fact: Definition pretty_N_char (x : N) : ascii := match x with | 0 => "0" | 1 => "1" | 2 => "2" | 3 => "3" | 4 => "4" | 5 => "5" | 6 => "6" | 7 => "7" | 8 => "8" | _ => "9" end%char%N.
imports: stdpp(relations numbers) Coq(Ascii) stdpp(options)