exception ParsingError of string val parse': string list -> Num.nf list * string list 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