open Buffer
type scanning = InputVarName | InputRest;;
let testcharsq x = match x with
        | 'A'..'Z' | 'a'..'z' -> true
        | _ -> false;;
(* We're getting a string. *)
let process x =
        let s = ref InputRest in
        let r = Buffer.create 100 in
                for i = 0 to (String.length(x)-1) do
                        if x.[i] = '$' then s := InputVarName;
                        if !s = InputRest then add_char r x.[i];
                        if !s = InputVarName and testcharsq x.[i] then

                                ();
                done;
                contents r;;


open Printf;;
printf "%s" (process "abc$or");;
---
File "p.ml", line 13, characters 24-27:
Error: Syntax error