anchor.diff:      res.AddVerticesAndEdgeRange edgesParserGraph |> ignore  
       res
   
  -let Tokenize (fstLexer : FST<_,_>) (actions : array<GraphTokenValue<_> -> _>) eofToken (inputGraph : Appr<_>) =    
  +let Tokenize (fstLexer : FST<_,_>) (actions : array<GraphTokenValue<_> -> _>) (alphabet: HashSet<_>) eofToken (inputGraph : Appr<_>) =    
       let inputFst = inputGraph.ToFST() 
  -    let inputFstLexer = FST<_,_>.Compos(inputFst, fstLexer) 
  +    let inputFstLexer = FST<_,_>.Compos(inputFst, fstLexer, alphabet) 
       //inputFstLexer.PrintToDOT (@"..\..\Tests\CalcTestLexerk.dot", printSmbString)
  -    let parserInputGraph = Interpret inputFstLexer actions eofToken 
  -    let epsRes = EpsClosure.NfaToDfa parserInputGraph
  +    let epsRes = 
  +        match inputFstLexer with
  +        | Success fst -> 
  +            let parserInputGraph = Interpret fst actions eofToken
  +            Success (EpsClosure.NfaToDfa parserInputGraph)
  +        | Error errors -> Error errors
  +    
       epsRes 
   
   let ToDot (parserInputGraph : ParserInputGraph<_>) filePrintPath toStr =
  
positive.code:         this.AddEdge e |> ignore
  
  [<Struct>]
  type GraphAction<'br(* when 'br:comparison*)> =
      val startAct: int
      val endActs: HashSet<int>
      val graph: GraphTokenValue<'br>
  
negative.code:     member this.EndPos = (snd t).end_offset
      member this.Label = fst t
  
  type GraphTokenValue<'br>() =
      inherit AdjacencyGraph<int,TokenEdge<'br>>()
  
      member this.AddEdgeForsed (e:TokenEdge<_>) =
  