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map/mapi/foldl/foldli

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-05-04 01:10:18 -07:00
parent b3e0213cab
commit 87d2a3b4e5
5 changed files with 167 additions and 2 deletions
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121
src/ast/rewriter/seq_rewriter.cpp
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@ -673,6 +673,22 @@ br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * con
SASSERT(num_args == 3);
st = mk_seq_replace_all(args[0], args[1], args[2], result);
break;
case OP_SEQ_MAP:
SASSERT(num_args == 2);
st = mk_seq_map(args[0], args[1], result);
break;
case OP_SEQ_MAPI:
SASSERT(num_args == 3);
st = mk_seq_mapi(args[0], args[1], args[2], result);
break;
case OP_SEQ_FOLDL:
SASSERT(num_args == 3);
st = mk_seq_foldl(args[0], args[1], args[2], result);
break;
case OP_SEQ_FOLDLI:
SASSERT(num_args == 4);
st = mk_seq_foldli(args[0], args[1], args[2], args[3], result);
break;
case OP_SEQ_REPLACE_RE:
SASSERT(num_args == 3);
st = mk_seq_replace_re(args[0], args[1], args[2], result);
@ -850,6 +866,14 @@ br_status seq_rewriter::mk_seq_length(expr* a, expr_ref& result) {
result = str().mk_length(x);
return BR_REWRITE1;
}
if (str().is_map(a, x, y)) {
result = str().mk_length(y);
return BR_REWRITE1;
}
if (str().is_mapi(a, x, y, z)) {
result = str().mk_length(z);
return BR_REWRITE1;
}
#if 0
expr* s = nullptr, *offset = nullptr, *length = nullptr;
if (str().is_extract(a, s, offset, length)) {
@ -1640,6 +1664,13 @@ br_status seq_rewriter::mk_seq_nth_i(expr* a, expr* b, expr_ref& result) {
return BR_REWRITE1;
}
expr* f, *s;
if (str().is_map(a, f, s)) {
expr* args[2] = { f, str().mk_nth_i(s, b) };
result = array_util(m()).mk_select(2, args);
return BR_REWRITE1;
}
expr_ref_vector as(m());
str().get_concat_units(a, as);
@ -2008,6 +2039,96 @@ br_status seq_rewriter::mk_seq_replace_all(expr* a, expr* b, expr* c, expr_ref&
return BR_FAILED;
}
/**
rewrites for map(f, s):
map(f, []) = []
map(f, [x]) = [f(x)]
map(f, s + t) = map(f, s) + map(f, t)
len(map(f, s)) = len(s)
nth_i(map(f,s), i) = f(nth_i(s, i))
*/
br_status seq_rewriter::mk_seq_map(expr* f, expr* seqA, expr_ref& result) {
if (str().is_empty(seqA)) {
result = str().mk_empty(get_array_range(f->get_sort()));
return BR_DONE;
}
expr* a, *s1, *s2;
if (str().is_unit(seqA, a)) {
array_util array(m());
expr* args[2] = { f, a };
result = str().mk_unit(array.mk_select(2, args));
return BR_REWRITE2;
}
if (str().is_concat(seqA, s1, s2)) {
result = str().mk_concat(str().mk_map(f, s1), str().mk_map(f, s2));
return BR_REWRITE2;
}
return BR_FAILED;
}
br_status seq_rewriter::mk_seq_mapi(expr* f, expr* i, expr* seqA, expr_ref& result) {
if (str().is_empty(seqA)) {
result = str().mk_empty(get_array_range(f->get_sort()));
return BR_DONE;
}
expr* a, *s1, *s2;
if (str().is_unit(seqA, a)) {
array_util array(m());
expr* args[3] = { f, i, a };
result = str().mk_unit(array.mk_select(3, args));
return BR_REWRITE2;
}
if (str().is_concat(seqA, s1, s2)) {
expr_ref j(m_autil.mk_add(i, str().mk_length(s1)), m());
result = str().mk_concat(str().mk_mapi(f, i, s1), str().mk_mapi(f, j, s2));
return BR_REWRITE2;
}
return BR_FAILED;
}
br_status seq_rewriter::mk_seq_foldl(expr* f, expr* b, expr* seqA, expr_ref& result) {
if (str().is_empty(seqA)) {
result = b;
return BR_DONE;
}
expr* a, *s1, *s2;
if (str().is_unit(seqA, a)) {
array_util array(m());
expr* args[3] = { f, b, a };
result = array.mk_select(3, args);
return BR_REWRITE1;
}
if (str().is_concat(seqA, s1, s2)) {
result = str().mk_foldl(f, b, s1);
result = str().mk_foldl(f, result, s2);
return BR_REWRITE3;
}
return BR_FAILED;
}
br_status seq_rewriter::mk_seq_foldli(expr* f, expr* i, expr* b, expr* seqA, expr_ref& result) {
if (str().is_empty(seqA)) {
result = b;
return BR_DONE;
}
expr* a, *s1, *s2;
if (str().is_unit(seqA, a)) {
array_util array(m());
expr* args[4] = { f, i, b, a };
result = array.mk_select(4, args);
return BR_REWRITE1;
}
if (str().is_concat(seqA, s1, s2)) {
expr_ref j(m_autil.mk_add(i, str().mk_length(s1)), m());
result = str().mk_foldli(f, i, b, s1);
result = str().mk_foldli(f, j, result, s2);
return BR_REWRITE3;
}
return BR_FAILED;
}
/*
* Returns false if s is not a single unit value or concatenation of unit values.
* Else extracts the units from s into vals and returns true.