fact: Fixpoint pretty_N_go_help (x : N) (acc : Acc (<)%N x) (s : string) : string := match decide (0 < x)%N with | left H => pretty_N_go_help (x `div` 10)%N (Acc_inv acc (N.div_lt x 10 H eq_refl)) (String (pretty_N_char (x `mod` 10)) s) | right _ => s end.
imports: stdpp(relations numbers) Coq(Ascii) stdpp(options)