klex/src/NFAState.i3

 Copyright (c) 2000 California Institute of Technology 
 All rights reserved. See the file COPYRIGHT for a full description. 
 $Id: NFAState.i3,v 1.2 2001-09-19 15:05:08 wagner Exp $ 


INTERFACE NFAState;
IMPORT NFA;
IMPORT Word;
CONST
  Brand = "NFAState";
TYPE
  T <: REFANY;

 An NFAState.T represents a collection of NFANode.T's
   which are the nodes occupied after an input sequence 
 Targets = REF ARRAY CHAR OF T; 


 Don't forget to call NFA.AssignIDs(a) before calling New

PROCEDURE New(a: NFA.T): T;           (* the start state *)

PROCEDURE Step(s: T; key: CHAR; VAR keyEnd: CHAR): T;
  (* copy and advance to the next state.
     same results will apply up to key=keyEnd. *)

 PROCEDURE Steps(s: T): Targets; (* low-performance version of Step.
  Some elements in the returned array can be NIL, signifying Dead  
*)

PROCEDURE Dead(s: T): BOOLEAN; (* Are there no more transitions to be made? *)
PROCEDURE Output(s: T): INTEGER;  (* lowest output from last step, or
                                  0 if none *)

PROCEDURE Equal(s, t: T): BOOLEAN;
PROCEDURE Hash(s: T): Word.T;

PROCEDURE Test(a: NFA.T);
PROCEDURE Format(s: T): TEXT;

END NFAState.