-let rec string_of_term l =
- let rec string_of_term_w_pars l = function
- | `Var(n,ar) -> print_name l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "")
+let rec string_of_term =
+ let boundvar x = "v" ^ string_of_int x in
+ let varname lev l n =
+ if n < lev then boundvar (lev-n-1)
+ else if n < List.length l then List.nth l (n-lev)
+ else "`" ^ string_of_int (n-lev) in
+ let rec string_of_term_w_pars lev l = function
+ | `Var(n,ar) -> varname lev l n ^ (if debug_display_arities then ":" ^ string_of_int ar else "")