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seq + API

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-01-04 18:01:48 -08:00
parent 68a532d066
commit c1ebf6b4fc
9 changed files with 484 additions and 77 deletions

View file

@ -125,6 +125,7 @@ namespace Microsoft.Z3
private BoolSort m_boolSort = null;
private IntSort m_intSort = null;
private RealSort m_realSort = null;
private SeqSort m_stringSort = null;
/// <summary>
/// Retrieves the Boolean sort of the context.
@ -163,6 +164,20 @@ namespace Microsoft.Z3
}
}
/// <summary>
/// Retrieves the String sort of the context.
/// </summary>
public SeqSort StringSort
{
get
{
Contract.Ensures(Contract.Result<SeqSort>() != null);
if (m_stringSort == null) m_stringSort = new SeqSort(this, Native.Z3_mk_string_sort(nCtx));
return m_stringSort;
}
}
/// <summary>
/// Create a new Boolean sort.
/// </summary>
@ -223,6 +238,27 @@ namespace Microsoft.Z3
return new BitVecSort(this, Native.Z3_mk_bv_sort(nCtx, size));
}
/// <summary>
/// Create a new sequence sort.
/// </summary>
public SeqSort MkSeqSort(Sort s)
{
Contract.Requires(s != null);
Contract.Ensures(Contract.Result<SeqSort>() != null);
return new SeqSort(this, Native.Z3_mk_seq_sort(nCtx, s.NativeObject));
}
/// <summary>
/// Create a new regular expression sort.
/// </summary>
public ReSort MkReSort(SeqSort s)
{
Contract.Requires(s != null);
Contract.Ensures(Contract.Result<ReSort>() != null);
return new ReSort(this, Native.Z3_mk_re_sort(nCtx, s.NativeObject));
}
/// <summary>
/// Create a new array sort.
/// </summary>
@ -4872,6 +4908,7 @@ namespace Microsoft.Z3
m_boolSort = null;
m_intSort = null;
m_realSort = null;
m_stringSort = null;
}
#endregion
}

View file

@ -1849,6 +1849,184 @@ public class Context extends IDisposable
arg2.getNativeObject()));
}
/**
* Sequences, Strings and regular expressions.
*/
/**
* Create the empty sequence.
*/
public SeqExpr MkEmptySeq(Sort s)
{
checkContextMatch(s);
return new SeqExpr(this, Native.mkSeqEmpty(nCtx, s.NativeObject));
}
/**
* Create the singleton sequence.
*/
public SeqExpr MkUnit(Expr elem)
{
checkContextMatch(elem);
return new SeqExpr(this, Native.mkSeqUnit(nCtx, elem.NativeObject));
}
/**
* Create a string constant.
*/
public SeqExpr MkString(string s)
{
return new SeqExpr(this, Native.mkString(nCtx, s));
}
/**
* Concatentate sequences.
*/
public SeqExpr MkConcat(params SeqExpr[] t)
{
checkContextMatch(t);
return new SeqExpr(this, Native.mkSeqConcat(nCtx, (uint)t.Length, AST.ArrayToNative(t)));
}
/**
* Retrieve the length of a given sequence.
*/
public IntExpr MkLength(SeqExpr s)
{
checkContextMatch(s);
return (IntExpr) Expr.Create(this, Native.mkSeqLength(nCtx, s.NativeObject));
}
/**
* Check for sequence prefix.
*/
public BoolExpr MkPrefixOf(SeqExpr s1, SeqExpr s2)
{
checkContextMatch(s1, s2);
return new BoolExpr(this, Native.mkSeqPrefix(nCtx, s1.NativeObject, s2.NativeObject));
}
/**
* Check for sequence suffix.
*/
public BoolExpr MkSuffixOf(SeqExpr s1, SeqExpr s2)
{
checkContextMatch(s1, s2);
return new BoolExpr(this, Native.mkSeqSuffix(nCtx, s1.NativeObject, s2.NativeObject));
}
/**
* Check for sequence containment of s2 in s1.
*/
public BoolExpr MkContains(SeqExpr s1, SeqExpr s2)
{
checkContextMatch(s1, s2);
return new BoolExpr(this, Native.mkSeqContains(nCtx, s1.NativeObject, s2.NativeObject));
}
/**
* Retrieve sequence of length one at index.
*/
public SeqExpr MkAt(SeqExpr s, IntExpr index)
{
checkContextMatch(s, index);
return new SeqExpr(this, Native.mkSeqAt(nCtx, s.NativeObject, index.NativeObject));
}
/**
* Extract subsequence.
*/
public SeqExpr MkExtract(SeqExpr s, IntExpr offset, IntExpr length)
{
checkContextMatch(s, offset, length);
return new SeqExpr(this, Native.mkSeqExtract(nCtx, s.NativeObject, offset.NativeObject, length.NativeObject));
}
/**
* Extract index of sub-string starting at offset.
*/
public IntExpr MkIndexOf(SeqExpr s, SeqExpr substr, ArithExpr offset)
{
checkContextMatch(s, substr, offset);
return new IntExpr(this, Native.mkSeqIndex(nCtx, s.NativeObject, substr.NativeObject, offset.NativeObject));
}
/**
* Replace the first occurrence of src by dst in s.
*/
public SeqExpr MkReplace(SeqExpr s, SeqExpr src, SeqExpr dst)
{
checkContextMatch(s, src, dst);
return new SeqExpr(this, Native.mkSeqReplace(nCtx, s.NativeObject, src.NativeObject, dst.NativeObject));
}
/**
* Convert a regular expression that accepts sequence s.
*/
public ReExpr MkToRe(SeqExpr s)
{
checkContextMatch(s);
return new ReExpr(this, Native.mkSeqToRe(nCtx, s.NativeObject));
}
/**
* Check for regular expression membership.
*/
public BoolExpr MkInRe(SeqExpr s, ReExpr re)
{
checkContextMatch(s, re);
return new BoolExpr(this, Native.mkSeqInRe(nCtx, s.NativeObject, re.NativeObject));
}
/**
* Take the Kleene star of a regular expression.
*/
public ReExpr MkStar(ReExpr re)
{
checkContextMatch(re);
return new ReExpr(this, Native.mkReStar(nCtx, re.NativeObject));
}
/**
* Take the Kleene plus of a regular expression.
*/
public ReExpr MPlus(ReExpr re)
{
checkContextMatch(re);
return new ReExpr(this, Native.mkRePlus(nCtx, re.NativeObject));
}
/**
* Create the optional regular expression.
*/
public ReExpr MOption(ReExpr re)
{
checkContextMatch(re);
return new ReExpr(this, Native.mkReOption(nCtx, re.NativeObject));
}
/**
* Create the concatenation of regular languages.
*/
public ReExpr MkConcat(ReExpr[] t)
{
checkContextMatch(t);
return new ReExpr(this, Native.mkReConcat(nCtx, (uint)t.Length, AST.ArrayToNative(t)));
}
/**
* Create the union of regular languages.
*/
public ReExpr MkUnion(ReExpr[] t)
{
checkContextMatch(t);
return new ReExpr(this, Native.mkReUnion(nCtx, (uint)t.Length, AST.ArrayToNative(t)));
}
/**
* Create a Term of a given sort.
* @param v A string representing the term value in decimal notation. If the given sort is a real, then the
@ -3683,6 +3861,19 @@ public class Context extends IDisposable
throw new Z3Exception("Context mismatch");
}
void checkContextMatch(Z3Object other1, Z3Object other2)
{
checkContextMatch(other1);
checkContextMatch(other2);
}
void checkContextMatch(Z3Object other1, Z3Object other2, Z3Object other3)
{
checkContextMatch(other1);
checkContextMatch(other2);
checkContextMatch(other3);
}
void checkContextMatch(Z3Object[] arr)
{
if (arr != null)

View file

@ -2186,6 +2186,10 @@ public class Expr extends AST
return new FPRMExpr(ctx, obj);
case Z3_FINITE_DOMAIN_SORT:
return new FiniteDomainExpr(ctx, obj);
case Z3_SEQ_SORT:
return new SeqExpr(ctx, obj);
case Z3_RE_SORT:
return new ReExpr(ctx, obj);
default: ;
}

View file

@ -141,6 +141,10 @@ public class Sort extends AST
return new FPSort(ctx, obj);
case Z3_ROUNDING_MODE_SORT:
return new FPRMSort(ctx, obj);
case Z3_SEQ_SORT:
return new SeqSort(ctx, obj);
case Z3_RE_SORT:
return new ReSort(ctx, obj);
default:
throw new Z3Exception("Unknown sort kind");
}

View file

@ -8991,7 +8991,7 @@ class SeqRef(ExprRef):
def __getitem__(self, i):
return SeqRef(Z3_mk_seq_at(self.ctx_ref(), self.as_ast(), i.as_ast()), self.ctx)
def is_string_sort(self):
def is_string(self):
return Z3_is_string_sort(self.ctx_ref(), Z3_get_sort(self.ctx_ref(), self.as_ast()))
def is_string_value(self):
@ -9026,12 +9026,12 @@ def is_seq(a):
"""
return isinstance(a, SeqRef)
def is_string_sort(a):
def is_string(a):
"""Return `True` if `a` is a Z3 string expression.
>>> print (is_string_sort(StringVal("ab")))
>>> print (is_string(StringVal("ab")))
True
"""
return isinstance(a, SeqRef) and a.is_string_sort()
return isinstance(a, SeqRef) and a.is_string()
def is_string_value(a):
"""return 'True' if 'a' is a Z3 string constant expression.
@ -9042,11 +9042,27 @@ def is_string_value(a):
"""
return isinstance(a, SeqRef) and a.is_string_value()
def StringVal(s, ctx=None):
"""create a string expression"""
ctx = _get_ctx(ctx)
return SeqRef(Z3_mk_string(ctx.ref(), s), ctx)
def String(name, ctx=None):
"""Return a string constant named `name`. If `ctx=None`, then the global context is used.
>>> x = String('x')
"""
ctx = _get_ctx(ctx)
return SeqRef(Z3_mk_const(ctx.ref(), to_symbol(name, ctx), StringSort(ctx).ast), ctx)
def Strings(names, ctx=None):
"""Return a tuple of String constants. """
ctx = _get_ctx(ctx)
if isinstance(names, str):
names = names.split(" ")
return [String(name, ctx) for name in names]
def Empty(s):
"""Create the empty sequence of the given sort
>>> e = Empty(StringSort())
@ -9101,6 +9117,10 @@ def Contains(a, b):
>>> s2 = Contains("abc", "bc")
>>> simplify(s2)
True
>>> x, y, z = Strings('x y z')
>>> s3 = Contains(Concat(x,y,z), y)
>>> simplify(s3)
True
"""
ctx = _get_ctx2(a, b)
a = _coerce_seq(a, ctx)

View file

@ -23,6 +23,7 @@ Notes:
#include"ast_util.h"
#include"uint_set.h"
#include"automaton.h"
#include"well_sorted.h"
struct display_expr1 {
@ -843,37 +844,33 @@ br_status seq_rewriter::mk_eq_core(expr * l, expr * r, expr_ref & result) {
return BR_REWRITE3;
}
bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs) {
bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_vector& lhs, expr_ref_vector& rhs) {
expr* a, *b;
zstring s;
bool change = false;
m_lhs.reset();
m_rhs.reset();
m_util.str.get_concat(l, m_lhs);
m_util.str.get_concat(r, m_rhs);
// solve from back
while (true) {
while (!m_rhs.empty() && m_util.str.is_empty(m_rhs.back())) {
m_rhs.pop_back();
while (!rs.empty() && m_util.str.is_empty(rs.back())) {
rs.pop_back();
change = true;
}
while (!m_lhs.empty() && m_util.str.is_empty(m_lhs.back())) {
m_lhs.pop_back();
while (!ls.empty() && m_util.str.is_empty(ls.back())) {
ls.pop_back();
change = true;
}
if (m_lhs.empty() || m_rhs.empty()) {
if (ls.empty() || rs.empty()) {
break;
}
expr* l = m_lhs.back();
expr* r = m_rhs.back();
expr* l = ls.back();
expr* r = rs.back();
if (m_util.str.is_unit(r) && m_util.str.is_string(l)) {
std::swap(l, r);
m_lhs.swap(m_rhs);
ls.swap(rs);
}
if (l == r) {
m_lhs.pop_back();
m_rhs.pop_back();
ls.pop_back();
rs.pop_back();
}
else if(m_util.str.is_unit(l, a) &&
m_util.str.is_unit(r, b)) {
@ -882,8 +879,8 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
}
lhs.push_back(a);
rhs.push_back(b);
m_lhs.pop_back();
m_rhs.pop_back();
ls.pop_back();
rs.pop_back();
}
else if (m_util.str.is_unit(l, a) && m_util.str.is_string(r, s)) {
SASSERT(s.length() > 0);
@ -892,13 +889,13 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
SASSERT(m().get_sort(ch) == m().get_sort(a));
lhs.push_back(ch);
rhs.push_back(a);
m_lhs.pop_back();
ls.pop_back();
if (s.length() == 1) {
m_rhs.pop_back();
rs.pop_back();
}
else {
expr_ref s2(m_util.str.mk_string(s.extract(0, s.length()-2)), m());
m_rhs[m_rhs.size()-1] = s2;
rs[rs.size()-1] = s2;
}
}
else {
@ -910,22 +907,22 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
// solve from front
unsigned head1 = 0, head2 = 0;
while (true) {
while (head1 < m_lhs.size() && m_util.str.is_empty(m_lhs[head1].get())) {
while (head1 < ls.size() && m_util.str.is_empty(ls[head1].get())) {
++head1;
}
while (head2 < m_rhs.size() && m_util.str.is_empty(m_rhs[head2].get())) {
while (head2 < rs.size() && m_util.str.is_empty(rs[head2].get())) {
++head2;
}
if (head1 == m_lhs.size() || head2 == m_rhs.size()) {
if (head1 == ls.size() || head2 == rs.size()) {
break;
}
SASSERT(head1 < m_lhs.size() && head2 < m_rhs.size());
SASSERT(head1 < ls.size() && head2 < rs.size());
expr* l = m_lhs[head1].get();
expr* r = m_rhs[head2].get();
expr* l = ls[head1].get();
expr* r = rs[head2].get();
if (m_util.str.is_unit(r) && m_util.str.is_string(l)) {
std::swap(l, r);
m_lhs.swap(m_rhs);
ls.swap(rs);
}
if (l == r) {
++head1;
@ -947,13 +944,13 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
SASSERT(m().get_sort(ch) == m().get_sort(a));
lhs.push_back(ch);
rhs.push_back(a);
m_lhs.pop_back();
ls.pop_back();
if (s.length() == 1) {
m_rhs.pop_back();
rs.pop_back();
}
else {
expr_ref s2(m_util.str.mk_string(s.extract(1, s.length()-1)), m());
m_rhs[m_rhs.size()-1] = s2;
rs[rs.size()-1] = s2;
}
}
else {
@ -963,10 +960,10 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
}
// reduce strings
zstring s1, s2;
while (head1 < m_lhs.size() &&
head2 < m_rhs.size() &&
m_util.str.is_string(m_lhs[head1].get(), s1) &&
m_util.str.is_string(m_rhs[head2].get(), s2)) {
while (head1 < ls.size() &&
head2 < rs.size() &&
m_util.str.is_string(ls[head1].get(), s1) &&
m_util.str.is_string(rs[head2].get(), s2)) {
unsigned l = std::min(s1.length(), s2.length());
for (unsigned i = 0; i < l; ++i) {
if (s1[i] != s2[i]) {
@ -977,64 +974,105 @@ bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_ve
++head1;
}
else {
m_lhs[head1] = m_util.str.mk_string(s1.extract(l, s1.length()-l));
ls[head1] = m_util.str.mk_string(s1.extract(l, s1.length()-l));
}
if (l == s2.length()) {
++head2;
}
else {
m_rhs[head2] = m_util.str.mk_string(s2.extract(l, s2.length()-l));
rs[head2] = m_util.str.mk_string(s2.extract(l, s2.length()-l));
}
change = true;
}
while (head1 < m_lhs.size() &&
head2 < m_rhs.size() &&
m_util.str.is_string(m_lhs.back(), s1) &&
m_util.str.is_string(m_rhs.back(), s2)) {
while (head1 < ls.size() &&
head2 < rs.size() &&
m_util.str.is_string(ls.back(), s1) &&
m_util.str.is_string(rs.back(), s2)) {
unsigned l = std::min(s1.length(), s2.length());
for (unsigned i = 0; i < l; ++i) {
if (s1[s1.length()-i-1] != s2[s2.length()-i-1]) {
return false;
}
}
m_lhs.pop_back();
m_rhs.pop_back();
ls.pop_back();
rs.pop_back();
if (l < s1.length()) {
m_lhs.push_back(m_util.str.mk_string(s1.extract(0, s1.length()-l)));
ls.push_back(m_util.str.mk_string(s1.extract(0, s1.length()-l)));
}
if (l < s2.length()) {
m_rhs.push_back(m_util.str.mk_string(s2.extract(0, s2.length()-l)));
rs.push_back(m_util.str.mk_string(s2.extract(0, s2.length()-l)));
}
change = true;
}
bool is_sat;
unsigned szl = m_lhs.size() - head1, szr = m_rhs.size() - head2;
expr* const* ls = m_lhs.c_ptr() + head1, * const*rs = m_rhs.c_ptr() + head2;
if (length_constrained(szl, ls, szr, rs, lhs, rhs, is_sat)) {
unsigned szl = ls.size() - head1, szr = rs.size() - head2;
expr* const* _ls = ls.c_ptr() + head1, * const* _rs = rs.c_ptr() + head2;
if (length_constrained(szl, _ls, szr, _rs, lhs, rhs, is_sat)) {
ls.reset(); rs.reset();
return is_sat;
}
if (is_subsequence(szl, ls, szr, rs, lhs, rhs, is_sat)) {
if (is_subsequence(szl, _ls, szr, _rs, lhs, rhs, is_sat)) {
ls.reset(); rs.reset();
return is_sat;
}
if (szl == 0 && szr == 0) {
return true;
}
if (szl == 0 && szr == 0) {
ls.reset(); rs.reset();
return true;
}
else if (!change) {
lhs.push_back(l);
rhs.push_back(r);
// skip
}
else {
// could solve if either side is fixed size.
SASSERT(szl > 0 && szr > 0);
lhs.push_back(m_util.str.mk_concat(szl, ls));
rhs.push_back(m_util.str.mk_concat(szr, rs));
if (head1 > 0) {
for (unsigned i = 0; i < szl; ++i) {
ls[i] = ls[i + head1];
}
}
ls.shrink(szl);
if (head2 > 0) {
for (unsigned i = 0; i < szr; ++i) {
rs[i] = rs[i + head2];
}
}
rs.shrink(szr);
lhs.push_back(m_util.str.mk_concat(ls.size(), ls.c_ptr()));
rhs.push_back(m_util.str.mk_concat(rs.size(), rs.c_ptr()));
ls.reset();
rs.reset();
}
return true;
}
bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs) {
m_lhs.reset();
m_rhs.reset();
m_util.str.get_concat(l, m_lhs);
m_util.str.get_concat(r, m_rhs);
if (reduce_eq(m_lhs, m_rhs, lhs, rhs)) {
SASSERT(lhs.size() == rhs.size());
if (!m_lhs.empty()) {
SASSERT(!m_rhs.empty());
lhs.push_back(m_util.str.mk_concat(m_lhs.size(), m_lhs.c_ptr()));
rhs.push_back(m_util.str.mk_concat(m_rhs.size(), m_rhs.c_ptr()));
}
for (unsigned i = 0; i < lhs.size(); ++i) {
SASSERT(is_well_sorted(m(), lhs[i].get()));
SASSERT(is_well_sorted(m(), rhs[i].get()));
SASSERT(m().get_sort(lhs[i].get()) == m().get_sort(rhs[i].get()));
TRACE("seq", tout << mk_pp(lhs[i].get(), m()) << " = " << mk_pp(rhs[i].get(), m()) << "\n";);
}
return true;
}
else {
TRACE("seq", tout << mk_pp(l, m()) << " != " << mk_pp(r, m()) << "\n";);
return false;
}
}
expr* seq_rewriter::concat_non_empty(unsigned n, expr* const* as) {
SASSERT(n > 0);
ptr_vector<expr> bs;

View file

@ -92,6 +92,8 @@ public:
bool reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs);
bool reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_vector& lhs, expr_ref_vector& rhs);
};
#endif

View file

@ -368,11 +368,19 @@ bool theory_seq::propagate_length_coherence(expr* e) {
// len(e) >= low => e = tail;
literal low(mk_literal(m_autil.mk_ge(m_util.str.mk_length(e), m_autil.mk_numeral(lo, true))));
add_axiom(~low, mk_eq(e, tail, false));
assume_equality(seq, emp);
if (upper_bound(e, hi)) {
expr_ref high1(m_autil.mk_le(m_util.str.mk_length(e), m_autil.mk_numeral(hi, true)), m);
expr_ref high2(m_autil.mk_le(m_util.str.mk_length(seq), m_autil.mk_numeral(hi-lo, true)), m);
add_axiom(~mk_literal(high1), mk_literal(high2));
// len(e) <= hi => len(tail) <= hi - lo
expr_ref high1(m_autil.mk_le(m_util.str.mk_length(e), m_autil.mk_numeral(hi, true)), m);
if (hi == lo) {
add_axiom(~mk_literal(high1), mk_eq(seq, emp, false));
}
else {
expr_ref high2(m_autil.mk_le(m_util.str.mk_length(seq), m_autil.mk_numeral(hi-lo, true)), m);
add_axiom(~mk_literal(high1), mk_literal(high2));
}
}
else {
assume_equality(seq, emp);
}
return true;
}
@ -428,6 +436,15 @@ bool theory_seq::is_nth(expr* e) const {
return is_skolem(m_nth, e);
}
bool theory_seq::is_tail(expr* e, expr*& s, unsigned& idx) const {
rational r;
return
is_skolem(m_tail, e) &&
m_autil.is_numeral(to_app(e)->get_arg(1), r) &&
(idx = r.get_unsigned(), s = to_app(e)->get_arg(0), true);
}
expr_ref theory_seq::mk_nth(expr* s, expr* idx) {
sort* char_sort = 0;
VERIFY(m_util.is_seq(m.get_sort(s), char_sort));
@ -602,9 +619,9 @@ bool theory_seq::simplify_eq(expr* l, expr* r, dependency* deps) {
}
}
TRACE("seq",
tout << mk_pp(l, m) << " = " << mk_pp(r, m) << " => ";
tout << mk_pp(l, m) << " = " << mk_pp(r, m) << " => \n";
for (unsigned i = 0; i < lhs.size(); ++i) {
tout << mk_pp(lhs[i].get(), m) << " = " << mk_pp(rhs[i].get(), m) << "; ";
tout << mk_pp(lhs[i].get(), m) << "\n = \n" << mk_pp(rhs[i].get(), m) << "; \n";
}
tout << "\n";);
return true;
@ -614,6 +631,8 @@ bool theory_seq::solve_unit_eq(expr* l, expr* r, dependency* deps) {
if (l == r) {
return true;
}
//propagate_max_length(l, r, deps);
if (is_var(l) && !occurs(l, r) && add_solution(l, r, deps)) {
return true;
}
@ -712,6 +731,21 @@ bool theory_seq::solve_eq(expr* _l, expr* _r, dependency* deps) {
return false;
}
bool theory_seq::propagate_max_length(expr* l, expr* r, dependency* deps) {
unsigned idx;
expr* s;
if (m_util.str.is_empty(l)) {
std::swap(l, r);
}
rational hi;
if (is_tail(l, s, idx) && has_length(s) && m_util.str.is_empty(r) && !upper_bound(s, hi)) {
std::cout << "max length " << mk_pp(s, m) << " " << idx << "\n";
propagate_lit(deps, 0, 0, mk_literal(m_autil.mk_le(m_util.str.mk_length(s), m_autil.mk_int(idx+1))));
return true;
}
return false;
}
bool theory_seq::is_binary_eq(expr* l, expr* r, expr*& x, ptr_vector<expr>& xs, ptr_vector<expr>& ys, expr*& y) {
xs.reset();
ys.reset();
@ -889,13 +923,35 @@ void theory_seq::solve_ne(unsigned idx) {
--i;
}
}
if (num_undef_lits == 0 && n.m_lhs.empty()) {
if (num_undef_lits == 1 && n.m_lhs.empty()) {
literal_vector lits;
literal undef_lit = null_literal;
for (unsigned i = 0; i < n.m_lits.size(); ++i) {
literal lit = n.m_lits[i];
switch (ctx.get_assignment(lit)) {
case l_true:
lits.push_back(lit);
break;
case l_false:
UNREACHABLE();
break;
case l_undef:
SASSERT(undef_lit == null_literal);
undef_lit = lit;
break;
}
}
TRACE("seq", tout << "propagate: " << undef_lit << "\n";);
SASSERT(undef_lit != null_literal);
propagate_lit(n.m_dep, lits.size(), lits.c_ptr(), ~undef_lit);
}
else if (num_undef_lits == 0 && n.m_lhs.empty()) {
literal_vector lits(n.m_lits);
lits.push_back(~mk_eq(n.m_l, n.m_r, false));
set_conflict(n.m_dep, lits);
SASSERT(m_new_propagation);
}
if (num_undef_lits == 0 && n.m_lhs.size() == 1) {
else if (false && num_undef_lits == 0 && n.m_lhs.size() == 1) {
expr* l = n.m_lhs[0];
expr* r = n.m_rhs[0];
if (m_util.str.is_empty(r)) {
@ -903,13 +959,21 @@ void theory_seq::solve_ne(unsigned idx) {
}
if (m_util.str.is_empty(l) && is_var(r)) {
literal lit = ~mk_eq_empty(r);
if (ctx.get_assignment(lit) == l_true) {
switch (ctx.get_assignment(lit)) {
case l_true: {
expr_ref head(m), tail(m);
mk_decompose(r, head, tail);
expr_ref conc(m_util.str.mk_concat(head, tail), m);
propagate_is_conc(r, conc);
m_new_propagation = true;
break;
}
case l_undef:
m_new_propagation = true;
break;
case l_false:
break;
}
m_new_propagation = true;
}
}
}
@ -941,14 +1005,13 @@ bool theory_seq::simplify_and_solve_eqs() {
bool theory_seq::internalize_term(app* term) {
TRACE("seq", tout << mk_pp(term, m) << "\n";);
context & ctx = get_context();
if (ctx.e_internalized(term)) {
enode* e = ctx.get_enode(term);
mk_var(e);
return true;
}
TRACE("seq", tout << mk_pp(term, m) << "\n";);
unsigned num_args = term->get_num_args();
expr* arg;
for (unsigned i = 0; i < num_args; i++) {
@ -1090,7 +1153,7 @@ void theory_seq::collect_statistics(::statistics & st) const {
st.update("seq branch", m_stats.m_branch_variable);
st.update("seq solve !=", m_stats.m_solve_nqs);
st.update("seq solve =", m_stats.m_solve_eqs);
st.update("seq add axiom", m_stats.m_add_axiom);
}
void theory_seq::init_model(model_generator & mg) {
@ -1266,6 +1329,29 @@ expr_ref theory_seq::canonize(expr* e, dependency*& eqs) {
return result;
}
void theory_seq::canonize(expr* e0, expr_ref_vector& es, dependency*& eqs) {
dependency* dep = 0;
expr* e = m_rep.find(e0, dep);
expr* e1, *e2;
if (m_util.str.is_concat(e, e1, e2)) {
canonize(e1, es, eqs);
canonize(e2, es, eqs);
}
else if (m_util.str.is_empty(e)) {
// skip
}
else {
expr_ref e3 = expand(e, eqs);
if (m_util.str.is_concat(e3) || m_util.str.is_empty(e3)) {
canonize(e3, es, eqs);
}
else {
es.push_back(e3);
}
}
eqs = m_dm.mk_join(eqs, dep);
}
expr_ref theory_seq::expand(expr* e0, dependency*& eqs) {
expr_ref result(m);
dependency* deps = 0;
@ -1516,10 +1602,12 @@ void theory_seq::add_length_axiom(expr* n) {
if (n != len) {
TRACE("seq", tout << "Add length coherence for " << mk_pp(n, m) << "\n";);
add_axiom(mk_eq(n, len, false));
m_trail_stack.push(push_replay(alloc(replay_axiom, m, n)));
}
}
else {
add_axiom(mk_literal(m_autil.mk_ge(n, m_autil.mk_int(0))));
m_trail_stack.push(push_replay(alloc(replay_axiom, m, n)));
}
}
@ -1753,7 +1841,14 @@ void theory_seq::propagate_step(literal lit, expr* step) {
expr_ref nth = mk_nth(s, idx);
TRACE("seq", tout << mk_pp(step, m) << " -> " << mk_pp(t, m) << " = " << nth << "\n";);
propagate_eq(lit, t, nth);
propagate_lit(0, 1, &lit, ~mk_literal(m_autil.mk_le(m_util.str.mk_length(s), idx)));
rational lo;
rational _idx;
if (lower_bound(s, lo) && lo.is_unsigned() && m_autil.is_numeral(idx, _idx) && lo >= _idx) {
// skip
}
else {
propagate_lit(0, 1, &lit, ~mk_literal(m_autil.mk_le(m_util.str.mk_length(s), idx)));
}
ensure_nth(lit, s, idx);
}
@ -1774,7 +1869,7 @@ void theory_seq::ensure_nth(literal lit, expr* s, expr* idx) {
expr_ref_vector elems(m);
get_concat(s1, es);
unsigned i = 0;
for (; i < _idx && i < es.size() && m_util.str.is_unit(es[i]); ++i) {};
for (; i <= _idx && i < es.size() && m_util.str.is_unit(es[i]); ++i) {};
if (i == _idx && i < es.size() && m_util.str.is_unit(es[i], e1)) {
dep = m_dm.mk_join(dep, m_dm.mk_leaf(assumption(lit)));
propagate_eq(dep, ensure_enode(nth), ensure_enode(e1));
@ -1792,7 +1887,9 @@ void theory_seq::ensure_nth(literal lit, expr* s, expr* idx) {
propagate_eq(lit, s, conc, true);
// TBD: examine other places for enforcing constraints on tail
add_axiom(~lit, mk_eq(m_util.str.mk_length(s), m_util.str.mk_length(conc), false));
conc = m_autil.mk_add(m_autil.mk_int(_idx+1), m_util.str.mk_length(s2));
add_axiom(~lit, mk_eq(m_util.str.mk_length(s), conc, false));
//add_axiom(~lit, mk_literal(m_autil.mk_ge(m_util.str.mk_length(s), m_autil.mk_int(_idx + 1))));
}
literal theory_seq::mk_literal(expr* _e) {
@ -1823,8 +1920,9 @@ void theory_seq::add_axiom(literal l1, literal l2, literal l3, literal l4) {
if (l2 != null_literal) { ctx.mark_as_relevant(l2); lits.push_back(l2); }
if (l3 != null_literal) { ctx.mark_as_relevant(l3); lits.push_back(l3); }
if (l4 != null_literal) { ctx.mark_as_relevant(l4); lits.push_back(l4); }
TRACE("seq", ctx.display_literals_verbose(tout, lits.size(), lits.c_ptr()); tout << "\n";);
TRACE("seq", ctx.display_literals_verbose(tout << "axiom: ", lits.size(), lits.c_ptr()); tout << "\n";);
m_new_propagation = true;
++m_stats.m_add_axiom;
ctx.mk_th_axiom(get_id(), lits.size(), lits.c_ptr());
}

View file

@ -261,6 +261,15 @@ namespace smt {
}
};
class replay_axiom : public apply {
expr_ref m_e;
public:
replay_axiom(ast_manager& m, expr* e) : m_e(e, m) {}
virtual void operator()(theory_seq& th) {
th.enque_axiom(m_e);
}
};
class push_replay : public trail<theory_seq> {
apply* m_apply;
public:
@ -282,6 +291,7 @@ namespace smt {
unsigned m_branch_variable;
unsigned m_solve_nqs;
unsigned m_solve_eqs;
unsigned m_add_axiom;
};
ast_manager& m;
dependency_manager m_dm;
@ -357,6 +367,7 @@ namespace smt {
bool solve_unit_eq(expr* l, expr* r, dependency* dep);
bool is_binary_eq(expr* l, expr* r, expr*& x, ptr_vector<expr>& xunits, ptr_vector<expr>& yunits, expr*& y);
bool solve_binary_eq(expr* l, expr* r, dependency* dep);
bool propagate_max_length(expr* l, expr* r, dependency* dep);
bool solve_nqs(unsigned i);
void solve_ne(unsigned i);
@ -383,9 +394,11 @@ namespace smt {
bool is_var(expr* b);
bool add_solution(expr* l, expr* r, dependency* dep);
bool is_nth(expr* a) const;
bool is_tail(expr* a, expr*& s, unsigned& idx) const;
expr_ref mk_nth(expr* s, expr* idx);
expr_ref mk_last(expr* e);
expr_ref canonize(expr* e, dependency*& eqs);
void canonize(expr* e, expr_ref_vector& es, dependency*& eqs);
expr_ref expand(expr* e, dependency*& eqs);
void add_dependency(dependency*& dep, enode* a, enode* b);