hov_box vs box

gistfile1.ml

open Format

let rec hovb ppf = function
  | 0 -> ()   
  | n ->
      fprintf ppf "(@[<hov>-----------------------------------%03d@," n;
      hovb ppf (n-1);
      fprintf ppf "@])"  
      
let rec b ppf = function    
  | 0 -> ()   
  | n ->        
      fprintf ppf "(@[<>-----------------------------------%03d@," n;
      b ppf (n-1);
      fprintf ppf "@]@,)"

let rec hovb' ppf = function
  | 0 -> ()   
  | n ->        
      fprintf ppf "(@[<hov>-----------------------------------%03d@," n;
      hovb' ppf (n-1);
      fprintf ppf "@]@,)"  
      
let () =    
  eprintf "@[%a@]@." hovb 3;
  eprintf "@[%a@]@." b 3;
  eprintf "@[%a@]@." hovb' 3