Signature splits

Fixed dot printing errorfor Skolems

src/params/smt_params.cpp

@@ -57,6 +57,7 @@ void smt_params::updt_local_params(params_ref const & _p) {
     m_nseq_max_nodes = p.nseq_max_nodes();
     m_nseq_parikh = p.nseq_parikh();
     m_nseq_regex_precheck = p.nseq_regex_precheck();
+    m_nseq_signature = p.nseq_signature();
     m_up_persist_clauses = p.up_persist_clauses();
     validate_string_solver(m_string_solver);
     if (_p.get_bool("arith.greatest_error_pivot", false))

src/params/smt_params.h

@@ -252,6 +252,7 @@ struct smt_params : public preprocessor_params,
     unsigned m_nseq_max_nodes = 0;
     bool m_nseq_parikh = false;
     bool m_nseq_regex_precheck = true;
+    bool m_nseq_signature = false;
 
     smt_params(params_ref const & p = params_ref()):
         m_string_solver(symbol("auto")){

src/params/smt_params_helper.pyg

@@ -127,6 +127,7 @@ def_module_params(module_name='smt',
                           ('nseq.max_nodes', UINT, 0, 'maximum number of DFS nodes explored by theory_nseq per solve() call (0 = unlimited)'),
                           ('nseq.parikh', BOOL, False, 'enable Parikh image checks in nseq solver'),
                           ('nseq.regex_precheck', BOOL, True, 'enable regex membership pre-check before DFS in theory_nseq: checks intersection emptiness per-variable and short-circuits SAT/UNSAT for regex-only problems'),
+                          ('nseq.signature', BOOL, False, 'enable heuristic signature-based string equation splitting in Nielsen solver'),
                           ('core.validate', BOOL, False, '[internal] validate unsat core produced by SMT context. This option is intended for debugging'),
                           ('seq.split_w_len', BOOL, True, 'enable splitting guided by length constraints'),
                           ('seq.validate', BOOL, False, 'enable self-validation of theory axioms created by seq theory'),