7 #if defined __cpp_concepts
8 template <
typename Aut>
11 return requires (Aut a)
13 typename state_t_of<Aut>;
14 { a->null_state() } -> state_t_of<Aut>;
15 { a->pre() } -> state_t_of<Aut>;
16 { a->post() } -> state_t_of<Aut>;
18 typename transition_t_of<Aut>;
19 { a->null_transition() } -> transition_t_of<Aut>;
23 # define Automaton typename