anchor.diff:          | Some ind -> ind
   
       let getNonterminalStringByProd prod =
  -        match numToString with
  +        match !numToString with
           | None -> failwith "numToString is not specified"
           | Some nts ->
  -            match leftSide with 
  +            match !leftSide with 
               | None -> failwith "leftSide is not specified"
               | Some ls -> nts <| ls.[prod]
   
  
positive.code:         | true -> arr.[0]
  
      let getNonterminalIndex nonterminal =
          match numToString with
          | None -> failwith "numToString is not specified"
          | Some nts ->
              match leftSide with 
              | None -> failwith "leftSide is not specified"
              | Some ls -> ls |> Array.tryFind (fun x -> String.Equals (nts x, nonterminal))
  
  
negative.code: type ErrorDictionary<'TokenType> = Dictionary<Family, ErrorNode<'TokenType>>
  
  [<AllowNullLiteral>]
  type Tree<'TokenType> (tokens : array<'TokenType>, root : AstNode, rules : int[][], _leftSide : array<int> option, _numToString : (int -> string) option) =
      let rootFamily, isEpsilonTree =
          match root with
          | :? AST as ast -> ast, false
  