[SOLVED] CS (* IMPORTANT: YOU MAY NOT MODIFY THIS FILE!

(* IMPORTANT: YOU MAY NOT MODIFY THIS FILE!
* OUR TESTS USE THE ORIGINAL VERSION.
* YOUR CODE WILL NOT COMPILE IF YOU CHANGE THIS FILE. *)

(* This is the type used to describe the form of a regexp *)

type regexp_t =
| Empty_String
| Char of char
| Union of regexp_t * regexp_t
| Concat of regexp_t * regexp_t
| Star of regexp_t

(* These are the regexp functions you must implement *)

val regexp_to_nfa : regexp_t -> (int, char) Nfa.nfa_t

val string_to_regexp : string -> regexp_t

val string_to_nfa : string -> (int, char) Nfa.nfa_t

exception IllegalExpression of string