(* encodetext.ml - Don Yang (uguu.org)

   Given text data in stdin, generate BF program that will output the
   same text data.

   09/03/04
                                                                           *)

(* Open first argument for input if available, otherwise use stdin *)
let input () =
   if Array.length Sys.argv > 1
   then open_in_bin Sys.argv.(1)
   else stdin;;

(* Open second argument for input if available, otherwise use stdout *)
let output () =
   if Array.length Sys.argv > 2
   then open_out_bin Sys.argv.(2)
   else stdout;;

(* Output character difference *)
let diff x c =
   (
      if (snd x) > c then
         (output_string (fst x) ((String.make ((snd x) - c) '-') ^ "."))
      else if (snd x) < c then
         (output_string (fst x) ((String.make (c - (snd x)) '+') ^ "."))
      else
         (output_char (fst x) '.')
   ); (fst x, c);;

(* Parse file character by character *)
let rec parse_txt infile x =
   let (d, eof) =
      try (diff x (input_byte infile), 0)
      with End_of_file -> (x, 1) in
      if eof != 0 then output_char (fst x) '\n'
      else parse_txt infile d;;


(* Program entry point *)
let infile = input() in
   let outfile = output() in
      parse_txt infile (outfile, 0);
      close_out outfile;
      close_in infile;;