exception ParsingError of string

val problem_of_string:
 string ->
  string (* problem label *)
  * Num.i_var option (* div *)
  * Num.i_n_var list (* conv *)
  * Num.i_n_var list (* ps *)
  * string list (* names of free variables *)
val from_file : string ->
 (string (* problem label *)
 * Num.i_var option (* div *)
 * Num.i_n_var list (* conv *)
 * Num.i_n_var list (* ps *)
 * string list (* names of free variables *)) list