(* The shallow abstract syntax *)

type location =
    Location of int * int

type regular_expression =
    Epsilon
  | Characters of char list
  | Sequence of regular_expression * regular_expression
  | Alternative of regular_expression * regular_expression
  | Repetition of regular_expression

type lexer_definition =
    Lexdef of location * (string * (regular_expression * location) list) list

(* Representation of automata *)

type automata =
    Perform of int
  | Shift of automata_trans * automata_move array
and automata_trans =
    No_remember
  | Remember of int
and automata_move =
    Backtrack
  | Goto of int