY(substr(x,y,str.len(x)-y))
    id = SK_PURIFY;
    a = utils::mkSuffix(a, b);
    b = Node::null();
  }

  if (d_useOpts)
  {
    a = a.isNull() ? a : Rewriter::rewrite(a);
    b = b.isNull() ? b : Rewriter::rewrite(b);
  }
  Trace("skolem-cache") << "normalizeStringSkolem end: (" << id << ", " << a
                        << ", " << b << ")" << std::endl;
  return std::make_tuple(id, a, b);
}

Node SkolemCache::mkIndexVar(Node t)
{
  NodeManager* nm = NodeManager::currentNM();
  TypeNode intType = nm->integerType();
  BoundVarManager* bvm = nm->getBoundVarManager();
  return bvm->mkBoundVar<IndexVarAttribute>(t, intType);
}

}  // namespace strings
}  // namespace theory
}  // namespace cvc5


Generated by: GCOVR (Version 3.2)

Line	Exec	Source
1		/******************************************************************************
2		* Top contributors (to current version):
3		* Andrew Reynolds, Andres Noetzli, Yoni Zohar
4		*
5		* This file is part of the cvc5 project.
6		*
7		* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
8		* in the top-level source directory and their institutional affiliations.
9		* All rights reserved. See the file COPYING in the top-level source
10		* directory for licensing information.
11		* ****************************************************************************
12		*
13		* Implementation of a cache of skolems for theory of strings.
14		*/
15
16		#include "theory/strings/skolem_cache.h"
17
18		#include "expr/attribute.h"
19		#include "expr/bound_var_manager.h"
20		#include "expr/skolem_manager.h"
21		#include "theory/rewriter.h"
22		#include "theory/strings/arith_entail.h"
23		#include "theory/strings/theory_strings_utils.h"
24		#include "theory/strings/word.h"
25		#include "util/rational.h"
26
27		using namespace cvc5::kind;
28
29		namespace cvc5 {
30		namespace theory {
31		namespace strings {
32
33		/**
34		* A bound variable corresponding to the universally quantified integer
35		* variable used to range over the valid positions in a string, used
36		* for axiomatizing the behavior of some term.
37		*/
38		struct IndexVarAttributeId
39		{
40		};
41		typedef expr::Attribute<IndexVarAttributeId, Node> IndexVarAttribute;
42
43	10388	SkolemCache::SkolemCache(bool useOpts) : d_useOpts(useOpts)
44		{
45	10388	NodeManager* nm = NodeManager::currentNM();
46	10388	d_strType = nm->stringType();
47	10388	d_zero = nm->mkConst(Rational(0));
48	10388	}
49
50	24414	Node SkolemCache::mkSkolemCached(Node a, Node b, SkolemId id, const char* c)
51		{
52	24414	return mkTypedSkolemCached(d_strType, a, b, id, c);
53		}
54
55	11590	Node SkolemCache::mkSkolemCached(Node a, SkolemId id, const char* c)
56		{
57	11590	return mkSkolemCached(a, Node::null(), id, c);
58		}
59
60	24635	Node SkolemCache::mkTypedSkolemCached(
61		TypeNode tn, Node a, Node b, SkolemId id, const char* c)
62		{
63	49270	Trace("skolem-cache") << "mkTypedSkolemCached start: (" << id << ", " << a
64	24635	<< ", " << b << ")" << std::endl;
65	24635	SkolemId idOrig = id;
66		// do not rewrite beforehand if we are not using optimizations, this is so
67		// that the proof checker does not depend on the rewriter.
68	24635	if (d_useOpts)
69		{
70	22682	a = a.isNull() ? a : Rewriter::rewrite(a);
71	22682	b = b.isNull() ? b : Rewriter::rewrite(b);
72		}
73	24635	std::tie(id, a, b) = normalizeStringSkolem(id, a, b);
74
75		// optimization: if we aren't asking for the purification skolem for constant
76		// a, and the skolem is equivalent to a, then we just return a.
77	24635	if (d_useOpts && idOrig != SK_PURIFY && id == SK_PURIFY && a.isConst())
78		{
79	1302	Trace("skolem-cache") << "...optimization: return constant " << a
80	651	<< std::endl;
81	651	return a;
82		}
83
84	23984	std::map<SkolemId, Node>::iterator it = d_skolemCache[a][b].find(id);
85	23984	if (it != d_skolemCache[a][b].end())
86		{
87	11562	Trace("skolem-cache") << "...return existing " << it->second << std::endl;
88		// already cached
89	11562	return it->second;
90		}
91
92	12422	NodeManager* nm = NodeManager::currentNM();
93	12422	SkolemManager* sm = nm->getSkolemManager();
94	24844	Node sk;
95	12422	switch (id)
96		{
97		// exists k. k = a
98	12360	case SK_PURIFY:
99		{
100		// for sequences of Booleans, we may purify Boolean terms, in which case
101		// they must be Boolean term variables.
102	24720	int flags = a.getType().isBoolean() ? NodeManager::SKOLEM_BOOL_TERM_VAR
103	12360	: NodeManager::SKOLEM_DEFAULT;
104	12360	sk = sm->mkPurifySkolem(a, c, "string purify skolem", flags);
105		}
106	12360	break;
107		// these are eliminated by normalizeStringSkolem
108		case SK_ID_V_SPT:
109		case SK_ID_V_SPT_REV:
110		case SK_ID_VC_SPT:
111		case SK_ID_VC_SPT_REV:
112		case SK_FIRST_CTN_POST:
113		case SK_ID_C_SPT:
114		case SK_ID_C_SPT_REV:
115		case SK_ID_DC_SPT:
116		case SK_ID_DC_SPT_REM:
117		case SK_ID_DEQ_X:
118		case SK_ID_DEQ_Y:
119		case SK_FIRST_CTN_PRE:
120		case SK_PREFIX:
121		case SK_SUFFIX_REM:
122		Unhandled() << "Expected to eliminate Skolem ID " << id << std::endl;
123		break;
124	62	case SK_NUM_OCCUR:
125		case SK_OCCUR_INDEX:
126		default:
127		{
128	62	Notice() << "Don't know how to handle Skolem ID " << id << std::endl;
129	124	Node v = nm->mkBoundVar(tn);
130	124	Node cond = nm->mkConst(true);
131	124	sk = sm->mkSkolem(v, cond, c, "string skolem");
132		}
133	62	break;
134		}
135	12422	Trace("skolem-cache") << "...returned " << sk << std::endl;
136	12422	d_allSkolems.insert(sk);
137	12422	d_skolemCache[a][b][id] = sk;
138	12422	return sk;
139		}
140	191	Node SkolemCache::mkTypedSkolemCached(TypeNode tn,
141		Node a,
142		SkolemId id,
143		const char* c)
144		{
145	191	return mkTypedSkolemCached(tn, a, Node::null(), id, c);
146		}
147
148	40	Node SkolemCache::mkSkolemSeqNth(TypeNode seqType, const char* c)
149		{
150		// Note this method is static and does not rely on any local caching.
151		// It is used by expand definitions and by (dynamic) reductions, thus
152		// it is centrally located here.
153	40	Assert(seqType.isSequence());
154	40	NodeManager* nm = NodeManager::currentNM();
155	40	SkolemManager* sm = nm->getSkolemManager();
156	80	std::vector<TypeNode> argTypes;
157	40	argTypes.push_back(seqType);
158	40	argTypes.push_back(nm->integerType());
159	80	TypeNode elemType = seqType.getSequenceElementType();
160	80	TypeNode ufType = nm->mkFunctionType(argTypes, elemType);
161	80	return sm->mkSkolemFunction(SkolemFunId::SEQ_NTH_OOB, ufType);
162		}
163
164	1110	Node SkolemCache::mkSkolem(const char* c)
165		{
166		// TODO: eliminate this
167	1110	SkolemManager* sm = NodeManager::currentNM()->getSkolemManager();
168	1110	Node n = sm->mkDummySkolem(c, d_strType, "string skolem");
169	1110	d_allSkolems.insert(n);
170	1110	return n;
171		}
172
173	3860	bool SkolemCache::isSkolem(Node n) const
174		{
175	3860	return d_allSkolems.find(n) != d_allSkolems.end();
176		}
177
178		std::tuple<SkolemCache::SkolemId, Node, Node>
179	24635	SkolemCache::normalizeStringSkolem(SkolemId id, Node a, Node b)
180		{
181
182	24635	NodeManager* nm = NodeManager::currentNM();
183
184		// eliminate in terms of prefix/suffix_rem
185	24635	if (id == SK_FIRST_CTN_POST)
186		{
187		// SK_FIRST_CTN_POST(x, y) --->
188		// SK_SUFFIX_REM(x, (+ (str.len SK_FIRST_CTN_PRE(x, y)) (str.len y)))
189	2333	id = SK_SUFFIX_REM;
190	4666	Node pre = mkSkolemCached(a, b, SK_FIRST_CTN_PRE, "pre");
191	6999	b = nm->mkNode(
192	9332	PLUS, nm->mkNode(STRING_LENGTH, pre), nm->mkNode(STRING_LENGTH, b));
193		}
194	22302	else if (id == SK_ID_V_SPT \|\| id == SK_ID_C_SPT)
195		{
196		// SK_ID_*_SPT(x, y) ---> SK_SUFFIX_REM(x, (str.len y))
197	366	id = SK_SUFFIX_REM;
198	366	b = nm->mkNode(STRING_LENGTH, b);
199		}
200	21936	else if (id == SK_ID_V_SPT_REV \|\| id == SK_ID_C_SPT_REV)
201		{
202		// SK_ID_*_SPT_REV(x, y) ---> SK_PREFIX(x, (- (str.len x) (str.len y)))
203	400	id = SK_PREFIX;
204	1600	b = nm->mkNode(
205	1600	MINUS, nm->mkNode(STRING_LENGTH, a), nm->mkNode(STRING_LENGTH, b));
206		}
207	21536	else if (id == SK_ID_VC_SPT)
208		{
209		// SK_ID_VC_SPT(x, y) ---> SK_SUFFIX_REM(x, 1)
210	1449	id = SK_SUFFIX_REM;
211	1449	b = nm->mkConst(Rational(1));
212		}
213	20087	else if (id == SK_ID_VC_SPT_REV)
214		{
215		// SK_ID_VC_SPT_REV(x, y) ---> SK_PREFIX(x, (- (str.len x) 1))
216	1959	id = SK_PREFIX;
217	5877	b = nm->mkNode(
218	7836	MINUS, nm->mkNode(STRING_LENGTH, a), nm->mkConst(Rational(1)));
219		}
220	18128	else if (id == SK_ID_DC_SPT)
221		{
222		// SK_ID_DC_SPT(x, y) ---> SK_PREFIX(x, 1)
223		id = SK_PREFIX;
224		b = nm->mkConst(Rational(1));
225		}
226	18128	else if (id == SK_ID_DC_SPT_REM)
227		{
228		// SK_ID_DC_SPT_REM(x, y) ---> SK_SUFFIX_REM(x, 1)
229		id = SK_SUFFIX_REM;
230		b = nm->mkConst(Rational(1));
231		}
232	18128	else if (id == SK_ID_DEQ_X)
233		{
234		// SK_ID_DEQ_X(x, y) ---> SK_PREFIX(y, (str.len x))
235		id = SK_PREFIX;
236		Node aOld = a;
237		a = b;
238		b = nm->mkNode(STRING_LENGTH, aOld);
239		}
240	18128	else if (id == SK_ID_DEQ_Y)
241		{
242		// SK_ID_DEQ_Y(x, y) ---> SK_PREFIX(x, (str.len y))
243		id = SK_PREFIX;
244		b = nm->mkNode(STRING_LENGTH, b);
245		}
246	18128	else if (id == SK_FIRST_CTN_PRE)
247		{
248		// SK_FIRST_CTN_PRE(x,y) ---> SK_PREFIX(x, indexof(x,y,0))
249	4670	id = SK_PREFIX;
250	4670	b = nm->mkNode(STRING_STRIDOF, a, b, d_zero);
251		}
252
253	24635	if (id == SK_ID_V_UNIFIED_SPT \|\| id == SK_ID_V_UNIFIED_SPT_REV)
254		{
255	2547	bool isRev = (id == SK_ID_V_UNIFIED_SPT_REV);
256	5094	Node la = nm->mkNode(STRING_LENGTH, a);
257	5094	Node lb = nm->mkNode(STRING_LENGTH, b);
258	3592	Node ta = isRev ? utils::mkPrefix(a, nm->mkNode(MINUS, la, lb))
259	6139	: utils::mkSuffix(a, lb);
260	3592	Node tb = isRev ? utils::mkPrefix(b, nm->mkNode(MINUS, lb, la))
261	6139	: utils::mkSuffix(b, la);
262	2547	id = SK_PURIFY;
263		// SK_ID_V_UNIFIED_SPT(x,y) --->
264		// ite(len(x) >= len(y), substr(x,0,str.len(y)), substr(y,0,str.len(x))
265	2547	a = nm->mkNode(ITE, nm->mkNode(GEQ, la, lb), ta, tb);
266	2547	b = Node::null();
267		}
268
269		// now, eliminate prefix/suffix_rem in terms of purify
270	24635	if (id == SK_PREFIX)
271		{
272		// SK_PREFIX(x,y) ---> SK_PURIFY(substr(x,0,y))
273	8259	id = SK_PURIFY;
274	8259	a = utils::mkPrefix(a, b);
275	8259	b = Node::null();
276		}
277	16376	else if (id == SK_SUFFIX_REM)
278		{
279		// SK_SUFFIX_REM(x,y) ---> SK_PURIFY(substr(x,y,str.len(x)-y))
280	5378	id = SK_PURIFY;
281	5378	a = utils::mkSuffix(a, b);
282	5378	b = Node::null();
283		}
284
285	24635	if (d_useOpts)
286		{
287	22682	a = a.isNull() ? a : Rewriter::rewrite(a);
288	22682	b = b.isNull() ? b : Rewriter::rewrite(b);
289		}
290	49270	Trace("skolem-cache") << "normalizeStringSkolem end: (" << id << ", " << a
291	24635	<< ", " << b << ")" << std::endl;
292	24635	return std::make_tuple(id, a, b);
293		}
294
295	270	Node SkolemCache::mkIndexVar(Node t)
296		{
297	270	NodeManager* nm = NodeManager::currentNM();
298	540	TypeNode intType = nm->integerType();
299	270	BoundVarManager* bvm = nm->getBoundVarManager();
300	540	return bvm->mkBoundVar<IndexVarAttribute>(t, intType);
301		}
302
303		} // namespace strings
304		} // namespace theory
305	28191	} // namespace cvc5