virtual bool perform(execution_context & ctx) {
if (m_store) {
if (ctx.reg(m_reg)) {
ctx.get_datalog_context().store_relation(m_pred, ctx.release_reg(m_reg));
}
else {
context & dctx = ctx.get_datalog_context();
relation_base * empty_rel;
//the object referenced by sig is valid only until we call dctx.store_relation()
const relation_signature & sig = dctx.get_relation(m_pred).get_signature();
empty_rel = dctx.get_rmanager().mk_empty_relation(sig, m_pred.get());
dctx.store_relation(m_pred, empty_rel);
}
}
else {
relation_base& rel = ctx.get_datalog_context().get_relation(m_pred);
if ((!ctx.eager_emptiness_checking() || !rel.empty())) {
ctx.set_reg(m_reg, rel.clone());
}
else {
ctx.make_empty(m_reg);
}
}
return true;
}
void external_relation::mk_accessor(decl_kind k, func_decl_ref& fn, const relation_fact& f, bool destructive, expr_ref& res) const {
ast_manager& m = m_rel.get_manager();
family_id fid = get_plugin().get_family_id();
ptr_vector<expr> args;
args.push_back(m_rel);
for (unsigned i = 0; i < f.size(); ++i) {
args.push_back(f[i]);
}
if (!fn.get()) {
fn = m.mk_func_decl(fid, k, 0, 0, args.size(), args.c_ptr());
}
if (destructive) {
get_plugin().reduce_assign(fn, args.size(), args.c_ptr(), 1, args.c_ptr());
res = m_rel;
}
else {
get_plugin().reduce(fn, args.size(), args.c_ptr(), res);
}
}
void operator()(relation_base & t, const relation_base & negated_obj) {
m_args[0] = get(t).get_relation();
m_args[1] = get(negated_obj).get_relation();
m_plugin.reduce_assign(m_negated_filter_fn.get(), 2, m_args, 1, m_args);
}