static int get_choice(lua_State * L) {
check_choice(L, 1);
expr const & c = to_expr(L, 1);
int i = lua_tointeger(L, 2);
if (i < 0 || static_cast<unsigned>(i) >= get_num_choices(c))
throw exception("arg #2 is an invalid choice index");
return push_expr(L, get_choice(c, i));
}
list<list<name>> collect_choice_symbols(expr const & e) {
buffer<list<name>> r;
for_each(e, [&](expr const & e, unsigned) {
if (is_choice(e)) {
buffer<name> cs;
for (unsigned i = 0; i < get_num_choices(e); i++) {
expr const & c = get_app_fn(get_choice(e, i));
if (is_constant(c))
cs.push_back(const_name(c));
else if (is_local(c))
cs.push_back(mlocal_pp_name(c));
}
if (cs.size() > 1)
r.push_back(to_list(cs));
}
return true;
});
return to_list(r);
}
static int get_num_choices(lua_State * L) {
check_choice(L, 1);
return push_integer(L, get_num_choices(to_expr(L, 1)));
}
