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seq

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2015-12-27 04:41:25 -08:00
parent 31302ec851
commit 071a654a9a
8 changed files with 360 additions and 212 deletions
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64
src/ast/rewriter/seq_rewriter.cpp
View file

@ -693,17 +693,76 @@ br_status seq_rewriter::mk_str_to_regexp(expr* a, expr_ref& result) {
return BR_FAILED;
}
br_status seq_rewriter::mk_re_concat(expr* a, expr* b, expr_ref& result) {
if (is_epsilon(a)) {
result = b;
return BR_DONE;
}
if (is_epsilon(b)) {
result = a;
return BR_DONE;
}
return BR_FAILED;
}
/*
(a + a) = a
(a + eps) = a
(eps + a) = a
*/
br_status seq_rewriter::mk_re_union(expr* a, expr* b, expr_ref& result) {
if (a == b) {
result = a;
return BR_DONE;
}
if (m_util.re.is_star(a) && is_epsilon(b)) {
result = a;
return BR_DONE;
}
if (m_util.re.is_star(b) && is_epsilon(a)) {
result = b;
return BR_DONE;
}
return BR_FAILED;
}
/*
a** = a*
(a* + b)* = (a + b)*
(a + b*)* = (a + b)*
(a*b*)* = (a + b)*
*/
br_status seq_rewriter::mk_re_star(expr* a, expr_ref& result) {
expr* b, *c, *b1, *c1;
if (m_util.re.is_star(a)) {
result = a;
return BR_DONE;
}
if (m_util.re.is_union(a, b, c)) {
if (m_util.re.is_star(b, b1)) {
result = m_util.re.mk_star(m_util.re.mk_union(b1, c));
return BR_REWRITE2;
}
if (m_util.re.is_star(c, c1)) {
result = m_util.re.mk_star(m_util.re.mk_union(b, c1));
return BR_REWRITE2;
}
}
if (m_util.re.is_concat(a, b, c) &&
m_util.re.is_star(b, b1) && m_util.re.is_star(c, c1)) {
result = m_util.re.mk_star(m_util.re.mk_union(b1, c1));
return BR_REWRITE2;
}
return BR_FAILED;
}
/*
a+ = aa*
*/
br_status seq_rewriter::mk_re_plus(expr* a, expr_ref& result) {
return BR_FAILED;
// result = m_util.re.mk_concat(a, m_util.re.mk_star(a));
// return BR_REWRITE2;
}
br_status seq_rewriter::mk_re_opt(expr* a, expr_ref& result) {
sort* s;
VERIFY(m_util.is_re(a, s));
@ -1014,6 +1073,11 @@ bool seq_rewriter::length_constrained(unsigned szl, expr* const* l, unsigned szr
return false;
}
bool seq_rewriter::is_epsilon(expr* e) const {
expr* e1;
return m_util.re.is_to_re(e, e1) && m_util.str.is_empty(e1);
}
bool seq_rewriter::is_subsequence(unsigned szl, expr* const* l, unsigned szr, expr* const* r,
expr_ref_vector& lhs, expr_ref_vector& rhs, bool& is_sat) {
is_sat = true;

1
src/ast/rewriter/seq_rewriter.h
View file

@ -75,6 +75,7 @@ class seq_rewriter {
void add_next(u_map<expr*>& next, unsigned idx, expr* cond);
bool is_sequence(expr* e, expr_ref_vector& seq);
bool is_epsilon(expr* e) const;
public:
seq_rewriter(ast_manager & m, params_ref const & p = params_ref()):