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differentiate A and B derivatives

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2026-06-25 14:27:41 -07:00
parent ee20c9963b
commit 618a30f5d8
5 changed files with 78 additions and 45 deletions
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48
src/ast/rewriter/seq_derive.h
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@ -36,6 +36,7 @@ class seq_rewriter;
namespace seq {
enum class derivative_kind { antimirov_t, brzozowski_t };
/**
* Symbolic derivative engine for regular expressions.
*
@ -60,15 +61,15 @@ namespace seq {
seq_rewriter& m_re;
// Cache: maps (ele, regex) pair to its derivative
obj_pair_map<expr, expr, expr*> m_cache;
obj_pair_map<expr, expr, expr*> m_top_cache; // post-simplify cache
obj_pair_map<expr, expr, expr*> m_acache, m_bcache;
obj_pair_map<expr, expr, expr*> m_atop_cache, m_btop_cache; // post-simplify cache
expr_ref_vector m_trail; // pin cached results
// Op cache for ITE-hoisting operations (union, inter, concat, complement)
// Path-aware caches: key is (a, b, path_expr) for binary ops, (a, path_expr) for complement
obj_triple_map<expr, expr, expr, expr *> m_union_cache, m_inter_cache, m_xor_cache;
obj_pair_map<expr, expr, expr*> m_concat_cache;
obj_pair_map<expr, expr, expr*> m_complement_cache;
obj_triple_map<expr, expr, expr, expr *> m_aunion_cache, m_bunion_cache, m_ainter_cache, m_binter_cache, m_axor_cache, m_bxor_cache;
obj_pair_map<expr, expr, expr*> m_aconcat_cache, m_bconcat_cache;
obj_pair_map<expr, expr, expr*> m_acomplement_cache, m_bcomplement_cache;
// Depth limiting
unsigned m_depth { 0 };
@ -77,7 +78,7 @@ namespace seq {
seq_util::rex& re() { return m_util.re; }
seq_util& u() { return m_util; }
bool m_antimirov_derivative = true;
derivative_kind m_derivative_kind = derivative_kind::antimirov_t;
// The element (character) for the current derivative computation
expr_ref m_ele;
@ -101,6 +102,34 @@ namespace seq {
void pop(); // restore state to matching push
expr* get_path_expr() { return m_path_expr; }
obj_pair_map<expr, expr, expr *> &cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_acache : m_bcache;
}
obj_pair_map<expr, expr, expr *> &top_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_atop_cache : m_btop_cache;
}
obj_triple_map<expr, expr, expr, expr *> &union_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_aunion_cache : m_bunion_cache;
}
obj_triple_map<expr, expr, expr, expr *> &inter_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_ainter_cache : m_binter_cache;
}
obj_triple_map<expr, expr, expr, expr *> &xor_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_axor_cache : m_bxor_cache;
}
obj_pair_map<expr, expr, expr *> &concat_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_aconcat_cache : m_bconcat_cache;
}
obj_pair_map<expr, expr, expr *> &complement_cache() {
return m_derivative_kind == derivative_kind::antimirov_t ? m_acomplement_cache : m_bcomplement_cache;
}
// Hoist ITE: apply_op through ite(c, t, e) with path pruning
expr_ref apply_ite(expr* c, expr* t, expr* e, expr* r, std::function<expr_ref(expr*, expr*)> apply_op);
expr_ref apply_ite(expr* c, expr* t1, expr* e1, expr* t2, expr* e2, std::function<expr_ref(expr*, expr*)> apply_op);
@ -182,12 +211,12 @@ namespace seq {
* When ele is a de Bruijn variable, produces a symbolic ITE-tree.
* When ele is a concrete character, produces the concrete derivative.
*/
expr_ref operator()(expr* ele, expr* r);
expr_ref operator()(derivative_kind k, expr* ele, expr* r);
/**
* Convenience: symbolic derivative using de Bruijn var 0.
*/
expr_ref operator()(expr* r);
expr_ref operator()(derivative_kind k, expr* r);
/**
* Nullable check: returns a Boolean expression that is true iff r accepts the empty string.
@ -224,9 +253,6 @@ namespace seq {
*/
void derivative_cofactors(expr* r, expr_ref_pair_vector& result);
void set_antimirov(bool flag) {
m_antimirov_derivative = flag;
}
};
}