Cleanup

pga.ml

-open Printf
 open Types
 open Stringify
 open Parse
 
 let main () =
-  let argc = Array.length Sys.argv in
   let usage status =
-    printf "usage: %s command [args]\n" Sys.argv.(0);
-    printf "command:\n";
-    printf "  help\n";
-    printf "  echo PROGRAM\n";
-    status
+    prerr_endline ("usage: " ^ Sys.argv.(0) ^ " command [args]");
+    prerr_endline "command:";
+    prerr_endline "  help           show this help page";
+    prerr_endline "  echo PROGRAM   pretty-print a program";
+    prerr_endline "input program syntax:";
+    prerr_endline "  - omit omega sign after closing parenthesis";
+    prerr_endline "  - write dollar sign ($) instead of pound sign";
+    exit status
   in
-  if argc = 1 then begin
-    usage 1
-  end else
+
+  let argc = Array.length Sys.argv in
+  if argc = 1 then usage 1;
+
+  begin
     match Sys.argv.(1) with
     | "help" ->
       usage 0
     | "echo" when argc > 2 ->
-      printf "%s\n" (string_of_program (parse_string Sys.argv.(2)));
-      0
+      print_endline (string_of_program (parse_string Sys.argv.(2)))
     | _ ->
       usage 1
+  end;
+
+  exit 0
 
-let () = exit (main ())
+let () = main ()

stringify.ml

 open Types
 
+let omega = "\207\137"
+
 let string_of_basic ins = ins
 
 let string_of_primitive = function
@@ -12,5 +14,5 @@ let string_of_primitive = function
 let rec string_of_program = function
   | Primitive p -> string_of_primitive p
   | Concat l    -> String.concat ";" (List.map string_of_program l)
-  | Repeat p    -> "(" ^ string_of_program p ^ ")\207\137"
+  | Repeat p    -> "(" ^ string_of_program p ^ ")" ^ omega
   | Empty       -> ""